Alpha 3 with Estes B4-4 fire

[Egoldee]

Does anyone know what may have caused this?
The fire was lucky put out before it spread.
https://drive.google.com/file/d/1hsJn-7H_zOsMN6EZiE3Q8S3NbmRbZgpa/view?usp=sharing

 

[kuririn]

Don't know what the specific cause was in this case, but I once had an igniter pop out of the nozzle after I had clipped it up. Didn't notice it and when I pressed the fire button on the controller the igniter pyrogen lit up a balsa fin. That's why now I always carry a small fire extinguisher in my range box.

 

[Egoldee]

Don't know what the specific cause was in this case, but I once had an igniter pop out of the nozzle after I had clipped it up. Didn't notice it and when I pressed the fire button on the controller the igniter pyrogen lit up a balsa fin. That's why now I always carry a small fire extinguisher in my range box.

This what I think might have happened though the alpha 3 has a plastic fin can, so it most have been a lot of heat. Unfortunately i didn't have a fire extinguisher so i had to use a water bottle. I will bring one next time.

 

[SharkWhisperer]

This what I think might have happened though the alpha 3 has a plastic fin can, so it most have been a lot of heat. Unfortunately i didn't have a fire extinguisher so i had to use a water bottle. I will bring one next time.

What did the motor look like after you put out the fire? Was the nozzle still intact? Does it feel a little lighter?

Kinda hard to imagine a wimpy Estes Startech "starter" igniting a plastic fin can that quickly, even if you were leaning on the launch button... And your rocket looks a little askew vs the launch rod. What happened in the moments before you started filming your already-engulfed model?

 

[Egoldee]

Unfortunately, I don't have any more pictures.
The motor casing looks a little burned but not like it caught fire. Otherwise, the motor was fine. It may have not been straight because these rockets were built by kids for a STEM Engagement activity. Before I took the video the launch button was pressed there was a poof of smoke but we didn't realize that there was a fire. We waited a minute to approach the rocket when I approach it I saw the fire and someone went to get a water bottle I then backed away from the rocket and took the video when he was getting the water bottle.

 

[Ted Cochran]

I once saw something similar happen when the igniter was shorted below the nozzle and the heat of the short caused the paper spacer on the igniter to catch fire, which spread to the body tube.

 

[Back_at_it]

Doesn't look like the motor fired. I have seen an instance where the igniter dropped out and caught the grass on fire but never seen one catch a rocket on fire like that.

 

[KennB]

I once saw something similar happen when the igniter was shorted below the nozzle and the heat of the short caused the paper spacer on the igniter to catch fire, which spread to the body tube.

This scenario happened at one of our launches. It didn't fire immediately and a voltage drop (indicating a short) wasn't noticed. After leaning on the switches for a few seconds it seemed the short ignited the paper separator on the Estes starter and that induced the rocket to catch on fire. Fortunately, like in the OP, the engine didn't light.

 

[Woody's Workshop]

I once saw something similar happen when the igniter was shorted below the nozzle and the heat of the short caused the paper spacer on the igniter to catch fire, which spread to the body tube.

One of the reasons I spread TB III on the outside of the BT and sand it smooth before building.
Paper tubes can't catch fire if it's covered in TB III.
If it happens to land in water, it gives it greater time to recover before it becomes unusable again.
I also coat the inside of the tube for a heat protectant.
Same goes for the fins before they are glued on.
I haven't built a rocket with plastic fin cans in years.