Heavy wing fix...a quandary

[painless]

Group:

I have a heavy left wing, and I notice that my left aileron hinge bracket is making the inboard of the aileron sit about 3/16" lower than the flap. In other words, when the aileron is in trail and the flap is retracted, the upper surface of the flap is 3/16" higher than that of the aileron.

I was visiting Dan C's site and I see that he had a similar situation, with the inboard edge of his aileron being set lower than his flap on his left wing, but that he had a heavy Right wing. DOH!!!

So if I correct this discrepancy, will I worsen the situation??

Need some info here folks.........


Thanks in advance.


Regards,

[sprucemoose]

Yes, you will likely make it worse, as a lowered left aileron should cause a heavy right wing. However, you should still correct it, then hunt down the cause of the heavy wing. You certainly don't want to have a series of off-setting mis-riggings, you want the thing rigged right!

If you haven't read Van's article on the subject:

http://www.vansaircraft.com/pdf/Wing_Heavy.pdf

[szicree]

Not sure I agree here. Having an aileron below the left wing should produce an upward force and cause a right roll, but I believe that an aileron that's too high could also cause a draggy wing that wants to yaw the plane left (and produce some roll that way too). In any case, you gotta get it rigged right and then track down the problem. Good luck.

[fodrv7]

My RIGHT aileron was 1/8" low and LEFT wing heavy.
Like Dan's wing opposite the low aileron was heavy.
I did not use the tooling holes to check the difference, but instesd found by holding a straight edge (I used my digital level) on the lower surface of the aileron I was able to see that the right aileron was below the bottom of the wing whilst the left was in the same plane. (Not a pun. The same geometric plane.) I was able to measure the gap between the straight edge and the lower wing surface with my vernier calipers. I also used the vernier calipers to confirm the diference by measuring the gap between the top of the aileron and the top wing to skin on both ailerons.
As Vans per Vans article I slotted the ailron brackets to raise the aileron. Did a short flight test to confirm the result; which was good and the drilled the new brackets to match. Actually, as the brackets are pre-punched I could not drill them 1/8" offset and so labouriously used a diamond file to create a hole in the required place. Chromoly is HARD.
Szicree, I suspect that the lower aileron leading edge, directs more air through the aileron gap, which creates a lower pressure in the gap, sucking (Bad word in aerodynamics, but you know what I mean) the leading edge of the aileron up into the gap and the deflection causes the wing to want to rise. But, I am certainly open to other ideas on this. It's just a guess.
Pete.

[osxuser]

Move the flap instead of the aileron then...

[sjhurlbut]

Moving the flap does not work. Trust me after 2 RVs, if you correct a heavy wing using flaps, one flap will be deflected in flight a lot. To correct my heavy wing on my previous RV, the flap was defected almost 3/4" down compared to the other.

The real fix is slotting the aileron brackets and the squeezing the aileron trailing edge for fine adjustment. Assuming of course angle incidence is correct and equal on both sides.

Steve
RV7A #2