Control stick mounting

[svyolo]

I am fixing something today I did early on. I mounted my control stick assembly on the 4 place as far back as I thought I could. But I had 3/8" farther aft to go, and to line up with the lower aileron pulleys, I need all of that.

I would recommend doing what I am doing now. Carefully check the location of the cables. The pulleys are canted a bit aft on my kit. They are not perpendicular to the fuselage centerline. I need to go as far aft with the stick assembly as I can to reduce friction on those pulleys. Using an AN4 nut as a guide, I will mount the stick as close as far back as I can, which looks like it will make it line up perfect with the pulleys.

I am plugging the original holes now, and will re-drill.

I could feel the friction in those pulleys when I had the wings on and aileron cables rigged.

[Battson]

Make sure to drill the hinges so they are running tight against the outer bushes welded into the control stick assembly, and lube them well. Otherwise you'll end up with sloppy ailerons in ten years time.

[svyolo]

I hadn't thought of that, thanks.

[AKKen07]

Careful to leave room for the nuts under your attach points. I was barely able to fit nuts after grinding the corners down because I was a hair too far back.

[Battson]

Another consideration is the stick hitting the seat upholstery.
Having the hinges further aft could make this issue more common / worse.

Once upholstered and placed at the full-forward position, the seats can interfere with the joystick travel to full up elevator. Although the stick position can be adjusted with the bellcrank arm length, you don't want to be reaching too far forward to get full down elevator travel. The sticks also have to pass under the instrument panel, so anything you put back there is another consideration.

[svyolo]

I originally just took a guess at how far back I could go and still have room for the nut. After rigging everything, the stick was too far forward and I had a lot of friction on the pulleys on both sides.. Putting it so that the nut will barely fit looks like it will fit better. I will try tomorrow. I may end up grinding some of the nut off myself. Placed against the tube, the new hole is less than 3/8" farther to the rear, but that misalignment was enough to cause siginificant friction on both sides.

Easier to fix now.

[Nev]

I’ve just been fitting mine so this post is topical for me too. I was able to alter the cable turnbuckles as well as the bellcrank arm to move the stick forward. Early days though, so I don’t know where it will sit in relation to the upholstery.

[James]

Has anyone tried mounting the controls with nutplates, to get around the nut interference issue?
If not, can you tell me why not? I did that for the rudder pedals, and it looks like it'll work fine.

The spec book I use says a MS21044 nyloc nut and a MS21047 nutplate have the same tensile strength rating.
But I'm not an engineer

I haven't got up to the controls yet, but this post has probably saved me a ton of heartache, giving me things to look for before drilling. Thanks!

[svyolo]

A few weeks ago I wanted to post something I fixed because I screwed it up months ago. Someone else screwed it up. I felt guilty.

I will check an -3 nut plate to see if it gives any more room.

[Mark Goldberg]

I have ground down one side of a nut to help it fit in tight places. There are also some small nuts. Mark

[James]

I've used MS21043-3 and -4 nuts extensively, again rated for tension at 125Ksi, and they have a much smaller profile than MS21044N3 type nuts.
NAS1804 type nuts have a smaller profile again, and a higher tension rating again, but require a 12pt socket to get onto them, so not so good for tight spots.
From experience, both of these nuts will usually snap an AN3 bolt before they let go, whereas you can sometimes (rarely) pull the threads out of a nutplate if it's not mounted squarely.

SV - can I check the alignment of the aileron cables with the wing off by mounting the pulleys and just pulling the cable tight to see the lay?

Thanks again for the post mate,

James

[Nev]

I ran a line between the aileron pulleys through the control tube that is mounted to the floor to check alignment.

69E96401-4807-4619-98BD-808988681B15.jpeg

[svyolo]

I am going to clamp my sticks back in place and try to take a couple of pics. If I remember right if you put them on that line, the stick will be too far forward.
My pulleys are canted slightly aft. If I took a line exactly in line with both pulleys, it would form a slight V in the middle, aft of a straight line between the bottom of both pulleys.

[svyolo]

The geometry is not as simply as a straight line, at least on mine. I would completely assemble the stick assembly, take a piece of cable with a thimble and nicopress on it, and move the stick around to make sure it isn't rubbing on the sides of the pulley.

Right now "perfect" is a bit farther aft than I can go on the rear holes. Even grinding a nut won't do it. i think "close enough" will work by grinding the nut slightly.

[svyolo]

The cable is centered in the pulley when centered, but comes close to the edge of the pulley with opposite stick. I move the stick fore, aft, right and left and make sure there is no rubbing.

[Nev]

I’ll check this thanks John. Mine is mounted far enough aft that I had to modify a spanner to tighten the Nylocs.

FDF17AE7-D98F-4F68-ACE0-ECB12CB1157D.jpeg

[svyolo]

Before I drill I have to make sure I can hold it as well.

[James]

John, at the top post, you mention gauging your clearance with an "AN4 nut" (presumably MS21044N4), as per my plans page 26, and the holes in the control mounting tabs, the holes are 3/16", i.e. for a -N3 nut.

[svyolo]

Yea sorry, -3. I think the rear bolt will need to be a Cap head screw as well. I can't turn the nut or the bolt.

[James]

Yeah, well that's another good idea. Did you look at the nutplate option?

[svyolo]

In theory it works and you have more room to move the nut a bit farther aft. I am not sure about max torque on a nut plate vs an ordinary nut. As long as torque is no problem I think it definitely makes assembly and disassembly easier as well.

[James]

Yeah, I thought about this also - in my experience installing tens of thousands of 10/32 screws and 3/16 bolts into nutplates, 95% of the time the threads on the bolt fail before the threads on the nutplate. As long as it's not drilled in at an angle with any side loading, it should be just as good. Because it's under tension once installed, I'll use a one-legged one to get further aft, rather than a mini-one mounted cross-ways.

This thread's been floating around the forum for a few days now - if there were alarm bells ringing for any of the old hands, they'd have said something by now I guess!

[edmo]

Most of this discussion seems to be about fore/aft mounting of the control sticks. Has anyone run into the rod end interfering with the supports for the top of the flap quadrant? Even without the rod end bearing installed the control horn itself would still contact that tube. I have tried mounting as far forward on the fuselage tabs to as possible to as far aft as seems to be the general consensus here . That would put the bearing behind the tube, but then it would contact it in the forward direction. Per the plans, it seems the neutral control position should have the other end that attaches to the elevator bellcrank in line with the V braces under the seats which is where I currently have it. Is this a simple matter of threading the rod end bearings further out, or is there guidance on that other than what puts the control stick in a comfortable position? I have model B fuselage 22B.

[Chris Werner]

edmo, I would recommend reaching out to Mark on this. He can advise you on a solution. I was at that same spot very recently.