[apkp777]

Hey all,

I have installed my flaps and find that at the INBD end there is about a 1" gap between the "metal tab" to the fuselage. If I bring them up further the flaps are misaligned with the ailerons, if I bring the ailerons up, they are misaligned with the tips. Besides pulling out a "bigger hammer" whats the ideal fix here.

 

[647jc]

Tony,

I had a similar experience and most other 9's I've seen are the same. I think I ended up with about a 5/8" gap at the trailing edge of the flap tab to the fuselage bottom. You can bend the tab up a bit if you want but that will not totally hide the issue. Most important is the alignment of the flap to the main wing airfoil and alignment with the aileron which should be aligned with the end rib tooling hole and the tip. If the outer end of the aileron is alligned with the tooling hole and there is no twist in it then I would just make sure the outer flap end alligns with the aileron and accept the gap at the fuselage. That's pretty much what I did and the plane flies straight and level with neutral trim.

 

[apkp777]

Thanks Joe,

Seems everything is aligned, just have the gap on the INBD side. I will tweak the rigging a bit and then just live with the result.

 

[alpinelakespilot2000]

The problem is probably with the flap. It's pretty tough to build a perfectly flat 8 foot flap--something the shorter winged RV's don't have to deal with. I have the opposite issue where I've got,with the flap all the way up to the fuselage, a 1/4-3/8" gap b/w flap and aileron at neutral. Ken at Van's said just park with the flaps down so no one notices. : ) He thought it wouldn't affect the flight characteristics too much, if at all. The only alternative is to build a new flap, which I may do just because it's not terribly expensive to do so.

 

[apkp777]

The problem is probably with the flap. It's pretty tough to build a perfectly flat 8 foot flap--something the shorter winged RV's don't have to deal with. I have the opposite issue where I've got,with the flap all the way up to the fuselage, a 1/4-3/8" gap b/w flap and aileron at neutral. Ken at Van's said just park with the flaps down so no one notices. : ) He thought it wouldn't affect the flight characteristics too much, if at all. The only alternative is to build a new flap, which I may do just because it's not terribly expensive to do so.

The flap is straight. The Aileron hasn't any twist either, although my LH one is wiggly across the T.E.

I am sure the flaps "suck up" a bit in flight I just don't know how much.

Also, I know that there is some thought that you should have the flight controls "droop" a bit to aid in drag reduction (seems counter intuitive).

Anyone have any thoughts on that?

 

[647jc]

My wings and control surfaces were QB and I verified they were flat with no twist. Not sure why the gap at the fuselage exists but it's consistent on both sides and I'm pretty sure it is not due to control surface twists. Anyway, with the 5/8" gap I have the plane seems to fly great.

One thing you may want to check; the placement of the outer hinge bracket on my ailerons were not quite right and the end result was the outer top surfaces of the ailerons were not flush with the top surface of the tip, they were actually about 1/8 to 3/16 of an inch higher. So to get the trailing edge of the aileron to align with the tooling holes on the end rib and the wing tips, the trailing edge had to be lowered more than normal. This ultimately required the flap trailing edge to be lowered to align with the aileron and thus increased the gap between the flap lower skin and the fuselage belly. Not sure I explained that very well but, my solution was to get a couple new undrilled hinge brackets from Vans and drill and mount them so the top surface of the aileron was flush with the top surface of the tip. Then I had to raise the aileron trailing edge to get it back into alignment with the tooling hole and tip. So then I had to raise the trailing edge of the flap to get that back into alignment with the aileron thus minimizing the gap between the flap tab and the bottom of the fuselage. I never flew the airplane with the top surface of the aileron sticking up too high so I don't know how it would have behaved but I have since seen other RVs with similar problems and they appear to fly OK. I suspect if one side was different than the other you may end up with a heavy wing.