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5 Days ago I started the E Viper 3 same numbers as two. A few changes are battery set back farther and a Stab and Flap system that is new to me. Its been around 50 plus years but takes a lot of work to make them. Sharks use them. The hinges are set into the flaps 1/2 the thickness and the trailing edge is routed out so there are n gaps. Its my first time but I like a challenge. Anyway tomorrow I build the wing. everything is made so it should go together in a few days. It will be light.
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33811.0;attach=139539;image)
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Cool! So... You're moving the battery aft, so there won't be a CG shift when the power quits?
Ha ha. Just kidding. Not to mention all the static electricity, when you wipe the plane down after a flight. That's the residual voltage.
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Robert,
Is this along the idea as to what you are doing?
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Robert,
Is this along the idea as to what you are doing?
Yes thanks for posting this
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These hinges make inset hinglines a breeze to make. Russian modelers(those that don't make everything themselves that is) have been using them for years.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXET57&P=ML
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These hinges make inset hinglines a breeze to make. Russian modelers(those that don't make everything themselves that is) have been using them for years.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXET57&P=ML
I bought 2 sizes of these and they are not loose enough for what I am doing. So I made my own.
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Robert,
Nice framing so far.
What size is your LE stock? Does it taper towards the tip?
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Robert,
Nice framing so far.
What size is your LE stock? Does it taper towards the tip?
All tapers are dictated by the spar. On a beam airplane everything is set to the spar. (bad spar = bad wing) The LE stock is 1/2 X 1 and will be shaped after all the ribs are set. I have devised a new system (at least to me). Its a floating spar. The spar floats in the fuse when jigging and is held in with clips after everything is aligned.
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Things have been moving slow but this is where I am at sense the 1st of the year.
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33811.0;attach=139687;image)
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You're right up to speed, and it looks quite nice!
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Looking good and you are further along than I am with my stuff.
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I was asked to show my hinges. I hope this picture explains how its done. I am still detail sanding the wing and getting all the little stuff done like sewing the ribs. Fuse and wing with tips is 9 ounces.
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33811.0;attach=139779;image)
If you notice there is a C in the trailing edge and a rounded LE of the elevator. The pivot is set back 1/2 the thickness of the elevator and will act like a socket never having any hinge gap.
Flaps are the same set up with three hinges instead of two. I have a dremel router and I used a 1/4 inch half cutter. I made 2 passes one in each side and then sanded the finish for the C.
I will add that they are at least ten times free'er than regular hinges I have used. They flop. This will be a bushed horn set up. I have tried all the modern stuff and still think some of the old ways are better for me.
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So you made the hinges then? Can't quite tell, are they plywood?
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So you made the hinges then? Can't quite tell, are they plywood?
Yes with brass bushings
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Got it.
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Simple hinge
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33811.0;attach=139785;image)
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I think the way you sew the ribs wit Kevlar thread is really cool!! Do you CA them at the point of contact with each rib?
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I think the way you sew the ribs wit Kevlar thread is really cool!! Do you CA them at the point of contact with each rib?
Yes and where the X in the center too. Weighs nothing and it 1000 times stronger than balsa
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Would you show us a close up of the hinge detail, if you can? This looks really neat. D>K
Ken Pitts
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I'm pretty new to this, is that what's referred to as an I-beam wing? Is it always done with the spar installed in the fuselage?
Jim
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What about the hinge pins ? Are you using a long single wire to make the surface removable, or individual pins permanently installed ?
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When I do the flaps I will do a detailed photo spread. This is not a new thing its from the 40tys (there abouts) and works great.
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I'm pretty new to this, is that what's referred to as an I-beam wing? Is it always done with the spar installed in the fuselage?
Jim
This is a beam wing and mostly done with spar in fuse. It allows perfect alignment of everything. However I guess you could build it out of the fuse but why? Looks complicated but once you have built a few its simple.
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Thanks Robert
Ken Pitts
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Here is where E Viper 3 is at now.
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33624.0;attach=139946;image)
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loving them bones. Almost a shame to cover.
Ken
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Yes and where the X in the center too. Weighs nothing and it 1000 times stronger than balsa
Is it possible to put up a picture of this detail, or is it covered by now? I'm having trouble visualizing this.
Thanks a lot,
Dan McEntee
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Is it possible to put up a picture of this detail, or is it covered by now? I'm having trouble visualizing this.
Thanks a lot,
Dan McEntee
Somewhere on the other viper thread I put up a pic of what it would do but my camera is limited and it blurs.
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Here is a picture
(http://stunthanger.com/smf/index.php?action=dlattach;topic=32511.0;attach=132789;image)
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Yes with brass bushings
Back in the good old days, the lubrication took care of itself. Now, you have to oil them from time to time, even on piped airplanes. The hinge pin will rust if you are not careful.
Brett
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Back in the good old days, the lubrication took care of itself. Now, you have to oil them from time to time, even on piped airplanes. The hinge pin will rust if you are not careful.
Brett
Dissimilar metal corrosion sets in and I did think of making the bushings from Nylon. But Nylon would not be as free as the bearing surface would be larger. I want floppers. I guess on the next plane I will make them from oil-lite.
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Here is where E Viper 3 is at now.
(http://stunthanger.com/smf/index.php?action=dlattach;topic=33624.0;attach=139946;image)
Heck, you oughta have it ready to fly by this weekend! n~
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8) 8) 8) 8) 8) 8) 8)
Marcus
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Dissimilar metal corrosion sets in and I did think of making the bushings from Nylon. But Nylon would not be as free as the bearing surface would be larger. I want floppers. I guess on the next plane I will make them from oil-lite.
I would think that the pressure of the air pushing on the control surfaces would far outweigh the drag of any standard control system. That being said, there is nothing wrong with smooth controls.
Derek
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I think that the best material (with steel hinge pins) would be cotton reinforced phenolic. Or Tufnol 6F/45 if you don't like the stinky stuff. They are easy to glue and hold oil or grease well.
Yuriy's hinges are similar but molded from some kind of Nylon. No metal bushings needed.
L
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I would think that the pressure of the air pushing on the control surfaces would far outweigh the drag of any standard control system. That being said, there is nothing wrong with smooth controls.
It's additive. I think you would be very surprised how much effect even a tiny bit of drag makes.
Brett
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It's additive. I think you would be very surprised how much effect even a tiny bit of drag makes.
Brett
No, I wouldn't be surprised, I fly solids... But you are right, I didn't think about it that way.
I am "assuming" that Sparky is looking for a way to get around the Netzeband wall.
Derek
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Motor offset and light weights.
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Motor offset and light weights.
By all means do what you like but it seems to me that motor offset would cause more trim problems than its worth. I build all my planes strait, no rudder or engine offset and no adjustable rudder. I use leadout, and tipweight to trim the plane.
Just my .02
Derek
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By all means do what you like but it seems to me that motor offset would cause more trim problems than its worth. I build all my planes strait, no rudder or engine offset and no adjustable rudder. I use leadout, and tipweight to trim the plane.
Just my .02
Derek
Would you agree that the Shark fly's well? It has 3 degrees Motor offset. Would you agree that Billy's T-Bolts fly's just as well. There again about 3 degrees. The only line tension overhead is off set.. Just my thinking
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Offset? No offset? It's all personal preference, each individual should just build to fit their own.
And you all do know that even a plane that's built straight (with no built in offset) still flies as though it has some offset, because it's on a tether.
Plane is looking great Sparky. y1
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Would you agree that the Shark fly's well? It has 3 degrees Motor offset. Would you agree that Billy's T-Bolts fly's just as well. There again about 3 degrees. The only line tension overhead is off set.. Just my thinking
It won't hurt anything too much, but the offset, trimmed tangent otherwise, gives you virtually nothing overhead or anywhere else, less than 2 ounces over what you would otherwise have. Almost all of the overhead tension comes from centrifugal force - in this case, tension = centrifugal force - weight when you are dead overhead.
Most of the effect of offset is to create (or null out) the yaw torque by aiming the thrust vector so it passes inboard of the CG. The more offset you have, the more right thrust you need (because the CG will need to be offset to the inboard side of the fuselage). That's the main thing wrong with the All-American, the engine is lined up with the fuselage but the CG is well inboard, so it yaws in at you at takeoff.
I use around 2 degrees, somewhat indifferently measured, and I have about 3/4" of wing asymmetry. It's very insensitive and of all the unnecessary offsets, thrust line offset is the least objectionable.
Brett
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Centrifugal force over head? Come on. The Centrifugal force overhead is less than gravity. Guess I never learn simple physics.
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I think the way you sew the ribs wit Kevlar thread is really cool!! Do you CA them at the point of contact with each rib?
x2! Excellent Engineering.
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Centrifugal force over head? Come on. The Centrifugal force overhead is less than gravity. Guess I never learn simple physics.
It's all over my head LL~ LL~ LL~ LL~ LL~ LL~
Ken
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Centrifugal force over head? Come on. The Centrifugal force overhead is less than gravity. Guess I never learn simple physics.
Since this is off-topic and further comment on it in this thread is unwelcome, I will post the answer in the Engineering section (it's that dreaded high -now middle - school math).
SK
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Since this is off-topic and further comment on it in this thread is unwelcome, I will post the answer in the Engineering section (it's that dreaded high -now middle - school math).
SK
Please do I would like to know how much centrifugal force is applied if the engine quits. I would be nice to know the amount of line pull there is overhead dead stick.
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Please do I would like to know how much centrifugal force is applied if the engine quits. I would be nice to know the amount of line pull there is overhead dead stick.
When your engine quits directly overhead, does it fall straight down at you from the top of the circle? Of course not, most of the time, that's perfectly recoverable.
I call shenanigans, this time you are just pulling our legs.
Of course, when the engine quits, it slows down pretty quickly, so you start losing it rapidly. Particularly if your airplane is too light, the drag is the same as everybody else's airplane, but the momentum is less, so it the acceleration slowing it down is higher. But you have to get down to less than half speed to get the centrifugal force down to zero.
By the way, my satellite is dead overhead right now, and the engines aren't running, what keeps it from falling straight down into the ocean?
Brett
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By the way, my satellite is dead overhead right now, and the engines aren't running, what keeps it from falling straight down into the ocean?
Brett
Either zero gravity or a elliptical orbit around the earth. I don't know. But I do know for sure 3 degrees off set is better than none.
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I remember a few over head dead sticks. I dove out, a bit scary for sure.
Ken
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Well its all framed up and to the point where I weigh the planes before adding covering. The EV2 was Airframe before paint 21.20 and this one is 19.10 two ounces lighter than the Viper before it. That means all things being equal in finish 6.5. I can mover the battery farther back and still be in balance. Gross weight target now is 53 ounces. That means I will probably end up 54 and I can live with that.
I am also using a lighter motor on this one the Cobra 3515/18 and moving the esc farther back.
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You cut wight, then you did real good.
Ken
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Most of it was in the spar. The second one had a white pine spar and the third one has a balsa spar. Lets hope I eyeball engineered it right.
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Please do I would like to know how much centrifugal force is applied if the engine quits.
Whoah, Whoah, Whoah, wait a minute. If we go back toward the beginning of this thread didn't this latest "exchange" start out talking about engine offset? If the engine quits, especially overhead, no amount of engine offset is going to help.
Also, and I'm no Fississist either, but as long as the plane is moving forward at all there is going to a certain amount of centrifugal force produced. It may not be enough to feel or measure, but it's there. At a normal flying speed of say 50 plus MPH I could easily see that force having a stronger effect on the plane than gravity.
This theory can be easily tested, and proven, with a rock and a string. There were some really hairy knuckle-dragger dudes thousands of years ago that figured that one out, shortly before the wheel I think. :##
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All I know from experience is that if my engine quits at the top of the circle, I give the plane down elevator to get line tension back. It when I give up without thinking that things bad happens. Sparky, is there a limit on how light a plane can be for it given size?
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All I know from experience is that if my engine quits at the top of the circle, I give the plane down elevator to get line tension back. It when I give up without thinking that things bad happens. Sparky, is there a limit on how light a plane can be for it given size?
With the fixed weights now a days and the quality of wood available I think I have reached the limit with this type of construction. So if anyone says they can build it too light they will need to show me. Not tell me SHOW ME.
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Well I tried once to build a super light airplane. But, I am club fisted and by the time I got it all glued up and finished the plane weighed as much as some of my other planes. Had a long talk with Walter U. about the super light wood a year or so ago. Yes the wood was super light, but I kept punching holes in the sheeting while working on the plane. Also there is the stress cracks some of the wood has from the tree when it was growing or was going through the mill.
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Good Morning Robert;
Given the pace at which you build, I assume you use CA as your primary adhesive. I've heard it said in the past that CA is actually heavier than aliphatic resin (AR) adhesive (due the evaporation of water/moisture from the latter as it cures).
Since you are such a prolific and skilled builder, you would likely represent a preferred trial scenario. Have you ever constructed two of the same part/sub-assemblies, one with CA and the other using AR as the adhesive?
It would be interesting to see whether there is really a significant weight savings versus CA, and if there is it may provide you the pathway to a still lighter model...
All the best,
Dave
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Good Morning Robert;
Given the pace at which you build, I assume you use CA as your primary adhesive. I've heard it said in the past that CA is actually heavier than aliphatic resin (AR) adhesive (due the evaporation of water/moisture from the latter as it cures).
Since you are such a prolific and skilled builder, you would likely represent a preferred trial scenario. Have you ever constructed two of the same part/sub-assemblies, one with CA and the other using AR as the adhesive?
It would be interesting to see whether there is really a significant weight savings versus CA, and if there is it may provide you the pathway to a still lighter model...
All the best,
Dave
I don't know if there is a weight deference, but I just started using double glued AR. Boy is it strong. I am now using it in many places I would have used epoxy. Yes I still use epoxy in very critical places, like firewalls, etc.
Time consuming, real time consuming. Saves a lot of glue money though. ;D ;D
Ken
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Good Morning Robert;
I've heard it said in the past that CA is actually heavier than aliphatic resin (AR) adhesive (due the evaporation of water/moisture from the latter as it cures).
Since you are such a prolific and skilled builder, you would likely represent a preferred trial scenario. Have you ever constructed two of the same part/sub-assemblies, one with CA and the other using AR as the adhesive?
It would be interesting to see whether there is really a significant weight savings versus CA, and if there is it may provide you the pathway to a still lighter model...
I've also heard that many times over the years, but I haven't ever tested or compared the difference.
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I could not say. I like CA for its speed.