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Whiplash elevon modification

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Old 07-20-2003, 10:00 PM
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LGM Graphix
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Default Whiplash elevon modification

Well, after receiving my Whiplash, and reading about the servo power required to move them, I decided there had to be a better way. They are FAR to tight, in fact, the airbrush graphic was all cracked at the hingeline because of it. So here is what I did.

1. Take a steel straightedge and a sharp blade, and cut the elevons free.

2. Use thin CA to carefully saturate the edge you just cut. Then once dry, sand smooth, you will need to remove a slight bit of material when sanding.

3. Using Robart Hinge point hinges (4 per elevon, and use the good ones, the 4 finger ones, not the 2 finger) and a dremel with the 1/8" carbide burr, cut holes in the elevon and the wing for the hinges. You will need to cut half rounds into the upper surface of the elevon and the wing for the knuckle of the hinge.

Note that the wing and elevons are not solid, however, on mine there was a ton of glue that I was able to at least get a location hole in there.

4. Check the fit of the hinges, make sure all 4 line up without binding.

5. Mix up a batch of 15 minute epoxy and micro ballons or milled fiberglass, DO NOT omit the micro balloons or milled fiber.
Smear a little vaseline on the knuckle only of the hinge so they don't glue shut.

6. Fill the hole you just put in the elevon and build up alot of epoxy in the void. Then put the hinge in, add epoxy all around the hinge until it's completely captured in the epoxy. There is a gap between the top and bottom skin so this is not hard to do. Let the hinges cure in the elevons, I found that 4 hinges can be done with one batch of epoxy, you could use 30 minute I suppose and do both at once though.

7. Once cured, grab the hinges and pull on them, make sure they aren't going anywhere. Then mix up another batch and put it in the holes in the wing. Align the elevon hinges and push it into place, there should be about a 1/32" gap between the elevon and the win from sanding, you'll need this to allow the elevon to move up properly.

8. Once dry use hinge sealing tape on the top and bottom of the elevon to seal the gap, NOT JUST THE BOTTOM, use it on the top and bottom so that air cannot get into the elevon and cause it to delaminate.

note: the hinges I put in were spaced 1" from the outboard end, and on the inside of the control horn on the inboard end, then 2 more equally spaced along the elevon in the center. This makes for no flex in the elevon, they now move effortlessly.

Some people complain about the robart hinge points, but I've used them on Turbine jets without any issue whatsoever. As well as Pattern and pylon stuff. My magnum holds together just fine with CA hinges.

I'm sure with this mod, that my 88oz servos will be more than sufficient now and my battery shouldn't be drained after every flight!

Well, I'm off to paint the bottom now, they do such a nice graphic on the top, but the bottom is just that off white primer, yuck!

Jeremy
ps, I'll post some pics tonight of the mod.
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Old 07-20-2003, 10:13 PM
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ChuckAuger
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Default Whiplash elevon modification

That's one way..I didn't re-use the elevons, I made a new set from solid hard balsa, sheeted with 1/64" AC ply.

I cut the elevons off, but left 1 1/4" attached to the plane and epoxied the 1 1/4" piece to the wing tip.

After I cut the elevons off, I Dremeled the glue out of the pocket left in the TE of the wing and epoxied a 5/15" sq piece of hard balsa in for the TE. There was a balsa "spar" about 5/16" inside the wing, I glued to it as well.

Beveled the new elevon and hinged in place, I used 6 Robart HD hinge points per side.

I just sealed the bottom, I have no worries of de-lamination.

These elevons are much stiffer than the hollow elevons I cut off, stiffness was the other feature I was looking for other than de-lamination.

The hollow elevons will be fine with a Jett 50, and your servos will love you for it!
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Old 07-21-2003, 02:15 AM
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Default Whiplash elevon modification

here's a pic of the elevon with robart hinges.

Chuck, each whip must just be that much different, my elevons were filled enough with glue that they are very solid, no flex to them at all, they are rock solid
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