We have derived the ideal rocket car equation earlier. Next step was to compare the result of the equation with an experiment. The test rocket car vehicle is shown below. The rocket car weighed 460 g and was propelled by two C6 blackpowder model rocket engines. On one of the front wheels was a wheel encoder with two Hall sensors mounted. The wheel encoder had a resolution of 30°. The ignition of the rocket motors was remote controlled. After the burnout time was reached, a small PIC counted the wheel encoder impulses in a defined time intervall (30 ms) and displayed the value on a 2-digit-7 segment display. It was then easy to calculate the velocity by the given wheel diameter. Several tests showed a burnout velocity of 20 m/s, which is in accordance with the rocket car equation, if we consider the neglected air drag.

Seleneteam - Burnout velocity measurement from seleneteam on Vimeo.