MICRO MECHANICAL RETRACTS - small and light

Derek Micko's "Fun Scale Models" park flyers have featured mechanical retracts which he designed, and Rabid Models is making them! 

This small and simple gadget was designed specifically for lightweight RC models (less than one pound flying weight). The retract is about the size of a quarter! For best results the wheels and tires need to be as small and light as possible. 

Please see the DESIGN NOTES below, this product has 3 versions.

The 3D-printed micro-retract is operated by a small micro servo and a pushrod (not included). The plastic frame holds a trunnion (the rotating part) which holds the landing gear leg and the trunnion has an attachment point for a pushrod. There is a 90-degree range of movement.  Use a 4.3gm metal-gear servo to operate one retract, OR a single 9-gm metal-gear servo to operate two retracts at the same time.  (We offer these servos.)

The retract frame is designed to be mounted on wood "rails" about 8mm apart. Attach with 4 micro-screws (which we sell) or simply glue it using Foam-Tac. The trunnion pivot is a 9 mm length of 1/16" wire (1.6mm). The gear leg is 1/16" wire and the pushrod is smaller .032" wire (0.8mm) with a Z-bend. The modeler can install different length wire gear legs as needed. The pushrod can be mounted from the left or right side.  Note: the wires are not included in the package! 

The modeler will need to carefully install & adjust the retract to set the proper geometry and operation.   They can be set up so the wheel retracts towards the fuselage, or towards the wingtips.  The 1/16" wire gear legs are installed last, they are simply pushed into the trunnion and glued using thin CA. There is no "shock absorber" built into these units - the 1/16" wire has sufficient "spring" for the intended use (small models). NOTE: The parts are very small and we expect the frame or trunnion may break under certain conditions (hard landings). Dear customer, please realize that its preferrable for the retract to break instead of breaking the wing! Split plastic can be carefully fixed with CA glue, and spare parts can be ordered if you need them.   Painting is recommended.

Please check this short "live action" video (CLICK HERE) demonstrating the basic operation. Note the small Z-bend.

This video (CLICK HERE) shows a CAD animation with a few different angles. You can see that the pushrod can be used from either side. Towards the end there is a pop-up link where you can also watch a CAD animation of the nose gear!

AND THIS VIDEO (CLICK HERE) from Derek Micko provides some important tips regarding exactly how the retracts are installed!

DESIGN NOTES - THERE ARE THREE VERSIONS AVAILABLE!

"Version 1" (V1) is the smallest at 18x20x12mm and 1.7gms. The trunnion has a very small tab for the pushrod, which is delicate. This unit is meant for very small models, say 6-12oz flying weight. V1 is supplied with an extra trunnion since its easy to break the tab. On a small model you could operate this with our small 2gm servo. V1 is printed in orange.

"Version 2" (V2) is slightly larger at 20x23x12mm and 2.1gms. The V2 trunnion has a larger tab which is more robust. This unit can be used on models in the 14-18oz flying weight range. V2 is printed in gray.

"Version 2T" (V2T) is the same as V2 but the bottom part of the frame has been trimmed so that the entire unit is "low profile" and can fit into thinner wings! This unit is best for slightly lighter models, say 12-14oz., as the thinner frame is not quite as strong as the regular V2.

ALSO - we have a "nose gear" unit which has the trunnion on the opposite side - the frame is mounted on a flat surface (for example on the back of the motor firewall). The nose gear unit is taller and slightly heavier than the main-gear units. The nose gear retract is not steerable but we think its possible to make it steerable with a little ingenuity. (Contact us for details).

These products could also be used to operate speed brakes or spoilers or retractable floats and other moveable items! 

WE ALSO have rotating micro-retracts for models like the Corsair and P-40, you can see them HERE! 

Keep in mind - adding retracts to your plane will add some weight (2 servos, wire, wheels, etc.) which can affect its performance.

The main gear micro-retract is $8.95 for a set of TWO units.   (Set V2 is $9.95)

The nose gear micro-retract is $4.95 for ONE unit.

Replacement trunnions are available separately for both versions. V1 and V2 parts are not interchangeable!

This picture shows the slightly larger V2 on the left, and V1 on the right

This next picture shows the V2 "nose gear" retract, which is designed to mount on a vertical or horizontal flat plate instead of between two rails:

SPECIFICATIONS for the Micro Mechanical Retract:

Version 1: 18x20x12mm, 1.7gms   (orange)

Version 2: 20x23x12mm, 2.1gms, Version 2T: 20x23x6.8mm, 1.8gms

Material: 3D-printed PETG Plastic    (V2 is printed in gray.)

The retracts are paintable, you may use acrylic or enamel.

Tools and items required: 1/16" drill bit with pin-vise, 1/16 wire for pivot and gear leg, 0.032" wire for pushrod, thin CA, small screws or Foam-Tac glue for mounting, servos, and micro-pushrod connectors. These items are NOT included but Rabid Models offers CA and Foam-Tac glue, micro servos and micro pushrod connectors separately.

This product was originally designed by Derek Micko/Fun Scale Models and Rabid Models, Made in the USA. Copyright © 2024.

We're able to modify this product and produce it in larger sizes (custom measurements) and various colors but its not appropriate for large models. Contact us for details.