Converting my old pneumatic retracts to electric.

[Flyinfool]

No limit switches. The controller monitors amp draw and when it sees a set peak amp at the end of travel it stops, then backs the motor up slightly just to unload it and then turns off until the gear is commanded to move the other way.

 

[Flyinfool]

OK It took some time and futzing around but I have the first gear assembled and it moves up and down.
I have not yet tried it with a heavy wheel and strut but that will be coming soon. At least it all moves and works. I did order a couple more motors with different speeds to see what will be the best compromise between what works best and what I think I want. this has been a heck of a project, There were a lot of mess ups and just as many saves.





And even a video link...

 

[Dhal22]

Wow! The RC world would go crazy with this.

 

[Dhal22]

OK It took some time and futzing around but I have the first gear assembled and it moves up and down.
I have not yet tried it with a heavy wheel and strut but that will be coming soon.

The real test would be my landing skills test…………….

 

[Flyinfool]

Oh I can assure you that they will be getting impact tested once I start flying them.

I still have to trim the threaded shaft to final length so that they can get full travel.

Then I will mount the wheel and strut to be sure that the motor can actually lift the weight.

Then another test with the leaf blower to be sure that the loads imposed by flying thru the air plus the weight will not overload the motor. I may still have to go one or 2 steps slower with the gear motor for more power.

The very last step will be to take everything completely apart to apply Loctite on all fasteners and lube all moving parts.

 

[David2011]

I really admire this work. Fortunately I bought a big box full of Spring Air retracts a few years ago; probably more than I’ll ever use. Someone asked me if I would be interested in making a set of large airplane retracts for them recently. After some discussion I offered him access to my shop.

 

[Flyinfool]

Wow! The RC world would go crazy with this.

Not really There are many makers of electric retracts. I am not sure if anyone even still makes air retracts.
But then the RC world is kind of crazy to begin with.

 

[kenh3497]

Not really There are many makers of electric retracts. I am not sure if anyone even still makes air retracts.
But then the RC world is kind of crazy to begin with.

Robart, the premier manufacture of pneumatic retracts just announced they will be ending production of their retracts. They will be selling current stock but when it's gone it's gone.

Ken

 

[Dhal22]

I have many sets of 60 size retracts (Spring Air, Supra, MK, etc. Don’t know what I need until I need it though. Hate to see Robart ending though.

 

[Flyinfool]

Well a final update.
I have doing a lot of playing with different motors. It is pretty tedious switching out motors, between the assembly / disassembly of the whole gear assembly, soldering a filter capacitor and the power wires and then adjusting the bearing to take the axial load off of the gearbox. I guess I am finding out why they are so cheap. Once I added the weight of the wheels and struts the gearboxes are breaking after 10 to 15 cycles of the gear. I have tried every speed motor available (200, 300, 400 and 500 RPM) in this series and get the same result.
It was a lot of fun designing and making all these parts. I learned some new things and acquired some new tools. But in the end the motors were just not up to it. I am looking at getting some replacement motors for other electric gear to try to adapt into my landing gear. This may or may not require some new parts to adapt them.

If I make any progress I will post it here. I do need to get something working. This poor jet is collecting dust right now. It wants to go out and play.