Heavy / Dropping Wing

Folks,

Bought a nice RV-9A currently in AZ being painted. Hope to get it back towards W32 in the coming weeks. I noticed it has a heavy right wing and it dropped when the previous owner demonstrated a stall for me. Didn't realize what all that meant at the time. After reading a few threads the other day, realize now it could be a misaligned wing tip or possibly a less than flat aileron under surface. It has been painted so not sure how to address this without affecting the new paint. I asked Arizona Aircraft Services to check if the flaps / ailerons / wing tips are flush along the top to the trailing edge.

Not sure if the 6" spreader to help flatten the bottom (if needed) can be used on painted control surfaces without affecting the paint too much.

I could be wrong, maybe it only requires some rigging adjustments.

Thanks in advance for any thoughts.

Have a great Sunday,
Tim

The changes are subtle, so you could probably do it without damaging the paint. Use an old t-shirt between the seamer and surface to protect it and be gentle. Reading past threads, you will find that it takes less than you might think. First, though, finish checking the rigging.

maybe not..

Heavy wing issues are common, and are addressed a bit differently in regards to the 9. First, make sure you are ball centered in cruise flight. Adjust rudder trim as required. Take your time and get it right. Then, with equal fuel, and equal weight side to side, assess the heavy wing at cruise speed. Don't try to make adjustments until you have made several flights, and don't use solo flights for the assessment. Add a passenger, or ballast. Manage your fuel. If you determine that indeed you are wing heavy, remove the wingtips, and adjust your ailerons and flaps per the procedure. (Check incidence and sweep first) Reinstall the tips, and check their alignment. they must be aligned very carefully. use a long straightedge across the retracted flap and aileron. A six foot level is a good tool for this. If you find the tips are out of alignment, you will need to cut and reglass them in most cases. Search the archives here for lots of suggestions. The longer moment of the 9 wing makes the wingtip alignment more critical it seems. That was all that was wrong with my quite heavy right wing, and I only moved the wingtip 1/4" to make it fly level.
After all of that, if you still have a heavy wing, Follow Vans instructions to relocate the aileron hinge to correct the issue.
Careful attention to alignment and rigging will really make the airplane a joy to fly. Time consuming, but well worth the effort. A systematic approach is essential to ensure a fast and trimmed aircraft.
Just a note. If you drop a wing in the stall and you are not wing heavy in cruise, you are most likely not ball centered at the stall. Mine drops straight every time if I am perfectly centered, but will exhibit a wing down if I am off by just a little. To be truthful, that takes some attention if even a slight wind or turbulence is about.
My best advice is to fly the plane for a while to get a real good feel for it before making adjustments. Make a few flights between tweaks to see how you are doing. Take your time!!

Regards,
Chris

Kutta rules!

I had the same problem. http://gikonfly.blogspot.com/2009/07/squeezing-aileron.html might help you. GO GENTLY!

The Wing Heavy Analysis document on Vans web site is worth reading.

Thanks all for the help. Will check it using this information and let you know what I find out in a few weeks.

929JA Made it to Hyde Field

929JA made it back to its home base at W32 / Hyde Field 2 Dec. Flew great and seemed like it picked up at least 15 mph with the new paint job as compared to bare metal. Also the heavy wing problem was no longer an issue it seems. Thanks to all for your responses and help.

Tim

I haven't had that problem with my 9A, but I would check the rigging adjustment very...very...very closely before I started bending any control surface metal.

Maybe I'm missing something here but the trailing edges on the nine are not bent like the 6 and 7. They are already flat riveted surfaces so mashing the trailing edge is not something you can even do as there is no radius.

rv9aviator said:

Maybe I'm missing something here but the trailing edges on the nine are not bent like the 6 and 7. They are already flat riveted surfaces so mashing the trailing edge is not something you can even do as there is no radius.

Click to expand...

Jim,

You are correct. You cannot squeeze the trailing edge of the ailerons and/or flaps on the -9 like you can other RV's.

twcroy said:

929JFlew great and seemed like it picked up at least 15 mph with the new paint job as compared to bare metal.

Click to expand...

15 mph seems like an improbably large speed gain from a paint job. Maybe something got fouled up while it was at the paint shop. You might want to check for a static system leak, as that could cause the airspeed system to read 10 - 15 mph too high.

Kevin, y'know how chrome plating works....

....on valve covers! The airplane is obviously faster....ask Robby Knox

Best,

Wheel pants add 15 MPH...

Were the wheel pants on the airplane before it was painted? If not, and they were installed after the paint job, there is your 15 MPH speed increase!