Can't get my right flap to line up

I'm befuddled. Fitting my wings, already did the left one, rigged the flap so top of travel is even with aileron in neutral position. Now I'm on my right wing, sweep at zero, incidence locked in exactly. I mounted my aileron, rigged it to neutral on neutral control stick, checked neutral using the tooling holes on the outboard rib. Mounted my flap, cut the fuselage opening to fit. Here's the problem, I cannot get the flap high enough to match the aileron. I top out with the flap skin that extends under the fuselage being flat against the bottom of the fuselage for the forward 75% of the overlap. This has me 2 degrees below the neutral aileron.

These are quick build wings, so I didn't build the flaps or ailerons. So my questions are

Is this close enough?
Since I don't have the same problem with my left wing, is this going to lead to a heavy wing?
Should I adjust "neutral" to match the flap (I seriously doubt it).
Is there anything I can try to get these to line up?

I won't be able to fit both wings on at the same time until I can move outdoors partially, which in this part of the world is in about 5 months.

Have you checked these??

Sounds like there may be a twist in either the flap, aileron, flap or aileron mount center lines, or the wing itself.

Try pulling a string along the trailing edges of the flap and aileron ??

Setting Flaps

Claude,

It's been a few yrs since I installed the wings/flaps/ailerons, but I had some similar issues. It took some fiddling to get it all worked out, but in the end, the plane flew perfectly level on first flight. Similarly, one of the flaps was initially overly tight up against the base of fuselage when aligned with the aileron. You may want to go back and tweak the aileron position(s) against the outboard rib alignment holes-possibly slightly lowering the two ailerons. In turn, this will bring down the flap positions and allow the flap to align with the aileron. In the end, just be sure the left and right aileron/flap positions are symmetric with the other side.
Can you do any inboard trimming of the flap to allow it to come up a bit more?
Hope this helps. I spent a lot of time adjusting and readjusting the flap/aileron positions 'till it all lined up. Be Patient.

Jim Diehl
7A
Lock Haven, Pa.

I'm not sure how it is supposed to work on that model, but I always (on the RV-10), rig the flaps all the way up (bottom flush with the bottom of the fuse), then rig the ailerons to the flaps, then rig the wing tips to the ailerons. If there is no twist, this should take care of rigging. Any slight imperfection in the installation or length of the sheds will cause what you are seeing, so just adjust to fit the flap with stick in neutral and verify no interference throughout full travel of all controls.

Hi Claude,

On my QB 9A, I aligned the ailerons with the tooling holes/board method, and then aligned the flaps to match. There's a 3/4" gap on both sides between the aft edge of the flap skin and underside of the fuselage.

Are you sure your alignment marks to set the aileron neutral position are correct?

I'd definitely put in a call to Van's on this one. Good luck!

Jesse,
Your method sounds logical. It's probably the way I will do mine. I think the manual recommends the method that Doug illustrated with the alerions first then flaps and wingtips to match. I guess if everything was perfect, then both methods would be the same but it just doesn't seem to work out that way in real life. I guess my question is if you start with the flaps being flush with with the fuselage, is it possible to end up with the flaps possibly being a bit "reflexed"? Reflexed flaps means less drag and more speed on some wings so not sure if that would be a good thing on this already efficient design.
Cj

Jesse said:

I'm not sure how it is supposed to work on that model, but I always (on the RV-10), rig the flaps all the way up (bottom flush with the bottom of the fuse), then rig the ailerons to the flaps, then rig the wing tips to the ailerons. If there is no twist, this should take care of rigging. Any slight imperfection in the installation or length of the sheds will cause what you are seeing, so just adjust to fit the flap with stick in neutral and verify no interference throughout full travel of all controls.

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On the -10 the flaps and ailerons are reflexed 3 degrees when fully retracted. This yields higher speeds.

There was a discussion on another thread where it was determined that the 9's Roncz airfoil doesn't benefit from reflex.

On my 7A quickbuild one of my flaps bottom skin hit the fuselage before it was high enough to match the neutral aileron. I had to carefully bend the bottom skin so allow it to be flush with the bottom of the fuselage and yet allow it to go high enough. It is a bit of an odd angle and a slight joggle bend but it worked out fine.

The flap not lining up with the fuselage could be caused by a twist in the aileron, flap or wing.

Check for twist in the aileron by locking it in place and measure the incidence at both the inboard and outboard ends with your digital level/smart phone placed on the top skin of the aileron. If the readings are different then there is a twist. Do the same for the flap.

You can use a similar method to check for twist in the wing but you will have to fabricate a simple tool for the digital level to rest on (suggest a length of wood and wood blocks glued together).

If there is any twist determine if it would explain the flap/fuselage mismatch?

Fin
9A

jjconstant said:

On my 7A quickbuild one of my flaps bottom skin hit the fuselage before it was high enough to match the neutral aileron. I had to carefully bend the bottom skin so allow it to be flush with the bottom of the fuselage and yet allow it to go high enough. It is a bit of an odd angle and a slight joggle bend but it worked out fine.

Click to expand...

I don't know how close the pre-drilled stuff is, but this was very common on the 6. That little overhang skin on the flap was either bent to fit or cut-off once final alignment is set. Do not compromise your rigging so that this appendage lines up properly as built. Follow best practices for rigging then deal with that overhang as necessary to accommodate. I aligned my ailerons to the tooling holes and then the flaps to the ailerons. I then tested higher flaps positions at cruise speed. I stopped raising them when the incremental adjustment stopped produced speed increases.

Larry

You didn't mention.... Have you already set wing incidence and drilled the aft spar attachment? Seems that if you can't get both wings on at the same time, you haven't done this. This would be the reason for misalignment.

You need to accurately set wing incidence and wing sweep with both wings on before moving forward.