Converting my old pneumatic retracts to electric.

[Flyinfool]

I have an old turbine powered jet with retractable landing gear. This jet is now about 20 years old. The old pneumatic system is getting old and tired. Between age attacking the seals and just plain wear they just do not work well any more. There is also the fear that I always have while filling the air system with 120PSI of air, and the fear that one of the 2 air tanks will explode and destroy the aircraft. since almost all new retracts are mow powered with electric motors I am planning to try to convert these old air powered gear to modern electric actuators. The original manufacturer of this gear is long out of business so no parts are available. SO I get to make all my own parts for the modifications.

I found some tiny little gear motors on amazon so I ordered one each with a m3 shaft at 300 rpm and the other with an m4 shaft at 200 rpm. These two should each give me about a 3 second retract speed. The coarser pitch of the M4 means faster speed thus the lower rpm. They are rated for 6-12Vdc and I will be running them on a 2S LiPo at 8.4V.

Once the motors get here and I get the gear removed from the plane, I can start laying this all in 3D CAD. I already have a good mental picture of what I think will work, I have most of the materials needed on hand, Tooling may be another matter.

As of the moment I am only planning to convert the 2 main gear, I am leaning toward just buying a new nose gear since the mechanics of the mains are in great shape but the nose is very badly worn and never was a good design anyhow. the modern stuff is way better. But who knows, once I get it out I may just end up building a new one from scratch that will correct all of the original design deficiencies. Modern electric gear would run around $900 for the set of 3. there gear motors are around $10 each, makes it very worth a shot at the conversion.

Once I start getting parts in hand I will start posting pics of the progress.

 

[C-Bag]

Sounds like an involved project. So you have the stands etc to be able to swing the gear?

Look fwd to seeing your adventure

 

[Dhal22]

Down and Locked is/was a retract conversion company. Not sure about exact spelling of company.

 

[Flyinfool]

I looked at D&L and they do not make a conversion for my 20 year old gear.

Sounds like an involved project. So you have the stands etc to be able to swing the gear?

Look fwd to seeing your adventure

This is a RC Model section. so not much needed for stands.
It will be fairly involved as the parts will be very small and need good precision.

 

[C-Bag]

This is a RC Model section. so not much needed for stands.

DOH! Sorry, I was thinking “this guy has some $$ when he has his own jet, a who’s going to sign off on these mods”….didn’t even see the sub forum…..

 

[Flyinfool]

LOL, That is what I figured. I do have a private pilots license but do not own a plane that can get my fat but off the ground. So I just play with toy airplanes and dream about getting a real one.

 

[C-Bag]

I should have known better when it was said you could get the whole setup for $900. I’m not sure there any part of a jet landing gear for $900.

Still am interested in how it goes as I’m also deep in a project that’s pretty small and is all linkage. Had to end up going back through and replacing my DRO and doing upgrades I’d been putting off on my tool grinder in prep of making specialized cutters.

 

[Flyinfool]

Well it took a month but the motor has finally arrived.
It is really tiny. The shaft has a M3 thread and it is supposed to turn at 300 rpm.
I have started to design the housing in CAD. It will be really hard (for me) to machine the inside parts.
The pocket that will hold the gearbox and motor will need the final machining done with a 1/16 dia x 1/2 length of cut end mill for the part that will hold the gearbox, and a 3/32 x 1 inch cut end mill for the pocket that the motor fits into. Yes I will be stepping down with smaller and smaller cutters to minimize the material that needs to be removed with the tiny fragile cutters. There are also versions with a M4 or M5 shaft thread and RPM choices from 30 to 500 RPM.

 

[verbotenwhisky]

I have an old turbine powered jet with retractable landing gear. This jet is now about 20 years old. The old pneumatic system is getting old and tired. Between age attacking the seals and just plain wear they just do not work well any more. There is also the fear that I always have while filling the air system with 120PSI of air, and the fear that one of the 2 air tanks will explode and destroy the aircraft. since almost all new retracts are mow powered with electric motors I am planning to try to convert these old air powered gear to modern electric actuators. The original manufacturer of this gear is long out of business so no parts are available. SO I get to make all my own parts for the modifications.

I found some tiny little gear motors on amazon so I ordered one each with a m3 shaft at 300 rpm and the other with an m4 shaft at 200 rpm. These two should each give me about a 3 second retract speed. The coarser pitch of the M4 means faster speed thus the lower rpm. They are rated for 6-12Vdc and I will be running them on a 2S LiPo at 8.4V.

Once the motors get here and I get the gear removed from the plane, I can start laying this all in 3D CAD. I already have a good mental picture of what I think will work, I have most of the materials needed on hand, Tooling may be another matter.

As of the moment I am only planning to convert the 2 main gear, I am leaning toward just buying a new nose gear since the mechanics of the mains are in great shape but the nose is very badly worn and never was a good design anyhow. the modern stuff is way better. But who knows, once I get it out I may just end up building a new one from scratch that will correct all of the original design deficiencies. Modern electric gear would run around $900 for the set of 3. there gear motors are around $10 each, makes it very worth a shot at the conversion.

Once I start getting parts in hand I will start posting pics of the progress.

Jet engine or ducted fan? Just curiosity....

 

[Flyinfool]

Jet turbine of course.......