Park Flyer Main Gear Retract

I created this mechanism for an aircraft that required the landing gear to retract vertically into the wing or fuselage. The linkage provides a simple way to raise and lower the wheel while keeping the assembly relatively compact.

This design has been printed, assembled, and tested.

Required Parts

In addition to the printed components, you will need:

• Compatible RC aircraft wheel:
  https://www.amazon.com/dp/B07GXNJQCR

• Metal rods from this set:
  https://www.amazon.com/dp/B08R9DNX83

• One 2 mm nut and bolt for the servo linkage

• 3 mm nuts and bolts for mounting

• Suitable servo and control hardware

Rod Cut List

Cut the rods to the following lengths:

• 3 × 20 mm

• 1 × 8 mm

• 1 × 30 mm

Deburr the cut ends and test-fit each rod before final assembly. Depending on your printer’s tolerances, the rod holes may need to be cleaned or lightly reamed.

Printing Settings

I printed all components using:

• Material: PETG

• Infill: 30%

PETG provides a useful combination of strength and flexibility for the linkage components. Pay particular attention to layer orientation on parts that will carry landing loads.

Assembly and Setup

Assemble and test the complete retract mechanism before installing it in the aircraft. Check that:

• The mechanism moves freely through its full travel

• The wheel reaches the intended extended and retracted positions

• The linkage does not bind or flex excessively

• The servo is not stalled at either end of its travel

• All pivot and mounting hardware is secure

• The retracted wheel clears the surrounding wing or fuselage structure

Set the servo endpoints carefully so the mechanism reaches both positions without forcing the linkage. Cycle the retract several times on the bench before flight.

Because landing gear is subjected to repeated impact loads, inspect all printed parts, rods, pivots, and mounting hardware regularly—especially after a hard landing.

License

Remixes and adaptations are welcome. Please credit the original design and share your modifications under the same license. Commercial use is not permitted without prior written permission.