Down elevator stop not being hit

[Paul Eastham]

Hey everyone,
I just realized that there's a part called a "down elevator stop" that lives just forward of the elevator horns. Problem is, it's not acting as a stop -- my control sticks/grips are hitting the instrument panel first.

My elevator deflection angles are well within Van's limits (near the maximums, actually). My pushrods are roughly set to the lengths shown on the plans.

Is this a problem? If I try to correct by changing pushrod lengths, I suspect I will start running into problems with sufficient up elevator travel (due to the stick weldment striking the center section). I guess I could also shorten my sticks, which isn't too appealing...

[pierre smith]

Paul,
Our elevator doesn't contact the down stop either. I don't see any problem with that on an A model. The taildragger guys may need full down travel with a heavy in the back but other than that, you'll probably never use that much down anyway.

Regards,

[Walt]

I shortened mine so the grips would not hit the panel!

[Bryan Wood]

Originally Posted by Walt

I shortened mine so the grips would not hit the panel!

Me too Paul.

On another note, did you ever contact Robin Reid about your first flight? Any idea when you'll be blasting off for the first time? Let me know if you need somebody to fly chase or take some in flight pictures or video for you.

[Paul Eastham]

Hi Bryan,
Yes, Robin came by my hangar a while ago -- he was willing to fly it and spent some time looking for any problems. I will probably ask him to do the first flight.
I'm not in a big rush because I can't do my transition training anytime soon. I'll certainly let you know when it's time.

Paul

[Dave Cole]

All control surfaces need a hard stop to prevent overtravel in both directions. The stop should act on the control surface directly, not through the control linkage. The stick grip hitting the control panel is not an acceptable control surface stop.

[rvbuilder2002]

If you add grips to the sticks and they make the sticks longer, the stick should be shortened the necessary amount to maintain the same length.

The comment about RV trigear models maybe not needing as much down elevator travel as a tail dragger is not correct. There are other factors that are effected by elevator travel , such as spin recovery at aft C.G. positions.

Builders should make sure they meet the minimum deflection angles for each control surface to avoid their RV being even more experimental than it already is.

I did notice that Paul already meets the deflection angles but you should still try and have it hit the travel stop. This will help prevent any damage to the control system (and the instrument panel) should a wayward prop blast at a fly-in slam your elevator, etc.

[Mel]

Scott is right on target. And I will add that if you have switches on your stick, your thumb must clear any controls and/or the panel in all possible positions.

[joeboisselle]

I was taught in a&p school that control stops should be met at the control serface, not in the cockpit. You should be able to correct it by lengthening your linkage, unless you're already as far out as you can. I, like everyone else I guess, cut my stick down probably 3 inches and installed a ray allen stick grip on top. It doesn't even come close to touching the panel and hits both stops in the back. Just another $.02

[Paul Eastham]

Thanks for the comments everyone. Turns out that it wasn't just the sticks that were preventing the stop from being hit, it was the stick weldment versus the top of the seat ribs as well.

So I pulled out the aft elevator pushrod and shortened it quite a bit by screwing in the bearings some more.

Now I can hit the stop, with the passenger stick removed. I'll shorten that tomorrow and should be good to go. Obviously the neutral position of the sticks has changed, but everything else still seems within tolerances.
Thanks again!