8th March 2013 http://rcexplorer.se/projects/2013/03/fpv-to-space-and-back/
David Windestål from Sweden used an 800g army surplus weather balloon to carry an RC plane to over 20,000m and release it; to then be guided back to earth. Such a project has been tried several times before but this one was notable on several counts. The plane had a Go Pro Hero 2 which had been hacked and a video transmitter added. David reported that the images were grainy and black and white but, non the less, he describes a successful attempt to transmit pictures from the Hero.
The project is another good example of a remotely operated release mechanism. David explained the release as follows, “To be able to release the plane from the balloon before it burst, I made this simple rope cutter. It’s just a 10 ohm resistor that is hooked up to a RC switch. When I activate that channel on the receiver 12V is applied to the resistor. Ohms law tells us that the current passed through a 10 ohm resistor at 12V is 1.2A. That is 14.4W, way more than the 1/4W the resistor is rated at. This will make the resistor heat up to the point where it’s so hot it starts to glow. It doesn’t burn out straight away, in fact it usually last for 10-30 seconds before finally burning up. This energy is plenty to melt the rope and release the plane. But just in case, I glued a match head to the resistor, to give it a bit of a boost. When the match ignites it’s self oxidizing, which means that it creates it’s own oxygen and can therefore burn (for a short time) in a vacuum.”
Other notable facts on the flight were that it’s total flight time was 108 minutes and the balloon was filled with hydrogen.
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