February 15, 2026
Description
The price of original retract (1-01759) seemed rather high for a pack of screws and plate of milled plastic, so I decided to design my own based on photos available on the internet. I had to alter some dimensions (mostly main body length) to have it fit correctly inside the fuselage, as reverse engineering wasn't 100% perfect. The servo motor has been moved to a different location, making installation easier and allowing use of a simple wire pushrod. Free space for old servo location also makes perfect space for electronics, although the plate on top of the assembly is still available.
Everything is optimized for 3d printing, reducing the number of parts to just 7 (3 of which is a printable wheel). The main body and fork have integrated supports, the only part requiring manual support is the wheel cover. A treaded 72 mm printable wheel is also included.
CA, or any other glue to glue wheel rims together
Foam safe CA or UHU Por for gluing mounts into fuselage
~1 mm dia x 60 mm steel wire
5x m3 nylock nuts
1x m3x30
2x m3x35 (or longer)
2x m3x10
2x m3x20
Rubber band
HITEC HS-85BB and provided screws
Use of provided .3mf files is advised, as these include modifiers for best strength/weight ratio. For tire, I've used 55D TPU, but lower value is preferable. The rest was printed in PETG, but ASA can be used to minimize weight. Integrated supports have 0.2 mm separation, so layer height lower than 0.15 mm may result in them failing.
Remove integrated support from main body's wheel cover hinges, and fork's slots. Clean all surfaces and holes. Make sure that screws can slide freely inside fork's slots.
Glue both rim halves and tire using CA and screw wheel into fork with m3x30 screw and nylock nut. Do not overtighten it, the wheel should rotate freely.
Bend Z ends to the pushrod, distance between vertical sections should be 38 mm. Install into middle part of actuating arm.
Screw in fork and actuating arm into main body with pushrod facing servo holder direction using 2x m3x35 screws.
Align all parts as shown in the picture and screw in m3x10 screws on both sides.
Check if everything moves smoothly and reaches either end of travel.
Set servo to middle position and screw in servo horn facing closer edge. Install with pushrod in 3rd hole.
Connect to receiver and set correct PWMs. Mounting the pushrod close to the servo's axis of rotation may require to extend range beyond 1000-2000 us, but results of less strain on the servo. Also, slowing down retraction to at least 1 s makes everything go smoother.
Tack in rear mounts into fuselage and check if everything fits, only then glue in mounts permanently.
Insert 2x m3 nylock nuts into tube clamp, and slide it under square tube.
Insert landing gear assembly with landing gear retracted, but unlocked.
Insert gear bay doors with assembly not fully seated.
Clamp whole assembly onto square tube with 2x m3x20 screws.
Tie a rubber band between the cover and the fork.
Have fun!
Feel free to post makes and ask any question. Native Fusion360 native and STEP files are provided for any modification you need.
Also, check out my other RC related stuff. Fly safe and happy printing!
License:
Creative Commons — Attribution — Noncommercial — Share Alike
8
Jadozub
