Opel RAK 1. : A foamboard vintge rocketplane!

by Dr. Looping Looie | December 14, 2019 | (8) Posted in Projects

Are you looking for a cool oldscool scale plane that offers a lot of fun, but is also very beginner friendly?

Well, here might be something for you!

This plane is part of the Flite Test Forum Challenge 2020 balsa to foamboard conversion. The goal is to take an old balsa plane and adapt it to foamboard. I choose the Opel RAK 1 because it was one of the first rocketplanes and combines stable flight caracteristics with cool looks and the option of adding a rocket engine.

The original balsa plane and plans:



Wingspan: 1200 mm

AUW: 850gramms

Powerpack: F-Pack

Prop: max. 5"

Battery: 3S 1200mAh

Servos: 3x 9gramm

Flight time: ca. 10 minutes

Features and special things:

This plane features a new wing bulding technique using ribs. The special thing is that its using a bottom plate providing a whole lot of strenth. This wing produces extreamely much lift and drag. The model also features a huge tail section which gives it lots of pitch stability. For beginners, this is especially interesting, because it gives it the ability to fly with a wide CG range. Its also very good at recovering to a stable flight from almost any position except inverted. Thats because the main wings lift increases when the plane speeds up. So it always tryes to hold the same glide slope. on a calm day, it can fly on its own for minutes.

It also offers a great unique look and the ability to launch it using a motor, rocket engine or high start. A pilot figure makes it look almost exactly like the 1929 original.

The model can do some very cool looping moves which you can see in the video. If you really let it rip, it feels almost like a miniquad.

Pros and cons of the model:

+easy to fly

+stable flying


+ability to cange the motor to a rocket engine

+cool looping stunts possible

+easy straightforward build

-lazy roll axis

-doesnt like inverted

-uses many new build techniques

-the battery is extreamely deep in the front

-very loud and bad prop efficiency

Flight videos:

Build plans:



For more detailes and build instructions, please visit my forum threat:



jmw9 on December 29, 2019
Wow, looks really awesome!
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Jackson T on December 20, 2019
That looks like a very nice flyer, nice work!
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Opel RAK 1. : A foamboard vintge rocketplane!