ground adjustable rudder pedal problem

[tmillican]

My son is 6'3" and I am 5'11". He will be flying the RV on a long XC later this month, and while he can fly it fine with the pedals where they were (one notch aft from the front), he states that his legs cramp up after about more than an hour in the plane.

So, we moved the pedals to the furthest forward position today (what a pain). While I haven't put the plane completely back together agaiin, I am concerned about some apparent limited travel in the forward motion of the pedals (right a little worse than left) due to them hitting the approximately 3/4" foam insulation up against the firewall. I considered yanking out the foam, but decided to wait and see how it feels to fly. I made a mental note of the new spin recovery procedure including the step "reach down and yank on the rudder cable opposite the direction of spin."

Has anyone else had similar problems with getting full rudder deflection with the pedals in the full forward position?

Thanks,
Troy

[roee]

Troy, I don't have a specific solution to offer (other than yanking out the insulation). But I feel I'd be remiss if I didn't speak up and say that flying the airplane in its present condition, even once, is a very bad idea. I hope you will reconsider. One way or another, you should do whatever is necessary to ensure that the pedals have sufficient travel with no interference to move the rudder from stop to stop. If that is not the case, the airplane should not be considered airworthy.

Respectfully,
-Roee

[Chris Hill]

Not airworthy? Really? Hm. As long as you can use the brakes and not do aerobatics that put you in a near spin condition and be mindful of x-winds...should be fine depending on just how much rudder travel you are losing.

The only time I ever give full rudder travel is hammerhead turns...my 2 cents

[lancef53]

I have the sliding pedal assembly(in flight adjustable) and with individual brake reserviors, I had to limit the slide so my pedals wouldn't hit the firewall. I don't have any insulation on my firewall.

[roee]

Originally Posted by Chris Hill

Not airworthy? Really? Hm. As long as you can use the brakes and not do aerobatics that put you in a near spin condition and be mindful of x-winds...should be fine depending on just how much rudder travel you are losing.

The only time I ever give full rudder travel is hammerhead turns...my 2 cents

That's a lot of ifs and depends.

The airplane was not designed nor tested with those reduced control limits. It was also not designed nor tested with the pedal deflection limiting out before the rudder stops. There are reasons for this.

Letting the pedals limit the travel is a major alteration of a primary flight control, which will affect various regions of the envelope, including spin recovery, to a yet unknown extent.

My objections are technical, not legal. But also from a legal point of view, if you were to do this, it would warrant placing the aircraft back in phase 1 and repeating the flight test program.

But this time, the flight test program would be required not to just confirm, but rather to determine the new operating envelope, which is not the operating envelope of the aircraft designed by Van's.

Otherwise, the aircraft should be deemed not airworthy. Yes, really.

-Roee

[N208ET]

Drill new cable attach holes higher on the ground adjustable pedals. This will give you more travel on the rudder for the same amount of pedal movement. I too have ground adjustable pedals and when they were in the furthest forward position the pedal would hit the firwall before the rudder hit the stop at full deflection. BTW, you might try the next position aft for the pedals and when your son flies, have him slide his feet under the pedals and rest them on the firewall.

Randy
8A

[tmillican]

Originally Posted by N208ET

Drill new cable attach holes higher on the ground adjustable pedals. This will give you more travel on the rudder for the same amount of pedal movement. I too have ground adjustable pedals and when they were in the furthest forward position the pedal would hit the firwall before the rudder hit the stop at full deflection. BTW, you might try the next position aft for the pedals and when your son flies, have him slide his feet under the pedals and rest them on the firewall.

Randy
8A

Thanks to all of you.

I had not yet replied to the initial concern, and although I'm certain I could fly the aircraft safely with the rudder going about one-half-inch less than full travel to the right, I do not discount the concerns raises. And I actually do not plan to fly the aircraft until I can get back out there and solve the problem more adequately.

In thinking about it, and having gone to look at it again, with the pedals at the previous (one hole away from full forward) position, the rudder cable attachment bracket (my best description for lack of a part number--I just looked and my "preview" plans do not include DWG OP-3A) made the cables too TIGHT once the pedals were moved further forward. So during the process of moving the pedals, having attached that bracket at its most distal position, the cables have too much LAXITY. So I am thinking of drilling another hole between the distal and middle hole of that bracket.

Those of you who may be wondering why it has been about two weeks, and I have still not finished this project, please note the Texas weather has (up until today) been >100 deg. F on a daily basis. Thank God for today's rain!!

[DanH]

Pull the insulation...leave the pedals.

[tmillican]

The rest of the story....

I pulled out the insulation, as per Dan's recommendation. This did give full travel of the rudder in each direction.

Test ground ops: No brake actuation possible with full rudder. Counterintuitive neutralization of the rudder pedals required in order to get brake actuation. Also there was a disconcerting metallic popping when the full rudder applied in each direction. Subsequently it was noted that the manifold pressure was reading 30.0 mmHg at idle....hmm.

So, I made the conclusion that fully forward rudder pedals are not operationally feasible in this particular aircraft. After another two hours, I got them all back to the original configuration.

Next project: fix the manifold pressure line which was broken by the full right rudder (disconcerting metallic popping sound). (http://www.vansairforce.com/communit...864#post555864)
Fortunately the cabin heat (lfull left rudder popping sound) connection remains intact. I guess the insulation is superlative. I will leave that out for the time being.

Lessons learned.

Thanks to all.

[moodyjr]

Troy

I had the same problem. I'm 6'5" & use the forward-most pedal position. My firewall insulation is only about 1/8" thick but I still just touched the firewall.

Solved the problem by remaking the flat steel links connecting the cables & pedals about 1/2" shorter to allow full pedal travel & brake actuation. Might be worth considering if your son will be a regular user of your aircraft.

John Moody