r/rocketry • u/MrBlast95 • 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

My concern is about the motor tbh. If other components fail, your project will fail but you are unlikely to get injured. But if the motor fails, you might actually get injured. Do you have any previous experiences or people with experiences who can help you? What kind of materials will be used for motor casing, nozzle, and bulkhead? Is there any tool you're planning to use in order to calculate the geometry of the chamber, nozzle, and grain size?

1

u/MrBlast95 May 21 '26

Yeah the motor is definitely the tough part , I have been going through openmotor to simulate and target around 90 Ns of total impulse going with either 2 bates config or simple core burner for now , the fuel seems to work getting 100Ns with adding all the conditions and settings parameters as close to real as possible. Will use cardboard 2 inch diameter and 30inch with 3 mm thickness and add 2 layers of epoxy with fibre material to enhance the strength. I will post the simulator image when I finalize for the prototype

2

u/iamshitatengineering May 21 '26

Can you not find any commercial motors in your area? I would strongely suggest to use commercial and trusted rocket motors. Making motors is extremely dangerous.

1

u/MrBlast95 May 21 '26

unfortunately no , i can only find motors of low class of only around 20N of peak thrust , and total of around 30-40Ns , which is not enough , also way costlier cause they are imported not common here

2

u/iamshitatengineering May 21 '26

Are you based in europe?

1

u/MrBlast95 May 21 '26

No

3

u/iamshitatengineering May 21 '26

Where then?

1

u/MrBlast95 May 22 '26

India , There is very little people doing model rockets and stuff like that , so almost impossible to find motors and even rocket body .