Removable Co-Pilot Control Stick

[Archer39J]

I'm thinking about ways to increase comfort for my SO, and therefore my overall comfort as well. Being able to remove the co-pilot control stick seems like it might be worth the effort.

My plan is to split the co-pilot's stick an inch or so above the top hinge point just before the 90 deg part, there's not a lot of space there so it might be 1/2" or 3/4" I'll have to see. Then ss pop riveting in a sleeve on the lower part that the upper stick will slide over. The upper stick will be retained with a quick release pin of appropriate size, 1/4" might do just fine.

Ideally a sleeve overlap of 3/4" would provide sufficient edge-margin for attachment, but again I'll have to see what I'm working with. Just wanted to run the concept by the forum and see what the thoughts are.

ETA: Actually, I could sleeve past the upper attach point and just put a clearance hole through the sleeve, so not so worried about space in that case. Since that bolt would then also be retaining the sleeve I could do away with the pop rivets and just use adhesive to hold the sleeve in place, hmm...

[whee]

That's basically my plan. Though I will likely rosette weld the sleeve into the stick. That's how it was done on my Luscombe.

[Battson]

You have a long lever there, cutting into it will weaken it a lot. I suggest talking to Bob.
You'll need to ensure there's enough overlap to avoid very large bending moments. I don't think you can cut at a 90 degree angle - AC43.13 requires an angle cut to reduce point loads, if you are going to weld in a fillet.

[Archer39J]

Right about the bending moment there, but a good and long sleeve will solve that. Then there's the rotation of that shaft during aileron movement which will bear solely on that pin, but they're rated something like 2400lbs shear. Attached is a pic of what I'm thinking, but I'll run it by Bob for good measure. I'm not planning to weld any of this at this time, and my green pin should be the other way around...

Blue sleeve, green bolts and pin, red cut line.

[Battson]

If I may offer a little more (unsolicited nay-saying):

Tolerances need to be very tight down at the hinge point. In terms of "Engineering Fit", a tight press-fit is desirable (or tight location fit). A clearance fit - even just close running clearance - translates to an awful sloppy feel at the top of the stick. It makes landing and flying a well controlled approach very unpleasant and dissatisfying. Honestly, I have been trying to undo some reaming I did in the main joystick bolt for years.

Just a fraction too loose in the pin joint or fit of the stick would translate to a huge dead zone in the joystick. Definitely think about it carefully.

[S Lathrop]

If you put the slip joint in the horizontal section, you can extent the horizontal receiver tube beyond the section coming up from the pivot. I would have a cross pin in the removable part of the control stick that fits into a slot in the receiver. On the back side I would split the tube and have a wedge that when drawn into the tube expands the removable tube inside the receiver, locking everything in place.

Just an idea for a solution that will give a solid connection.

Sorry that I can't explain the idea any better.

[JJohnston]

IMG_0001.jpg

How about a "pipe flange" arrangement? Like this. This may not be allowed, though, since it's got a 90° cut and fillet weld - but it would have zero play. If you don't have a PTT wire running down the stick, the plates would not have to have holes in them.

[James]

Or maybe a threaded pipe end, with a knurled nut to hold the flanges together?
It'd have to be pretty solid though.

[Archer39J]

If I may offer a little more (unsolicited nay-saying):

Tolerances need to be very tight down at the hinge point. In terms of "Engineering Fit", a tight press-fit is desirable (or tight location fit). A clearance fit - even just close running clearance - translates to an awful sloppy feel at the top of the stick. It makes landing and flying a well controlled approach very unpleasant and dissatisfying. Honestly, I have been trying to undo some reaming I did in the main joystick bolt for years.

Just a fraction too loose in the pin joint or fit of the stick would translate to a huge dead zone in the joystick. Definitely think about it carefully.

No that's a really good point, you articulated what I was just beginning to wonder myself. Any looseness would be unacceptable for a control assembly. Since I'm not really interested in the ability to remove on-the-fly, so to speak, I might look at replacing the copilot stick with a solid piece just to get more room for my lady.

[Mark Goldberg]

You might give your lady a chance to try it as designed first. The stick is really not in the way except when getting in or out. Maybe she would enjoy learning how to fly the thing a bit. You could always do a mod on the stick after you are flying as it is very accessible. Mark

[jaredyates]

A day of ground school and a few hours of dual, and she might just take up flying.

[JJohnston]

Then you'd have to take the right stick out, to keep her from trying to take over.

[whee]

Battson makes good points the anyone that is thinking about doing this needs to consider. However, I still plan to chop off my co-pilot stick. All Luscombes have the same kind of splice in both sticks that we are discussing here but the sleeve is rosette welded into the stick and has an AN4 bolt that fastens the stick to the control assembly. If you hold both sticks you can feel the slop but it is imperceptible during flight, at least to me and I've never heard anyone in the Luscombe community mention it. Obviously the Luscombe assembly was designed to come apart but the BH stick wasn't so bending moments need to be considered but they won't be hard to mitigate. Also, any copilot that yanks on the stick hard enough to break it need not be invited back into the cockpit.

Archer, what you have depicted is better than what I had rattling around in my head. Thanks for sharing.

[Archer39J]

Battson makes good points the anyone that is thinking about doing this needs to consider. However, I still plan to chop off my co-pilot stick. All Luscombes have the same kind of splice in both sticks that we are discussing here but the sleeve is rosette welded into the stick and has an AN4 bolt that fastens the stick to the control assembly. If you hold both sticks you can feel the slop but it is imperceptible during flight, at least to me and I've never heard anyone in the Luscombe community mention it. Obviously the Luscombe assembly was designed to come apart but the BH stick wasn't so bending moments need to be considered but they won't be hard to mitigate. Also, any copilot that yanks on the stick hard enough to break it need not be invited back into the cockpit.

Archer, what you have depicted is better than what I had rattling around in my head. Thanks for sharing.

Right on, I'm not yet decided and will certainly marinate on it some more. Getting that assembly rock solid would be key, perhaps with a nut and bolt like you suggest. I'll have to mock some up and see what I think is acceptable.

[Bcone1381]

Would your stick attachment be a good place to use an AN386 Taper pin?
an386taperpin.php

[bergy]

Reminds me of my first experience flying a Champ, spring of 1970. Guy had a '46 Champ with an 85 for sale at local airport. $2K + $200 for the skis. I called owner and asked him if I could try it out. He said OK, but I should take the local FBO with me because I had never landed a taildragger. The Champ did not have a stick for the rear-seater, just a socket on the floorboards. The FBO went to a toolbox along the wall and picked up a socket-wrench breaker-bar and checked to see if it would work for a stick. It went into the socket with about 1/4" of slop. "Good enough" he said, and we were off. The Champ flew well but the cotton fabric was getting brittle. Wish now that I had bought it tho. Thankfully the breaker-bar was not needed, and technically I am now grandfathered in as taildragger qualified