control column pitch centering using gas struts

[David Withers]

sorry i'm not yelling...just love my exclamation marks.

pm if you need help

[Michael S]

Thank you, David.

Sorry. Imho your draft only makes sense when using gas struts, that are pulling. I´ve got gas struts, that are pushing. They are compressed when they move in. This is how they work:



Maybe I misunderstood it but I think you are refering to pulling gas struts.

I also don´t really understand why I should use both gas struts and springs.

I do understand that the gas struts equal each other when both are compressed and thats why my centering didn´t work. But why should I use springs additionally?

Thanks anyway.

[Radar]

Mayby this could help. Ian P.Sissons did a awsome job on his column

[David Withers]

Yep no problem.. You are correct. Most gas struts and the screen door closers gwyn was on about are pulling ones. They are nowhere near
powerful enough so we add springs for the return cycle.

Something that has sorta been perfected here in Australia and works like a charm.
The spring pulls and the gas strut dampens the pull.

Your pushing struts are another matter. Good luck on that one.
Btw the springs have no connction to the column.. They simply help the piston retract .

[Michael S]

Mayby this could help. Ian P.Sissons did a awsome job on his column

Thanks. I know his documentation. But I don´t understand how he did the centering because his gas struts are also compressed both. That´s what I mentioned before:

I was just wondering: when researching for this project, I relied for example on Ian`s page:
http://www.737ng.co.uk/Boeing_B737_Control_Column.pdf
His gas struts are not free to slide. So I don´t really understand how he achieved the centering. I´m just curious.

--------

They are nowhere near
powerful enough so we add springs for the return cycle.

Thank´s alot, David, for your help. My gas struts are really powerfull, 110N both. So I think I can do it without springs.

[Michael S]

I have now designed something working similar to the drafts that you guys posted. I would like to know what you think of it and if it will work.

The outer ends of the gas struts are mounted into a rail. In center position both gas struts are decompressed and fitting at the outer ends of the rails. If the column is moved to one side, one gas strut will be compressed because it already sits at the outer end of the rail. The other gas strut is free to slide towards the column. I hope you understand what I mean. Just have a look at the picture.






Thanks in advance.

[Crescent]

This system should work fine. I came up with almost the exact same design when looking at my own, but it didn't give me the correct tension I needed for the Lancaster, otherwise I would have used it. I had to go with a spring system instead. Good work.

Chris.

[Michael S]

Thanks a lot to all who helped.

I will try it like shown above and keep you posted.

[ak49er]

Make a very gradual "v" block, dead center under the desired column centering point. Then add a spring loaded rubber wheel onto the bottom of your column. Then when it rolls back and forth, it will lightly catch the bottom of the "v" shape. If you make the spring loaded rubber wheel adjustable, you can then adjust it for feel, and for if you add anything else later like switches, checklist holders, etc.

[spitfire9]

Michael S,, your last post is just about exactly what I was getting at with my very poorly drawn tube method.