No abstract

In this paper, the world's fi rst application of hybrid rockets to rocket sled system is described. By using N 2 O oxidizer which has self-pressurizing capability, simple handling and low-cost operation was enabled. On the other hand, accurate prediction of the time-velocity profi le of the rocket sled becomes diffi cult because the thrust curve of the N 2 O hybrid rocket varies with the outside temperature. Based on the preliminary thrust measurement, we predicted the velocity profi le of the rocket sled and compared to the actual sled run. Both were well agreed with an error of 10 % in velocity.

This paper describes onboard balance system used in the rocket sled test on the high speed test track. Newly developed acceleration-compensated balance mechanically cancels inertia force and enables us to use suitable size load cells for expected aerodynamic force. Lift force was evaluated by another internal 6-axis balance. With a flat plate and AGARD-B model, system verification tests were conducted to clear the accuracy of this system. Although the cancellation of the onboard G-force was almost accomplished, uncertainty of the wind speed or mechanical friction in the system caused severe error to the measured drag coefficient.