Landing Gear Door Cylinder

Retract Gear and Accessories

MK-20 Retract Gear System

The MK-20 Retract Gear System was designed to meet the needs of models in the 17-30 lb. weight range.  It had to be light enough for ducted fan applications and tough enough for scale models operating from rough grass fields.  It is hand-crafted from aircraft grade aluminum with an emphasis on simplicity of design and ruggedness. 

The MK-20 operates off compressed air.  The 2-way valve is controlled by a servo and activates the cylinders attached to each individual retract gear to either retract or extend the struts.

All of the gears are mechanically locked down and pressure held up.  By eliminating the need for up locks and holding the gears retracted with pressure, it allows the modeler a variety of installations possibilities.

Many variations in strut geometry require less than 90 degrees of strut travel.  It is possible with the MK-20 System to stop the gear retraction wherever desired by merely adding a stop in the wheel well.   

The actual weight limitation on the gear is somewhere around 30 lbs. of aircraft weight, but this largely depends on the strut length, field conditions, and ultimately piloting techniques.
 

MK-30 Retract Gear System

The MK-30 Retract Gear System was designed to meet the specific requirements of turbine models in the 20-35 lb. weight range.  Light, but tough enough for models operating from rough grass fields, the MK-30 retract gear are CNC machined from aircraft grade aluminum with an emphasis on simplicity of design.  Down locks and up locks are used with a 90 degree retraction angle as standard.  Massive ¾” bored pivot blocks receive and clamp the upper strut body.  The main gear struts retract away from the actuating cylinder and provide a high retracted strut center line.  The nose gear strut can retract over the cylinder or away from the cylinder.  The retract unit dimensions are as follows.  Height 1.375”-Width 2.5”-Length 5.0”

A 2-way valve driven by a standard JR or Futaba mini servo controls the retract gear system.  Installations that include gear doors utilize the JMP Gear Door Sequencer.  The gear retraction and door closing is timed by the Sequencer.  Also available is the Air Line Manifold which maintains equal line pressure and simplifies air line routing. 

The actual weight limitation on the gear is somewhere around 35 lbs. of aircraft weight, but this largely depends on the strut length, field conditions, and ultimately piloting techniques.