Boeing 727 Control Yoke

[Michael Carter]

I recently received my Boeing 727 control yoke from the APHS. It's a very nice one and came from N7294U, an American Airlines 727. Flown many times by the man I bought the yoke from. It's now probably beer cans as Nick put it.

Anyway, I've been searching for a few days now for information about how to mount this thing to a PVC pipe control column. I didn't really find anything useful.

There is a short round section that exits the rear of the yoke about 1-1/8" ID that is splined internally. The Boeing control yokes fit perfectly on a 3" PVC 90degree elbow.

I know I'll have to afix a plate inside of the PVC elbow and mount some sort of a threaded extention inside the splined shaft and attach it to this plate.

Has anyone here done this, and if so, how did you go about it?

http://img264.imageshack.us/img264/2604/727controlyoke2fj4.jpg

http://img264.imageshack.us/img264/8181/727controlyoke1js0.jpg

[Westozy]

Check out my album pics there are close-ups of the yoke pivot base etc.


Gwyn

[Michael Carter]

Thanks Gwyn, but I could only find the image of the control columns pictured from the underside of the flight deck base.

I'm really trying to find info about how to mount the wheel to the 90 degree elbow.

If you have other pictures in the gallery of this, I couldn't find them.

[Westozy]

http://www.mycockpit.org/photopost/showphoto.php?photo=825

As you can see I used a tee with a bit cut off, not an elbow because I wanted to be able to have access to the wiring and cable adjuster. I machined a round PVC plug which is glued into the tee and this is drilled 1/2" in the centre. Do you have access to a lathe? I used some 1/2' stainless tube as an axle and the rainbow wire from my yoke switches comes through the centre and down the column. There is a pulley fixed to the axle with 2mm wire rope attached and this goes around pulleys at the base and across to the other yoke. (Both yokes rotate together). at the top of the pulley there is a cable grip on the wire that sits in a notch on the pulley, this gives an adjustable point for synchronizing and it is a positive drive with no slipping. I would say you need to make a hollow stepped axle to fit your spline and a bush to fit your elbow. Maybe you could find a roller bearing that fits in the elbow. If you are making a single seater just fit the roll pot to the back end of the axle. If you lived next door I could make you a solution in an hour!

Gwyn

[Trevor Hale]

Gwyn

I am still having troubles with the cable between my two columns. For some reason I allign everything, and then over time the FO column gets out of adjustment to the Capt. Any idea's how to solve this without going to chain and sprocket?

Trev

[Michael Carter]

Thanks for the advise Gwyn.

I think I have the problem solved.

I had a stick of Delrin rod left over from my throttle knobs. With some gentle tapping, it went right into the splined hole in the back of the yoke and will not rotate.

I cut two bulkheads, one of 1/2 MFD that nearly encircles the casting on the back of the yoke, and another that sits farther back in the elbow with a hole cut for the Delrin rod.

As the Delrin rod exits the hole in the second bulkhead I'll be using a shaft collar clamp around the Delrin rod to hold the yoke in the elbow up against the second bulkhead.

THe bulkheads will be JB Welded to the inside of the elbow.

I took apart a power antenna assembly for a car, and struck gold with all of the gears inside. I cut a small piece of one of the larger gears to make a ring gear to attach to the Delrin rod. The pots I K-Balled from a Thrustmaster joystick had a gear on it of the same pitch as the ring gear.

All that's left is to fabricate a mount for the pot and get it aligned correctly.

That wasn't as hard as I thought it would be.

I have to order the collar clamp so it may be a few days before it's completely assembled.

I'll post a pic or two later tonight.

THanks again for the ideas.

[Westozy]

Trevor,
My yoke set up doesn't slip so I will describe it a bit further.

The pulleys on the back of the yoke axles are identical and they both have notches cut out at the top, (see the pic from the previous post, the notch and rope grip are just visible). The 2mm stainless wire rope pass through a small electrical cable grip which is a small brass bush with a screw on the side. This screw locks on to the cable in the same position on both yokes so they are both physically locked to the wire rope. I have a small turnbuckle under the floor for tensioning the wire rope, it's not tight like a piano wire it's just tightened enough to still allow free yoke movement. If your yoke pulleys are fixed to the wire they can't possibly slip, did you miss making the rope grips? I can email you some sketches if this doesn't clear it up for you.
The turnbuckle is visible in this shot - http://www.mycockpit.org/photopost/showphoto.php?photo=576
The pulleys at the bottom of my yoke columns - http://www.mycockpit.org/photopost/showphoto.php?photo=622
Gwyn

[Michael Carter]

Here's a couple of shots of work so far. It's essentially complete except for the shaft collar for the Delrin rod you can see with the 1/4 ring gear. The shaft collar will butt up right against the aft bulkhead (the round piece of wood in the photo) to hold the yoke in the 3" elbow.

No shot of the forward bulkhead, but it carries the cast-in splined extention that the Delrin rod was inserted into.

The gears mesh very well and it has about 60 degrees of turn left and right.

The collar will be in on Tuesday and I will do the final assembly then.

Sorry for the camera-phone quality.

http://img81.imageshack.us/img81/1325/yokebuilding1ai4.jpg

http://img81.imageshack.us/img81/2684/yokebuilding2tc4.jpg

[Michael Carter]

I built a box for the column today. I have four really heavy-duty springs holding it upright. It leans back just about 10 degrees in the nuetral position. Right where it's supposed to be.

I need to find a flexible boot for the base. I also have to order another set of spherical rod ends to hook up the elevator axis.

http://img63.imageshack.us/img63/8129/yokebuilding3it2.jpg

[Bob Reed]

I would realy like to see pics of the base! Man that looks great!!!

[Michael Carter]

Standby one...

[Bob Reed]

2,3,4,5,......heheheeh :)!!

[Michael Carter]

I still have the top and ends to install, but I have to wait until the spherical rod ends arrive so I can hook up the pot.

http://img59.imageshack.us/img59/4968/yokebuilding4kh2.jpg

Those round things on the yke axis on either side of it are crutch cushions. I cut one in half and added it for friction. They're sandwiched in there pretty tight.

[Bob Reed]

Wow!! How are the springs fastened to the PVC? This is just what mycockpit is all about! What a great way to use a real yoke! This would not be real hard to convert to dual controls either!

[Michael Carter]

I just drilled small holes in the PVC for the springs.

This is probably the easiest piece of equipment I've built so far. There's just not much to it.

I still have to figure out the wiring harness, but that's no biggie.

[Bob Reed]

Now I do not remember where I saw it, but, someone has done that already. I am trying to remeber... Woops, there goes the magic smoke.... Sniff sniff, you smell something??!!!!

[Radar]

Now I do not remember where I saw it, but, someone has done that already. I am trying to remeber... Woops, there goes the magic smoke.... Sniff sniff, you smell something??!!!!
Do you mean this Bob?:D

[Michael Carter]

Amazing how similar the designs are. I guess there are only so many ways to get a piece of PVC pipe to stand up with a three pound yoke perched on top.

Oh, and by the way, I found the boot I was searching for earlier today. If anyone need one for a yoke they are building or thinking of building, here is the link:

http://pipebootexpress.com/index.aspx?lname=roundbase#data_sheet

I'll be getting the (I think) 3" to 6" size. $15.95

[Bob Reed]

No I was talking about the wiring diagram for the yoke. But that does look pretty close, yes?

[Michael Carter]

The cable exiting the yoke only has about 10 or 12 wires. It shouldn't be too hard to figure out which wire goes to what with a meter.

I'm going to use a Molex connector for the harness and leave the elbow/yoke assembly removeable in case it ever becomes neccesary.

[Trevor Hale]

Oh, and by the way, I found the boot I was searching for earlier today. If anyone need one for a yoke they are building or thinking of building, here is the link:

http://pipebootexpress.com/index.aspx?lname=roundbase#data_sheet

I'll be getting the (I think) 3" to 6" size. $15.95

Thats exactly it, you can buy these at your local Home Depot or Lowes as well, they have ones with a larger flange on the bottom if you like that is to go under your shingles, however this gives you lots of room to secure it from below.

[Michael Carter]

All I'm waiting on now is the boot and the shaft collar for the yoke axle.

I'm covering the box with sheet styrene and will be painted the same gray as everything else.

All wired up and nowhere to go!!!

http://img340.imageshack.us/img340/1860/yokebuilding5tr1.jpg