Conversion of Hydraulic actuator to pnuematic(nitrogen) 1

[mrcadman2u]

What I am trying to accomplish is eliminate hydraulic fluid in landing gear actuators and use nitrogen to produce extend and retract. The actuators have an internal lock system that locks the gear down and when the gear are retracted the hydraulic fluid pressure releases the internal lock. If it is not possible is there anything I can do, internally to the actuator seals o-rings, to accomplish this task.

 

[israelkk]

Where will you store the nitrogen? The hydraulic system works in a closed loop. The pressure of the hydraulic system is 3000psi (I think). You will need to have a large very high (>>3000)pressure vessel to store the nitrogen. How will you accomplish multiple landings? will you change/refill the nitrogen every landing?

I know about an emergency pneumatic system in case the hydraulic system fails, is this what you are looking for?

 

[mrcadman2u]

israelkk

Thanks for the prompt reply. We are going to store the nitrogen in a storage bottle. On the current modified aircraft there is already a nitrogen bottle for emergency extension of the gear and operates the gear doors also. We want two additional bottles to work the extend and retract operations. The bottles will be recharged after each flight. The current system is 1500 psi hydraulic and the emeergency nitrogen bottle is charged at 3000 psi. You hit it on the head.

Thanks

 

[israelkk]

The emergency system uses an pyrovalve which is a one shot device. You will need here a pnumatic valve for 3000psi which is a different design than the hydralic valve. From he cylinder and seals point of view there should not be any major change except maybe seal mateials and lubrication which will have to fit the dry nirogen environement.

 

[mrcadman2u]

israelkk,

Thanks for the help. After some research it did appear as you said that the seals should be okay as is with some minor changes as long as the system is lubricated and conforms to surface finishes. We are re-plumbing the entire aircraft from scratch and this was part of a trade study to find a viable alternative to using the Hydraulic fluid. This looks to be a viable option.

Thanks for your input.