FAR February 2012

As the weekend approached my initial plans had changed, so a last minute decision to head out to the desert was made. The winds in Mojave were gusty, however, as my wife and I got closer to the launch site the wind became calm. The goal for the day was to have a test flight of my new rocket Incredulous out of my new launch tower. The rocket was designed for 1.5 calibers of stability with the 98-17.5k motor, so my initial thought to test it on a 98-10k would not work without some additional mass in the nosecone. Instead I opted for a 76mm  adapter and a 76-7600 load to provide a single caliber of stability.

For recovery I used my new Featherweight Raven 2 altimeter with the Power Perch nestled nicely in the 6:1 Von Kármán nosecone. Additionally, I packed both a Beeline 70cm RF tracker and a 900MHz GPS transmitter to locate it after the launch. I was also testing a new patch antenna on the receiver end of my GPS tracker which was mounted on a camera tripod.

The wind was still calm when we loaded the rocket into the tower, and after powering up the altimeter with the handy magnetic arm switch we headed back to push the button. I was excited to see how things would fair with so many new variables in the equation, and as it would turn out luck was on my side. Upon ignition a violent cloud of dirt and rocks erupted around the tower with the rocket quickly leaving the mayhem perfectly straight into the sky. After burn out it was roughly 20-30 seconds before we regained a signal on the GPS, but after that clean data streamed back the whole way down. As I was fooling around with the yagi trying to narrow down the signal just for kicks, we heard a sharp bang from the line cutter releasing the main chute at 900′. Someone quickly spotted it and we were able to watch it land a quarter mile away.

The rocket landed softly with the over-sized chute and was ready to fly again. There was some minor aero heating to the paint on the nosecone but the fins were in perfect shape. Incredulous reached 21,457′, not too bad for a 4″ rocket on a 3″ motor.

With plenty of the day left and some wind picking up, I loaded a 54-1050 motor into my newly made test rocket. Constructed from miscellaneous parts, the rocket is 4″ in diameter with a 54mm MMT, perfect for casual I-L motor flights. This particular motor lobbed the rocket over 3,000′,  and after the chute popped out it drifted gently back to the property.

(Video by Rick Maschek)

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