Full scale control stick design

[VO101_MMaister]

Hi,

 

I am new at this forum. I started a control stick building project, and I would appreciate some feedback and input by others. So please review it and don`t keep your opinion, even if it is criticism.

 

The plan was the following;

 

- Stick length and travel acc. to the original Bf109 specifications (+20/-20 deg. deflection, ca. 500mm stick length)

- Stick forces ca.3kg at max. deflection

- Mechanism rolling on oversized ball bearings

- Centering forces provided by extension springs, independent springs for both axis.

- No concrete centerpoint

- Damping by rotary dampers on both axis

- Hall effect rotation sensoring

- BU0836A control board.

 

Here is what I have today. The biggest problem is the placement of the springs. The 40deg overall deflection cause a long travel ,so it was needed to place the springs as low as possible (to keep the travel within their working range). But it also means that the lever arm of the torque is short. To produce sufficient torque I had to choose powerful springs. All of them produce 390N at maximum deflection. That is a lot. I made some stress analysis to check the parts, but I am not feeling confy about the overall design. All ideas welcomed

 

 

 

The cylindric parts are not pots but rotary dampers.

 

Thank you

 

MM

[Slammin]

Careful, Ian may have a patent for the Cougar Nxt2 and that looks identical!

[Peter_Pilot]

MM,

 

Welcome to the ED Home Cockpit forum.

 

Your design looks good, do you know what materials you will use and do you have the tools you will need to make the parts? I was wondering also where the springs will be for the other axis.

 

I have made a stick with Hall sensors and a BU0836X card but I prefer much lighter stick forces so I have only 10N at the hand grip for +/- 15 deg of stick travel (30deg total). I only used one vertical spring attached to the stick below the gimbal assembly.

 

Which part did you do the stress analysis on? maybe bending of the spring attachment spigots?

 

I am no expert but I doubt there is anything in your design that is protected by a patent, copyright might be an issue if your design is identical to someone else's and you tried to sell some for commercial gain.

 

I am sure there would be plenty of other builders who would like to see your progress.

 

Best wishes,

 

Peter

[Moa]

Copyright is only an issue if you copied the files of someone else's design.

 

If you produce an identical design by yourself from scratch that is known as "re-engineering" and is not copyright infringement.

 

If you do it without reference to their design it is known as "clean room re-engineering" and is not copyright infringement.

 

A patent on the design would not be enforceable if there were any 'prior art' of similar designs that were published to the public domain.

 

I'm not a lawyer, but I wouldn't be too worried. Peter_Pilot you are right to raise these as possible issues to always consider, but I don't think they'd be a realistic problem in this case.

[Frazer]

VO101_MMaister, you might want to take a look @ TARMAC ACES as they sell Bf109 grips. As for the mechanizm, building your own is probably best.

 

Your design looks promising. :) Keep it up!