With its low profile design, strong torque and precision movement the HS-75BB is a great choice to move your retract gear in the realistic manner that you want it to.  
 
Connector : Hitec\JR\Airt-Z Futaba™  
31075S

Where To Buy
31075J

Where To Buy
 
 
 
Motor Type : 3 Pole Ferrite  
Bearing Type : Top Ball Bearing  
 
  English Metric  
Size : 1.7"x 0.9"x 1.0" 44 x 23 x 25 mm  
Weight : 1.23 oz.
35 g.
 
Torque 4.8/6.0v : 92 / 114 oz. 6.6 / 8.2 kg.  
Speed 4.8/6.0v : 0.45 / 0.34 Second  
Price $29.99