7a aileron pushrods

[frankh]

Morning all,

Just did the fianl rigging of the ailerons only to find the rod ends only screw in about 5/16th inch on all four rod ends.

My sticks are vertical and I set the neutral point of the ailerons and the belcrank with the template guage on the spar.

I pulled one tube out of the wing and measured it and its exactly the length shown in the drawings..

Anyone else seen this and what did you do about it?

Current thoughts are 1) buy 2 longer rod end bearing, one for each rod.

2) machine up an insert that fits inside the big tube, cut the tube in half and use the insert to extend the length of the tube.

I like #2 cus I can do it without ordering more stuff and waiting for it.

Thanks for your thoughts.

Frank

 

[sf3543]

Try making adjustments to the push tube from the bellcrank to the aileron, first. By adjusting this tube to a little bit longer (or shorter, can't remember which) length, you will decrease the length needed for the stick to bellcrank tube. But, make sure you still get the required deflection on the aileron. (Basically, you would be setting neutral stick with the bellcrank set as if it already had started is movement to push down the aileron.)
I can't remember how much extra travel there is there, but it might be worth looking at before you start cutting.

 

[frankh]

Spoke to Gus at Vans

Gus tells me the minimum thread engagement should be 3/8ths and I can put a second jam nut on if necessary to stop the thing unscrewing off of one end. As I am only about 1/16th short of that I will try adjusting the belcrank inwards a little like you propose...For that matter if the sticks wern't perfectly parallel that wouldn't be the end of the world either.

Still hpoing hoping for a Doh! moment where I have done something dumb thats easily corrected...

Frank

 

[dgrayent]

Frank, I had EXACTLY the same "length problem" after carefully cutting the tubes to the "plans length". UNSATISFACTORY. They needed to be about 3/8" longer than the plans call for. I went to the local surplus store and got some aluminum bar stock and machined two new (longer) ends, one for each push tube, like your #2. After drilling out the original rivets and installing the new end on each push tube, I had the required safety depth on the threads. Hope this helps.

Don

 

[Brambo]

Frank, I had EXACTLY the same "length problem" after carefully cutting the tubes to the "plans length". UNSATISFACTORY. They needed to be about 3/8" longer than the plans call for.
Don

Dang, I hope this isn't always true. I just cut my pushrods yesderday - to exactly plan length.

Brambo
RV-7a (QB wings)

 

[cytoxin]

longer ends

the longer ends are 28.00$ apiece. if you cut all to the exact lengths i suspect a rigging issue. check check check..imho

 

[RV7ator]

Just load up the exposed threads with extra nuts. Then the pushrod can't unscrew itself. There's enough thread engagement to not be a strength concern. I wouldn't go compromising crank positions and stick parallelism for so simple a fix (for a Van's screw-up).

John Siebold
Boise, ID