Elevator Up Stop question

I've posted on this before because I built my "up stop" as per the plans and it was just a hair too short. I rebuilt it with 1"x1" angle and left the whole 1" there and it seemed to do the trick.

Well, a new problem has come up...I connected all of the pushrods and linkages for the elevators and the control stick is "bottoming out" before the elevator can hit the stop. When I say "bottoming out", what I mean is the eye-bolt on the control column is contacting the clevis when the stick is moving to the extreme aft position. There's another 1/3-inch or so before the elevators hit the up-stop.

I measured the angle on the elevators in the full up position (when the clevis & eyebolt are touching at the control column) and I'm getting about 27 degrees. I'm wondering if I will be limiting the range if I make a new control stop that's even longer - say 1-1/2 long.

Anyone else see this?

Update: Upon reading my own post, I started thinking that maybe the pushrods are too short, thereby limiting the amount of elevator travel. Any thoughts on this?

Yep, when the forward pushrod is adjusted to the proper length it is scarey short. maybe 4 threads in the bearing. I like others, made this rod approximately 3/4" longer and threaded the bearings in place after the rod was in place. Ultimately you want to make it so when its properly adjusted and installed, if both jam nuts came loose, there would be no way it could unscrew from either end. Thats how I did mine and it gave me a good peace of mind. However, if you made everything per plans, once adjusted properly the elevator horn will hit the stop and the control stick will be positioned correctly when the elevator is in the neutral position.

-Jeff

You have to grind or file away part of the clevis to allow the rod end body the clearance it needs.

If it's anything like my -6 you need to adjust the push/pull rods so that the elevator has full travel between the stops plus some clearance between possible points of interference at either end of the column such as the wing through spar, dash panel and pilot's abdomen!
Jim

OK, for some reason I thought that the bellcrank had to be vertical when the elevators were neutral and the stick was neutral. Shortening either of the pushrods will make the bellcrank tilt so that it's not vertical. I made the pushrods according to plans and if I center everything (control stick, bell crank and elevators) I will hit the clevis on the control column.

So is my thinking correct that if I shorten the front pushrod I will have to shorten the aft pushrod (otherwise it will push the elevator up) and the bellcrank will then lean aft? Is this OK?

I'm trying to do this in my head, but I think if I shorten the whole linkage it will allow the elevator to hit the stops first. I think.

Alignment procedures on the plans work perfectly. Modify nothing and it will work perfect.

-Jeff

Stick position?

Is the stick in the proper position when elevator is in neutra positionl? It should be slightly forward of vertical. Seems like this may cause the problem you're having.

lostpilot28 said:

OK, for some reason I thought that the bellcrank had to be vertical when the elevators were neutral and the stick was neutral. Shortening either of the pushrods will make the bellcrank tilt so that it's not vertical. I made the pushrods according to plans and if I center everything (control stick, bell crank and elevators) I will hit the clevis on the control column.

So is my thinking correct that if I shorten the front pushrod I will have to shorten the aft pushrod (otherwise it will push the elevator up) and the bellcrank will then lean aft? Is this OK?

I'm trying to do this in my head, but I think if I shorten the whole linkage it will allow the elevator to hit the stops first. I think.

Click to expand...

Just shorten the front push/pull rod. The top of the column will tip forward a bit but the bottom of the column will then clear the structure when the elevator hits the up stop. The bell crank can still be vetical when the elevators are in trail with the HS.

Jim Sharkey

Got it...

That's what I couldn't figure out...I saw another thread that showed the stick leaning forward just a little bit. I think that's where I was getting hung up. With the bell crank vertical and the stick vertical and the elevators neutral, the clevis was hitting the eye bolt. So, I think the stick will pivot forward a couple degrees with everything else lined up, but that's what the plans say it should do.

Thanks for the help!

Here are a few pictures for reference. I was schooled by another person on this board a while back so I cant take all the credit for my knowledge. Thats why I love this site!!!

-Jeff

Stick in near neutral position.


Longer pushrod for deeper insertion.



Bellcrank in vertical position.