N1 - Motor SP1 Static Firing Thursday 25th March 2021

Basic Motor Details

Grain Length - 40mm

Propellant mass - 24g

Total Motor Mass - 114g

Grain Diameter - 24mm

Core Diameter - 7.2mm

Results and Discussion

Summary

Total Impulse: 3.95 N-sec

Specific Impulse: 164.75 N-sec/Kg

Average Thrust: 1.36 N

Motor Class: B

Burn time: 2.9s

Thrust Curve

https://raw.githubusercontent.com/nakujaproject/thrust-analysis/main/post-analysis/graph.png

Sources of Error

Sampling rate of the program. Due to the addition of live animation to the program used to record load cell data, the sampling rate was drastically reduced due to time taken to generate animations.

The nozzle diameter was slightly increased when a plug from the pyrogenic igniter had blocked it. This might have decreased chamber pressure by 30% for 1mm increase.

The pyrogenic igniter failed to start the motor and resulted in a blockage of the nozzle.

Recommendations

Separating data sampling from the load cell from the live plot animation.

Make a shorter pyrogenic igniter.

Conclusion

The data collected shows an improvement in motor performance. The errors in data sampling show that the motor performance might have been better than recorded. The sampling error has been corrected by using threads in the program to separate the live plot and data recording.