4 Rocket Engine Ignition Test

When firing a cluster of four model rocket engines it is very critical to get all four engines started before liftoff. A failed ignition on one or more engine means the rocket will not achieve proper altitude before parachute deployment, or worse will not fly straight up.

In this test, there was 0.17s (170 ms) from the start of the first engine to the ignition of the other three engines, which appear to have all started at the same time.

I think that trying to find igniters that are more "matched" (similar amounts of material) would improve ignition synchronization.

On the slow motion, you may note the motors' initial high impulse thrust for the first half-second or so, meant to get the rocket off the pad, before it backs off to a lower impulse thrust just before the coasting phase begins.

I'm calling this test a 'success', as all 4 engines ignited before the ignition clips were blown away from the test bed by the high impulse thrust.

The engines were all Estes A3-4T and were glued together prior to this test.

Category:

Entertainment

Tags:

• model rockets
• engine test
• rocket engine

[1legofreak]

a have a modified estes patriot with 7 half a's =D havent tried it... tips on igniter wiring?

[bikingchad]

I redid the test with igniters that were within 0.01 ohms. Again, there was a short delay in one of the motors. My thoughts are that the resistance isn't the key to matching igniters - go with ones that appear to have the same amount of material on them. The second test was still over 100ms apart so I guess its down to a little "luck".

I rewired the launcher so all the leads are same length and silver-soldered all the joints on the clip-whip. Will it matter? I guess we'll see...

[nicksynnz]

That is cool vid, thank you, it shows that even in parallel circuitry the motors do not ignite at the same time, this would impede flight performance.

[bikingchad]

Thanks. For the next test before I fly the model I'm going to use an ohmmeter to find matched igniters. I'll post the vid along with the igniter selection process.

[4D3monHunt3rs]

nice :D could you do some pics and a video?

on the saturn 1b?

[bikingchad]

I actually just got the kit.. hasn't even been opened yet.  I'll put up more videos of that one as it progresses, tho.

[randy12368]

Can you please explain the ignitor setup to ingnite multiple engines, and how do you attach the ignitor wires to the motors?

[leventis1991]

you said that the resistor is 0.01 ohm in how many watts? and in how many volts do i need?

[Raketemax1]

T " ; )

[bikingchad]

Thanks. I built this controller for flying the Semroc Saturn 1B kit which uses four engines.