hi, guys
I know something new and perfect! I think you should try!
Robust E-Retracts from PZ-SERVOS!
PZ-15090

Servoless Retractable Landing Gear
After 10 seconds Auto power-off Protection system
Double Shock Absorption Design
Completely protect the gears
Dimension：65.8*35.1*25.1mm 2.59*1.38*1.0inch
Maximum travel: 90°
Torque: 2.5kg-cm
Speed: 1.8s/60°
Operating Voltage: 4.8v-6v
Weight: 32g
Applications:
Used for airplanes wing span around 1.5m


PZ-15091

Large Servoless Retractable Landing Gear
After 10 seconds Auto power-off Protection system
Double Shock Absorption Design
Completely protect the gears

Dimension：73.5*44.0*28.0mm 2.89*1.73*1.1inch
Maximum travel: 90°
Torque: 3.5kg-cm
Speed: 1.8s/60°
Operating Voltage: 4.8v-6v
Weight: 54g
Application field:
used for airplanes wing span around 2m
PZ-15090
It can work with 2A BEC
Current (at no load): Less than 80mA
Build-in circuit design to absorb interference wave
Key character:
Safe, Low noise and Stable.

PZ-15091
It can work with 3A BEC. Strongly suggest you use 4A or 5A BEC. It's SAFE!
Current (at no load): Less than 120mA
Build-in circuit design to absorb interference wave
Key character:
Safe, Low noise and Stable.

From:http://www.rcuniverse.com/magazine/NewProduct.cfm?product_id=4661