TOPIC: Electrified JETEX Rocket Motor

Still working on the 'electric fuse' and 'burn time' - so to speak.

Here is the circuit board to run the motor electronics. When you push the start button, it has a 2 second delay before turning on the motor. It is also able to set the on time in 5 second steps from 5 to 30 seconds. It can cancel at any time while the motor is on by pushing the button again.

The board is currently 10mm x 6.6mm in size.

This is splendid progress and it's small enough to fit even a Starfighter. What batteries do you reccommend?

Hi Roger,
I have continued to reduce the footprint of the circuit board and added a few glaring missing functions to it ( it's a learning curve ).
The speed controller MUST have zero throttle set for 2 seconds for it to arm itself, so having the circuit simply go to the preset throttle position won't work. I have corrected this. Also, slamming on the throttle is a bit rough too, so after 2 seconds, the motor will gracefully throttle up to the set throttle setting. The run time selection is still the same and the function of the start switch is too. Push to start - push to stop/reset if needed. A small green LED will light up to when the button has been pushed to indicate the timer has been triggered.

Lipo
The minimum lipo required is a 1S 150mah - 25C. This can provide the required amp draw of the edf unit. It will allow appox. 8 runs at 20 seconds before needing a recharge or swap over.
Dimensions: 42mm x 11mm x 5.5mm.
Weight 4.4 grams.
The lowest cost I found for these locally is ~7.95AUD per Lipo.

Circuit Board
The board is now 28mm x 6mm in size - down from the previous size of 48 x 12 .

This is getting better and better! Is there provision for the controller to serve two EDF units? I've already started a 44mm span model of the neat 1950's Arbalete which will take two units mounted on the wings:



It's made of Depron (ugh!) so this too is a learning curve for me. I'll cover it in authentic yellow model aircraft tissue, though!

Yes, it can power more than one. It outputs a PWM signal which the fans ESC converts to throttle level.

I have ordered the PCBs. A firm in China makes them for next to nothing. I will order the components locally.

I'm up to the geek stage where I have set up and programmed an Arduino Nano to use to program the Microprocessor I am using on the board. I have to program the chip first and then solder it to the board along with the other components. I'm thinking of buying a PCB microscope to help with the soldering process.