electro-mechanical actuators for Landing Gear

[whph]

Has anyone been involved with, or know about using electromechanical actuators in aircraft landing gear systems. Are they as reliable as hydraulic ones? How does the cost and weight compare with hydraulics? Any advice would be much appreciated!
Thanks

 

[aerodog]

If my memory serves me right, Mooney Aircraft has used electromechanical actuators for years.

Pratt & Whitney would like to eliminate accessory gear boxes on small turbine engines and incorporate electrical power generation right on the main engine shaft. This will lead to more aircraft designs that would use electrics for gear and flap actuation.

Boeing's is looking at using electric actuators for the 787 as well.

 

[plasgears]

The trend is away from hydraulic to electric. This happened in robots, also. A compact DC motor with gear reduction can be made reliable, and the leakage question is sidestepped.

 

[Barry1961]

Brother makes some light weight, high reduction, high torque gearboxes. They use them on some type of mobile missile system for raising the rack if I remember.

http://www.brother-usa.com/gearmotors/index.html

Barry1961

 

[whph]

thanks!! what about emergeny extension, how would this be done with an electric actuator?? i know that with hydraulics you can just bypass the fluid to the reservior and let gravity do the work.

 

[rb1957]

can't you do the same with electronics ... pop the CB and let gravity do the work ?

 

[thruthefence]

in fact, there is usually a means of disengaging the motor from the gearbox, and a hand crank ( Beech Bonanzas, Barons, & Dukes or the 'tip-tank' twin cessnas ) or a lever operated ratchet-and-pawl affair ( Beech Kingair series ) to lower the gear.

 

[bgl]

what type of electric actuator do you have in mind ?
Electric motors and mechanics are both reversible, so where is the problem ?

 

[MGaberik]

http://www.nasa.gov/centers/dryden/history/pastprojects/SRA/epad.html

Boeing 787 will use EMA's
Boeing X-45 currently uses (only)EMA's.
They are gaining acceptance for certain applications.
For any new design, a cost, weight, reliability, maintainability comparison with hydraulics would be appropriate.
Redundancy can be provided by a variety of methods.