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alpinelakespilot2000

Well Known Member
After having the untouched wingtips for 5 years now, it's finally time to fit them. They were stored on edge but nonetheless must have gotten a little warp in them b/c the trailing edges of the ailerons don't match the trailing edge of the tips.

After drilling the tips to the wings--and trying to do whatever possible during the drilling to make the trailing edges line up--the full span of the tip trailing edges are almost 1" below that of the ailerons when the latter are in the neutral position. A full inch seems like a lot, but it is what it is. (FWIW, the tips are exactly the same on both wings, which is the silver lining in all this, so there shouldn't wing heavy issues related to the tips.)



Thus, I think I need to do what many others have done and slit the trailing edge of the tips. Am I correct in assuming I need to do this, and re-bond them to match the ailerons, BEFORE I install either of the tip ribs?

Thanks for any suggestions
 
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tip fun...

not sure how your 1" measurement relates exactly but here is my general recommendation after finishing mine recently...


first fit the tip for a good leading edge fit.

next try to get the outboard trailing edge as close as you can to being on the flap / aileron line... you can get it to move a bit by rotating the leading edge fit some.

drill the tip to the wing.

split the trailing edge with a cut-off wheel.

if the outboard point is pretty close to the projected line just re-join the trailing edge of the tip so that the inboard edge matches right on.

if the outboard point is too far offline you will need to split the outboard side of the tip as well as the trailing edge to get it to move much.

after it is bonded back together fit the tip rib.


for me, finishing everything on the tips felt like it just went on and on... at least until i did the baffles... ha! talk about a task that went on and on...
 
Install the wing tip with leading edge as snug as possible, use an adjustable tie down strap. Then rotate the wing tip in this position to line up the tip. You may want to use a strap or two around the wing tip to the wing root to hold it in position. Drill and fasten down.
 
Are you sure the flaps and ailerons are properly rigged?

Are you sure the flaps and ailerons are properly rigged? This seems unbelievably bad to me. I have made my own molds and made 4 different configuration wing tips and I have never experienced anything off at all let alone an inch. I guess that you have a full airfoil template that you used to rig the flaps and ailerons. Never mind me I'm not there and I don't know what you are faced with but alarms go off for me as I'm sure they did for you when you ran into this problem. If there is a reflex in the rigging and you alter the tips to match it it may be a bit faster in cruise.

Bob Axsom
 
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Bob Axsom said:
Are you sure the flaps and ailerons are properly rigged?
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Just about as sure as I can be. The later kits use a straight edge between the outboard wing rib tooling holes extended out to the trailing edge of the aileron. I'd love to say I messed up the aileron rigging by 1" because then everything else would be perfect, but if so, I'm not sure how.
 
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Maybe it's an inch but ....

Having just split my wingtips twice ( once just for fun ;-0 ) I would bet that you didn't really have them in the right place when you drilled them. If you haven't put the platenuts on yet, I would make another pass at fitting the tips. The holes in the tip don't really matter if you are putting on the reinforcing strip with the platenuts attached to that.

What I found out was that if I had someone hold the tip in place by pushing from the outside in toward the wing, I could just lift the whole rear edge (outboard and inboard) and all of the drilled holes would move about 1/2 inch forward on top and a 1/2 backward on the bottom and the front of the tip would rotate slightly in place. Unfortunately, I had read the stuff about splitting so when mine was 3/8 off, I just went ahead and set the platenuts and then planned to split the tip later.

Man, I wish I had backed off one more time. Spitting the tip isn't a big deal but you can't just split the rear inboard otherwise when you pull the tip in place to match on the aileron side, the outboard edge doesn't move and the tip will slope down from the aileron. Meaning that the inboard can be pulled up but the low outboard edge stays in place unless you go way up the sides. It's enough that from the rear it looked like a droop tip. That was the result of my first split seen below. (my excuse was that I was in the hangar and couldn't get far enough back to see it)



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Long story short, I had to split it again and then about 2 feet up the side in order to be able to pull it all back into straight alignment with the aileron and flaps. If you do split, be sure that the outboard rear edge is staight with the aileron and not just the edge where it meets.

What this means for yours with a full inch to allow for,.... is that from the side, your tip will not have a straight line parrallel to the wing cord because it will have to move a lot up as it gets close to the rear of the tip. If you sight down the edge of the tip, you will see it rise toward the rear with a full inch to move up. Just think it all through but if you haven't put the plate nuts in place, I would stop and have a refit session.

Good luck either way!

Bill S
7a flying next month!
 
Thanks Bill. That really helps. Perhaps I was tricked by my tips fitting so nicely into the leading edges right from the start. I see what you mean about trying to compensate for 1" (actually 15/16"). If it took a slit halfway up the tip just to compensate for a 3/8" droop you had, I really would have a hard time taking 15/16" of droop out!

Are you suggesting that my same flange width should work, but that my existing holes will just have to shift forward or aft? (Indeed, I've only #40 clecoed to this point.) Because my wing skins only overlap the outboard ribs by 1/2", that's what I sanded my wingtip flanges to in the process of even-ing up the flange as per the first step in Van's directions. I have a 1/2" even flange all the way around. If I sanded too much of my flange off I may be sunk, but if it's just about shifting the holes fwd or aft, I may still have a shot.

Thanks again.
 
BillSchlatterer said:
What I found out was that if I had someone hold the tip in place by pushing from the outside in toward the wing, I could just lift the whole rear edge (outboard and inboard) and all of the drilled holes would move about 1/2 inch forward on top and a 1/2 backward on the bottom and the front of the tip would rotate slightly in place.
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That was it, Bill!

Surprisingly though, all it took was one #40 hole diameter fwd on the top and one #40 hole diameter aft on the bottom to move the whole wingtip up a whole inch! It did take a lot of force to do it, but now everything lines up perfectly. Unfortunately, since it only took a hole diameter, when I redrill I'll have a bunch of figure-8 holes, but a metal backing strip for the platenuts, and filling the original with epoxy/flox should address that. I sure wish I would have known it might take that much force to begin with!

Thanks again, though!
 
Maybe the tips on the RV-4 are completely different but the tips in the picture are ver different from what I intalled. They look upside down.

But its early and maybe I am just seeing things.
 
rbibb said:
Maybe the tips on the RV-4 are completely different but the tips in the picture are ver different from what I intalled. They look upside down.

But its early and maybe I am just seeing things.
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Yes, the tips are different in the later series RV's. There's no way to put a tip on upside down. Thanks for checking though.

Bill's suggestion seems to have solved the problem for me. Will know more later this afternoon after I fill the original holes and redrill.
 
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