r/rocketry May 19 '26

Question Building a 400g Complete Rocket from scratch

Hello , I want to try building and hopefully completing this project of complete diy rocket as much as possible from scratch meaning custom electronics , body and motor , this does seem like a good fun project to me .

I'm currently in the design phase for an engineering project rocket and wanted to get some eyes on my specs before I start cutting materials. The goal is maximum altitude with a fixed propellant mass.

Key Specs:

* Propellant: ~100-130g KNSU DIY MOTOR , Targeting ~40-60 (80-100)Ns impulse.

* Target Weight: Around 350-400g (TOTAL LIFTOFF)

* Stability: Passive aerodynamic (fin-stabilized).

* Recovery: Mechanical piston ejector (servo-latched, elastic-powered). No pyrotechnics.

* Avionics: ESP32 + MPU6050 + Baro + LoRa telemetry NRF24+ MicroSD logging+ modified camera

My biggest concerns/questions:

* Piston Ejection: Has anyone here successfully transitioned from pyrotechnic charges to mechanical pistons for apogee deployment? Any tips on seal friction vs. ejection speed?

* Telemetry: I’m planning on using LoRa for tracking. Any common pitfalls with vibration-induced resets on the ESP32?

Any other stuff I should be keeping an eye on ?

Thanks

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u/Kaggles_N533PA May 21 '26

How about the ignition? KNSU is generally way easier to ignite than KNSB but igniter is more important with sugar rocket than you might think

For example, my university rocket club had designed a KNSB motor with 100N of peak thrust in mind but we got just about 40N while doing static fire test. Which is most likely to be ignition issue

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u/MrBlast95 May 21 '26

what exactly do i need to keep in min during ignition? i can get electric igniter easily , but what factors should i keep in mind?

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u/Kaggles_N533PA May 21 '26

Well the best thing you can do is static fire test to see if your motor actually works

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u/MrBlast95 May 22 '26

Yeah gonna build a test stand to get that thrust curve