stunthanger.com
Electric Stunt => Gettin all AMP'ed up! => Topic started by: TDM on September 15, 2017, 01:37:19 PM
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REvolutions
I am returning to my old project Revolutions
Initially I have designed this model to be possible either IC or Electric. I gave up the idea of going IC and now I go purely electric on this one.
Span 61in
Length 52.75
Height 7in
Weight goal sub 50oz
I am throwing all my knowledge in to this model. I am implementing the most advanced methods of modeling known to the modeling community, and as a fact is also most advanced to the manufacturing community too. One goal is to have interchangeable parts coming out of the mold. The wings will be detachable plug in type. Also the horizontal stabilizer and the landing gear will be two piece plug in type. Perhaps once all the molds are done the time from build start to first flight will be somewhere around 8 days (that is finished painted on the flight line). It can be faster but I would need another set of wing and horizontal molds but 8 days is alright with me.
Yes the model will be done with composite construction 100%. It will be made with carbon fiber foam core fiberglass throughout. There will be two types of composite construction being implemented in this one (hollow molding and compression molding). There will be No balsa in this build so if you want to see wood this is not the place. I will make special bell-cranks to adjust flaps bias. I might even go to logarithmic control but am not sure yet.
I designed this bird in CAD, right now I am cutting on my CNC machine from Aluminum billet one part at a time. After I cut them I will be the polishing of the molds in order to remove cutter marks and get a mirror finish. Once all are done I am going to treat the molds and after that I make parts.
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Some more pictures from CAD
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Looking forward to seeing more on this project.I am learning to make molds "old school" fiberglass lay up over plugs.Machining them from aluminum is very interesting indeed!! I love the composite stuff #^ #^
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What is a PERKY ??? ??? ???
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Looking forward to seeing more on this project.I am learning to make molds "old school" fiberglass lay up over plugs.Machining them from aluminum is very interesting indeed!! I love the composite stuff #^ #^
Yes they are good molds but never perfect. What part-parts are you trying to mold Jeff?
By the way gents I put some PICTURES in the FORUM GALLERY. They are under construction pictures. https://stunthanger.com/smf/index.php?action=gallery;cat=19
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When finished do you plan to market a set of molded parts or perhaps a ARP (P=paint)?
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I have to check on the sales. Definitely i would want to recover the investment at a minimum.
Yes there may be an opportunity to get parts or whole model in our hands. You could just use some of the components too.
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Will the motor be a front mount or rear (firewall mount) ?
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Will the motor be a front mount or rear (firewall mount) ?
The motor assembles from the front. Keep in mind that the nose comes off (Fuselage is 2 pieces)and there is easy access to the motor. The blue part is the machined insert. It will be turned on the lathe then milled to get the screw clearance holes and cooling slots etc.
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I looked in to Aluminium for making molds for fuselage and for the wing and prices and availability are through the roof.
Then I was looking for alternatives and what happened was that I stumbled on what is called "tooling boards"
Basically they are some kind of epoxy or urethane poured in to shapes and are relatively inexpensive. 2'x16'x60 275$ a piece plus ship. The bad part is that they do not sell this in small quantities so you are stuck with what you get but the good part is that it opened the door to make the mold in one shot rather than make several pieces that are assembled after molding. So now I have to reprogram all the fuselage and redo the CAD for the fuse and the wing. It is not a big deal but more of a nuisance and time lost. I wish I thought of it earlier. Now I am happy i had that problem because it made my life 300% easier.
Originally I wanted to make the flaps wing tip and wing separate and join the parts after the molding is done. Now I get the whole wing finished included the flaps with hinges attached out of the mold. Also I was going to mold the back side of the fuse the rudder fin vertical stab and turtle deck separate and join them after molding to create the rear side of the fuselage now i mold the whole piece in one shot and there will be no separate component joining to worry about. #^ #^ #^ #^ #^ #^ #^
I plan to S?P paint in the mold then lay the skins and vacuum bag the skins. D>K After that I join the two mold halves S?P. Next day after demolding presto finished part painted ready to be installed. Maybe some gold leaf ink lines some clear to put the final touches but that should be about it.
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Traian,There is a place in Avon Ohio called Freeman Supply that has a similar product.Not sure how the prices are but they have it all the way up to 6 inches thick.Might look them up.Trax
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Thanks Jeff
I saw Freeman and talked to their customer service.
I zeroed in on this product http://www.alro.com/divplastics/plasticsproduct_pp1052_hd.aspx. It is made by Axon and after talking to their support guise they said that it polishes very nicely. Some tooling boards require sealers (coat of epoxy sprayed or painted) to be able to impart a nice finish. PP-1052 does not need that at all. You can go from cut to sand and polish and you are done. What is even nicer is that it costs some 275$ per sheet plus ship which is nice vs 1000+ for aluminium.
Placing an order this week for this stuff.
If I am lucky and have an open machine I may make some as early chips next weekend.
One more thing about tooling board: If you make a mistake you can use a special matched filler glue patch the mistake, re cut the mold and you are good to go. Try to do that that in Aluminum. I might switch to this product from now on.
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Some more development.
I was working for a long time trying to think of a good take apart system and yesterday :! i came with the best idea i had to date #^.
This is the inspiration: It comes from furniture cam locks. The practical idea is if i have removable nose i might as well use that to change batteries. I am planning to make some custom latches and put one on each side of the fuselage. If I want to remove the nose I use a flat driver half a turn then pull the nose off to change battery.
Initially i was afraid to have it come loose in flight but after that I came up with a simple solution and that is to add an O ring to the lock that will have several functions: first is an anti-slip so the lock does not come loose, second it stops the lock from falling out change position during handling of components transport etc, third it works as a bumper as you tighten the lock it squezes the oring. The pin can be sized to act a alignment pin on assembly to register the parts dead on in correct position.
Pin lock set should not be more than 5g. perhaps much lighter than that. If i make it out of aluminium it will be even lighter.
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I will be following this. D>K
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This is what I came up with so far.
The lock has 4 components plus an O-ring.
I made a model in CAD and analyzed the weight of the components. All 4 components add to about 3.05g in CAD and in reality they may be a tad lighter yet since the threads are not represented on two components and the cup gets 2 holes in it. So for sure it will be sub 3g per assembly. 7075 T6 will be the material used. The pin has a 1/8 diameter at the smallest point so i think it is strong enough even for the wing main attachment points. I will use this system through the whole model for removing all major components nose wings horizontal.
I am making some design decisions now. I can add a cap for battery access but I have decided to remove the nose for that. Half turn on each side with a driver and presto nose comes off. Change battery put nose back on half turn per side done battery is in. Since i plan to go with active timer i am gluing a plug to the nose that will connect disconnect as I remove the nose. The weakest point in the system is the threaded 8-32 screw. An aluminium 7075 screw sheer strength is 860lb, so with that in mind I think I am plenty safe here even with the weaker 7075 material. There are two grades of 7075 one is 62000 PSI and the other 73000 PSI ratings. I calculated the strength for the weaker of the two.
At over 700 lb tensile strength conservative strength I am good with it. The real weak point is in the way the cup and the pin holder are being glued in the structure.
With that here are CAD pictures for the components. Thread are left out so use your imagination. On the lock you can see the space provided for the O-ring.
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This is what I came up with so far.
The lock has 4 components plus an O-ring.
I made a model in CAD and analyzed the weight of the components. All 4 components add to about 3.05g in CAD and in reality they may be a tad lighter yet since the threads are not represented on two components and the cup gets 2 holes in it. So for sure it will be sub 3g per assembly. 7075 T6 will be the material used. The pin has a 1/8 diameter at the smallest point so i think it is strong enough even for the wing main attachment points. I will use this system through the whole model for removing all major components nose wings horizontal.
I am making some design decisions now. I can add a cap for battery access but I have decided to remove the nose for that. Half turn on each side with a driver and presto nose comes off. Change battery put nose back on half turn per side done battery is in. Since i plan to go with active timer i am gluing a plug to the nose that will connect disconnect as I remove the nose. The weakest point in the system is the threaded 8-32 screw. An aluminium 7075 screw sheer strength is 860lb, so with that in mind I think I am plenty safe here even with the weaker 7075 material. There are two grades of 7075 one is 62000 PSI and the other 73000 PSI ratings. I calculated the strength for the weaker of the two.
At over 700 lb tensile strength conservative strength I am good with it. The real weak point is in the way the cup and the pin holder are being glued in the structure.
With that here are CAD pictures for the components. Thread are left out so use your imagination. On the lock you can see the space provided for the O-ring.
Traian,
Just some thoughts... $0.02 (CDN)
IMHO I would not exercise a structural take apart just to change the battery. Repeated use of such an over center cam type fastener will wear the cam and pin surface too fast. Once worn, there is no fix. Use a hatch. Won't you have to have one regardless so you can access the other equipment. You said you will undo each side than take the nose off. Will you have two or four connectors? (two is not enough) How will you connect the battery if you are inserting it from the back? The front of the battery enclosure would seem to need to be closed in. Using very long wires is not weight friendly and it seems that you would need very long wires to be able to connect to. Then where will you put all that wire since it will have to go back inside the battery box?? Have you calculated where the CofG will be and what the fore/aft position of the battery will do to your desired CofG? Where will the battery actually sit? (vs the plane of the take apart face) Gluing any plug permanently into the structure is not a good thing since all connectors wear. Once worn then what??
Not criticisms, just curious.
Kim.
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Kim thanks and good points
First about the latch, both the pin and the lock are removable. If it gets loose it turn the pin in a little more. If is worn out I simply replace the two parts.
I have no solid data for battery position. Once the model is complete I will know exactly where the battery will go. Till then I have no idea. Also at that time I will figure out how I wil wire and layout the power related stuff.
Two pins can hold 1400lb why is that not enough?
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Kim you still did not answer my question.
I am pushing ahead on the take apart components.
According to the CAD models the 4 parts needed per assembly weigh in the 3g total weight. I played with the CNC and managed to make some prototypes to see how feasible this is. I am encouraged and think this is about as good as it gets for now.
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Kim thanks and good points
First about the latch, both the pin and the lock are removable. If it gets loose it turn the pin in a little more. If is worn out I simply replace the two parts.
I have no solid data for battery position. Once the model is complete I will know exactly where the battery will go. Till then I have no idea. Also at that time I will figure out how I wil wire and layout the power related stuff.
Two pins can hold 1400lb why is that not enough?
Traian,
Sorry for the delay (oops!)
I have no problem with the pin and the way it is captured. As long as there is no possibility of vibration as the forces on the pieces are fairly large vs their size.
I would not want the fuselage sides/mating surfaces to carry any of the load. So three would be the minimum number of connectors.
But I will repeat the suggestion to NOT take the nose off each time you want to change the battery! Use a hatch.
As to the battery and the nose, I think you should take a similar fuselage and mount similar (the ones you will actually use would be preferable) components on it ( just with elastics and tape) to determine the approximate CofG. You would want it to balance slightly tail heavy with the battery in the rearmost position. This step will save you a lot of aggravation later on.
Looks cool! (want a test pilot?? :) )
Kim.
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Traian,
Sorry for the delay (oops!)
I have no problem with the pin and the way it is captured. As long as there is no possibility of vibration as the forces on the pieces are fairly large vs their size.
I would not want the fuselage sides/mating surfaces to carry any of the load. So three would be the minimum number of connectors.
But I will repeat the suggestion to NOT take the nose off each time you want to change the battery! Use a hatch.
As to the battery and the nose, I think you should take a similar fuselage and mount similar (the ones you will actually use would be preferable) components on it ( just with elastics and tape) to determine the approximate CofG. You would want it to balance slightly tail heavy with the battery in the rearmost position. This step will save you a lot of aggravation later on.
Looks cool! (want a test pilot?? :) )
Kim.
I was worried about the parts coming loose too that is why i have added the Oring. It is similar to the same way a lock nuts work. The Oring will prevent it from coming loose.
As for the fuselage sides carrying the load the beauty of composite construction is that if you need extra strength you simply lay in a little extra material exactly where you need it. And since you have molds is easy to make a new part plane etc. and implement the new changes. For that it need to do some experimenting after i build the bird to see how it holds up to the normal use. There are 6 small pins (1/16 carbon) that align the fuselage sides in position to get a super nice parting line in addition to the 2 side latches and they are missing from the pictures.
The hatch will have to wait. I want to see how complicate is the nose removal in context and if i need a hatch it can be added. A hatch also means more complexity added to the whole thing and a weak spot extra parts and weight added to the model. Again I will have to build the first one to figure out what where will go regarding batteries ESC wiring electronics. The jury is still out on that one.
Thanks for all advice.
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Traian,
I'm keeping an eye on this Thread with amazement.
Looks to me as though you're raising the bar quite a bit with this design.
I also have confidence, you do know what you are doing!
I'm learning stuff.
Charles
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I made a test rig out of aluminium 6061. I assembled a latch and tested it using my fat ass body weight. One latch held to it just fine so at over 185lb of force. Moreover I threaded the latch pin in the 6061 aluminium. The real parts the latch will thread in 7075 which even in the lower strength rating is some over 40% stronger than the 6061 which means also those threads will be 40% stronger at minimum. So we can add another 40% to the 185lb to this test to come to the true strength of at least 250lb force for one assembly. In my book i call this overkill strength and I am happy with this result.
The next target i want to work on is the bellcrank assembly. What i want to have in it is a NO TOOL necessary lead out wire connection to the bellcrank. The trick will be to make it light easy to use reliable.
Charles yes I plan to push the existing envelope a little. And for all you who watch many thanks. I hope we can learn from each other and push this hobby forward. No one who did exactly like the one next to him has ever helped making any progress.
Traian
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I am watching this as I like people who think out side of the box. H^^
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I have sample material coming in soon and I will start to make some chips on the CNC soon.
I figured out how to make the lead out removal on the bellcrank.
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I call this food for thought:
I have spent some time in the last 3 weeks crunching numbers in the thrust calculator and motor calculator, and I think I found something I call significant. What is significant revolves about the idea that you can use higher pitch props running lower RPM that produce same thrust and Speed and this totally contrary the lower pitch high RPM currently employed by the CL community.
1: One blade prop is most efficient but since I do not want to go there I will use 2 blade props in the future.
2: As the pitch increases many good thigs start to happen: the power requirements to drive that prop goes down, the rpm goes down, the lighter props come in place and become feasible, and off course the gyroscopic precession is cut nearly in half (by the way gyroscopic precession comes from the motor too mot only the prop), as the electric motors develop max torque at low RPM we run them toward their optimum sweet spot rather than stretching them out.
What is not so great is the fact that the current goes up with the lowering of RPM which creates more heat in the system and this brings me to the third point.
3: Bigger motors with low KV rating seep Amps. I was using a motor calculator for a 4250 motor 510KV running on 4S that spins the intended prop 13.25x7 6900rpm and the amps are in the low 20A range. This also addresses the low rpm current increase higher temperature. Another thing a slightly oversize motor will do is to have plenty available power to quickly change rpm when commanded to do so. Keep in mind a heavier motor doesn’t mean heavier system because whatever you add in the motor you take away from the battery. Consequently smaller batteries with lower cell count are also cheaper on the pocket too.
I feel I need to go back to this point I started with earlier and is about the lower pitch high RPM currently employed by the CL community. When the electric revolution started we took old models, threw in the electric motor and away we went. This was a great step forward towards reliable super consistent motor runs etc. The problem is the way we did it. We kept playing by IC rules instead of electric rules. We had roughly 36mm spacing in between the IC motor mounts we went to the 35mm OD electric motors (the biggest we could fit in there), then since we had the props from the 40-60 piped motors or the ST60 we kept whatever was in the tool box and continued with it, that meant we had to maintain the high rpm they demand and here we go we also needed the 5-6S systems to keep up with the demand from the prop to make possible our stunt flying. The thig is even after that when we built new electric CL models we still kept the first tried systems without considering other alternatives. It sure works but the question is whether or not is best it can be, my assessment is that we went the wrong direction here.
For REvolutionds I am starting at 13.25x7 (might have to up the pitch a little) and will go to a 4250 510KV motor running on 4S.
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I call this food for thought:
I have spent some time in the last 3 weeks crunching numbers in the thrust calculator and motor calculator, and I think I found something I call significant. What is significant revolves about the idea that you can use higher pitch props running lower RPM that produce same thrust and Speed and this totally contrary the lower pitch high RPM currently employed by the CL community.
1: One blade prop is most efficient but since I do not want to go there I will use 2 blade props in the future.
2: As the pitch increases many good thigs start to happen: the power requirements to drive that prop goes down, the rpm goes down, the lighter props come in place and become feasible, and off course the gyroscopic precession is cut nearly in half (by the way gyroscopic precession comes from the motor too mot only the prop), as the electric motors develop max torque at low RPM we run them toward their optimum sweet spot rather than stretching them out.
What is not so great is the fact that the current goes up with the lowering of RPM which creates more heat in the system and this brings me to the third point.
3: Bigger motors with low KV rating seep Amps. I was using a motor calculator for a 4250 motor 510KV running on 4S that spins the intended prop 13.25x7 6900rpm and the amps are in the low 20A range. This also addresses the low rpm current increase higher temperature. Another thing a slightly oversize motor will do is to have plenty available power to quickly change rpm when commanded to do so. Keep in mind a heavier motor doesn’t mean heavier system because whatever you add in the motor you take away from the battery. Consequently smaller batteries with lower cell count are also cheaper on the pocket too.
I feel I need to go back to this point I started with earlier and is about the lower pitch high RPM currently employed by the CL community. When the electric revolution started we took old models, threw in the electric motor and away we went. This was a great step forward towards reliable super consistent motor runs etc. The problem is the way we did it. We kept playing by IC rules instead of electric rules. We had roughly 36mm spacing in between the IC motor mounts we went to the 35mm OD electric motors (the biggest we could fit in there), then since we had the props from the 40-60 piped motors or the ST60 we kept whatever was in the tool box and continued with it, that meant we had to maintain the high rpm they demand and here we go we also needed the 5-6S systems to keep up with the demand from the prop to make possible our stunt flying. The thig is even after that when we built new electric CL models we still kept the first tried systems without considering other alternatives. It sure works but the question is whether or not is best it can be, my assessment is that we went the wrong direction here.
For REvolutionds I am starting at 13.25x7 (might have to up the pitch a little) and will go to a 4250 510KV motor running on 4S.
This is the second time I have read something about low rpm high pitch prop setup. The first problem it rpm governors. The KR timer that I use won't go below 7500, well above the 6900 you propose. Also the 4250 size motor you propose is huge. So it begs the question: what hardware, (motor, speed controller, timer, etc), are you looking at that fits your proposed setup? ???
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Traian,
at low revs the motor torque will be higher than usual.
This implies that the C/G should be well above the exit point of the leadouts (with conventional props).
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Not everyone runs low pitch props!
I'm using a wooden 13 x 7 three-blade on a 7.2 oz motor, 745 k/v at 7,700 rpm on a four cell battery.
Yes, less gyroscopic precession and the battery usage is the same as it was when I ran 6 pitch props at about 9,200 rpm.
This set-up was originated by Barry Robinson in the UK. He makes the props out of two bladed props.
It works great on my 72 oz model.
I think light models may not benefit as much as a heavy model with this set-up. (My theory) ???
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2: As the pitch increases many good thigs start to happen: the power requirements to drive that prop goes down, the rpm goes down, the lighter props come in place and become feasible, and off course the gyroscopic precession is cut nearly in half (by the way gyroscopic precession comes from the motor too mot only the prop), as the electric motors develop max torque at low RPM we run them toward their optimum sweet spot rather than stretching them out.
What is not so great is the fact that the current goes up with the lowering of RPM which creates more heat in the system and this brings me to the third point.
3: Bigger motors with low KV rating seep Amps. I was using a motor calculator for a 4250 motor 510KV running on 4S that spins the intended prop 13.25x7 6900rpm and the amps are in the low 20A range. This also addresses the low rpm current increase higher temperature. Another thing a slightly oversize motor will do is to have plenty available power to quickly change rpm when commanded to do so. Keep in mind a heavier motor doesn’t mean heavier system because whatever you add in the motor you take away from the battery. Consequently smaller batteries with lower cell count are also cheaper on the pocket too.
Well we probably do something wrong if concept of 3 blade low pitch props developed and winning last decades is wrong. :-))
BTW do you have any math background to support that 2 blade high pitch prop has lower precession than high pitch 3 blade of the same power?
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Traian,
at low revs the motor torque will be higher than usual.
This implies that the C/G should be well above the exit point of the leadouts (with conventional props).
The torque is clear, the lower the RPM, the higher the torque at the same power, however you cannot balance the torque by CG position, it will make rolling as product of line pull changes (up wind, down wind, over head etc). It needs to be balanced by flaps and that is also not optimal, flight speed is stable, but also not 100% constant, so that shows the motor torque must be minimized = that is why we use high RPM setups. Current available outrunners are usually designed for RPM below 14000 rpm so current setups are designed for maximally 12000 RPM in boost - and that shows why we use 5" pitch props.
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Thanks guys for the info. Just want to say that none of the power plant is set in stone for now. I will check with experimentation and see what will give good results. It might end up a Igor type setup or it might end up a Traian out of box setup. I can always change that it takes a few $$ a screwdriver and 4 screws.
Gyro precession will go down with two things in my common sense thinking. One is lighter components (anything turning) and rpm.
You drop rpm or rotating component weight you drop precession.
4250 is a big motor but only 30g heavier than what we use 175g to 205g. What I am thinking is to rob Peter to pay Paul here (when the motor is oversize it requires less current to do the job and batteries are getting smaller). Another thing happens is that transitions in rpm when commanded happen faster because it has more available power in reserve.
This is only theory at this moment that remains to be proven or disproved. I spent quite a few hours in the calculators looking to see the variation in power necessary to achieve a baseline thrust and speed. Long story short the first (theoretic) thing I found out is that the lower the number of propeller blades the lower the power was necessary to turn those props even though the diameter was going up to maintain thrust the same as in the baseline. The second (theoretic) thing I found out is that as the pitch goes up the power necessary to drive the prop goes down again since the rpm will go down (at same time as the pitch goes up also the diameter has to increase to maintain thrust at the new lower rpm). This all pushes against, and makes me question the current trend of low pitch high rpm everyone is copying what the person next to them are doing. I am willing to go the other way and try something new. The question is can we push the existing to the next level and start to use the electric power plants to the best they can deliver. We might already do that.
But there is only one way to check that out and that is experimenting and pushing the range till we push too far or we tried it all. If anyone has ventured in the high pitch low rpm setup please tell so I don't waste my time, else I will try it.
Igor I am not saying that whatever we do now is wrong. It sure works well and yes it won a world championship (congratulations to you Igor). Even though I think the person at the handle won it rather than the motor in the nose of the plane. I bet the result would be similar if you borrowed any model that showed up at the worlds. Igor you say something about torque and i am a learning kind of guy and I don't fully grasp the torque concept. Torque or moment of force is the force time the moment arm. In our case is the prop blade drag times the distance from center to the blade center of pressure (this is the torque we need to turn the prop blade). Prop blade is a wing in essence and the faster a wing flies the more drag it has to fight. If you have many wings (prop blades) so you have more drag sources and it sounds counter intuitive to up the Rpm and number of blades and expect the torque to go down. Maybe I understand this one wrong.
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Well feeling is sometimes misleading, quick eyeballing tells me this:
12x5" prop of weight approximately 30g runs at 10 000 RPM
I will ignore units, because they does not matter as we are going to make ratio on the end and it is dimensionless number and converting will only make chaos.
Its moment of inertia is (1/12) x (12^2) x (30) = 360
and its precession is linear (with pitch speed) to angular momentum = moment of inertia * 10 000RPM = 360 * 10 000 = 3 600 000
We want prop with 2/3 of the original RPM (6666RPM) and 3/2 of pitch (7.5") compared to original prop
Such prop needs larger diameter to have the same power. (power is that wat make speed stability)
Since power goes with power of 4 to diameter, and we have 2/3 or original RPM we will need prop 3/2 larger - means diameter must be (3/2) ^ (1/4) = 1.11 - means the diameter must be 11% larger = 13.2" and its volume and thus weight going up with power of 3 is 1.11^3 * 30 = 41g
so now the same calculation for new prop:
moment of inertia is (1/12) x (13.2^2) x (41 ) = 595
and its precession is linear (with pitch speed) to angular momentum = moment of inertia * 6666 RPM = 3 966 270
so lowering rpm from 10 000 to 6666 will lead to precession which is 3 966 270 / 3 600 000 = 1.1 = 10% stronger.
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Could this be compensated by a Rabe Rudder with 10% more effect?
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Possible to fix that with a Rabe ruder.
Igor I took a look at those numbers and you are right amusing that the bigger prop will weight more. However if I have a lighter prop or one that brakes even with the baseline prop i am in great shape then correct?
I know that your 3B prop is in the 16g range or somewhere about there. I also know that I can make my prop in the same range as yours is how do those calculations look then? I can get my 2B prop as heavy as your 3B easily.
So if i baseline your number with the original 30g
moment of inertia is (1/12) x (13.2^2) x (30 ) = 435.6
and its precession is linear (with pitch speed) to angular momentum = moment of inertia * 6666 RPM = 2 899 710
so lowering rpm from 10 000 to 6666 will lead to precession which is 290 3709 / 3 600 000 = .805 = 19.45% better with low rpm a 2B prop that breaks even in weight with your 3B prop.
That means the challenge is to produce the prop and I should be fine. And will definitely pocket the 20%. Does this sound right?
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Igor I took a look at those numbers and you are right amusing that the bigger prop will weight more.
Yes larger prop heavier than smaller is my best bet ;D
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I received the tooling board sample and I want to say It looks very promising. So much so that I may change the way I do hollow molding or anything that doesn’t require postcure from now on.
There are advantages and disadvantages going on here. Because it is softer than AL it is easier to finish that means easier to sand, with that I can afford a bigger step over and cut the machine time in half. The disadvantage is that postcure in the mold is harder as I don’t want to overheat the mold and also is harder to polish a softer material. Overall I don’t need postcure and I have to be a little more careful when sanding and polishing.
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I have received the sample material so I threw the material in the mill and started to make some chips. After about one hour of cutting here is the result.
I am happy with this material, it cuts nice it sands nice and now i need to find a good polish compound. Here you goo I call this eye candy %^@. OK I need to stop druling.
The rest of the material comes in tomorrow or early next week. #^ #^ #^
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I got excited about this material until I realized that I don't have a mill, can't afford to get one, and wouldn't know how to operate one if I had one. Nice mold, though.
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Howard
These type of projects are usually tackled by a team of people each one with a specialty. You have the aerodynamicist who created the overall design (shape), you have the engineer who puts the parts together and make them work, you have the draftsman who takes the engineers creation and creates the models, you have the machinist ho makes the molds and individual hardware reality, and finally you have a composite manufacturer who puts the final parts.
Or you just have Traian who happens to have experience in all of the above.
That being said this is the current level of modeling in most disciplines that require absolute performance. You can’t find a speed model a glider or a high efficiency machine made out of balsa wood plywood and tissue paper. This is next generation modeling. Some have already embraced this kind of modeling especially in the glider world some have elements of this in the control line world too.
At least I can stir your imagination and present the possibilities, the eternal WHAT IF.
I am quoting a quote I like very much “no one has ever made a difference by being like everyone else” and another one i like a lot "where there is a will there is a way".
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Traian,
Gotta give you credit for reinventing the wheel.
Outstanding!
Charles
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Thanks for the encouragement.
Guess what the cat dragged in here. Two slabs of tooling board. I still work on cut strategy. The thing is that the machine doesn't have the travel to cover the whole part and because of that I have to work around the limitations.
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Depending on the part I will use 3 types of molding techniques.
Most parts (wing fuselage horizontal will be molded vacuum bag shells the I join them when i close the two halves of the mold. I might have some operations taking place after molding like cutting cooling pockets etc. The take apart hardware is installed during the close operation when I close the two halves.
The landing gear will employ two other techniques for molding. The struts will be done with compression molding and the wheel pants will be done with inflation bladder (overlap is necessary for the inflation bladder).
When you are done with the top and bottom you simply mix some splurge (Epoxy Cabosil Microbaloons combinations), and like you ice the cake, put this splurge on the edge, then you close the 2 halves of the mold. Those 2 halves have 2 alignment pins built in the mold so when you close them they will align within .001-.002in precision. There is no overlap here as all parts are finished bellow the parting line so you can close the mold without having the halves crashing in to each other.
A sandwich layout is preferred either glass balsa glass or glass foam glass will work well. Foam is better lighter but more expensive than balsa. If you go with balsa then 1/32 in the wings will be enough (add a couple of vertical walls inside) with 1/16 balsa in the fuselage will work too.
The beauty of composites is that if you are not happy with strength then you can make another wing panel or whatever part you want to in a couple of days. If you need extra strength in an area then add some material and strengthen that area. As long as you have the molds you can put anything in them and because it takes days to replace parts you can test anything. Carbon is not a requirement but if you put it on the outside surface then it will be a whole lot more durable just be careful to what you select because it will add weight fast.
What do you mean by "lay without a plug"?
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An update.
The CNC ATC is broken so until they fix the machine I am on stand by. I was really hoping to cut these molds this week. If there was no bad luck i would not have any at all >:( '' ~^
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Probably the heaviest way to do it and you hope the cloth conforms to the mold.
So you vacuum bag the top and bottom of the wing then trim down to the flange then glue the molds together and end up with a butt joint on the LE and TE.
Yes that way is heavy because you need to build up the thickness to get any kind of rigidity on the skin.
Almost: Vacuum bag the top and bottom of the wing then glue the halves together and end up with a butt joint on the LE and TE.
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Today's work
Is a pain in the ass when the ATC is not working. Ideally you want to set the machine and go home. When you return next day the part is done.
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Very nice. I'm very jealous.
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The evil twin has arrived VD~
The aluminium plates are used to hold the nose section and the back section together in perfect alignment so I can sand in assembly. That way when I assemble the nose section to the rear section the parting line will be perfect or so I am dreaming of.
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Traian,
Absolutely outstanding! H^^
I've never seen this kind of workmanship in this Forum before?
There's also balloon bladders that are placed inside the mold and the material. When inflated they push the material against the mold. I believe some parts are made this way, wings for an example.
Or am I thinking of something else?
Great work!
Charles
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Charles that is called “inflation bladder molding” it is good for parts that are fabric only like a only carbon fuselage (when you lay the material it stays on the mold walls without pulling off the mold) and for that you need a rigid mold because it has to take the pressure without distorting. I will use this technique in making the wheel pants for this bird. Ant that is the only place I will use this technique. And baloons are bad for bladders because the epoxy eats then they burst and make a mess. I had many of them burst and destroy hundreds of dollars 💵 worth of material.
Happy thanksgiving to everyone thanks for watching I hope we all learn something new and make better stuff all the time. Also thanks for all your impute and friendship.
Traian
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Since the machine is not behaving I am using the time polishing the fuselage molds. The part I do not like about this material is that is hard to see what is done or not done. As soon as it is wet (wet sanding) you do not see anything in there. You have to sand blind, and you have to dry it out and see the results from sanding.
But if that is the worst I am taking.
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Results from the last few days of polishing
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Nice!
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Wing molds are done ✅
Working on polishing those things
The flaps are built in the molds so there will be one step layout for the wing mold followed by the joining plus a little hardware inserts
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Impressive work Traian!
Do you intend to use kevlar or comparable to hinge the flaps as an integral part of the layup? Any concerns that the hinges will be too stiff if so?
r/
Dave
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Dave i can go either way with plastic hinges or Kevlar. If i go Kevlar then i will use a light Kevlar 1.7oz one layer of it for hinges. I left some 1/32 flat gap at the hinge which should give a nice flexible hinge. There are other alternatives of using several short hinges instead of a continuous one. Nylon cloth is also an option this will all be decided as the project evolves.
Thanks Traian
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I have got off my lazy butt and I managed to finish polishing the wing molds.
Enjoy the pictures.
By the way happy New Year’s guys.
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I have got off my lazy butt and I managed to finish polishing the wing molds.
Enjoy the pictures.
By the way happy New Year’s guys.
Traian,
BAM! You certainly have that airfoil down, locked and loaded!
You did mention an era for composites and a new look at building construction and materials for electric. Interesting your project being started just in time to celebrate 2018 with just that happening with the REvolution!
Well named also, a 'revolution' that model is!
Charles
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I am getting almost every day material in for this. Some from oversea some local.
I was playing with battery compartment and this is what I came up with. It can be configured for any TP battery pack whether it is a 3S up to 6S and i f i go with anything under 6S i can adjust it up and down in 5/16 increments. Each rail (gray color) is held in place with one screw.
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On my to do list is
Face plates (end plates for the molds) For the fuselage (2) one for the wing mold and one for the horizontal stab mold
Templates to cut components.
I will need templates for foam for carbon. That means templates to cut big parts and also I will means templates to cut several patches and small stuff. Each part gets several templates made.
Hardware
Take apart hardware control system hardware motor mount hardware battery compartment formers maybe landing gear stuff.
Paint templates most of the templates are vinyl cut but some are not.
I need to make special formers root ribs and hard points. these will be 1/6 balsa with 90g carbon on both sides.
I need to make sanding jigs for the fuselage inserts and cut the foam that will plug those areas.
Right now I have all the material on hand.
Some initial decisions for layout solutions (which i call best guesses) came after getting advice from may in the composite world specialists and some of the CL molders that dared to endeavor in this direction.
Fuselage will be 200g/M2 one layer with one layer of .75oz fiberglass cloth. and some reinforcements here and there. In the deep cavities there will be Divinycell machined to correct shape and 90g carbon on the outside. In the nose area i can go with perhaps 2 layers one 200g one 90g or the 90 will be patches here and there
Horizontal will be CW30 on the outside 1mm foam and .75 fiberglass on the inside. for spar I am usisng unidirectional 100g/m2 the hinge will be Kevlar
The wing will be same as the horizontal except the foam is 1.5mm.
So there is where I am heading.
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Traian,
Ohhhhhhhhhhh My Gosh!
Hey! Do you have any idea how inadequate you make me feel? I can't be the only one? n~
Where did you learn all these techniques? This can't be your first attempt?
Traian,
You should get the "Builder of the Year" award for 2018.
H^^
Charles
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Charles I have spent some 5 years plus in the glider community building DLG and learning a whole bunch about the composite construction techniques and have spent hundreds of hours just researching. I have learned about just every molding techniques there are possible and practiced them all too. In the process i made a CNC machine from scratch learned to do hot wire cutting and also made my own gravity hot wire cutter i learned about vacuum bagging regular molding techniques then about inflation bladder about layouts then moved to CNC molds (I do this for a job as I am a machinist) once i graduated to CNC molds then it open the door to do hollow molded components then the solid core components was next also a one piece fuselage was in the works too so I have learned to make that too. It was quite a journey a exiting journey full of disappointments and success.
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Charles I have spent some 5 years plus in the glider community building DLG and learning a whole bunch about the composite construction techniques and have spent hundreds of hours just researching. I have learned about just every molding techniques there are possible and practiced them all too. In the process i made a CNC machine from scratch learned to do hot wire cutting and also made my own gravity hot wire cutter i learned about vacuum bagging regular molding techniques then about inflation bladder about layouts then moved to CNC molds (I do this for a job as I am a machinist) once i graduated to CNC molds then it open the door to do hollow molded components then the solid core components was next also a one piece fuselage was in the works too so I have learned to make that too. It was quite a journey a exiting journey full of disappointments and success.
Traian,
I kinda figured you had some background or experience with these kinds of materials. What you are doing doesn't happen over night. H^^
Certainly puts the old school method of wrapping balsa skins around a foam mold or using planking around a crutch.
Guys like me certainly can appreciate your abilities and your 2018 contemporary approach to modeling.
Your better than me.
Better than anything I've seen actually. This means your efforts give guys like me ambition.
However, even with the ambition, what you are doing is far beyond the reach of most modelers. My 'reach' isn't long enough. LL~
I used planking strips on Pushy Galore. It tired me out. n~ Some guys are still doing sheeting over foam. It works for us old school guys.
I'm thinking, with all that engineering, math and tooling, you could go into production. I mentioned I have someone interested in your design AND would consider a model.
Are product sales in store for the future?
Good for you!
Charles
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Right now I am not sure about sales. Mainly because I don't have time to do this.
Speaking of Pushy i think you took the hard way approach to it. It is relatively easy to make a buck out of a few formers put foam between them and make a plug suitable to mold cigar-ish shaped objects. For mold you can do it with two layers of balsa wood cling wrap Elmers glue and Ace band aids. That is easy to do. after you mold you lay it flat and the you walk a Exacto knife blade around the parting line.
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Right now I am not sure about sales. Mainly because I don't have time to do this.
Speaking of Pushy i think you took the hard way approach to it. It is relatively easy to make a buck out of a few formers put foam between them and make a plug suitable to mold cigar-ish shaped objects. For mold you can do it with two layers of balsa wood cling wrap Elmers glue and Ace band aids. That is easy to do. after you mold you lay it flat and the you walk a Exacto knife blade around the parting line.
Traian,
I'm well aware of the method of which you describe. I made a choice and decided to build from the inside out, as I generally do.
I'd have to do my homework but I'll take a guess, I believe Lockheed, in their early days, the 20's possibly, built aircraft just about the same way. They pressed plywood together in large molds under tons of pressure to make fuselages.
I like planking because I've built many models this way. I have plenty of planking left over from many Berkeley kits. I'm kidding.
I may remove the wings on Pushy Galore and use what's left as a tether car.
Charles
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Started to work on hardware. This piece will be glued directly in the mold when i close the two halves. There is a 4250 in the picture but the AXI F2B will bolt right in. The motor mount closes the airflow to the outside on the motor. All airflow will travel through the core of the motor. It is not clear in the picture but on the outside of the mount there is a rough surface to get a good glue joint.
Enjoy
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I have most of the stuff in.
I am consulting with a firm on their release systems to make sure I give myself the best chases of success. Research and advice are priceless.
My initial goal is to make a model. I don't care too much about weight. What i want to do is learn as much as possible out of the first try. Things to learn are layout strength, planing and reality are two different things so that is another thing to consider, check templates and fine tune them this si something you almost always need to do, then I need to check strength of finished parts and also i need to check the oportunity to finish said parts after the molding process.
I have a lot more to do yet.
1: I need blocks cut for sanding the fuselage inserts. If you look at pictures you can see the fillets and root rib built in the fuselage mold. one way that is done is to put fiber in the cavity then plug the cavity with a piece of foam cut to the exact shape (this foam has two roles: first to push the fabric against the mold wall and second is a filler creating a smooth inner surface that is much easier to mold) then lay the continuous fuselage side layer of fabric
2: I need more templates for doublers
3: Hinge material (Kevlar with resin in it)
4: root ribs and fuselage former material ( carbon balsa carbon)
5: Mold for the battery rails and cut plates to insert in the rails.
6: make hardware (I will leave this for later towards the end)
7: bill of materials for what goes in each part
8: sheer web wing spar material (glass Rohacell glass)
Starting this coming week I am doing some little molding stuff to test some of the resale systems i have on hand and I can make the ribs and former materials as i don't need release materials for that.
I might fly this bad boy by the end of February who knows.
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I have worked on the mold end plate
This is a critical item for the take apart system. All parts coming out of the mold must be the same so they can be interchangeable, therefore the location of the spar pocket and alining pins and the control horn pocket must be the same from part to part.
Other functions for this plate is to make a perfectly perpendicular wall it needs to hold the root rib in position it creates a litle step for clearance so the elevator doesn’t rub against the fuselage and also it will make the control horn pocket.
This plate comes in place after the skins are molded as a secondary operation.
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I have to say, this is fun to watch!
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I have finished the last Mold component. The Wing root plate which works identical to the stab root plate only it is simpler in construction.
The focus this week is to fianlize the plate, fit the threded inserts in the mold, and apply release system. If I have time and the wether cooperates I will do hte first painting. The paint will be something simple an all white with some color on it. I have made stencils but I want to save them for #2.
My goals for initial build are to check fit, check templates, test the paints I have on hand I am very curious about color selection, in general prove the build sequence I envisioned when I started. There are a few things unanticipated that will go wrong, and i hope they will not be something major but as with all the new stuff things can and will happen. Nobody is perfect. If this week proceeds as planned then next week i am mixing epoxy and I start the actual build. All I have done so far was preparation towards this moment.
I have hinge material done. Maybe I can squeze in the balsa carbon sandwitch plates.
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Traian,
I can't wait!
I'm sure there are many others like myself who are looking forward to the actual build.
Kudos!
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My moto is something every day. Yesterday I finished instaling all the brass threaded inserts in all molds that needed them. I discovered that the pins I have in the base plates are stiking out too much. No big deal all I need to do is to press them deeper to the new level.
Relase system application is starting today.
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Chemlease Flex Z #2 semipermanent release. It is a system that has a cleaner a sealer and a final coat. Flex Z has numbers from 1-6 1 is on the sticky side 6 is like oil. 1-3 are paintable and release well. What is cool is that if the release is too slippery drop down to a lower number and try again.
PVA works too if you don’t want to paint or you just want to do any painting that doesn’t require any masking.
I want to paint in the mold the when I release the part i am done. Maybe more clear but that is it.
I was thinking of PVA for first parts but then there would be something missing fron the whole equation.
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I mixed up epoxy yesterday and laid the Carbon Balsa Carbon stock material.
Basically is molding but there is no mold, because the piece is flat. I basically pushed the layers against a flat board of 1/4 G10 board 2x3ft in size. The idea is if you tape a piece of plastic over the G10 and you can think of it as a bag with one hard side. If you remove the air from inside whatever is in the bag will be pushed against the flat hard piece of G10 (in this case) and you get a flat component. At least on one side.
So the part is Carbon 93g/M2 plain weave 0-90 orientation, 1/16 Balsa, and same Carbon again.
On top and bottom of the part I used a flat sheet of .006 mil polyethylene (polybag) material (from McMaster Carr), this is so the part will not get glued to the flat board and it also serves as a medium for a mold surface.
The last layer on top and bottom of the poly bag material was one layer of paper towels which serve as bleeder cloths for the air to travel out of the bag.
As technique used: I got the carbon wet with a small roller on one side, then I flipped it over and made ensure the resin did penetrate and the fibers are saturated. Then I laid the carbon piece between paper towels and with a hard roller i pressed hard on the carbon so the excess resin will be soaked out by the paper towels. After that I got the piece of polyethylene and got it stuck (kind of) to the carbon. I did the same thing for the other piece of carbon.
Then I added the balsa (made sure I got the dust off the balsa) and created the part sandwitch (poly, carbon, balsa, carbon, poly). This is now ready to be vacuumed.
I put paper towels on the G10 then the sandwitch them paper towel on top of sandwitch (these towel are there only to facilitate the air to exit the bag. Then one last layer of polybag taped to the G10 (this layer is to create the vacuum bag) applied vacuum and done.
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I feel like a freaking TV.
Here you go. I don't care about finish on these parts. What I care is that they are flat stiff and light. They will ultimately end up inside the fuselage at the root of the wing or root of the horizontal in other words you will not see them.
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For those of you who care TV speaking here again.
I am switching strategy here. I am shelving the idea of CNC cutting the ribs and laminating the ribs with carbon. I will use that material for something maybe a super light ship in the future. But the hustle of laminating Carbon over balsa then cut on the machine programming etc was a bad idea (mostly time consuming).
What will I change to:
In the nose F1 F2 F3 where F2 F3 are the mating formers between the fuselage nose and the fuselage body will me 1/32 G10. That will provide a bulletproof long lasting mating surface, a rigid nose, and a reliable and strong battery support (most my ribs are .2 wide anywise so there is not much weight there to be worried about in the first place). The rest will be 1/8 balsa wood medium strength. I will also use the 1/8 balsa for the wing and stab ribs and the aft formers in the fuselage.
That will more than enough for what I need and the weight penalty is perhaps 10grams or so.
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First part is in the bag. I started with the horizontal.
In the beginning the things go a Little slower that normal. so After about two hours worth of work I got the stuff in the molds. Of course the future will me much easier because much of things I had going wrong will not. But overall no big issues at all. I think I could use a better Vacuum pressure but that i snothing to worry about and perhaps add Phelps cloth to the bag to facilitate the air travel. Like I said just some details that are a little off.
Today when I get home I will join the two halves.
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Picture size does not allow for more pictures in a post.
Some things I will not do again like cut the foam then apply the glass layer and cut again. I did that because I wanted to check the size of the foam piece which I know is correct now so next time I will apply the glass to the foam sheet then cut the foam and glass at same time. That should take 5 min for a horizontal set. Also I am making a list of all parts that need cutting. I should be able to cut it all in 20 min or so max. I am thinking that I can do a wing and a stab panel molding in 2-3 hours easy. I predict that i can do all prep and paint in first day. then the second day I mold everything, the third day I join everything forth day demolded and paint the wing and stab molds, fifth day mold the second wing and stab sixth day join second wing and stab and seventh day and forth assembly work. Yup in two weeks you are flying assuming that is all you do and you have the time off no kids competing for your time wife kicking your ass to weed the garden etc. All the price in time is paid upfront, in making molds templates components etc.
Tonight I am joining the two halves and here I have a new set of parameters to adjust to. This is getting exciting now.
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OK gang. S?P Last night I joined the two halves. Learned a few things and overall things went smoothly. I will adjust the Foam templates here and there so I don't have to do some things. I have to check fit on the sheer spar and perhaps adjust amount of splurge I put in or maybe put a much tinnier bead on both sides. And make sure i have a paper clip ready for use next time around. Also i want to do something a tiny bit different on the hinge area next time around. By the looks of it the vacuum was OK.
These are minor things and first parts are always test parts where you prove techniques and try learn maximum. The second time around you nearly cut the time in half during the process.
Also I prepared the stencils for the fuselage last night and will put them on tonight. Maybe I get to do some painting tonight. Cant wit to see how this first part turned out. I bet a little heavier than the next part but I will take a 30g part and consider it a success. That is, a 30g for a finished painted with hinge installed ready to assemble part.
Later
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Ohhhhhhhhhh my gosh!! H^^ H^^
Outstanding workmanship.
Could well be the construction methods of future for full blown stunt ships?
CB
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For part is out of the mold and it weighs 38g. The release was not perfect and some paint remained in the mold.
The hinge is great and smooth and it would be ready to be installed in the model. Not bad for first try. Will treat the mold with number 3 next time to get an easier release.
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And here is the picture.
The release system has shelf life and it was old that is why I had little issues so take with salt shaker of salt what you see. 38g with hinge and hardpoint attachments.
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I am guessing that you refer to the paint left behind in the mold. It came out relatively easy with the help of a Popsicle stick and a damp paper towel (acetone).
I will re-polish the mold and reapply the stuff. This time I am using fresh stuff. I have fresh #1 and #3.
I put another picture so you can get an idea of the finish possible with this method. I did clear all areas that did not receive paint.
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I repolished the mold it took about 30 min to do. After that I started the relese application. Tonight I am puting the #3 release stuff on the horizontal then I am adjusting the templates.
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I am guessing that you refer to the paint left behind in the mold. It came out relatively easy with the help of a Popsicle stick and a damp paper towel (acetone).
I will re-polish the mold and reapply the stuff. This time I am using fresh stuff. I have fresh #1 and #3.
I put another picture so you can get an idea of the finish possible with this method. I did clear all areas that did not receive paint.
Ohhhhhhhhhh My Gosh!! H^^
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I used the #3 Chemtrend FlexZ-3 and i had good success with it. I tested to see how is the paint laying down in the mold and when I pulled the paint out of the mold it came out without fussing. #^ It confirmed that the expiration date of the product was the cause to all this mess.
I am waiting on some new stencils and after that I am ready to cook S?P a new part.
I was pondering on the fuselage layout for a while now. There will be a layer of 200g/m2 which should be enough, but because it is so course and it leaves gaps between the material weaves i expect a crappy finish. So I either leave the layout a little wet, and use Epoxy to fill and bridge the gaps, or go to plan B which is to add a layer of glass on the outside with a much finer weave. I am going to plan B. so I will have a layer of fiberglass on the outside then the carbon as a inner layer. What I think is that insted of adding heavy epoxy to fill gaps (this epoxy doesn't add any strength) better to add glass and evacuate epoxy from the mold in a dry layout with higher strength and break even weight wise (rob Peter to pay Paul). Yes I will do little test to prove this idea. The test will be: plain carbon, .75oz glass with carbon, 1.6oz glass with carbon. May the best win.
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I am learning at every step. when I painted the background the paint bounces and goes everywhere and them some. I was trying to use a cardboard flat on top of the mold and the paint was going mostly where i wanted it to go but some bounced and create a little haze of color in the mold like a fog. So now I am rethinking the masking for that step.
I got new stencils on hand too.
If I have time tonight I will mold the second stab. This will very likely be the last test mold I do for the wings or stabs.
By the way the Release in the Red tooling board molds works great too.
I will try to make open the schedule Saturday or Sunday to mold a bunch of stuff.
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Not all things are created equal. This cliche is holding true here too. The release number 3 works great on aluminum molds but if you use same thing in the Red tooling board after you paint and the paint is dry you can literay push the paint around. the roller picked the paint up off the mold. I will go to number 1 release to to get the paint to stick just a touch better.
A new horizontal is in the mold with a new layout in it and updated foam cores, you can see the cutouts that are already in the foam. I got rid of the uni in the TE that does nothing, I used the new vacuum bags which work much better than the last, I also evacuated a whole lot more resin this time around so Expecting a near perfect part.
I had some adventures in painting this part and found out that after I do stripes and switch to the fading mask free painting I need better way to do that other than a flat piece of cardboard laid on top of the mold.
I made a test to see what kind of finish do I get with .75 glass or 1.6 glass as an outer layer in the fuselage mold.
Lastly I cut the first plugs for the fuselage mold. these will go in the elevator area.
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I had to make some decisions lately.
After the test in the tooling board material I got hit by the fact that the paint is messing up the mold finish. So I can't paint in the molds made of tooling board.
Since the only mold I have made of aluminum is the horizontal stab mold it is not worth doing the painting in the mold for just one part. Long story shot I am molding with no paint and will figure out the paint part after that. On the plus side is that I gain a couple of days of work where I have to wait for the paint to cure overnight.
Today I prep the first wing to go in the mold. I closed the horizontal mold yesterday and I am puling out the part today. I might lay another horizontal today if I have time to spare after prepping the wing materials.
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Usable part nice finish 31.2g after I removed the flashing.
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First wing is in the mold.
There is always a first and that is used mostly to prove disprove find problems troubleshoot etc.
I already see a couple of places where i need to trim the foam sheet template. Also I need to have a faster way to get things in the mold. It took an hour and 45min to get the two halves in the mod and I need to drop it down to about 1hour total or a little over.
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First wing is in the mold.
There is always a first and that is used mostly to prove disprove find problems troubleshoot etc.
I already see a couple of places where i need to trim the foam sheet template. Also I need to have a faster way to get things in the mold. It took an hour and 45min to get the two halves in the mod and I need to drop it down to about 1hour total or a little over.
Traian,
That's one half of a wing vacuum bagged, correct?
I've seen vacuum bagged stuff before, that's really clean work.
I can't wait until this model is completed.
What are you going to do with all the unused trial and error parts? #^
Charles
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Charles thanks for the encouragement. There are both halves molded one is laying on the floor. I will try to speed things up next time around to get each mold loaded in 30 min. The trial parts I keep for testing. The usable parts will go in the first prototype. The first wing should be usable and if anything it can be the outboard wing if I feel is a little on heavy side.
I am thinking to lasercut the sheer web for next wing.
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Wing halves joining has started.
I want to say that I do not expect to have absolute success at the first try. All I want to achieve is to learn as much as possible from this.
First thig to do is to glue the cups for the take apart system in place. I am using the root mold plate to do that in conjunction with some aligning blocks.
Pictures say the rest of the story. The finish position alignment is within .003-.005in
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Looking good Traian!
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I just closed the wing mold last night. I hope it will be good. I do have some expectations but what I do not expect is a perfect part. When I pullet ha part out of the bag I noticed that the foam grabbed and puled the outer layer of carbon below the parting line and this is a lost part. I am already anticipating the result and I considering changes in the layout.
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Long story short
Wing is ok but I have to work on layout techniques a little.
The weight is lower than expected and it tipped the scale at 127g that’s 4.5oz for this panel.
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I cannot say how excited I am with this last result. I have been hovering around that wing all weekend long. I have spots in the wing where the outer layer of carbon was dragged below the parting line and I have bad structure in the LE of the wing. I have added a piece of carbon on the outside to repair the area but this wing is just for testing.
Now for changes in techniques:
1: On the TE, I am returning to the flat unidirectional carbon.
2: In the flaps hinge area there are two pieces that form the corner. I will hinge the two pieces together to have better handling of the components nicer harder better strength corner.
3: I made a tool with 6 blades 3mm distance in between the blades to score cut the foam in the hard turning areas.
4: In the wing, I want to add a couple of foam ribs to stiffen the skin a little bit more.
So tonight, I am prepping the stuff and tomorrow I mold the wing and stab shells. This time around, the goal is to make a perfect laid wing and stab with no flaws and weights close to the lightest parts I have made to date.
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When done I hope it flies as good as it looks. Your workmanship is amazing! y1 #^ H^^
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Thank you John
More prep tonight and tomorrow I have to go and put the stuff in the mold. Wish me luck. A friend of mine once said "I take luckover skill anytime".
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After discussions with some friends of mine, we came with some great ways to work out the remaining problems to deal with the issues that came up during the layout of the first part.
I had to adjust a few templates that cu the foam and carbon and I managed to cut prep all the stuff. Because of that, the prep took forever but I pushed through and ended up going to bed at 1pm.
I am finally ready go to the Moon now. #^
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My Progress
Worked on wings and fuse nose.
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Eye 🍭
Fuse nose assembly
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The part got stuck in the mold due to release issues. I spent all weekend fixing the mold. I am returning back to the Wax PVA system. Someone will say I told you so, and he would be right. The thing is you can not assume that what works on a mold surface (material) will work on another one. No problem in admiring a screw up but it was beyond my control and knowledge. Some one said if it was easy everyone would do it.
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How do we know if it will work or not if we don't try it. Glad you got it fixed. Hope to see end result in the future. H^^
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Looking good Traian. What does the wing panel weigh?
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Some updates
The new wing panel is 134g the horizontal piece is 33g the las nose that came out of the mold 57g.
I pulled out of the mold the first rear fuselage section. It got stuck in the mold because I rushed the polishing and waxing. I guess if you cant do it right the first time around you will find time to do thing again correctly '' .
the good new is that it weights 213g untrimmed. With nose together I have a 270g fuselage. 9.5oz fuselage.
The tally so far for a model wings stab fuse is roughly 612g. That is 21.6 oz for the model. in adition to that there will be the landing gear the control system motor spinner prop ESC timer tip weight. I am using a 215g motor 5S 2800 Prolite TP. I think I put that data somewhere in here.
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I spent time making new foam plugs for the next fuselages.
Here are some things I would like to change in the next layout.
1 Carbon foam glass in the flat areas.
2 Carbon ribs laid in the mold from start.
3 CW30 Foam glass for vertical fin and rudder.
4 get rid of all ribs
5 Stringers alongside the fuselage for even better stiffness
6 Eliminate the scissors trim of material.
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It’s out of the mold tipping the scale at 200g
The whole fuse is 257g 250-255g after I cut the holes.
The whole airfarame (wings tail fuselage) is just under 21oz.
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Due to lack of interest I will stop posting here. Just tired of being a TV anchor. Thanks for watching.
I have the first bird put together and in final assembly right now. The airframe (fuse wings tails hard-points gear struts) weighs 642g 22.64oz for a plane the size of a Strega. Total weight with heaviest motor battery setup 45oz. In adition to the 45oz zit needs a tail wheel spinner and props axles and wheels and control system parts. So final will be around 50oz.
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Due to lack of interest I will stop posting here. Just tired of being a TV anchor. Thanks for watching.
Topic: REvolutions (Read 7422 times)
Looks like there is plenty of interest in your project. I know that I follow your posts with interest.
There just is not a lot for most to say, unless you just want a continual string of "wow", or "looks neat!" or "keep it up!" It's so outside of the normal construction method box that there are very few that have anything productive to add to the discussion. That doesn't mean that it isn't being viewed or appreciated. Who else on this forum is doing full molded carbon construction besides you and Jose Modesto? Looks like a very clever process to use to build an airplane.
So, please keep posting. It is educational for us all.
Wow!
Looks neat!
Keep it up!
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Indeed. Please keep the posting up. It's actually very helpful. I have 2 planes I plan on building electric. My 59" stuka and my imitation kit from Mike Griffin / RSM.
Reading through these gives great insight and ideas. A lot of us don't jump in because we may feel we have nothing to add to the conversation.
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I'm watching! I just haven't seen the need to comment is all. Keep going, there's a lot of us watching with bated breath!
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Please don't stop posting. We're watching with great interest and learning a lot.
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Some pictures for take apart in the horizontal and control system
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Please forgive me if I missed this info earlier, but what are the red ball links you are using?
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Jim
They are close to a 4-40 size screw. Very smooth with no bind whatsoever, unlike the plastic type which can have a little bind in them. They are sold as pairs with LH and RH threads. I have made my own rod ends.
https://www.ebay.com/itm/20pcs-Aluminum-M3-Link-Rod-End-Ball-Joint-CW-CCW-for-1-10-RC-Car-Crawler-Buggy/262241396196?epid=1254466092&hash=item3d0ece25e4:g:IfwAAOSwoydWmJ1o
The rods I use are 6mm OD 5mm ID, and you can get them from here https://alofthobbies.com/carbon-fiber-tubes.html
To me the ball links are a little on the heavy side but they have an absolutely free movement (no bind), and are made out of aluminium anodized with steel ball and will likely never wear out.
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Your workmanship is amazing, can't wait to see the finished product.
Thanks for sharing this journey with us.
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Would love to see a photo of the final ship! #^
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The assembly went very much trouble free. All parts fit like a glove.
I have to do some final glue joints and I am off to bolting in the hardware and put the electric system in place.
I will put a final picture. Right now I am not worried about painting at all. I want to see how is the CG and judge the performance.
I will add some pictures when done.
There will be a bit of testing.
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I am still awaiting the flight reports. H^^
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Here you go
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Very nice. It looks just like the CAD drawings!! Harder to do than people think. What was the layup for the wings?
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Jim the wing layout is Carbon bias 45 degrees, 1.5mm foam, and .75 fiberglss 0-90 orientation. The weight of a wing skin section 100sq in is 11.5g.
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Is it just me or does that have a swept elevator hingeline?
While we're discussing hingelines - how were the control surfaces hinged?
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Is it just me or does that have a swept elevator hingeline?
While we're discussing hingelines - how were the control surfaces hinged?
Thanks
If you look in the first CAD pictures at the beginning of the thread you will notice the horizontal position. It sweeps back about 10 degrees total at hinge line and it also has a 5 degrees dihedral.
The hinge is made out of Kevlar over the full span. I insert the hinge when i close the two mold halves. You break it loose after you demold the part and work it out. As the resin inside the hinge line breaks down it gets looser and better.
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Looks like trhe Bees Knees , the Hight of technological / cutting edge . Hope you've some time on it , for the Nats . H^^
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I just have 4 full flights on this bird and it is soo good is unbelievable. My buddy Mark characterized the flight characteristics as “astonishing”. I share in his opinion. It corners like mad tracks like on rails and I have not yet started to explore the edge yet. Is so easy to fly.
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That sounds great. Now to impress the judges. LL~ LL~
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Great news. I'm jealous!
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I was waiting on the flight reviews before commenting. That control system is a work of art. Everything with unlimited adjustments all centered in one place that, with a little planning can be accessed through a hatch of some sort - genius. When I saw you were coupling that with zero gap flaps and elevators I deduced that you would have a plane that would be so tame as to fly like it was being controlled by a computer. I think you have done for control systems what electric engines have done for propulsion.
Only a handful of people will be able to duplicate what you have done but soon everybody will need one of these to to stay competitive. This could lead to another run on the BOM rule and maybe even a ban on fully composite air-frames. Let's hope not.
My hat is off to a truly superior effort. Post a video someday.
Ken
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maybe even a ban on fully composite air-frames
We could make them from Bamboo , Irish Linen and Banana Oil .
Would be about as inteligent , petty and backward , as baning Propellors .
Even if the Americas Cup things are one hit wonders , hardly last a season , the Composite F1 grand Prix Chassis are a bit more durable .
Maybe they could go back to timber chassis and wheels . With rear wheel brakes only . It could make it more intresting . S?P
C'mon !? the 22nd century's only 80 odd years away .
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Matt, can you imagine him doing your Folkerts with this type construction? Hey I still look at the plans and details.. H^^
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I am done with the NATS
Finished 5th with 1032 total score. Best flight at NATS was 536 my personal best as a matter of fact. This was mabe #15 patterns on the model. And we oly managed a crude setup at best. Battery usage is about 1350-1405mAh.
Weight is 58oz now with heavier power components and heavier tail.
Because low power consumption the door is open for a 4S 2800 witch will instantly shave 4.1oz lighter tails will open the door to a 52oz model.
It is all I have for now.
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WOW! Way to! Looks like a winner. #^
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Finished model pictures
After the NATS I let my buddy Mark fly REvolutions and after 3 flights most of which where handle settings he put what in his words was the best flight of his life. I think I mentioned how good this is in the air and my characterization of it's flight envelope is easy to fly effortless rounds corners and tracking.
I have not have the chance to optimize the model to my flying stile liking due to lack of time. I have not even started to tap in it's potential and am very curious to see how much farther can I push this bird. In a practice flight i tried to see what kind of corner is it capable of and had not enough handle to do it with. For future I want to find out what flaps elevator throws will give maximum corner. Then after I sort out the ground clearance I want to see what power packages are practical better etc.
Chris Rud will get his hands on it in the near future (next few days) and I am curious to see what trim changes he wants to do. We have a lot of work waiting ahead of us. We need trim evaluation and optimization we need more power plant optimization etc.
Nats funny stories:
Tuesday at appearance judging weigh in registration I walk in and get ready to pass the model to Gene Martine. When he sees the big bird he widens his footing to get better stands getting ready to receive the heavy beast. I pass it to him and he goes "holly shi..." he looks at me and his second question is "did you put the battery in?". I had a 6S 2800mAh in and i said "yes". Then his jaw dropped.
After Advanced was over Walter one of the judges cam to me and said "you flew the shi... out of that plane look at the scores".
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Very nice color scheme. Quite striking.
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TDM,
Congratulations with your accomplishment with your prototype REvolutions composite model and finishing 5th at the NATs.
Charles
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Dose anyone know what appearance points the REvolution received? :)!
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Dose anyone know what appearance points the REvolution received? :)!
I was told 15
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My initial set up is
1.5oz tip weight
out thrust 1 degree I think.
.015 68 feet handle to center line.
710 sq in wing area
58oz RTF
Motor is Joker 4250 510KV
Igor timer
TP 2800mAh 6S
flight time 5 min 30 sec
5.4-5.5s lap time
Back in the pack 1350-1405mAh
I set the bellcrank with little Expo in both flaps and elevator.
I do not have any temperature issues at all. The average amp draw per flight is 15.27A during the flight. Hardly any stress on the electric system. The motor is not even breaking a sweat.
I would like to try more Expo and a wider handle. That will maintain my flying stile make the corner harder and maintain predictable soft center for smooth rounds. I bought a 4250 820KV I want to try on 4S with an instant weight savings of 4.2oz. For the 4S i have to move the battery forward 3in. I also have something I want to try on 5S configuration.
Another thing I am considering is to make a new nose for 4S setup. The idea is to fly 6S in the wind and 4S in nice weather.
I want a new aft fuselage section with the landing gear in the right place. That will enable me to go to a 13in prop. Later when I settle on a setup I will consider making a Carbon prop.
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Congratulations and job well done Traian. I just went back and checked, you started this thread in September of last year and now, 10 months later you have a finished airplane that looks really nice and obviously flies very well also. 5th in advanced at the Nats with a relatively new airplane, you should be thrilled with that result. All that hard work and time invested really paid off. You designed it, you manufactured everything, even designing and hand machining some of the assemblies that you used, you should be very proud. I have no idea where you found the time to do everything, my hat's off to you.
Continued good luck as you proceed down this path.
Vince
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Traian, that is a really nice model. Very cool and spectacular workmanship.
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Traian, this has been some project and I wonder if given a little more time results might have placed you higher. Now will you start version number 2 and keep trimming on this great looking plane? H^^
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Yes I was matching the average score of the Advanced winner. I was also having my highest personal score in a competition, and this was at the NATS where judges are brutal on the scores. So yes considering I had about 16 patterns on the plane at the time you can say i needed a little more time on the handle.
Starting #2 in a week with new layout on the fuselage. Version 2 I am not sure I want to do this again anytime soon. I love this plane in the air as is.
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Hey, look at Dave F. still winning with a plane that has flown several NATS. Nothing wrong with flying the same plane several years unless you wear it out and keep improving. D>K
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I'm Not sure but I think it's the same design, but different plane! ??? different paint jobs!
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The airplane is beautiful!! Been following along since the beginning, and the lines of it are awesome! I'd love to get a pull on this airplane. Its so cool looking!
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If I do that, you will not want to give it back, then I will have to fight you for it. :)
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Here is my flight report.
First of all this is with only maybe 20 flights on the plane.
Triming was basically non existent. I added a little thrust offset and tip weight 1.5oz. Also I tweaked the flaps a tine bit. Because it is so stiff the flight was very predictable and it immediately showed when it did not like something, or if something was slightly off. In one flight the flaps screw was loose a little and it tweaked the flaps position in flight. I knew that instantly. We found the problem after that, tighten the screw a little, and we where back in business. Paul saw it and I confirmed the bug at the hotel. Yes I have flats on the rods, what happens if the rods are not perpendicular to the set screw when you tighten it it will stay there for a while and of course during the official flight it will move a couple of degrees enough to give you grief. This was about the extent of issues we had so far.
Per design I moved the stab up and added the dihedral to put it in clean air. This decision came after a discussion I had with Windy Urtnowsky. It was a perfect decision because the model tracks and locks is effortless.
I also moved the stab backwards to get more moment to turn the corner. Moment (aka Torque) is defined as distance from CG multiplied by force. For same force applied by the elevator the further back you apply it, it has more moment (torque) to turn the plane (change the AOA). I have to say, that box also received a check mark, because this bird turns so tight I have not found the edge yet. Yes I tried to find it.
Control system that is custom with a little Expo in both flaps and elevator combine that with the tracking ability make the round maneuvers a breeze. Put a check mark in that box too.
Because the build construction is composite and composite is over 400 times stronger than balsa (over 800 times if you compare ultimate tensile strength of carbon to ultimate tensile strength of balsa) there is no flex in the air frame anywhere so no funny business like: of one flaps flexing more than the other one, or wing torsion or flexing up and down during flight, there is none of that bull crap to deal with. Consequently I am flying very comfortable at 5.4-5.5s lap time. . The line tension is lighter because the model is relatively light but is everywhere, regardless how hard I hammer the corners, and after I realized that I had to change things in my flying and get rid of bad habits formed from the previous models.
This is with a crude setup. We have not even started to tap in the potential of this plane to this day and only God knows where the edge is. Well I want to know it too. My previous bird was an SV-12 model with a PA60 tuned pipe in it, and if I compare to that is like moving from a BMW M5 to a Bugatti Veyron. The difference is staggering. I just cant get enough of this bird.
It may sound bias but so far I did not hide anything. So take it with a grain of salt. My personal impression is that this is next generation model a leap over anything at very least I have done before.
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Can I buy one on Amazon?
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Can I buy one on Amazon?
And please make it available through Amazon Prime so I can get free 2-day shipping ;D ;D ;D
Awesome plane, btw. Been following since the beginning. Your c/l kung fu is strong.
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Nothing much new here. I discovered Paul Walker articles on trimming and I am studying them now. Started to get more Amp draw than I had at the NATS but I think it is because i fly on grass and it is not exactly short grass, perhaps the motor works hard to get the model in the air.
I did CAD analysis of the control system and found out that some things where opposite what I was thinking as cause and effect. I was investigating the response of the arm (opposite the bellcrank) based on same belcrank deflection but varying bearing positions. Initially I though that I will go Logarithmic if I get the bearing close to the arm and more expo if the bearing is close to the bellcrank, the fact is that there is only one setting in my system and that is Expo, and the closer the bearing is to the the bellcrank the less Expo I have, and the closer the bearing is to the arm the more Expo I have.
Right now I have very nice response in flight the model is Soft in the center and quick in the corner easy to fly. I will have to make a angle gauge to be able to read the current handle feel response which I like. I would like to soften the center a little more and speed up the ends. That is 30min of work in the shop with one Allen wrench. Set up work is still in the beginning. I need more good weather more good advice and more time.
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Ok gang I have a video of a flight that took place after the NATS. This is my buddy Mark at the center his flight number 4 on REvolutions so he is still getting used to it.
https://www.youtube.com/watch?v=k5YeEybkY5I&list=PLJ4i08zyYBcuWUraYfAqziZvle_zC0WCp&index=6&t=68s
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Ok gang I have a video of a flight that took place after the NATS. This is my buddy Mark at the center his flight number 4 on REvolutions so he is still getting used to it.
Impressive. Aside from some hunting inverted I saw no bad stuff from the plane. It looks like it is capable of much tighter corners (but we won't go there right now). You may have built what we all dream of - a plane that exceeds the capabilities of the pilot!
Ken
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Ken about the hunting, actually Mark was messing with the handle strap and yes it is capable of much tighter corners. Mark was babying the plane a bit. I have some kinks in the lines and after the loops they stick a little. I flew the plane inverted without lines twisted and it is just fine. I am also found that I have a little positive AOA on the inboard wing which is being fixed right now. It will get better. The flight program is still in it's infancy so there is more to come.
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The airplane is beautiful!! Been following along since the beginning, and the lines of it are awesome! I'd love to get a pull on this airplane. Its so cool looking!
The inside is even cooler looking than the outside.
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Random thoughts
Right now I am using about 1400 mAh on a 6S. The average Amps during flight is about 15-16A (the 66A ESC probably is not even breaking a sweat. That works perfect but it look like a 4S 2625mAH (per math) would get the job done just fine but since that is not really existing a 2800mAh 4S (2100 per flight @ 75%) will save me some 4oz off the plane. I just have to move it forward 3-4in to maintain overall balance. To achieve that I have on hand a new motor which is rate 820KV and also rated 4S. the power is slightly less a drop from 1150W to 1040W which is still plenty.
The question is how much more heat will this system will produce. The dilema is that with the extra heat means waisted energy and I wonder if this might push the 4S system past the 75%. I lke the idea of a 54oz model.
There is also the idea open to go on 5S with a 2200mAh battery and aproximately same 75% but the problem is that the battery doesn't exist. At least TP is not making it. I can hack something up at around 275g but at that point I might as well go with a 2800 5s TP.
So the way I see it I will make a new nose built for a 4S system and try it.
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I am done with the NATS
Finished 5th with 1032 total score. Best flight at NATS was 536 my personal best as a matter of fact. This was mabe #15 patterns on the model. And we oly managed a crude setup at best. Battery usage is about 1350-1405mAh.
Weight is 58oz now with heavier power components and heavier tail.
Because low power consumption the door is open for a 4S 2800 witch will instantly shave 4.1oz lighter tails will open the door to a 52oz model.
It is all I have for now.
TDM,
Nicely done and what a great looking model. Congrats on finishing 5th in Advance while flying a model with very little time on it. It’s not easy to place that high in Advance because the pilots you are flying against are close to becoming experts already. If you look at the Advanced Trophy you will notice the names of some very good pilots and my friends (We all fought hard battles).
Mike Pratt (a.k.a. Mikey)
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Thanks Mikey
Some updates here worth noticing.
Flight:
I think I have worked out the slight hunting issue, it came from a rather stiffer hinge that also created some flight trimming (ghost problems). So I cleared the hinge from the epoxy and now it is free and smooth so the problem is gone. No hunting anymore.
I played with the control system to customize it to my preference, which is a soft center for easy to fly loops and flats and also I want that explosive corner this model is more than capable of achieving.
Development:
#2 is flying now. It tips the scale at 53oz with a more forward CG compared #1. So we might go back to the AXI and have a 51+oz model (AXI is some 40g lighter motor). Yes those weights are RTF with battery on board 6S2800 TP. #2 has a much lighter aft portion of the fuselage build with a much smoother outer surface that doesn't require filling and putty to fill in the grain. Also we have a lighter layout for the aft fuselage. It was 186g out of the mold compared with the 210g, add to that the fact that we have much less finishing to do we are in much better shape weight wise. That being said #1 even at a heavier weight is still a solid performer. If we a really fanatic we can have even more weight savings in the future plus more increase in stiffness but as is it is unbelievable so we are good for now.
More testing will come over the winter. After the next contest I will change the position of the landing gear to be able to accommodate larger props. After that I am trying the smaller batteries. That can potentially save another ounce or more.
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Out to practice.
I had 4 unused batteries from after the contest so I pulled over on my way home to practice a little. I am trying to videotape the flights to see what I do right or wrong and It seems that the first thing I need to learn is to place the camera in the right place. Oh yes and I learned that the pilot needs more work too.
https://www.youtube.com/watch?v=4IeCxAZIXWk&list=PLJ4i08zyYBcuWUraYfAqziZvle_zC0WCp&index=7&t=82s
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Out to practice.
I had 4 unused batteries from after the contest so I pulled over on my way home to practice a little. I am trying to videotape the flights to see what I do right or wrong and It seems that the first thing I need to learn is to place the camera in the right place. Oh yes and I learned that the pilot needs more work too.
LL~ LL~ LL~ We used to let the wind tell us where to fly, now it is the camera! I resemble that comment.
"and I learned that the pilot needs more work too." The camera will not lie to you. n1 Sometimes I wish mine would! I love the way your design locks coming out of a corner and seem to rotate on the C/G in the rounds and forward of it in the corners. Best of both worlds.
Ken
Ken
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I am still transitioning from flying style from the previous model to this one. And I am still getting used to the rate of turn on this one. It corners so easy and fast I have to retrain my reflexes and get used to going much deeper before I enter the corner.For sure I have more corner reserve to be gained. What i am not so sure of is how can I keep track of the model at that rate of turn. I was watching the triangle and the first two corners are tight and crisp and the third one softer so I have to go a little deeper in to that one. Trimming is still work in progress and I am constantly trying to improve the performance. I will try to up the flaps travel a little to gain more lift.
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I am still transitioning from flying style from the previous model to this one. And I am still getting used to the rate of turn on this one. It corners so easy and fast I have to retrain my reflexes and get used to going much deeper before I enter the corner.For sure I have more corner reserve to be gained. What i am not so sure of is how can I keep track of the model at that rate of turn. I was watching the triangle and the first two corners are tight and crisp and the third one softer so I have to go a little deeper in to that one. Trimming is still work in progress and I am constantly trying to improve the performance. I will try to up the flaps travel a little to gain more lift.
I am not sure that human reflexes, certainly at my age, are up to much more than a 10' corner. I know mine are comfortable at around 12' but I don't have what you have. I am also pretty sure that the human eye will have a problem telling them apart, assuming the judges are human. IMHO it is more those -0- bubble flats that rake in the points.
Ken
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I am not sure that human reflexes, certainly at my age, are up to much more than a 10' corner. I know mine are comfortable at around 12' but I don't have what you have. I am also pretty sure that the human eye will have a problem telling them apart, assuming the judges are human. IMHO it is more those -0- bubble flats that rake in the points.
Ken
How about things like badminton, pingpong etc. Or even FAI combat? Or playing some instrument? Human eye/reflexes/coordination is much better than what we use in stunt. L
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TDM,
Nicely done.
Can't loose sight of the fact your model is the first prototype.
Astonishing, by itself, just for that reason.
Could be an excellent contender just as it is.
A while back I did say, "YOU NAILED IT!!, with the design and engineering.
You'll be watched closely.
A good thing.
A very good thing.
Charles
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How about things like badminton, pingpong etc. Or even FAI combat? Or playing some instrument? Human eye/reflexes/coordination is much better than what we use in stunt. L
To do a 10' corner at a normal flying speed, you need to consciously give two exact control inputs in less than .15 SECONDS. That is 1/2 of the time it takes you to blink.
I am not saying you can't do it, I am saying that it is nearly impossible to tell which is which from 140' away. A 10' corner is a whole lot tighter than you think it is.
I have played sports where hand/eye is critical and I think we are close to the limits. Some more than others!
Ken
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Little update
I went flying yesterday. I was working on going very hard on turns and this bird is cornering like crazy and for me is a completely new experience. In the next flying practices I will try to set the response on the handle. I can wail on the model so much more than anything else I have ever flown before to the point that a change in flying stile is a necessity.
I had so much fun with it over the weekend. It is amazing in the air no question about it. I need a little more handle spacing and I need to soften the down side a little to even the response. In the air I can go as hard as I can and there is no stall very little slowing down and it just drives to the next corner effortlessly even on the top of the hourglass. What a beast it is in the air.
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So far so good no failures. I think I know why people have an issue with these types of ball links. They install them incorrectly. If you install them in one direction they can slip out and fail. However if you install then the opposite way it is impossible for them to come out even if the pressed in stuff comes off. So be mindful about how you install them. The color anodized part of the links has to be against the horn. I bet all the failure people are complaining about is because they mounted them in reverse. By the way these are built for cars that take a beating and not the light use we subject them for our purposes.
Hope it helps.
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Thanks
The only way this is going on the market is if i get 10 or more orders paid upfront so I can buy all the material and get it done. I tried to get to market something else, ended up with a lot of material on my hands and some 60% of commitments bailing out on me.
I know this will sound bis because is my baby per say, but for me jumping from a Twister-ish plane to a SV-12 was a big jump and moving from SV-ish models to Revolutions is another big jump. Twister to SV to Revolutions = Honda Accord to Ferrari to Bugatti Veyron. To me and Mark it is drastic and for sure significant step up.
I will share with you at the NATS if you want to try.
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I spent a week building this year model or so I thought.
The thing is we tried some techniques in an effort to do paint in the mold that yelled some porky parts and I had to punt and regroup. Paint in the mold might work with rubber stencils that are quite expensive so I will revert to paint after molding process. Most likely candidate is the use of water transfer stencils with clear on top.
The good news is that now we have a flawless outer surface void of imperfections and we do that without the use of clear 2 part stuff we tried to use at the beginning of the build. I am very happy with that result. It is all in the techniques.
Another thing new here is a new way that we use to position the spars in the fuselage and that was perfect. The fixture included a way to glue the landing gear in position too but it was lacking clearance in on e spot so it was not applicable in this case. I will fix that so next time around we are golden. Another fixture we started to use is for nose ring attach, and that worked perfectly. We now truly have interchangeable parts in our arsenal.
Every time we make a part it just gets better and easier compares to the last time around. I am missing a wing and a elevator and landing gear struts. The goal was to make a whole plane but it failed due to trying new stuff and having to reboot and start again and that ate the time. More important is that we made a lot of progress. But I am still bumbled out the job was not finished.
That is all I have new for now.
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Still interested in how much one of these bad boys would cost. Since it's electric, no need to paint. And take apart makes shipping easy. If it ends up around $500 or so, each, I think you have a winner. Might even be a winner at $750.
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Let's see here.
Carbon fiber 200$
Foam 100
7 days of 8-10hr work days plus machine time which adds to that time tally.
And sell them for 500-750. ??? Ill keep my day job. This bird is on par if not better than the Shark that sells as a kit for over 2000. HB~>
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Wouldn't it be sort of a good idea to build one from conventional materials, and see how it flies...that, before investing time and money in a manufacturing exercise?
The most popular kit. RTF or RTC models have some sort of contest-winning history connected to them.
That seems like a more sensible goal..at this point.
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Let's see here.
Carbon fiber 200$
Foam 100
7 days of 8-10hr work days plus machine time which adds to that time tally.
And sell them for 500-750. ??? Ill keep my day job. This bird is on par if not better than the Shark that sells as a kit for over 2000. HB~>
As I see it you have two markets. Those with enough money to buy whateverTracking they want and those that don't. If you can't make it under $500 then you only have one market. Price it at $3,000 and give test flights to anybody (qualified to fly such a plane) that is interested and see if there is a market. You might also consider licensing it to somebody that has the equipment to produce one. But before you do any of that, get whatever part of it you can patented/copyrighted.
I am not being critical here so don't take it wrong. How do you know that this plane outperforms the current top planes? Have you flown any of them and have any of the owners of these planes flown yours? When I came back into the sport all I had ever flown were top of the line .35 size ships. My first .46 ship was like nothing I had ever flown till I flew a .60 size and I knew I was in stunt heaven. In the group I fly with those .60 size ships are to them what the .35 ships were to me 40 years ago. Just be sure that what you are seeing as a vast improvement is not simply that you fly better with it. It is not a "Revolution" till someone that has been to the top of the mountain tells you that it flies better than what they are currently flying and I truly hope it does!
Ken
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I am not being critical here so don't take it wrong. How do you know that this plane outperforms the current top planes? Have you flown any of them and have any of the owners of these planes flown yours?
Just be sure that what you are seeing as a vast improvement is not simply that you fly better with it. It is not a "Revolution" till someone that has been to the top of the mountain tells you that it flies better than what they are currently flying and I truly hope it does!
Ken
I don't want to justify my conclusion because no matter what I say will be taken as bias, and that is normal. So if you come to the NATS you are welcome to try it and make up you own mind. Actually anyone at the NATS can try it, all you have to do is ask and you shall receive. You might want to bring a blank handle with you so you set the neutral to your liking.
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I don't want to justify my conclusion because no matter what I say will be taken as bias, and that is normal. So if you come to the NATS you are welcome to try it and make up you own mind. Actually anyone at the NATS can try it, all you have to do is ask and you shall receive. You might want to bring a blank handle with you so you set the neutral to your liking.
Right answer. Set a price and bring order forms. Sadly I will not make this year's Nats but I am going to ask Mike Scott (another avid electric flier) to give it a shot as soon as he has flown his last official.
Ken
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Back from the NATS
I had some time to fine tune the setup of the plane to my liking. Dave Fitzgerald and Derek Barry helped me with the setup when I was at the Triple Tree event and they opened my eyes to some trim details I was not aware of. So now that I had some time I managed to set up the plane just perfect. It was so much better than before to the point it was a new plane.
I set the turn rate to be equal on both sides and then I fine tune the corner to react to my imputes based on my flying style and I became one with the plane. This was the point where I said I am ready to receive coaching. Too bad that the weather did not agree with that. It was either 95+ and 100% humidity or same plus crazy wind. Anywise it was not practice time at all so I went in competition with what I knew. Yes my flying leaves a lot to be desired but it is mostly because of lack of coaching. Most of my maneuvers where flown with 40 degrees top elevation which in my eyes where 45 and I made many mistakes. Give me another 200 flights and I will turn that around. I the final day I decided to try new things and change the flying I was doing prior to that. Needless to say that was stupid and I threw the contest away.
Notably Mark crashed his model before official flights began Wednesday but it was just a flesh wound and we patched the tail and flew normally after that. He hit the ground upside down turned the model in normal flight. The motor ejected with spinner and the leftover prop and fell in the grass just outside the circle. His REovlutions continued and landed normally. That was eye opening that with aft CG and missing the 9oz of stuff in the nose (motor, spinner, prop, motor mount) the model was still flyable at that time "safety". And yes there was a loud bang. The only damage sustained was some scratches on the top of the fuse 3/4 of the top of the rudder crumpled and a scratch on the top of outboard wing tip. We fixed all that in an hour at the hotel glued the nose ring back in place and we where back in business.
I had to have fun with this repair so I drew this on the nose with a sharpie :) :o :(.
The best part was to share the models with some of the contestants. Three flew it Samantha Dany and one other, all flew in wind, some with a smile on their faces that never stopped some showing a poker face. "I can get used to this" was common response and from past this is the response I kind of get from anyone that picks up the handle. Sharing the plane was the highlight of my NATS and I totally enjoyed it.
I think this model is awesome in the wind. The line tension is not overwhelming at all and it pulls everywhere without sacrificing corner it noses out upwind adding some line tension there and the vice versa downwind taking line tension away so there is no excessive added line tension added during the wind compared to the line tension in calm conditions, there is some but it is just a little more it is rather uniform upwind and down wind and nothing that will pull the hand out of your socket.
It is time to start practice with a purpose, hopefully a coach, and create a routine. I need to iron out inconsistencies relax and find myself. I have a solid machine I can depend on and all I need is practice.
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Made a video on assembly. I was challenged on how fast i install the battery in the plane so I went a step farther and assembled the whole plane plus the battery.
Here is the result. A little under 3 minutes to put the whole plane together minus the lines and handle.
https://www.youtube.com/watch?v=jHQPTiL8hZM&list=PLJ4i08zyYBcuWUraYfAqziZvle_zC0WCp&index=9&t=0s
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Made a video on assembly. I was challenged on how fast i install the battery in the plane so I went a step farther and assembled the whole plane plus the battery.
Here is the result. A little under 3 minutes to put the whole plane together minus the lines and handle.
Looking at this video I am beginning to realize how special this ship is. y1
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Very impressive. I am assuming that the wing joint is about 1/2 - 1" deep? I would think you would need that much to keep the wings from flexing without a center spar. I have done the pocket thing on a sailplane years ago but it only stressed one direction. Do you reinforce the interior of the center section to stop stress cracks from forming? Never thought of having a removable nose. All in all - really cool.
Ken
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I'm as fortunate as can be because not only have I seen this model but I've handled it
Nothing short of a work of art and the craftsmanship, this kind of quality is only found on other planets.
Yes, I've seen TDM put the model through a few excellent patterns. Flies on rails is cutting it short, It's simply outstanding in every aspect of the pattern.
I noticed with the third corner of the triangle, sharp, turned on the money and no nervousness could be detected in the maneuver, especially in that third turn.
I hope to see the model fly this weekend.
I'll take photos this time.
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There are only two in existence right now. I ran out of materials on #3. So that one is work in progress. I am considering to use the fuselage from #3 and put the wings from #1 on the fuselage.
The attach pins stick out some 3/8 in on the wing and nose and the blade spar in the horizontal is one inch. There are hard points at the root of the wing that hold the lock in, they spread the load to the wing spar.
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I managed to crash the plane in to the flight box on landing. I was flying to the camera, and after take off the wind started to blow in my face during the maneuvers, so the whole flight is upwind. I pushed as far as I dared but after loosing it in the vertical eight two times that was it for me.
The stupid thing is that I forgot to mark the circle center so immediately after touch down the outboard wing hit the flight box :(.
Most of the damage was in the aft portion of the fuselage and landing gear part of it.
In the new plane a desired to have some changes made. I wanted to correct the ground clearance by placing the gear mount in the right place. I wanted to have a more forward CG position. I also wanted to be able to move the battery to adjust the CG further if it was needed. Because all of that the decision to replace the fuselage became obvious. Interchangeable parts make that an easy task too. The fuselage had already the wing and gear attach parts installed and all I had to do is to place the elevator spar in position and transfer the hardware over to the new fuselage. And the hardest thing to do was to find the stuff in the house to do it with, syringes glue etc and in some cases I had to improvise.
https://www.youtube.com/watch?v=OxihOyyuBIo&list=PLJ4i08zyYBcuWUraYfAqziZvle_zC0WCp&index=11&t=83s
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Knowing, and having experienced your talents,
It's fixable and you'll do a great job.
Great, soothing, video BTW.
Charles
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Charles the picture bellow is already fixed minus little paint.
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Charles the picture bellow is already fixed minus little paint.
TDM,
I kinda had a feeling that was the repaired model.
You're good.
Look no balsa!
Charles
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You are a braver man than me, I could see the wind was taking the model out of your comfort zone. I'm not sure I would have even subjected my ARF Nobler to the rest of the schedule.
It was interesting to watch another "Leftie" perform a reverse wingover. I position my body similar to yours. It's good to know it's my ability rather than anything I'm doing wrong is the cause of my problems.
TTFN
John
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Here it goes. The first test flights under the belt are done. I kept all the previous settings the same minus the CG which obviously moved forward. Flew 9x2min flights to get the speed back on target fine tune the flaps to get wings level and after that I started to adjust the CG. So far I have very good tracking an lock but I am hunting for a little more corner. Anywise I am happy with the results so far.
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Here it goes. The first test flights under the belt are done. I kept all the previous settings the same minus the CG which obviously moved forward. Flew 9x2min flights to get the speed back on target fine tune the flaps to get wings level and after that I started to adjust the CG. So far I have very good tracking an lock but I am hunting for a little more corner. Anywise I am happy with the results so far.
You may have not planned to fly the pattern upwind but it is not a bad idea to study what your plane does when you put it outside it's comfort zone. I thought I was the only one certifiably crazy but I guess I was wrong! Still, mark the center of the circle but rest assured you are not the first, nor the last to hit your flight box. I have done it twice.
Ken
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I have an orange cone in my flight box to mark the center.
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I am out practicing and fine tuning the repaired bird. I ended up moving the lead-outs forward after these flights. The line tension got much better on top after that. Lap time about 5.5 sec 5min 30sec and 1300mAh max back in the pack. Typical consumption is 1250mAh.
https://youtu.be/YSsoN6IMYis
https://youtu.be/vc5a7dYuq1E
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I put three flights in today. The goal was to get the turn rate equal as i had a little less inside turn compared to the outside turn. I extended the flaps pushrod and presto a perfect turn rate both ways, because the way the system works in my model this is the equivalent of shortening the flaps to elevator pushrod in a typical model. I got rid of that soft number 4 corner in the inside square and hour glass and the 3rd corner in triangle.
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About one week ago I flew in bumpy air, the model was fine but the turbulence was felt everywhere, so I decided to move the CG forward and it started to plow through the turbulence. For added safety margin i moved the CG a touch more forward and left it there. Yesterday I had a big flying day where I worked on fine tuning the model based on the new CG location. I cant remember how many 2 min flight I did but the thing is I did not stop till all the bugs where worked out and till I was happy, I think there where some 20 flights in all. After all that was taken care of for my enjoyment I burned 3 full flights that are equivalent to the best I have flown so far. I have better tracking more line tension equal turn inside and outside and a little but less corner now to be able to keep up with the model. I can dial in more corner any time if I feel like I want it or need it but for not this slower turn suits me just fine.
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About one week ago I flew in bumpy air, the model was fine but the turbulence was felt everywhere, so I decided to move the CG forward and it started to plow through the turbulence. For added safety margin i moved the CG a touch more forward and left it there. Yesterday I had a big flying day where I worked on fine tuning the model based on the new CG location. I cant remember how many 2 min flight I did but the thing is I did not stop till all the bugs where worked out and till I was happy, I think there where some 20 flights in all. After all that was taken care of for my enjoyment I burned 3 full flights that are equivalent to the best I have flown so far. I have better tracking more line tension equal turn inside and outside and a little but less corner now to be able to keep up with the model. I can dial in more corner any time if I feel like I want it or need it but for not this slower turn suits me just fine.
Don't you just love the three flights to a battery trim! How tight are your corners now? One of the things that I liked about your plane was the corners.
Ken
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Ken I actually added some elevator travel to regain the corner that was there beforehand. I can add more but I don’t need it right now. My buddy flies with CG almost 3/4 further forward compared to what I do and he also has corner to spare. When we need more we just dial in and add some. 🙂
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Ken I actually added some elevator travel to regain the corner that was there beforehand. I can add more but I don’t need it right now. My buddy flies with CG almost 3/4 further forward compared to what I do and he also has corner to spare. When we need more we just dial in and add some. 🙂
Kudos.
I know how hard you work.
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I finally did it. I worked hard to get in the pool of hungry angry sharks now. What was going through my head ???
Open class next year for me.
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Congratulations!
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Nice job!
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Way to go!
You certainly earned it.
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You did great!!!!! Nice job! Great flying plane. Thanks for the flight.
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I almost forgot to add my Congratulations!
Ken
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Congratulation on you performance at the Nats.
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Thanks gentleman for the encouragement. Next year goal is top 20 in open. I want to fly Friday. Open AKA bowl of angry hungry sharks.
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Thanks gentleman for the encouragement. Next year goal is top 20 in open. I want to fly Friday. Open AKA bowl of angry hungry sharks.
TDM,
Way to go! I'm "Thunderstruck!"
https://www.youtube.com/watch?v=v2AC41dglnM
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Every time I fly this bird I fall in love with it over and over again. Yesterday it was a very nice day outside so I went out to put in some flights. Only if I could fly to it's potential that would be great indeed.
So it started with the insides a little loose on the lines so I tweaked the flaps and after that it was all fun. I am glad that i have made a video of the flights because I can see some bugs in my flying which will give me something to do in the next sessions. I need some work on the wing over in particular the second pass and the vertical eight, the rest looked pretty decent.
https://youtu.be/Ze3mS55P-vk
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TDM,
Congratulation on winning the Advance Trophy, great job. There is a funny story that goes with that trophy. At that point in time, there was not a Perpetual Trophy for winning Advance at the Nat’s. When John Davis approached me after he won Advance and said we should put up the funds for a Trophy and donate this to AMA to be award it to the Nat’s Advance winner every year. I ordered the Trophy and spent many long evenings talking to John about it, so we decided to include all the previous winner on the Trophy (and have their names listed). John and myself were homered to do so, just a little way to pay it forward for such a fine event.
Mike Pratt
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So I am back from the worlds competition n Poland. Revolutions has received great reviews from just about everyone there. Some have even flown the model after the competition was over, I might add with a big smile on their faces. The common denominator comment was "amazing". First they took notice of the carbon outer skin, then they look at the take apart features, after that when I showed them the control system their jaws dropped. Lastly i took a wing and the nose from the spare model and fitted it to the main model and demonstrated interchangeable parts at which point their mind just blew up.
I ended up mid pack with some very dubious low scores from some judges, and some of my scores were quite up there with the best of them.
But honestly I wasn't well prepared for this kind of level of competition. The model only had maybe 30 flight on it when I started to compete with it and I was constantly getting used to new setups as I was remedying thing I didn't like about it (mainly uneven turn which was a handle adjustment issue). This is an issue that I am still working on.
https://youtu.be/gCv3gXocZAc
https://youtu.be/-viEu4nkBpk
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Truely next level technology.
Motorman 8)