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Rick RV-4

Well Known Member
While rigging my RV-4 ailerons, I'm running into a problem of not having enough aileron travel. Book says to have 25 up (minimum) and 15 down (min). I'm currently getting about 21-22 degrees up and 15 down, so even my total range of motion is not where it needs to be. This is with NO control stops installed.

I started by following the plans - which say to displace the bellcrank 1 and 3/16 inches at neutral stick position. I then adjusted the length of the pushrods (slightly by adjusting the bearings in or out) to get the ailerons neutral.

When I deflect the stick full left or right I reach the limit of the stick travel before I get the desired total deflection of 40 degrees minimum.

Any ideas???

Thanks,

Rick
 
Rick RV-4 said:
While rigging my RV-4 ailerons, I'm running into a problem of not having enough aileron travel. Book says to have 25 up (minimum) and 15 down (min). I'm currently getting about 21-22 degrees up and 15 down, so even my total range of motion is not where it needs to be. This is with NO control stops installed.

I started by following the plans - which say to displace the bellcrank 1 and 3/16 inches at neutral stick position. I then adjusted the length of the pushrods (slightly by adjusting the bearings in or out) to get the ailerons neutral.

When I deflect the stick full left or right I reach the limit of the stick travel before I get the desired total deflection of 40 degrees minimum.

Any ideas???

Thanks,

Rick
Click to expand...

If your 4 has differential bellcranks you may have them in wrong.
 
I saw ths on a 7

I helped my buddy rig his 7.

It has different bellcranks in the wing, and they were not centered when the sticks were centered, and the ailerons were centered.

Each part needs to be centered to start with, the sticks the ailerons and the bellcranks in the wings. A 4 has the same bellcranks as a 6, remember they have un-equal distances from the pivot bearing and must be put in right or you will get the wrong and unsafe behavior with your controls.:confused:

I would start double checking everything, some of the differences can be subtle.

Best wishes! :cool:
 
Aileron Travel

Rick...

Could it be one or both of your aileron push tubes are running into the rear spar at full deflection?

The hole cut in the rear spar ends up with a sort of "L" shape because the bellcrank causes the push tube to move sideways slightly while the aileron moves the rod up and down at the same time. I had to "hog" my holes out with a rat tail file on my RV6 which should be the same as your RV4. You could have the same problem.

Dick DeCramer
RV6 N500DD flying
RV8 Fuselage
Northfield, MN
 
Aileron rigging

Fellas . . .

I have checked the bellcranks (to make sure they weren't installed backwards) but I'll check again. I have also checked the hole in the rear spar and there is no interference. I'm starting to wonder if I might have one of my bearings (that connect the elevators to the control assembly) a little off center which I could see might prevent full control stick deflection.

My big concern right now is that I'm not getting the full amount of travel (at least 40 degrees). If I can get that I would think it would be relatively easy to solve having the controls rigged properly with some tweaking.

I'll give Van's a call . . .

Thanks,

Rick
 
Rick, when I rigged my -4 I could not get full travel. The fuse sidewall was blocking the push rod as it moved up on the down going aileron side. I summarised with pictures here.

My suggestion for order of checking if it is still a problem.:

1. Disconnect the push rods from the central control yoke, and ensure the ailerons/pushrods can make the full movement.

2. Run a check on the central steel yoke.

3. Reconnect, if the problem only returns at that point you have the problem I had.

One other area that can 'block' is the elevator push rod where it joins the steel part. Disconnect that to check also.

Good luck
 
Thanks Steve,

I have a feeling it has to do with my connections to the steel control arm as you talked about. I'm not running into any kind of interference with the push tubes in the wings, so it must be a bearing issue.

I'll hopefully find out tonight!

Thanks,

Rick
 
Rick,
You may also double check the placement of the aileron stop. Mine is off slightly which prevents full travel by 2 degrees.

Glenn Wilkinson
 
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