3D printed release mechanism for cargo.

by MrCuervoRC | December 18, 2020 | (2) Posted in Projects

Hello FT community, I created this system to hold things to our planes and then release them, I find it very useful and I wanted to share it with all of you.

For a long time I have been thinking about how to make a system to join two aircraft in a robust way so that they do not move with respect to each other and that the servo does not suffer or get stuck if what it holds is too heavy. I am doing an experiment to launch 2 kg space shuttles from an aeroplane and I need a reliable and compact system.


The first model I made had two claws that held the bottom, and opened with a servo, but sometimes they opened in flight and didn't hold well.

this is the 3d model in thingiverse https://www.thingiverse.com/thing:3591833


Then I made a version in which the only moving part is the servo. What holds the piece that is released is fixed and when it slides backwards by air resistance or gravity it is released, in that way it is perfectly held without moving anything until the servo pulls out the pin and the mechanism is released. Moreover, no support is needed to print it.

this is the 3d model in thingiverse https://www.thingiverse.com/thing:4552053
It is super reliable, cannot be released unintentionally, it is very small, and it can be put on the top of an aeroplane to launch it from another one, and it is perfectly flush so it is aerodynamic.

It has a small spring to help release it but it is also not totally necessary, without it it also releases quickly.

In the minute 5:25 of this video you can see the mechanism in action, this weighs 600grams but I have released things up to 1.2kg and it works perfectly.

Apart from being used to link two planes together I also thought it could be used for other projects such as making a biplane that takes off easily and releases a wing in mid-flight and becomes a much faster monoplane. This is where everyone comes up with their own crazy inventions.

That's all in this article, I just wanted to share this design because I think it's very useful for the model plane community.

Thank you very much for reading me and I hope you find it useful.


NYCBobby on December 31, 2020
The footage of the release is amazing. The way you followed that object as it fell away from the airplane was fantastic. Cool looking plane too. Love to see the bi-plane break into a monoplane. Be like something out of a James Bond movie.
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MrCuervoRC on January 4, 2021
Those shots were recorded with the 4k runcam vertically and then in the editor I made the movement, at the end half of a frame in 4k has more quality than 1080p.

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AeroErgo on January 6, 2021
Looks like a Kalinin K-7 jeje, Buen trabajo!

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MrCuervoRC on January 10, 2021
It's stratolaunch, currently the largest airplane in the world. The double fuselage concept works well for lifting weight.
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3D printed release mechanism for cargo.