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Building Tips and technical articles. => Building techniques => Topic started by: Ken Culbertson on December 26, 2023, 02:29:46 PM
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I built Endgame as my last PA ship that I would fly till one of us died. Well, it got murdered in a house fire, so I built Endgame II to take its place. It flew OK but I have always wanted to try a canard, so I added one and II became Endgame III. III is an unqualified success but I am still above ground and I have always wanted a twin PA. I had one of those, I think it was Sterling, P-38's with two Fox 15's. Ever try and get two Fox 15's to start at the same time? It was a poor performer but the sound, ah the sound. Well, after seeing Frank McMillen's twin which I commented on in the Endgame III thread it is official. What appears to be the first twin canard is on the worktable. There will be enough changes to give it a new name but it still has the same roots so it will be IV. Aside from the twin setup it will have a 1" longer nose to give the canard more leverage and get it away from the props. It will be totally in clean air so it should be even more effective. One thing I noticed on III was that the large elevator/stab was too far back with the addition of the canard. The elevator became way too sensitive along with the logarithmic. Great for corners but you have to fly it in-between them too! So, I am moving it from 19 1/2 to 18 1/4. I am switching airfoils from the Geo-Bolt to Geo-XL. I used it on my Trifecta and the thinner wing seem to penetrate better and still have gobs of lift. The last change I am making is going to inline. I have no experience with this one so I am relying on those who have gone before to be right when they say that a twin electric should be inline. I will post drawings/plans when they are finished for any and all to laugh at. All suggestions will be appreciated.
Things that I have to decide on include the logarithmic. III has a tendency to "snap" in a turn. What I mean is that if I need to increase my turn rate in a round just a little it seems to overreact and "snap" making me miss the bottom. I attribute this to having the logarithmic set to transition too soon probably from adding the canard. I can't change the logarithmic to fix it on III without replacing it, which I may do, but I can correct in on IV. The question becomes, do I need a logarithmic at all with a canard? III will turn as tight a corner as I want to fly and keep the wing in one piece. I have yet to stall it in a turn or attempt a "bang" corner. I have done maneuvers with corners so tight as to be annoying to those watching - without any stall. Never thought that was possible.
I have another question but I will make it in a separate post, so my ramblings don't clog up Sparky's drive.
Ken
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This is the question. Do all of the horn, pushrod configurations have the same effect. Ignore the logarithmic, it is only there because it reverses the direction of the elevator pushrod. I really need to use #2. All angles are 90 degrees to the pushrod.
Ken
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To me I built the Sarpolis canard to prove to prove to myself and others that they will fly and do a pattern. I have witnesses to that when the LA 40 is set right. So I constructed my version of a Ringmaster canard without the rear moving surface The canard has no control of the plane until it gets moving through the air. I had an LA 25 for power. Had to extend the gear as far forward as I could get it so the plane would not nose over. Once it got moving and control of the canard started it flew better than I fly. I learned that is why the Sarpolis canard had the rear moving surface. It was to keep the nose up until some speed was obtained. Yes it was strange to look at while flying. When I get to rebuilding the Ringmaster canard it will get a moving tail surface. Works like an elevator.
By the way searched for canards on the internet. A lot of good reading and why people who have built the Bert Rutan canards had to learn a few things. They don't handle like a Cessna or Piper Cub. D>K
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This is the question. Do all of the horn, pushrod configurations have the same effect. I really need to use #2. All angles are 90 degrees.
Ken
Number 1 would be interesting to watch as flaps turn to wrong direction compared to elevator. L
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That was what sketching things in a hurry will do. I was trying to illustrate the direction with a logarithmic and left that tiny bit of information out. I will revise the illustration! Thanks for pointing that out. What about the other two?
Ken
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Construction underway. First order of business is always the stab with me. Then I make the fuselage. Last, the wing. Just me. I like cockpit detail so I make the fuselage with a removable cockpit module so that I can work on it whenever I get the urge then glue it in at the last minute, of make it a hatch.
Some pictures. Stab is using pocket hinges from Mark Wood's skunkworks. They are recessed 1/8" into the TE. The TE is 1/2" thick and airfoiled from a .025 radius LE to a 5/16" TE. 1/32" thicker than the elevator Top and Bottom. Used wire to protect the LE. The elevator is 1/4" tapered to 1/8" with full span 1/4" fences on the TE.
Fuselage will have "X" bracing in place of formers. Sides, top, bottom and center. Remember how solid those old Comet kits were. Without all that pounding from an IC I think this construction shows promise.
More to come.
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Got the aft fuselage framed. The 1 1/6 sides are fine. The twist capability is next to nil and I don't even have the bottom framing. That goes on after the pushrod is in. 53 grams including the CF doublers in the unframed nose. It is going to be a twin so all that will go in the nose is the battery and timer and perhaps the ESC's. I haven't decided if I am putting them in nose or the wing.
Ken
For what it is worth. That .3mm CF Sheet is fantastic. It cuts with scissors and is stronger and lighter than plywoood. The wing LE is reinforced for the pull test. I am going to use .5mm for doublers in the motor nacelles.
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One step closer. I have molded the top aft fuselage. 59 grams as it sits. Seems a bit light since it only weight 53 grams before the top shell. I will never use blocks again, that is for sure! Still trying to figure out where to put the ESC's. In the center with three long motor wires and short battery wires or in the nacelles with short motor wires and long battery leads.
I am using BadAss 2320-850 motors on a 2800mah 6s battery, If I cheat and use 13gauge wire I should be OK either way. I have a question on the long motor wires if anybody knows. Should I twist them so that there is not a long stretch with them straight? I suspect it doesn't matter.
Ken
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Nice project!! An ESC does not like twisted motor wires. I would use the motor wires as supplied.
Regards,
Wolfgang
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Nice project!! An ESC does not like twisted motor wires. I would use the motor wires as supplied.
Regards,
Wolfgang
Thanks for following the thread. You were the inspiration for my Canard. IMHO it has been a huge success. I hope you have had a chance to see it in action. If not here is a link.
https://www.youtube.com/watch?v=VB3xaXZB8G0&t=6s
This was only the 4th or 5th flight on the plane so it is still *way* out of trim. The overall pattern is still a bit rough but watch the corners! These are about 1/2 the tightest it will turn. It will do a 90 degree turn in about 2 plane lengths - scarry. Unfortunately, it has a stock Geo-Bolt wing and I don't think at 68oz, the center section is strong enough to take that kind of corner over time. The only design issue that I encountered was a tendency to self-tighten in the rounds. I got that trimmed out later by adjusting the flap elevator ratios. The III has a logarithmic flap horn and it was allowing too much elevator in the rounds. I am not going to use one in IV. Don't need it with the canard.
I am going to stiffen the center section on the new one. Partly because it is weak on the Geo-XL I am using in this build but also because it will be a twin and will need the extra support.
Ken
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I think that I read somewhere that there is a technical reason to always use short battery wires and long motor wires? Rather than vice versa.
Steve
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I think that I read somewhere that there is a technical reason to always use short battery wires and long motor wires? Rather than vice versa.
Steve
You are right. I got that answered in another thread. Thanks!
Ken
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My Phoenix Edge ESC´s work with 50 cm battery leads, Maybe cheaper ESC´s need shorter battery leads, because of their smaller input capacitor.
On the top horizontal of the square eights I noticed sudden RPM increase. Do you use the Circuit Flyer timer? That uses a gyro to influence the RPM when turning, I suppose.
Maybe you should test my new timer, which does not use the gyro, but only keeps the line pull constant....
Best regards,
Wolfgang
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My Phoenix Edge ESC´s work with 50 cm battery leads, Maybe cheaper ESC´s need shorter battery leads, because of their smaller input capacitor.
On the top horizontal of the square eights I noticed sudden RPM increase. Do you use the Circuit Flyer timer? That uses a gyro to influence the RPM when turning, I suppose.
Maybe you should test my new timer, which does not use the gyro, but only keeps the line pull constant....
Best regards,
Wolfgang
What is in that plane is a BadAss 3520-750, A Jeti Spin 66 and a Fiorotti timer. You are correct, there is a small boost there when the g-force of the Fiorotti timer kicks in. It is actually a signal to me that I made the maneuver big enough. I tend to fly small, and I would not get the boost under 45. It is really noticeable in the top half of the V8 and is also a signal that I have my intersection at 45. It stays on for all of the overhead 8 unless I dip down too much. It is a bit tricky to get set right and I have mine set higher than most because of the really strange winds we get over 45 degrees. You can see in the background of the video a train track on a levy. When the wind is from anywhere near over those tracks, we get serious turbulence over 45. Having the extra RPM's helps. I guess my transition to electric is complete since I no longer pay any attention to the sound the motor is putting out in flight. ::)
It is going to be interesting to see how the Canard responds in clean air. Both props on the twin will be behind it.
Ken
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What better use can there be for a cheap Chinese spinner than a radar dome doubling as a nose weight box! Nose is shaping up nicely. I am having to learn a new skill set to build with everything molded. Al would be proud!
Tomorrow I build the Canard drive. All that stuff needs to be in place before I can finish up the nose. I am itching to start on the cockpit interior. On the original I used wheel collars glued to the Canard to allow it to slide off of a 5mm carbon fiber rod and therefore be adjustable. It worked great for about 2 adjustments then the CF rod started slipping. So that was replaced with an arrow shaft that was fixed. Both were anchored to the wing with ball bearings Epoxied to the fuselage. My dream of having an extra surface to trim wings level went "poof".
Ken
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Ken, Burt Rutan would be proud of you.
Steve
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I am about to order the ESC's and motors from Russel at Okie. I will be using 2 BadAss 2320-820's and I hope the Jeti Spin 33 ESC. Problem is that the Spin 33 is only rated for a 5s battery but it is rated for 26 volts which is over 6s. I have plenty of 5s 2800 batteries so that would be a good thing but I question if the 5s has enough head room for 2 motors. I am having fun composing this plane. I like to do things in random order. Lots of subassemblies. Right now I am building out the nose. I will make the entire front top removable so that I can work on it and glue it on after the wing is installed. Next step will be the bottom hatch. That will be the tough one. Need a mount for the nose gear. First trike I have built since the 60's.
Ken
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Progress is slow when you are making the cool stuff. Never built using all 1/16. It is scary but the end result is just as stiff and so light. I am finding that .3mm CF Sheet makes a wonderful substitute for plywood and bass. First it is lighter and second it makes you fingers itch for days after sanding it. Here are some nose and fuselage shots and my combination nose wheel and battery box. Matt - The Nose wheel is adjustable.
Ken
Added 1/2 of the Canard. Composing this nose is fun. Everything is a first! Camera sure does distort things. The tips on the Canard are swept back at 15 degrees. Looks opposite in the pix.
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The most difficult thing in making a new plane is making the second elevator, flap, or in my case canard. They do look better with two. The motors, esc and timer came today. Haven't laid it all out yet. I am still trying to place the ESC's where they will cool properly and not be a pain to service. One question I have not answered to my satisfaction is whether they need to be separated and if so how far. I will be using a 5s 2800 battery so I can get away with 18 gauge wire which matters since there will be 9' of it from the ESC to the motors! (3@motor x 18"). "Bing" tells me that the wire will weigh 10 ounces - OUCH!. I am still shooting for a "start the timer" weight under 70 oz. I made a decision to go with a Geo-XL wing vs the Geo-Bolt I used on II & III because folks who have been at the electric game longer than I have convinced me that I didn't need the thickness of the GBolt. I sure hope they are right!
Some Pix of the "fun" stuff I have been working on. I have found that if I build the wing first it wants to fly and I do a hurry up on the fuselage and stab. So, I save the wing for last.
The adjustable logarithmic is in the works. I will skip the cam rudder. With the separate settings in the Fiorotti timer for each motor I will not have any use for it. The one fear I have with a twin is an inboard only motor failure. Have any of you adventurous types ever tried flying on just the outboard?
One of the things I had to do with III was restrict the bellcrank to 60 degrees to keep it out of the way of the canard pushrod. I am going to put in a 5" bellcrank to give me back some of the leadout movement I lost plus the extra leverage doesn't hurt. The 5" will also require some very smooth leadout guides.
Ken
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The new toys came in today from Okie. Spin33 Esc's, Badass 2320-820 motors (they are so cute), and a Fiorotti New Timer. I am still planning to put the ESC's in the fuselage with long motor wires. They are 16 gauge so it won't be too heavy. The Spin documentation says to not extend the motor wires which is opposite of what I hear from the forum. Props will start with 10 x 5 BadAss two blades.
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Started work on the nacelles. Got the props in pair of BadAxx 10 x 5's opposite rotation. That little motor sure is cute. I don't see how only two of these little things can power a 65oz plane but those who know far more than I do say the will. y1
Ken
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Nacelles done. My style is more like composing than building so making two of anything gets dicey. At least they came out looking similar! Anybody seen my other spinner? 20grams each w/o motors at this point. Once they are fitted to the wing I will glass them. Construction is 100% Balsa except for the CF reinforced engine mount. I have decided to put the ESC's in the fuselage. Motor wires will run through a smoothie straw built into the wing.
Ken
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Looks like the bots have lightened up. Only 70000+ reads. Here is the proposed power train. I have never wired a twin so if anything anybody sees that looks strange please post your concerns. Only one I have is placement of the ESC's. Some electronic components do not like to be next to each other. I have no clue if this is true for an ESC. Probably not. The rest is just making up the wiring so that you can get it out later if necessary. I do have a question on the ON/Off switch. Can one switch serve both ESC's or should I have 2. I assume one is OK.
One thing that saddens me. I have always used the 2nd ESC port on the Fiorotti timer as a programming port that I route to a receptacle on the side of the plane. I don't have to unhook anything, just plug in the Jeti-box to change settings on the timer. Now I have to plan on an easy to remove hatch for programming. Boo!
Soon as I have the whole thing wired I am going to bench run to see what it does. Being able to run the motors without a prop - priceless.
Oh, Plan "B" is to put the ESC's on edge to separate them more if necessary. I want to keep them side by side in the center to keep the wires to each motor the same length.
Ken
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Lots of changes to the electronics wiring thanks to some of our more experienced twin folks. Got the full shape of the fuselage finally with the control horn access hatch finished and most of the nose hatch. The 1st 12" of the bottom is a hatch giving me access to all of the goodies. I think that the nose looks a bit too much like a Sturgeon. I think I will reshape it more like a F-86. Covering is going to be Polyspan and laminating film. Can't paint much in the office. I really would like to do this in Dope, but it isn't going to happen.
Almost time to build the wing. Soon as the nose is done, the electronics positioned, the stab & rudder mounted. Wing is always last.
ken
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Composing an airplane can cause you to say things that are not acceptable in polite society.
Today was wiring day and I was able to get everything crammed into the nose, but the only way to fit the timer and still have access was to turn it with the pins pointing straight down. You can't bury the thing because you have to be able to unhook the timer to program the ESC's. With the six motor wires going into the wing the ESC has to be turned around and the leads to the battery box and the "Y" splitters have to go in the front where there is no room then there is that darn arming plug. Has to go in front of the positive splitter which meant another 6" of 14g wire. So instead of having it tucked neatly near the wing joint it will stick out like a woodpecker under the canopy. Either that or 14" of wire. Maybe I will shape the plug to look like an air-air refueling port. I had to use more bullets than a John Wick movie just so that I could take it apart later. With the wiring all in place it was time to check the top and bottom "blocks" to see what it looked like enclosed. Timer on the bottom, arming plug on the top didn't clear, not even close. So we now have a fake cannon blister to cover the timer leads and the pilot's left console is now 1/4" up. It was either that or amputate his left arm. Having the Canard's pushrod run smack down the center of the nose creates some serious design issues! I guess that is the price you pay for designing your own.
Reshaped the nose more like a F-86D. Not exact but close. All of the pieces are "finished" now except the wing. 34.89 oz with everything, motors, battery, esc's, timer. All that is left is the rudder, wing and wheels. I guess I can pull that off with about 15oz which puts me at 50oz. Finish will be a first for me. SLC over polyspan with a military paint scheme of some sort. I am optimistic that I can keep it under 60 which will be 10oz lighter that the single motor Endgame III.
If you are a "tinkerer" like I am you always come up with a better way just about the time you finish a component and that is why we never stop building and rebuilding even when we don't need any more planes!
Ken
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If you are a "tinkerer" like I am you always come up with a better way just about the time you finish a component and that is why we never stop building and rebuilding even when we don't need any more planes!
Ken
Rule 23: If you are not satisfied with the way things are coming out, don't fix it now. Wait till tomorrow so that you can worry about it all night. I had hooked up the battery to the splitters using a T-60. It really didn't fit and made the battery wires too short. So, after several hours of rationalizing how it would be OK, I went home. Today I took the wire cutters to the T-60 before I had a chance to back out. Replaced with bullets and everything fits. After all a T-60 is just two bullets in a pretty yellow wrapper. Raised the console so that the arming plug fits and finished the fake gun port to cover the timer. All that is left for the wiring is to shorten the timer cables. One thing I have noticed. Using Carbon Fiber in places you need to sand sure does make the plane look dirty!
Ken
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Everything excellent! Only the leading edge of the canard looks a little too sharp to me.
Regards,
Wolfgang
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Everything excellent! Only the leading edge of the canard looks a little too sharp to me.
Regards,
Wolfgang
Interesting that you mentioned that. Endgame III had a total of 4 Canards before I settled on this one. 1 & 2 had 1/16" radius LE and were 1/2" thick at the high point of a 3" chord and 5" span(each). They were independently adjustable, theory being that I could use them for trim. On 3, I extended the chord to 4" and span by 1" on each side and thinned them to 3/8" fixed. Having them adjustable didn't help anything. On 4 I added another 1/2" to the span and sharpened the LE to a 1/32" radius. This is what I am flying now on III and I copied it for the twin. The canards in the picture are unfinished. I have a CF strip imbedded in the LE which will be sanded to the 1/32 radius. I use .025 wire for the LE of the stab which is quite sharp but not 'razor' like some use. I studied a lot of the jet canards and most had sharp LE's. I am in uncharted waters with this one since it will be in front of the props in clean air. I won't know how it will react till I fly it, butterfly's are being put on standby!
I have had to dial back the corners on Endgame III. It has a stock geo-bolt wing which is not as strong in the center section as I would like for the turns it is capable of. I moved the CG forward 1" and changed the ratios on the controls to 20-20-30 from 15-30-40 maximum deflection. That calmed it down enough that I don't fear folding the wing anymore. Tight corners are creeping back into the AMA pattern, but they are still not anything like you fly in F2B. The new ship will have a wing capable of an 8' corner without breaking. One thing I do not want compromised is the ease that I can do sharp turns with less line tension. The canard takes so much pressure off of the flaps that I no longer worry about making the turns in the hourglass and overhead 8 with the reduced line tension. Even in a strong wind I get the deflection necessary to prevent sagging with very little line tension. Being able to fly an hourglass with the last corner as tight as the first is worth the effort all by itself.
Cheers - Ken
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Subsonic and in clean air I would use a NACA 0009 :-)
Regards,
Wolfgang
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Subsonic and in clean air I would use a NACA 0009 :-)
Regards,
Wolfgang
That is Pretty close to what I have. I have rarely, since my FF days used the NACA numbers. I use the "That Looks Good" table instead. My LE is a bit sharper but negotiable. I will round the LE to a 1/16 radius. I just love sanding CF. Fingers itch for weeks even if I wear gloves!
Ken
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Thought it would be worth posting what this beast will look like. I drew this up do that I could plan panel lines. I settled on SLC over polyspan for the finish base after a successful test on the canards. Everything else on this plane is a first for me, why not the finish!
Ken
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I think I found out why the high count. I just did a search for Endgame IV on Bing. My thread was in the top 50 out of 800,000 returns. Endgame 4 is a popular computer game. The AI probably sees it as the same thing. Up to 90,000 now. I hope they all don't build a stabalator canard! LL~
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Made the wing spars today and cut the right wing ribs. Those Warren Truss ribs sure are long! It's my first. Had to make a stripper to cut the spars. 2@ 1/8" x 1/4" strips making a sandwich with a .3mm CF strip of carbon fiber plate in the center (no mayonnaise). What is so cool about the carbon fiber plate is that you can cut it accurately with scissors. I figured with the motors on the wing and tricycle landing gear, having a beefed-up spar was not going to hurt.
I will ask it here just for grins since only bots seem to be reading this. How does one mount wing gear in a Warren Truss wing?
Ken
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My first Lost Foam Warren Truss wing is out of the jig! Have to complement Bob Hunt on making wing building easy. Found a good use for Wynn Paul's books when I am not reading them. The hard part was locating a place to put wing gear for a tricycle setup in that wing. Think I found it. The nacelles are going to attach on one of the two half rib sets so I am going to make a .5mm carbon fiber mount for the gear there. 5" bellcrank and flap mechanism should be here next week. Once the wing is built I go into "wanna fly it" mode! LL~
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Control box mounted and pushrods made up. So far so good. Elevator gives me 40 degrees in both directions with equal movement of the logarithmic horn. Next up will be the inboard wing.
Ken
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Controls tested and set aside till I get the wing installed. The 5" bellcrank worked perfectly. I have it set to give me full elevator with 1 3/4" of leadout travel which matches my other planes. Flaps and Canard max out at 20 degrees, elevator at 35. All are adjustable. Finished covering the stab and roughed in the recessed flap insert. Normally it would be a 1/32" molded insert but I found that smoothie straws are the perfect size and lighter that the balsa.
Ken
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Normally it would be a 1/32" molded insert but I found that smoothie straws are the perfect size and lighter that the balsa.
Ken
...and much more colorful! Nicely done.
Don
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One more subassembly nearing ready for the fuselage. The 5" bellcrank saves a complete full rib of shear web over the 4". I will be able to run CF out to the Nacelles and not hit the controls. I am using .3mm Carbon Fiber over the 1/16" balsa for the webbing. The Geo-XL wing center section was not designed to handle the weight of the motors and wing gear so I am reinforcing it using a lot of thin CF.
Ken
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Finally got he wing framed. Bellcrank and landing gear Monday. Thought it was time to put it together for a test fit. Pretty close, needs some work on the nacelles. Right about now I am cursing Bob for getting me into this but seeing it together has rejuvenated me!
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After reading a lot and listening to a lot of recommendations I have decided, and installed, a DPST switch to turn on both ESC's from one switch. I got some telling me to wire both switches to on and just use the Arming Plug, powering one from the switch and leaving the other one open, to having a switch for both. I liked the last one so it now has both ESC powered and the power lead on the 2nd BEC cut. I don't like the idea of the arming plug powering up the ESCs. I always insert it with the switches off.
Ken
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Wing is getting fitted out. Center spar reinforcement assembled. Consists of two laminations of .03 CF Plate over a 1/8" balsa core. This is my new plywood. Considerably stronger Bellcrenk pivot wire (1/8") goes through the center. Plumbing for the motor power cables added and cut the openings for the canard pushrod. Landing gear mounts next. Todays progress was interrupted by the wall mounted hook to hang Endgame III broke and THUD she fell three feet. Saved by the collett. It slipped and let the spinner absorb the shock. Aside from a broken battery limit - no damage!
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Mounted the flap control box and bellcrank. Works great. Absolutely no binding anywhere. Now I have a question. I hesitate to ask it here because I don't think anybody reads the build threads if they are in the building forum but here goes anyway. I have to have trike gear for the twin and I need to place the rear wheels at about 1" behind the CG. I have no clue where the CG should go on a GEO-XL airfoil. I know a million other factors play into the exact position but if I can at least get a ballpark I can bend some wire.
Ken
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Don’t forget, the canard will require moving the CG forward of a normal configuration.
Make a simple sheet scaled down model and tie some string to the wingtip. Swing it around to get some speed over the surfaces.
Move the CG aft till it flops around and you have discovered the limits. I would guess that 10% chord aft of that would be a good starting place.
Actually, my guess is that airfoil has little to do with stability on a symmetrical airfoil wing. Tail and canard area/moments are the controlling factors. 🤠
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Don’t forget, the canard will require moving the CG forward of a normal configuration.
Endgame III eventually had the CG 3/4" forward of it's non-canard but same airframe Endgame II (is there no end to Endgames? Maybe I need a new name!) With the twin canard I am so far out in uncharted waters I can't see the shore anymore. How does double the airflow over the center of the wings with the canard in clean air affect lift is a big one. As far as I can tell, there is not another example of a "stabilator" canard that I can pester the designer for ideas. Had I thought about it more I probably should have gone to a "stabilator" tail as well. Ball links and fiber pushrods make them possible. I tried one many years ago but slop in the controls made it difficult to track properly (nice corners).
My only concern with the CG at this point is where to mount the wing wheels. Two far forward and takeoff and landing get funky, two far aft and I need nose weight. The main spar on the Geo-XL wing (Bob Hunt's Lost Foam Version) appears to be close to where I would put the CG for the initial flight. I will put the main gear 1" behind that and if she doesn't fall on her butt - fly it. Two laps and a loop will tell me where the CG needs to be for trimming.
Thanks for the reply - Ken
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Back to the build. Assembled the main components and resized the pushrods. Found that the Flap gizmo was not giving me enough elevator so I shortened the distance between the levers and now I get 40 degrees with 1 1/2" leadout movement. 40 degrees on a canard is huge so I should be OK even though I had intended my stops to be at 1 1/4" movement each direction. Controls are so loose and slop free with the new ball links Bob Hunt suggested.
I did have to re-do the pushrods to have more thread exposed. These links have about a 1/8" recess before the threads make contact - better but if you have trimmed for the DuBro's you are too short!
Added 5/16" cap strips and wingtips glued on (they fit, imagine that). As soon as I get the gear mounts done the wing gets mounted and I can finally start beefing up the aft wing/fuselage joint and covering up all the false starts that come from composing an airplane vs building from plans HB~>
Ken
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Need to test the controls with all parts installed so I am taking a side trip to build the flaps. I am using the European / Sparkey style flap hinges except I am making them removable via a pull wire. With this type of hinge it is even more important that the flap horns are exactly on the same line as the hinge pivots. For that reason they are mounted using two hinge posts drilled out to match the brass bushings on both sides. The pictures show the construction of the flap LE with the wire tunnel. I use .025 wire for the hinge pivot and each hinge is accompanied by two 1/16" aluminum bushings, one on each side and one in the center of the post. i use a 3/32" drill to bevel the inside of the bushing openings so that there are no flats for the hinge wire to catch on and I sharpen the wire end to a dull "pencil point" shape so that it can be inserted at the wingtip and pass without obstruction through all 5 hinges. In forming this CA glue is not your friend. I swear that stuff has tracking capabilities and is trained to find a path to whatever place you do not want it to go or your finger. Bottom line, I wasted three bushings and 6" of wire just on the outboard flap. Once the bushings are in, alligned and the glue is cured, glue the top 1/8" strip on using slow cure CA, (it does not have trackers). Now run the wire in and out enough times that you are comfortable it will come out after you have applied that 20 point finish. (in my case 15 point) and add a 5/16" .3mm Carbon Fiber cap to the back of the LE. Now you can cut out the slots for the hinges without breaking things too much.
5/16" cap strips added to the wing and it is ready to install as soon as the controls with flaps are tested.
This is the 1st plane I have built since the 80's that will not have a CAM rudder. I have been assured that the rpm differential capability of the new Fiorotti timer will make it unnecessary. With IC I would be at the "screw the finish - let's go fly it" stage of a very long build but, with electric I don't even schedule the finish till after I have flown it! Life is good (as long as I can still build and fly!)
Ken
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Made a new set of flap horns when I found that the dogleg ones from Russel interfered with the logarithmic. The good part is that the logarithmic tray mounts to the back of the wing so that every part of the control system is accessible for fine tuning. Most of today was spend making the new horns after wasting half of the day trying to make the old ones work. Most of tomorrow will be spent recovering from the brain fart of the century. When I decoded to make Endgame IV I took my "plans" from Endgame III and traced them. One of the changes I made was to put the horn for the canard on the outboard inner side of the fuselage pointing down so that it would be accessible through the nose hatch and I could use a standard horn. For this I had to attach the pushrod to the opposite side of the bellcrank from the flap pushrod. After some discussions with Bob Hunt about twins I decided to jump the shark and go full inline. So I lowered the canard to the centerline but now the horn was too long to be on the bottom. The canard doesn't move much. I have about 3/4" up and down at the TE of the canard. That equates to about 10 degrees. I get that with the bellcrank hole at 7/16" and the "horn" for the canard at 1 1/8". It is adjustable to give me as much as 20 degrees deflection if I want but I doubt I will.
No biggie, plenty of room on the top. That was three months ago. Today, after making the new flap horns, I hook it all up and marvel at how free and smooth all it is. (Thanks Bob, those ball links are fantastic). Then it hit me, when the flaps went down, the Canard went up. Sh.......t. The Canard pushrod was on the wrong side. The main spar cutouts are cleared for the pushrod to be on the outside of the pivot. Now they are on the inside. One more hole in the main spar. Thankfully I used CF webbing out to the nacelles. Ok, the good news is that the canard pushrod is now straight down the nose center. The bad news is that the tunnel for it is still angled for the outboard position. and the Cockpit interior is built to hide that tunnel.
The beauty of the hobby to me is that I get just as much enjoyment from building as I do flying and I love to tinker with things.
Ken
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Built the TE flap tunnel and mounted the first flap. When I use imbedded flaps, I use a technique that insures a "perfect" fit. First I sand the flap to have a smooth 1/4" radius on the LE. Next, using a sandpaper covered dowel I sand the radius into the wing TE. Next, I mold a piece of 1/32 around a 1/4" dowel so that it is just over 1/2 the diameter and set it aside while I bush the barrel hinges. I use 1/16" aluminum or brass tubing for the bushings. Drill the holes in the hinges and push the tubing through the hole to about 1/8" . This is to keep glue out of the hinge. Run a bead of slow cure around both sides and work the tubing back and forth to get as much flue as you can in the hinge hole. When it sets, cut off the excess with a razor saw. I file the hinges flat then I take a 1/16" sharp drill in a finger drill and bevel the insides of the bushing just like I did on the guide. With the wire sharpened and all of the guides and bushings beveled, the wire will slide in and out effortlessly till you get tired of taking the flap off.
Put all of the hinges onto the flap using the hinge wire then take the molded TE and cut out the little squares for the hinges. Wet some 1/32 strips to act as spacers for mounting the flap. The spacers go one each between the hinges the flap LE. With the molded TE up against the flap with the spacers between them and the hinge legs through the LE, start the hinges i their holes them push the flap up against the TE as hard as you can. This will seat the hinges in their blocks and form the gap between the wing and flap in the tunnel. Now, with pressure still on the flap glue the tunnel to the wing TE by running a bead of thin CA along the seams. Pull the wire out glue the hinge. I poke a tiny hole in the sheeting then stick a glue tube tip into the hole and bathe it with CA.
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Mounted the flap control box and bellcrank. Works great. Absolutely no binding anywhere. Now I have a question. I hesitate to ask it here because I don't think anybody reads the build threads if they are in the building forum but here goes anyway. I have to have trike gear for the twin and I need to place the rear wheels at about 1" behind the CG. I have no clue where the CG should go on a GEO-XL airfoil. I know a million other factors play into the exact position but if I can at least get a ballpark I can bend some wire.
Ken
The general rule of thumb for trike gear is that the mains axle be placed at an angle 15 degrees behind the CG.
BTW, those is some nice looking control system parts....
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Wing is nearing completion. All hinges are installed and working and the flap control plate mounted. All of this is removable and hatch assessable. I weighed the wing unit today. With both landing gear wires, flaps and flap control box it weighs 14.9oz. I still think I can make my 65oz goal. Nacelle's are not glued on. I will mount the plane to them via Bob Hunt's method.
Ken
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Ken, thanks for doing the build thread. Most of it is more than I'm capable of but I always learn something new.
Mike
Sent from my SM-A146U using Tapatalk
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I posted my flap "sealing" method in the open forum:
https://stunthanger.com/smf/open-forum/imbedded-flaps/msg673327/#msg673327
Ken
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After careful consideration I decided to bite the howitzer and redo the canard linkage using a reducing lever. Making it was not easy.
I had to raise the cockpit floor 1/8" and move the arming plug to the other side. The lever is two pieces of .5mm carbon fiber sheet with a 3/16" hard balsa center. Ball links are a necessity because of the angles. IT WORKED! The canard now has an adjustment range of 5 to 35 degrees and by adding the reducing lever the pushrod angles are such that changing the throw does not change the center as much so I can easily adjust neutral. On Endgame III I am not able to change the canard much without upsetting the inside/outside turn balance.
The wing is fitted to the fuselage but not glued in yet. All the subassemblies except for the rudder are finished so it is time to start putting it together and cleaning it up. The controls are super free. Hard to believe that with the logarithmic with split flaps, a 5" bellcrank, two pushrods, 10 ball links and a reducing lever that the weight of the flaps is enough to move everything - and the flaps are pretty light!
I put everything on the scales to see where I am weight wise. 58oz including props and battery. All that is missing is the rudder. I figure that I will sand and the like for just about the weight of the rudder so that gives me 7oz to finish and still make 65oz. It is a big plane with lots of power so a few ounces over is not going to temper my enthusiasm.
Ken
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Maybe I got something wrong from your pictures, but if you add such a lever between the bellcrank and canard horn, doesn't it reverse the movement..?
I think you'll need a logarithmic gadget for the canard, too. n~
L
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Maybe I got something wrong from your pictures, but if you add such a lever between the bellcrank and canard horn, doesn't it reverse the movement..?
I think you'll need a logarithmic gadget for the canard, too. n~
L
The Canard is driven by the opposite side of the bellcrank from the flap pushrod. It needs to be reversed so that the canard moves in the same direction as the flaps. The lever also reduces the movement. When I first hooked it up I had over 40 degrees of movement. 5 - 15 is about all it will need.
If I wanted to build a whole new fuselage I would couple it to the logarithmic instead of the bellcrank.
Ken
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First pic of it all in one place. Almost half finished!
Ken
In case you are curious, or even if you aren't, the wing center section had to remain open to connect the rather elaborate control system and get all of the conduits for the wires going everywhere. So, I glued the wing to the bottom of the fuselage and left the top planking off. What I discovered doing it this way was having full access to the bellcrank with the wing glued into the fuselage is really cool. Regardless of bellcrank size I make all of my control systems to go from neutral to full deflection with 1 1/2" of leadout movement. That is 3" of wrist from full up to full down. With it finally assembled I got to see if it all worked. 3" exactly! Since I have a 5" bellcrank I was worried that I got the stops wrong.
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This has been keeping me up at night. First time twin and I have been told that the nacelles need to be as close to the wing as possible. Don't ask me why because I don't know YET, I just trust the source. So, by using state of the art reforming tools (Exacto #11), I reshaped the nacelles with the aft end of the motor 1/16" from the wing LE. Nearly 1" closer. If this doesn't work I know where to send the bill. LL~ I actually think they look better short.
Ken
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Made a design change. Experimentation with the Canard on Endgame III has led to the need for different positioning and different control methods. Since this plane is intended to be my 2025 NATS plane I have decided to leave the Canard off. :(
Ken
Or not...I am rethinking my rethinking. The Canard was not intended to be the pitch control. It was to take pressure off of the handle and add stability (tracking). It accomplished both of those on Endgame III so maybe it stays...or not.
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Finally finished the reshaped nacelles and it was time to put them on the wing. I didn't have much of a workbench, so I had to devise a method of mounting the nacelles that insured their alignment to the wing then mount the fuselage later. First task was to get them in alignment with each other. I used a variant of Bob Hunt's method and took a 2" x 18" x 1/4" piece of poplar and drilled holes on a centerline 14 1/4" apart. This spacing will allow me to use a maximum of an 11" prop even though 10" is all I plan on using. I put a piece of 80 grit sandpaper over the holes. Next I mounted both motors in the nacelles including the spinner backplate and mounted them to the poplar plank. As I tightened them I was able to spin the nacelle over the sandpaper until I had a perfect spinner fit. Now I have two nacelles perfectly aligned to each other. Next I used the lost foam rib as a template and cut two stands that will act as a cradle for the wing. Using a Robarts incidence meter, I leveled the wing on my 18 x 32" "workbench atop my tools cabinet and sanded my way to a perfect fit. Tack glued and remeasured it was still in aparent alignment. So the most dreaded and most critical task in building this beast is in the rear view mirror and thanks to Bob's advice to mount the plane to the motors, it may be done right. Unfortunately beauty is not in the eye of the beholder when making a PA. It is in the tracking of the plane when it flies.
Ken
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Today was fun if you like trying to remove parts glued in with JB Super Weld. I was testing my controls after installing the nacelles to make sure I didn't create a bind anywhere when I noticed how far back they seemed to be. I was marking the CG range that I wanted on the wing and about to position the leadouts about 3/4" behind that when I discovered that with the leadout guide fully forward I was 1 1/2" back from where they needed to be. That qualifies as a Quad "P". So I tried to figure how I had messed up and found the cause. As I mentioned in another thread the plane was supposed to have a GEO-Bolt wing but I changed it to a GEO-XL at the last minute. What I didn't so was change the tips. I used the same tip plan as Endgame III with the GEO-Bolt wing. So I ripped out the adjustable slider mount and repositioned it 1 1/2" forward and closed it back up. A little sanding and some filler and we are good to go. Well almost. The new angle needed to have it's path cleared for the leadouts.
Electrical wire came today. 16 gauge stranded copper. It is a little bit stiffer than the standard RC wire. These nacelles are cramped so I am making a mounting plate for the motor wires and cutting them back to about 1 1/4".
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Starting to put it all together and I discovered another quad "P". I put the timer in the same place it was in Endgame III, just in front of the wing LE where I could see the status light clearly. Well today I am checking alignment to tack glue the wing and guess what is blocked by the inboard nacelle. So, I need a new place for the timer. There is no place near the wing that will not be hidden by the inboard nacelle, so it has to be up front. I have never put one so far forward so I will ask those who might now. Will this work?
Finished installing the motor wires. I probably used too heavy wire. I used 16awg copper. Got rid of all the slack to save weight.
Ken
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What do you call the correction for a Quad "P" when it doesn't work? A Quint "P"? Moving the timer to the nose caused it to too far from the accelerometer mount. Aggh.... So now it is back to it's original location but lower in the bottom hatch so that I can see it behind the nacelle. Wing is glued in. I used the Hunt method. Mounted the motors in the nacelles and used a 14" piece of 3/8" poplar as faux prop set. Fixed that in a fixture 90 degrees to the workbench then mounted the wing using my trusted Robarts meter. Works, thanks Bob. Slid the bearings onto the canard shaft and glued them in alligned with the wing centerline. Checked the control linkages and added the center sheeting. The fourth pix is the adjustable accelerometer pad mount. The spacers are silicone fuel line. With this pad design, stolen from Crist Rigotti, you can achieve perfect alignment of the pad. Starting to look like an airplane!
To continue the timer saga I put the props on the motors to see what it would look like and discovered that the timer start button was in the prop arc. mw~ Moved it forward just enough to give me room to start it. Now the aft hatch hold down screw is blocked by the timer. HB~> Scratch building has it's challenges!
Ken
Ah, the bellcrank - 5" dual sided to let me mount the canard. I needed to add the lever arm to allow the pushrod to be far enough away from the post then reduce it so that I only got 10-20 degrees deflection.
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If I understand correctly, then you can lengthen the sensor wire with a little soldering and get the length needed. PM sent.
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Time to put everything together and see how it fits. Some does, some needs some persuading. 52 0z as it sits. Both motors, ESC's timer props and battery. All that is missing is the finish and wheels. It is conceivable I will make my 65oz target!
Ken
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If I recall my history of the P38, the prop rotation direction was very significant. Ultimately they had to swap the engines left for right to get the correct flight characteristics. It might be something to research. As currently set up, it looks like you will have upwash over the tail making takeoff more difficult. Perhaps someone with actual twin experience can set this straight, as I am only talking theory.
Otherwise a marvelous project! Thanks for sharing. 🤠
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If I recall my history of the P38, the prop rotation direction was very significant. Ultimately they had to swap the engines left for right to get the correct flight characteristics. It might be something to research. As currently set up, it looks like you will have upwash over the tail making takeoff more difficult. Perhaps someone with actual twin experience can set this straight, as I am only talking theory.
Otherwise a marvelous project! Thanks for sharing. 🤠
I worked allot with Mr. Twin, Bob Hunt in the early design. The nacelle spacing and inline setup as well as the wing have his blessing. He has commented that the prop rotation may need to be changed after it is flown. Super easy. Just swap in the ESC and swap props. Having the Canard in clean air will be interesting. On Endgame III the prop is in front of the canard.
Thanks for dropping by - Ken
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Close enough to assembled and ready for filling in all the "oops" and "ah sh**"'s. The paint scheme is now on the table. I am thinking in two directions. Treat it as military or civilian. It has the general outline of a Beech Baron and there are several interesting paint schemes there. Military is military. Gray or white with lots of panel lines. I want to use MonoKote as much as possible. Has anyone used the "Dove Gray"? How flat is it and will it take a clear coat? The jury is still out on the mylar over polyspan.
Has anybody done a full finish for a competition plane using the mylar over polyspan? I have done some tests and it appears to work but I have no clue how it holds up. I have to have a light finish, the build ended up 4oz over budget.
Ken
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My Rizngmaster is over 5 years old and the finish is fine.
🤠
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My Ringmaster is over 5 years old and the finish is fine.
🤠
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Plane is fully built and assembled that makes it about 50% finished. Sanding is the next 20% covering 10% and the last 30% finish - Ugg. Time to select a paint scheme. This is my sketchpad. Just to document the evolution I thought I would post the original design and what I actually built. I can't remember what made me decide to switch fuselages. I am afraid now that I am stuck with an USAF or Navy paint scheme.
Ken
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No wonder you say "UGG", your numbers add to 110% to build! I only do 100% on my builds, it takes less time! I'm a Navy Vet, but how about a Marine (Dept of the Navy) throw back scheme with a bit of color?
Don
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No wonder you say "UGG", your numbers add to 110% to build! I only do 100% on my builds, it takes less time! I'm a Navy Vet, but how about a Marine (Dept of the Navy) throw back scheme with a bit of color?
Don
Actually the numbers are understated. I just discovered that I glued in all of my pocket hinges too early and I have to drill them out and replace them. All for the best. I used too small a bushing and it all but guaranteed I would have an issue with the pull wire down the road. Beats me why, probably because I didn't have any brass at the time but I bushed them with aluminum. I like the Navy gray. My Father and little brother were Navy pilots. Me, I was Air Force ground crew. I may go with the USAF white. Yours is looking good!
Ken
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To Canard of not to Canard, that is the question. On another thread there is a rather inciteful discussion of what may make the canard I have on Endgame II work and that was thrust vectoring. Well where is the canard on Endgame 4 - In front of the props! I pulled it once before I glued the nose cover on. I can either pull it now or finish up to covering and fly it.
ken
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Fly it! You'll be forever curious about what might have been if you don't.
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Fly it! You'll be forever curious about what might have been if you don't.
You are right. Electrics don't make a mess!
Ken
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With it all glued together, no matter how hard you try not to, your mind starts to imagine paint schemes. These are two that were suggested patterned after Navy trainers. I am also thinking of something involving the flag of just gray with panel lines.
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I like the 2nd one, the Army Air Corp trainer styled one.
Steve
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I agree with Steve, the second one! Go Navy!!
Don
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Today was a milestone. Fully assembled with all electronics and wiring power up test!
https://www.youtube.com/watch?v=NesMpyBxuB4
It works! I decided after investigating more to wire both ESCs to the power switch. I like the old Air Corp trainer vs the new Navy one too. Needs some refinement.
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No wonder you say "UGG", your numbers add to 110% to build! I only do 100% on my builds, it takes less time! I'm a Navy Vet, but how about a Marine (Dept of the Navy) throw back scheme with a bit of color?
Don
Yes, but the last 10% takes 90% of the time.
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With it all glued together, no matter how hard you try not to, your mind starts to imagine paint schemes. These are two that were suggested patterned after Navy trainers. I am also thinking of something involving the flag of just gray with panel lines.
Everyone knows that yellow airplanes fly better.
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Finally got it up to the point of the first pass of Blue Stuff (Super Fil). 30 minutes of putting it on and three days of taking it off! Let the dust begin!
Did my favorite big soft balsa fillets!
Ken
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I really like those big balsa fillets! Looking good Ken!
Don
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Progress update. Construction is finished. Starting on sanding. First step is to fill every crack and crevasse with SuperFil. It looks like a lot, but it is actually a very small amount. All of the fillets, stab and wing are feather light balsa. I spread superfil over them to create the crust, rub it in with alcohol then sand it all off. I know the accepted method is to mask it off but I like the extra hardening of the wider area and how much better it feathers. Add to that having to build without the benefit of a proper workbench has resulted in a lot of places to fill! I found the three post on/on microswitch and have it installed so that I can plug in the Jeti box without having to disconnect the 2nd ESC.
Another 2 weeks of sanding and I will be ready for covering. My plan is a bit, perhaps allot, out of the mainstream.
I cannot use anything that has a smell. I have tried ModPodge but the final finish was not to my liking. I tried SLC over Polyspan which was good except for the curves and ended up no better than monokote. So, right now the plan is to use White Monokote on the wings and stab. Polyspan applied with Z-Poxy on the nacelles and fuselage with a slight overlap onto the monokote. I will try and put the actual finish over all of this with light coats low stink after hours so that the smell doesn't get into the AC. Finish will be light coatsI am open to suggestions on this. I need the aft fuselage strength. I built the fuselage from 1/16 with lots of "X" braces and I am not happy with it at all. I considered .5oz glass which may be lighter than polyspan. I will heat shrink the polyspan before rubbing in the Z-Poxy.
I am considering this for the paint. It comes in lots of colors. Has anybody tried this or something similar?
https://www.amazon.com/BELTECO-Odorless-Eco-Friendly-UV-Resistant-Substrates/dp/B0CZTS77D8/ref=sr_1_3?adgrpid=1338106215000375&dib=eyJ2IjoiMSJ9.6r2lxF8654OAhAkTg31z695l8AUxiQIQ1MdLka-od9ipVUKHe8Yex4_2fqXREK5m8LZ_MxeoRoNGqL1lp-w_5UUupeZ_GoZM2d5mYi_Zc3HHMhfskGsiZl_i4-ZcgpfEVfEnuaJ8G715dkg-hepu0AcUmdM5KTCZ8Z5JTsfnnyZ_kDjq11q-WkNo8FjTW-TpjJDvSkjAej7asWYcUxg2Wu5SD4OyXv06_0yszK5IVJ6rtBR61JO4QK0XZoanfmZzNNPt1Qbt_jbK0eE04pBcdupUrkEvkl7L0HUvLVUvTTI.h9047A5e-cfB0-mGfqVULbYzKxs4n2EmVHm0IjQZXHU&dib_tag=se&hvadid=83631877526041&hvbmt=bb&hvdev=c&hvlocphy=77349&hvnetw=o&hvqmt=b&hvtargid=kwd-83631982224536%3Aloc-190&hydadcr=343_1014977545&keywords=odorless%2Bspray%2Bpaint&msclkid=6d7807ce61fb1271d11a60feba02bbba&qid=1731255317&sr=8-3&th=1
Ken
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Interesting stuff, Ken. On the odorless front, I have been using Eze Dope from Deluxe Materials over here in Singapore because regular dope isn't available. It behaves pretty much exactly like dope and I have been using it with both silkspan and polyspan. It's completely odorless and thins with water. The only major difference I notice is that it seems to take a couple more coats than regular dope needs. But since it thins 70/30 water/dope, I don't think there's much, if any weight penalty.
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Interesting stuff, Ken. On the odorless front, I have been using Eze Dope from Deluxe Materials over here in Singapore because regular dope isn't available. It behaves pretty much exactly like dope and I have been using it with both silkspan and polyspan. It's completely odorless and thins with water. The only major difference I notice is that it seems to take a couple more coats than regular dope needs. But since it thins 70/30 water/dope, I don't think there's much, if any weight penalty.
Thanks a bunch! I will get some and try it out. Does it sand well and will rattle can colors work? Best news is that it is available at Hobby Town!! Thank you for the lead. I was starting to think that nobody read the build threads anymore.
Ken
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I read em all. Usually learn something new each time. But you guys have years more experience at this than I do.
Mike
Sent from my SM-A146U using Tapatalk
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Thanks a bunch! I will get some and try it out. Does it sand well and will rattle can colors work? Best news is that it is available at Hobby Town!! Thank you for the lead. I was starting to think that nobody read the build threads anymore.
Ken
Sure thing. It sands well, but not quite "real" dope well. I find that instead of the usual 2 coats, sand, 2 coats, sand; I have to do 3 coats, sand, 2-3 coats, sand. I'll even go down to 600 on the final sanding in some areas. And if you don't let it get totally dry before doing another coat or sanding, it'll roll up and create little marbles like tires do in car races. The final result is pretty close to real dope, though. Including on open bays. If it weren't for the lack of a yellowish tint, I'd find it hard to tell the difference if presented with two finished pieces. And yes, rattlecan goes over it totally fine. Deluxe Materials has a couple videos on Eze Dope on their YouTube page that may be of help when you start messing with it.
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I read em all. Usually learn something new each time. But you guys have years more experience at this than I do.
Mike
Sent from my SM-A146U using Tapatalk
Having years of experience doesn't do much if you keep doing it the same way all the time. I love trying new things and seeing others do the same. Sometimes they work, sometimes they don't but the fun is in what the next one might be! Now, having said that, if I was presently focused on making the top 5 I would be flying the simplest, straightest, lightest overpowered proven design I could get my hands on and flying nothing but that as often as I could. VD~
Now to go out and fly the same pattern I have been flying since 1961 - LL~ LL~ LL~ LL~
Ken
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Gave in to mass pressure and got some Canopy Glue. End result a perfect fit!
Ken
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The plywood caps that I put onto the TE to form the cavity for the flaps proved to be a mistake. When filled and sanded they distorted the airfoil at the TE so I am taking them off and putting a round cap on in their place. They will be hinged like a Shark or Aurora with no sealing. The indented flap was nice but the TE bump was not. I have also made the master decision to do a monokote finish. Since I can't use dope I came to the conclusion that monokote with some nice trim and maybe a clear coat when I can sneak on in. Weight is becoming an issue too. I have the horsepower and wing area to support 70-75 ounces and still be competitive, but I really don't want to go that high
Ken.
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With the ' WAKE ' / Vortice fred on the other day ,
it sprang to mind , LATER , that that was what those were for .
(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ9QnttE9AesuztUkFYFuNZLpIls5Rl2pkRKQ&s)
But youd still get VORTICES of heir Tips ( the End Plates )so if you put end plates on the end plates ,
and put some on the ends of them . . . . . ;D
These are the other tips , everybody fitted to everything .
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTaEoGu0FF7p_5p7N3ZAAvQw0YWoU6AEkH9ww&s(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTaEoGu0FF7p_5p7N3ZAAvQw0YWoU6AEkH9ww&s)
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Following up after a thread on vortex turbulence. The Canard on Endgame IV is ahead of the props whereas the one on Endgame III was behind the prop. Where III created a very nice thrust vectoring I am concerned that the one on IV will blanket the props and reduce thrust.
Any thoughts? I can't fix it but I can be prepared.
Progress consists of getting the electronics working and getting it covered. I will have to make a new set of 5s Li-Icon batteries. The 6s is too much of the Spin 33 ESC and a TP 5s is too fat to fit the battery box. In the service we called that a Quad "P". (@#$% Poor Prior Planning)
Humm, didn't think @#$% was a banned word. n1
Ken
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Small Update. Lots of work on the numerous detail issues. Hatches, hinges electronics and basically making part "A" fit into part "B" given that part "C" is now in the way. Next Twin, if there is one, will be laid out COMPLETELY differently.
I have given up on the front row finish I planned and am now going for the "Looks good in the Air" 12-13 pointer. Too many restarts in the construction and not being able to use smelly stuff to finish it I am giving up and just monokoting everything.
One surprise was finding some white gloss water based paint that is an exact match to Monokote Gloss White. I can sand the bumps and joints around the fillets and nose then paint over it. Looks pretty good but not what you want to take to the Nats.
One thing I discovered in doing the pocket hinges is that you don't want to use too small a bushing for the pivot wire. It makes removing and putting the flaps and elevator back on very difficult. I replaced the tight fit with one size larger and it seemed to make little difference in the slop, however they are easy to remove now.
A few shots of the 11 point finish in process.
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Got her tail number today. The 33'rd full size stunter since #1, my 1959 Nobler. Small number for this crowd but still, that's a lot of bellcranks!
Plane is finished as soon as the outboard wing gets covered tomorrow then it is a week of fixing all the little things and bench trimming. First flight in about two weeks.
It is seriously overweight primarily from my doing everything wrong the first time. I am guessing it will lift off on it's maiden flight at 75oz. That is about 5oz over my 14oz@sqft ceiling. I do know how to fly heavy, and it has a Fiorotti timer so I can trim it for wind. Who knows, I went with the 2320-810 motors instead of 2310's so it may turn out fine....or not.
I have learned much from this build but having to do it in my office has been a real nightmare at times.
Ken
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Ready for trim. May bench trim and fly it first. 68oz with battery but less props and spinners. 1/2oz fixed tip weight. As it started to take on pig like characteristics, I did some math and figured that I could live with it at 75oz. Looks like I will make it. I remember the butterfly's flapping like crazy when Endgame III first took off with the canard. I had no clue what it would do. This time it will be no different.
Ken
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Looking good Ken! I'm thinking a twin powered stunter at 75 ounces might have some pull to it. Better start working out so you can hold on to it! LOL!
Don
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Dang Ken, I'm sure reminded of a Hammer head Shark with this one..... Looks very interesting. I'm looking forward to flight reports as you tune it up. Congrat's on a fine job. y1
John M.
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Dang Ken, I'm sure reminded of a Hammer head Shark with this one..... Looks very interesting. I'm looking forward to flight reports as you tune it up. Congrat's on a fine job. y1
John M.
With all of the Sharks at worlds I was seriously considering using "Hammer Head" but it isn't even close to a Shark so probably not. The real test will be to see how the canard works in clean air vs directly behind the prop where I suspect it was providing thrust vectoring but also killing some lift over the wing center. Isn't this fun!.
Ken
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Yes, it is.
It might be able to claim distant heritage to the Shark 45, had Les ever developed a twin Canard stunter.
It will be interesting to see what happens with the Canard in clean air and all that combined prop disk area going over the wing. Keep up the good work.
John M.
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72 oz ready to fly with 5s 4200 battery. Removed 3@ of the pocket hinges. ^ @ flap was way too many and getting the hinge wire to hit 12 .030 holes was taking my patience. Also had to enlarge the battery hatch to fit the larger battery. I was totally too tail heavy so instead of adding lead, I added battery. 3oz under getting the "Miss Piggie Decal". I am comfortable flying a heavy plane and I think I have the power and with 710 squares I hope I am OK. It balances at just under 30% of center chord which has me worried some. It gets it's stripes, registration and name Monday. I am thinking of calling it what it is - "Endgame Mk4" on the Wing and "Hammerhead" on the fuselage side....or not.
Already getting the butterflies. 1st flight probably late this week.
Ken
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Dang Ken, I'm sure reminded of a Hammer head Shark with this one..... Looks very interesting. I'm looking forward to flight reports as you tune it up. Congrat's on a fine job. y1
John M.
I am renaming the plane to Hammerhead. It will still say Endgame Mk4 on the Fuselage but the wing is going to say Hammerhead. Working on the wing art now. Nothing exotic. Not sure which one I will use.
May keep Endgame on the wing and put this on the fuselage side.
Ken
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Very nice Ken. By the way I like logo number 3!
Don
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Very nice Ken. By the way I like logo number 3!
Don
Me too!!
Ken, very nice model.
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Yup, number 3 is the way to go!
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So Far the votes are 1-0, 2-0, 3-5, 4-0 both on and off this thread. I think I will use 4... LL~
It is 3 by a wide margin.
ken
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I'm happy to ee this Ken. It truly helps describe the approach and mission of your work with this concept. It looks devastatingly lethal and project's maximum purpose. By the way, #3's the one.
John M.
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Tomorrow, she loses her virginity. Bench trimmed and pre-flight completed. All that is left is wrapping the leadouts and mounting the Canard. I always do that right before flying the first time. I have the Canard off for the pictures since I did a 20 second full power run to test the electronics. I cannot believe how much air that little 2320 motor produces. I needed nose weight so my flight battery will be a 5s 4200. Lots of 1 min trim flights in that puppy. Balance came out at around 25% center chord.
Still have a lot of monokote trim and a few decals. The finish is a joke but it looks great at 10'. I will try and get some video. My trim regiment is to get wings level at 5.2-4 then some turns and a few laps inverted to get the timer set. Before I open it up to the full pattern I do an hourglass and overhead 8. If the trim lets me do that without having to change my underwear, then it is full patterns and trim baby trim.
This project has been a real adventure. Cramming a twin into a single motor fuselage and getting the canard to work with all the pushrods, wires (I have 18 pairs of bullet connectors and 10 ball links in play).
I applied the monokote with the intention of stripping it off if the plane performs well and refinishing with a classical silkspan and dope finish.
It weighed in at 72oz with an empty battery which puts her under 15ozft2 so she doesn't get the Mrs. Piggie decal.
Ken
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First flight in the books. Not much progress on the trim schedule but I can confirm that the 5" bellcrank and the up front Canard work as hoped. The plane is rock solid in level flight even being a bit tail heavy. It takes off and lands like it has tricycle gear with a long controllable glide. Only time for two sets of corners (really more like hard bumps) which responded better than the first canard. Line tension good through 45 degrees. Needs to speed up a bit. First flight was a 5.8. I want no more that a 5.4. Now that the butterflies are gone I can proceed with the real trim.
2nd flight was a disaster with a happy ending. A wheel fell off just as the motors started. it took nearly 1/2 lap but I got it air born with one wheel and a strut. The inboard motor was not running and I flew it out on just the outboard. I was told it would fly on one motor. They were right, I could even maneuver some and had good line tension. Still don't know why it stopped or for sure if it ever started. The inboard prop shows signs of a prop strike which may have shut off the inboard ESC or far worse, the inboard didn't arm. I will fix these little things and get back out again ASAP.
One thing that is abundantly clear. I need a portable rack to put her on upside down to do trim. I have a weak knee and getting my 220lb carcass up off of the ground is becoming a two man job.
Ken
https://www.youtube.com/shorts/3rPGDabplmw
I lost an update somewhere between here and there. I found the reason the outboard, yes it was the outboard not the inboard that didn't start. Some idiot forgot to turn off the programming mode on the timer so it thought it only had 1 ESC. The Spin 33 beeps when it arms so takeoff protocol now includes "Do not start the timer if you don't get two beeps"! I also learned that you really have to tighten the prop on the reversed one. I found that the castle propnut has a purpose.
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I've enjoyed watching your progress with this. Looking forward to hearing how it trims out for you. Thanks for sharing it.
Mike
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Time to close the build and open the trim thread. Today was the first flight with some limited maneuvering. Some loops and inverted a square and some lazy eights. The canard in clean air works better than the one on Endgame III behind the prop. The plane turns effortlessly and draws a straight line without fighting. Turns are equal and no hint of hunting. It needs some speed. Right now it is turning a 6.0. I need it down to at least a 5.6. I think I want more pitch as well. I am using BA 10-5s. I think it will do better on a 6. I am completely happy so far with my decision to go with a 5" bellcrank. The controls are so solid. The logarithmic box makes everything adjustable through one bottom hatch. The bench trimming routine is quite different with the Canard. Step 1 is to get the canard movement equal, then the elevators in line with the canard centered and locked down, and finally the flaps get centered.
The video is the first flight with maneuvering. The camera man must have misunderstood me when I asked him to not follow the plane. I am testing limits and much of it was flown upwind. I like to see how my planes perform when placed in the wrong spots.
The Twin has a completely different feel. I don't know how to describe it yet, other than to say if you get the opportunity to fly one you will know what I am talking about.
Ken
https://www.youtube.com/watch?v=j6iI_z__cYc
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Very cool...
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Next exciting adventure. These are the things you get right on the next one you build. I drew up plans and located all of the components. My original nacelles were an inch longer. An unnamed expert in twins suggested that I get the motors as close to the wing as I could, so I shortened them an inch. First flight I kept looking for the blinking light from the timer. You guessed it, I had moved the prop arc directly in line with the timer light. Time to call Mr. Gadget to see what I could do about it. On one of the RC forums there was a discussion about lights. They mentioned some that worked off of receiver servo connection and were powered by the servo lead. Then it dawned on me that the Fiorotti timer has a servo connection - the landing gear. If I am correct, and I find out Monday, this little light that is designed to run off of an RC channel should light up when the timer signals gear up and gear down for about 3 seconds or will light up when the timer starts and go out when the retracts signal is sent and come back on with the extend signal. Either will tell me it is time to get back upright and ready to land.
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Well so much for the extra light off of the timer for now. When attached to the gear port it either stays on all the time or blinks all the time depending on which way I put it in. That tells me that the signal from the timer to the LG servo is on full time. Bummer. Can anybody tell me where I can get a schmatic of the Fiorotti timer to tell me which pins I could solder a second light in parallel?
Ken
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The answer to the great light placement debacle has been solved. Rogerio is making one with a 12" lead for the LED. This along with a loosening of one of the canard bearings has led me to the conclusion that I need to re-do the lower nose. In doing that I can reposition the battery box to help shift the CG forward. Beats adding lead.
Ken
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Tuesday I finally got past the gross trim issues and got her close enough to do a pattern. Wind was around 10 so I was a bit cautious. I did my 2 minute qualifier I discussed earlier with a surprisingly easy vertical 8 and hourglass. No issues in the transitions on the V8 or the 3rd corner of the hourglass. So a fresh battery and we are off to a full pattern. Still needs some balancing between the turn rates and a
bit no a bunch tail heavy but overall very flyable. Tracks well in maneuvers, better than expected and corners tighter than it needs too. Those are easy fixes. Line tension is really good over 45 degrees and it turns well overhead. Enough of the good stuff. Here is the bad. It bounces around like a fishing cork on a windswept pond in level upright. Not as bad inverted. I am hoping that the CG change will fix that. It could have been the wind. The timer was working overtime keeping the groundspeed constant. It wasn't hunting, it was bouncing. Once under control it was rock solid. Next bad thing. A funny inboard yaw entering the RWO and the OH8. It immediately self-corrected in both places but if was quite distracting. I have the inboard motor running slightly faster than the outboard which should produce the opposite. Boost and brake should be equal between the ESC's but it acted like the outboard got more boost than the inboard. Nothing anywhere else turning vertical from level flight. Now for the next to last bad thing. I think, contrary to my own beliefs and those that know far more than I about hinge lines that they need to be sealed or at least covered so I am going to use some overhead projector transparency material to make hinge-line covers. This may be part of the bouncing in wind...or not. And Finally (drum roll) the Canard is picking up slop. One bearing has broken loose and lets the Canard wiggle.
Ken
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Tracks well in maneuvers, better than expected and corners tighter than it needs too.
Ken
How can "corners tighter than it needs to" be a problem? It is my understanding of the rules that if one pilot has "tighter" corners than another pilot, everything else be equal, the the pilot with the "tighter" corners will score better.
Keith
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How can "corners tighter than it needs to" be a problem? It is my understanding of the rules that if one pilot has "tighter" corners than another pilot, everything else be equal, the the pilot with the "tighter" corners will score better.
Keith
There is a point where the quality of the corner matters. I know you have not seen one of my canards fly but they will corner so tight as to appear to stop and pivot. Most everybody that has seen me fly that way has commented that it is irritating and detracts from the overall presentation and that included judges. I tend to agree. I know the rule book gives the higher points to the tighter corners all other things being equal, I just don't think it works out that way, at least not around here. The point of the canard never was a tighter corner, only a better one. It's real strength is in moving the center of rotation closer to the visual center of the plane so that it present a better visual track, especially in rounds.
https://www.youtube.com/watch?v=3mKuT69Qzfw
The video was shot AFTER I was convinced that the corners were too tight and are about 1/2 of what it was capable of. What I am after with the twin is just about what is in the video. I suspect the repeated testing of just how tight Endgame III could turn ultimately caused the outboard wing to fold.
Ken
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The initial flights with the barrel hinges and no flap sealing were not encouraging. It flies great in a maneuver but in level flight it shows all the symptoms flap sealing deals with. Inconsistent level in and out of wind primarily. So, how do you seal a barrel hinge? Simple, you can't. You have to cover it. I found a box of overhead projector sheets from back in the 80's that were paper thin, stiff and made to withstand heat. So I cut 3/4" strips, painted them to match the monokote and glued them on using Elmers spray glue. They are only attached to the wing and just cover the hinge line of the flap. No bind. The hardest part was figuring out how to put them on and painted. First wing took an hour and after three tries only looks marginally crappy but I got the method figured out. Next three panel's took 15 minutes total. Should work.
Ken
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The hinge covers worked great. No more bouncing! I have questions on motors. Which one should be the clockwise rotation and what should be the RPM differential. I use the Fiorotti timer. Below is "proof of life". I am finishing it a little bit at a time.
The green tape is holding on the new hatch so that I can adjust the canard lever. Next it is stars. The Red stripe is really the flap cover. Our local official plane namer dubbed it Hammerhead.
Ken
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Couple of snapshots of the first attempt at a full pattern. The flight was cut short by an inadequately charged battery, so she still is a virgin.
Ken