Unsuccessful Launch of the Estes Loadstar II. An illustration to the Rocket Altitude Calculator

Подробнее о видео

This short video is an illustration to the Model Rocket Altitude Calculators:



and



The rocket was launched with the Estes C6-0 and A8-3 motors. (B6-0 in the video description is indicated incorrectly).

Full video about this launch:

The analysis of the video taken by the rocket camera showed why that launch on July 24, 2021, was a complete failure. Several reasons led to the failure:

1. The Estes C6-0 booster stage motor is designed to lift only 113 g while the Estes Loadstar II two-stage rocket with two engines weighed 113 + 13.9 + 23.1 = 150 g. That is, even without any additional load, the rod separation velocity determined by our calculator is only 8.7 m/s, which is unsafe. That means it was not worth trying to launch the rocket with this engine even without any additional load although this is the engine indicated in the instructions for this rocket. Link to the calculations:

2. We installed a 27 g camera as an additional load on the rocket and its weight with two engines now was 140 + 13.9 + 23.1 = 177 g. The rod separation velocity determined by our calculator is only 6.4 m/s, which is half the recommended speed. That means, it was not worth trying to launch the rocket with this engine, but we tried. Link to the calculations:

3. The Estes C6-0 motor was supposed to burn for 1.86 s, but in reality (determined from the video) it burned for 2.7 s. That is if the amount of propellant was as stated in the specifications, the motor thrust was 1.5 times less than specified. We measured this time using the footage taken from the rocket camera (160 frames at 60 frames per second).

4. The actual rod separation speed measured using the camera footage was only 3.6 m/s, which is very low. Therefore, by the end of the operation of the first stage motor and by the time the second stage engine began to operate, the rocket nose cone has already been pointed toward the earth.