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====== Flight Support ======


===== Radar Reflector =====

What about adding a Radar reflector to your balloon project - to make it more “visible” to aircraft? 

A simple “corner” reflector is best - these produce an excellent radar echo because of their shape - the corners return the radar energy back in the direction it originated (the way “cats eyes” in the road work) - you will often see these used on boats. 

{{:ideas:corner.jpg|:ideas:corner.jpg}} 

FAR101 says "the reflector will present an echo to surface radar operating in the 200 MHz to 2700 MHz frequency range".

Size - commercial radiosonde radar refelctors are about 50cm tip to tip. 

A very lightweight reflector (less than 30g) can be constricted using carbon fiber kite spars and metalized plastic foil (as used in space blankets). 

  

===== Pyrotechnic Cutdown Device =====

This device is used to detach the payload from the balloon (or release items attached to the payload). Its an igniter (used in amateur rocketry) inside a small hard plastic tube (sealed with epoxy at both ends) - when fired the igniter has enough explosive force to shatter the tube (and hence release the balloon) - it works a treat in all the tests I have done, including some at -30dec C and in a vacuum chamber.

__**WARNING: wear full eye area wrap around safety goggles when testing these devices.**__

{{:ideas:release.jpg|:ideas:release.jpg}}

Size: 45mm x 8mm diameter.  Weight: a few grams.
The igniter needs about 2amps @ 3Volts for just a few milli seconds to fire - it can even be fired from a charged 4700uF capacitor.

{{ideas:cct0.gif|}}

The ignitor on the right hand side of the circuit can be replaced by a small 6V bulb for testing - the bulb will light briefly when fired. Once you are happy with the circuit try an igniter.

[''adeptium/STARS Project'': Not happy about the use of a wet cap for near-space use, but Farnell supplies an AVX 3300uF tantalum, 4-10V operating range, rated to -55C with no loss of capacity.  I'm going to try with one or two of these.]