Help with yoke construction.

[kurt-olsson]

Ok, while saving up for the FDS mip i will start to build my yoke construction.
I was lucky to get hold of the steering boxes and also the rod between the yokes.

I thought i had everything figured out and the previous owner had the canles setup aswell.

I thought the "silver-steel-thing-connection" between the yokes and the boxes was turned 90degrees so it could handle movement in the forward and backward motion with the boxes fixated. But when i look they are turned 90degrees the other way. Does this mean that i will have to fixate the boxes to the rod so they will rotate aswell when i move the yokes forward and backwards?

I have seen lots of constructions but none with original steeringboxes.
What would any of you who have knowledge with the yokes do with my hardware.

With "silver-steel-thing-connection" i mean the steelthing i have holding with my finger.

Really fun to start building the yokes, been waiting for space for 2 years. Hehe

[XOrionFE]

You wont want to bother with those lower boxes.   Remove the tabs and fit a piece of pipe to extend the shaft downward and attach pullys to the extension.  Yes, the pulleys will move with the bottom of te yokes.    See pictures i have posted or take a look at my youtube videos.   

Scott

[kurt-olsson]

Thanks Scott, just wanted to be sure that i was doing the right thing removing the boxes. Your videos is alot of help.

[kurt-olsson]

By the way, how did you make/buy your extension pipe?
Almost all builders have this technique.

I am thinking of some hard plastic tube that has the right measures?

Where did you find this part for your build Scott?

[Gallie]

You are very lucky to own original aileron linkage parts.
The only reason NOT to use the original aileron linkage is because of the lack of sim room height. You would probably need a cockpit floor height of 30/40cm maybe even a bit more.

The connection between the control column and aileron linkage is called "clevis & spade joint"

The aileron drums "boxes" are fixed to the aircraft (cockpit floor), only the control columns moves.

Its not just extending the "pipe" and fitting it with a pulley. You must also design bearing brackets, because of the shear force on the pulleys when the cable is put on tension with the turnbuckles. Without any bearings to support on the extended pipe, the tension of the cable will loosen over time.

Before i had my 737 cockpit, i used original 747 aileron linkage. This meant i needed a 30cm high floor, but it saved me a lot of time designing and building custom aileron linkage.

Michael

[XOrionFE]

You are very lucky to own original aileron linkage parts.
The only reason NOT to use the original aileron linkage is because of the lack of sim room height. You would probably need a cockpit floor height of 30/40cm maybe even a bit more.

The connection between the control column and aileron linkage is called "clevis & spade joint"

The aileron drums "boxes" are fixed to the aircraft (cockpit floor), only the control columns moves.

Its not just extending the "pipe" and fitting it with a pulley. You must also design bearing brackets, because of the shear force on the pulleys when the cable is put on tension with the turnbuckles. Without any bearings to support on the extended pipe, the tension of the cable will loosen over time.

Before i had my 737 cockpit, i used original 747 aileron linkage. This meant i needed a 30cm high floor, but it saved me a lot of time designing and building custom aileron linkage.

Michael

Excellent point on the bearing brackets at the bottom Michael.     Kurt, if you look at my videos you will see that Inhad tomdo exactly what Michael mentions.   You need bearings at the bottom with a plate and tied to the opposite side so the cable tension cannot cause all to bind up.   Plastic extension tubes will not work.   You need very precise fitting down tubes and a way to apply a bearing.    This all requires custom design and machining work.   Find a local machine shop to help you out.   Again, feel free to copy what I did but take your time...there are many angles and relationships to work out with the mountings.  You also need to make some mounts for the crossovertube bearings that all swivels on.

Even without the streering boxes tou will ultimatly need about 12-15 inches of space under your cockpit floor.  Hopefully your room height will support that. 

Scott

[Caflyt]

When I did mine, I had two solid aluminum rods machined to "press" into the original down tubes then the rod was drilled and tapped to accept a 1/2" bolt which has sprockets attached for the connecting chain. I did add a bearing plate to keep the rod from binding from the tension of the chain.
I don't have any pictures of that however.
I had a 1" square tubing frame welded to hold the entire assembly and used 1/2" long bolts at either end which fit into pillow block bearings on each side of the subfloor. Sorry the pictures are bad.

Craig

[kurt-olsson]

I have a picture from the previous owner, serious setup but as you say, require lot of height.

The thing  is that i dont event still with the picture understand how the clevis and spade joint is working. I dont see how it would work when pushing the column forward and backward as the clevis and spade is aligned with the front of the yokes.

[bernard S]

someone on this site   must have chapter 27 for thev73   flight controls that will give you all thevanswers including teentions

[kurt-olsson]

I would like to try with the original linkage because my roomheight is 2,5meters so i think i can do it.

[bernard S]

go with orginal in this case its going to be easier   if anything is actully easy with sim building ..heres why i suggest go orginal   because there are springs on yokes so if one chap pushrs tgr other pulls they pop   leaving onr working   they reset sonits fun   get the bits you miss

[kurt-olsson]

Thanks Bernard, i will try to get some drawing of the yokes so i can see how the actual thing is put together. I think i understand why the clevis and spade joint is rounded, so it can handle elevator movement.

[Gallie]

I also have 2.5 meters and my cockpit floor (original cockpit) sits at 50cm. ive only got 2 cm to spare with the ceiling....

The clevis and spade joint works like a charm... this setup has been working like a charm since the very first 727/737/747's... Just give it a try.

If for some reason you wont be able to use the original linkage parts, you can also try this:
My first linkage project (many years ago) included a aluminum insert into the bottom of the control columns. it supports a shaft through the center connecting both aileron tubes with angled gears. Its very strong, dont have problems with cable tension and so forth. The usage of high quality gears is recommended.
This also meant the total required floor height would be about 15cm..
The insert also made it possible to use a aluminum tube as crosstube, for people who dont have these.
The idea and design of the insert is not my own.

Ive included some pics of this project with measurements of the insert.

[Gallie]

A snippet from the manual.

[kurt-olsson]

I like to simplify stuff and building the "support floor" for the steeringboxes will be as challanging as creating a simple setup like the tube in the column approach.

Your setup looks awesome Gallie!

[kurt-olsson]

When I did mine, I had two solid aluminum rods machined to "press" into the original down tubes then the rod was drilled and tapped to accept a 1/2" bolt which has sprockets attached for the connecting chain. I did add a bearing plate to keep the rod from binding from the tension of the chain.
I don't have any pictures of that however.
I had a 1" square tubing frame welded to hold the entire assembly and used 1/2" long bolts at either end which fit into pillow block bearings on each side of the subfloor. Sorry the pictures are bad.

Craig

Hi Craig. How did you press the rods in? Did you donit yourself or did you find a company that could provide this service?

[Caflyt]

Peter,
I actually did it myself.
I slowly tapped it in with a mallet until it hit the riviets  about 1 1/2" in to the down tube. Then I drilled through the existing hole in the tube to insert a bolt to keep it in place. It is a very risky way to do it because there is no way to ensure it is exactly straight, I think I got lucky.
The rod was machined to be VERY tight in the tube.

Craig

[XOrionFE]

Very nice design Craig!

[kurt-olsson]

Wow, nice setup.

[kurt-olsson]

If i use the oroginal clevis and spade, does anyone know how these parts move when pulling back and forward of the columns?

[kurt-olsson]

After some more investigation i think i will try the beveled gears approach. The hardest part will be to find a good spot for the springs for resistance because of my plan is to have the long axel inside the crosstube.

[XOrionFE]

After some more investigation i think i will try the beveled gears approach. The hardest part will be to find a good spot for the springs for resistance because of my plan is to have the long axel inside the crosstube.

Beveled gears?  Long axel inside crosstube?   Now I think you are going down a rabbit hole.  You should rethink that.   You have two great examples on how to best set this up (mine and Craigs).  That is if you chose not to use your lower boxes.   If I had the lower boxes and the room height I likely would have used them incorporating them into my platform as that is the original design and best design by far.   However, with your room height which is similiar to mine I think it will be tight when you factor in the shell and especially if you were going eventually for projectors.

Scott

[Caflyt]

https://www.dropbox.com/s/imr7zsjhwckda8f/Pitch%20Mechanism.mov?dl=0

By the way, this video shows my "pitch" mechanism also.

Craig

[kurt-olsson]

After some more investigation i think i will try the beveled gears approach. The hardest part will be to find a good spot for the springs for resistance because of my plan is to have the long axel inside the crosstube.

Beveled gears?  Long axel inside crosstube?   Now I think you are going down a rabbit hole.  You should rethink that.   You have two great examples on how to best set this up (mine and Craigs).  That is if you chose not to use your lower boxes.   If I had the lower boxes and the room height I likely would have used them incorporating them into my platform as that is the original design and best design by far.   However, with your room height which is similiar to mine I think it will be tight when you factor in the shell and especially if you were going eventually for projectors.

Scott

Your right, that seems to be very complicated. There must be a reason for 99% of the conversions have the same setup as yours.
I have decided to go with a tube inside the columns and wires between them to connect the movement.

My first Profe-of-concept will not have any bearings, just the rods and the wires.
I have seen another conversion that have this.

But my first problem, if you look at the pictures below, how on earth can i remove the screw thats holding the clever?
i removed the screw on the one side but when screwing the other one the rod just rotates. What tool do i need to hold the rod while loosing the other side. And can this even be done, feels like the rod is designed in some special way. Shoudl i just try to cut it with a saw?

See pictures below...

[kurt-olsson]

i will copy this solution.
https://www.youtube.com/watch?v=s29E1CN_k6U