C

Camillo

Well Known Member
I installed my sticks on the control column, having previously drilled to full size the brass bushings, and connected elevators.

I noticed that when you push or pull the stick grip there is a certain "dead point" (I don't know the exact term) dued, I guess, to excessive tolerance of the bushings.

I'd like to know from others if this is an issue I have to deal with or not. I mean: when I will fly, will I notice this?

A colleague who built a few RV's told me he remade such bushing a bit larger...

Thanks.
 
control slop

You may in fact notice the small amount of slop in the control sticks after your plane is rigged. I found it annoying, so I had to go back and work the excess play out of my sticks, and it was a bit of a challenge. I found that any play in the stick assy as it slides laterally, or up and down on the outside of the brass bushing, needs to be removed. I accomplished this by shortening the steel tube that slides over the bushing, and installing well greased -4 thin washers on each end to take up the slack. This will all bind up if the legs of the center section are not at 90 degrees, so make sure they are not pinched together. I also removed the powder coat at these key areas, and polished up the washers a little. As for the bushing OD to stick tube fit, I ended up having to enlarge the bushing very slightly by prick punching the OD of the bushing very lightly around it's diameter. Careful here, it just takes a little. use a very sharp prick punch. emory it down to fit just a little snug in the tube. The punch marks will also trap lubricant, and the entire assy will wear in after just a few hours. On final assy, I left the whole thing just a little snug, and after a very short time it loosened up to give me a perfect feel.
On my list of "important things I learned" for sure, and I will pay close attention to this on my current project when I get there!!

Hope this helps,
Chris
 
Camillo,
I assume you also ground the bushings on the ends to fit the stick weldment correctly as they are not square.
 
Very normal.

Push tube and rod end type control systems are hard coupled, so you will feel every little bit of slop on the ground, when there is no opposing force against the control surfaces. You will not notice any slop when flying. Mine has about an 1/8" stick movement on the ground, feels like velvet in the air.
So, if it bothers you, take the time to deal with it. Personally, it does not bother me. I care how it feels in the air, not on the ground. It is a personal choice and some people are very bothered by it.
 
Thanks to everyone.

Well, I omitted to say that when I started installation of control column I made a mistake, because I shortened (as carguy suggested) the steel tube in which the bushing is inserted to "nest" the U shaped main column. The problem is that the latter was not 90?. So, when I installed everything, I discovered that it became tight as one goes to the left. I then straighted it up but...the steel tube was too short and the stick went slightly fore and aft. I ended up by inserting a thin washer and this problem was fixed.

Apart from this, I was worrying about the slop (is this its right position?) between bushing OD and steel tube ID. Now, I don't remember well, but I recall having sanded it just to achieve a tight fit. Or maybe not. However, I have that slop, now.

I did not understand well carguy techinque. Will I have to make a lot of punches along the outside surface of the bushing in order to let it become more rough?

Besided, I had the same issue (very little) with Tosten grips. The tube which goes inside is not a very tight fit, so when you try to move the grip along its "pitch" axis it adds a little more slop. I'm planning to remove this adding a 1/8'' pop rivet facing in the aft side of the stick. On the fore part of it there is already the Tosten bolt, so I guess that one on each side will definitely stop this very slight movement.

Thanks.
Camillo

carguy614 said:
You may in fact notice the small amount of slop in the control sticks after your plane is rigged. I found it annoying, so I had to go back and work the excess play out of my sticks, and it was a bit of a challenge. I found that any play in the stick assy as it slides laterally, or up and down on the outside of the brass bushing, needs to be removed. I accomplished this by shortening the steel tube that slides over the bushing, and installing well greased -4 thin washers on each end to take up the slack. This will all bind up if the legs of the center section are not at 90 degrees, so make sure they are not pinched together. I also removed the powder coat at these key areas, and polished up the washers a little. As for the bushing OD to stick tube fit, I ended up having to enlarge the bushing very slightly by prick punching the OD of the bushing very lightly around it's diameter. Careful here, it just takes a little. use a very sharp prick punch. emory it down to fit just a little snug in the tube. The punch marks will also trap lubricant, and the entire assy will wear in after just a few hours. On final assy, I left the whole thing just a little snug, and after a very short time it loosened up to give me a perfect feel.
On my list of "important things I learned" for sure, and I will pay close attention to this on my current project when I get there!!

Hope this helps,
Chris
Click to expand...
 
You must log in or register to reply here.