Richard Nakka's Experimental Rocketry Web Site

PHOTO 45 -- Flight B-6 : July 3, 1972

The rocket for Flight B-6 was equipped with the D-II motor, the largest I'd ever developed, which held up to kilogram of propellant. This was the second flight utilizing this motor (the rocket for Flight B-4, with the "C" motor, was lost, when that rocket climbed to an altitude well out of sight, and the parachute did not deploy. A "thud" sound was heard after about 30 seconds after liftoff, and despite an exhaustive search, could not be found).
The rocket for this flight was equipped with a "ball switch", which used a steel ball within a small cylinder fitted with electrical contacts. This was supposed to trigger parachute ejection as the rocket turned over at the peak. What actually did happen was that the parachute charge fired shortly after burnout, and the parachute tore off due to the high velocity. It was not until after two more such failures that I learned that such a method was ill-conceived, and that any such switch with an "inertial mass" would always activate immediately upon deceleration of the rocket. Basic physics!

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