[Xkuzme1]

I just recently bought a low time flying RV-4. It flies right wing heavy. I have read about smacking and squeezing the ailerons, but I would like to try something slightly less destructive first.

Right wing heavy, but I would like to try to adjust the LH flap a degree down to change things up a bit.

Thoughts? How is this done? How easy it is?

Thanks!

X

 

[RV7A Flyer]

Check all the alignments first...are the ailerons properly rigged per Van's instructions? If so, then the wingtips should line up perfectly with them, as should the flaps. Everything lines up with the aileron once it's properly rigged, including the flaps (not the other way around).

If there is roll trim, disconnect it to remove that possible source of error. Get it flying as close to having a centered "ball" as possible.

Then look at Van's instructions for fixing a heavy wing. The amount of "squeezing" required to fix it can be so slight as to be invisible to the eye. I had a moderately heavy right wing, and after all the checking and rechecking, we squeezed the appropriate aileron (IIRC, it's the opposite one to the heavy wing, but check the instructions). The first time it was so slight as to make us wonder if we'd changed anything at all, but it removed probably 80% of the roll.

 

[dlloyd3]

If you got the preview plans and builders manual with your plane, it has instructions about how to correct a heavy wing. I think the same is on the Van's Aircraft website.
First, the ball must be in the center. Tweaking the flap position did not do much for me. Three of my aileron hinges needed adjusting to lower the aileron in relation to the wing--huge effect. Took several tries to get it just right.

 

[BobTurner]

Three of my aileron hinges needed adjusting to lower the aileron in relation to the wing--huge effect. Took several tries to get it just right.

+1. Look carefully if the wing and aileron heights match. (see if the heavy wing has a high aileron). 1/16" makes a significant difference. Vans sells undrilled attach brackets if yours need adjusting.

 

[Infidel]

Figure I'll throw this out there just in case-fuel levels the same or close in each wing? How about the spring assist "roll lever" on the front of the control stick?

 

[riobison]

I have a 98 RV4 and it is also slightly heavy on the right wing with full tanks. Once I burn off 1/2 of the right tank then its good.

Now I load my 130 pd girl friend in the back seat and with the tanks full it flys hands off, nice a level. Go figure on a tandem seater.

 

[rvbuilder2002]

A heavy wing (roll trim imbalance) can be caused by a lot of different things...

- Improper shape of aileron trailing edges
- asymmetry (difference) in the shape of the two ailerons
- One or both ailerons not mounted at the correct elevation in relation to the wing
- A weight imbalance in the airplane (One occupant sitting to one side, etc.)

In many cases it is probably a combination of all of these.
For this reason, zeroing in on one specific method of correction without checking all possibility is for the most part a band-aid fix... not fixing the actual problem (or at least not all of them) is not the proper way to deal with a trim problem.

Having said that, incorrect aileron shape is the most common cause and should be the first thing checked. it can have a strong impact on the handling qualities of the airplane also, so bypassing it because of a fear of reshaping the aileron is not a good idea.

Every RV that has folded trailing edges on its control surfaces should have their control surface shapes checked closely prior to first flight, as well as any airplane that it is not known whether they have ever been check (you are second owner, etc).
The process is detailed in Chapter 5.7 of the current rev. of Section 5 of the construction manual. You can access it HERE