The Rocket Formerly Known as Black
Step Nine
Avionics and Recovery Systems
The unique shape of this rocket made it necessary to find a unique place to hold the electronics. The only availabe space was found between the walls of the 54mm motor mount and the 75mm central tube. This is the same electronics location solution I incorporated into the Happy Birthday Party Napkin rocket of the Apocalypse design.
I cut a slot in the aft centering ring that would fit my G-Wiz flight computer. I then mounted the G-Wiz to the Avionics Bay cover, which is another ring that fits over the fixed aft centering ring. The arming switch is also mounted into the Av Bay cover. The screws used for motor retention also hold on the cover of the avionics bay.
Shown is the motor mount/av cover assembly before installation into the rocket. (note the use of the fiberglass drywall tape inside the rings...). The forward centering ring holds a 1.5" pipe clamp for the shock cord mount. A small piece of 1/2" copper pipe with an end cap was installed to hold the ejection charge. An aluminum tube connects the charge holder to the avionics bay -- this will be used to feed the squib leads into the av bay. I added another centering ring at the midpoint of the tube to compensate for any strength lost in the aft ring when I created the opening for the avionics.
The cramped parachute bay was packed with matching home-sewn elliptical-cupped parachutes. I experimented with a new design that could pack smaller than commercially available parachutes (primarily because there are fewer seams and seam reinforcments). I made a ten-foot (measured across the canopy) version and an eight-foot version.
I attached the 10-foot parachute and a large Kevlar-Nomex flame shield to the fuselage with a 4-foot length of tubular Kevlar . The eight-foot parachute was attached to the nose. I opted to let the two pieces recover separately for two reasons: 1) the extreme mass of the nose cone created a high risk of separation, and; 2) there is no room for any additional recovery harness in that space anyway .
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My estimates showed that each section would descend and about 12.5 feet per second. The avionics and parachutes performed perfectly.
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TRFKAB Index
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