For a separate discussion of rail speed/safe vertical flight, I measured 480fps video of more than 100 flights. Erratic flight (by otherwise stable rockets) looked largely random, and the two biggest sources of randomness I could identify (but not measure) were wind gusts and failure of motors to light cleanly and come to thrust as designed. I did not have anything helpful to contribute on ignition but am glad to see a thread on the subject.
We can choose to fly when wind is benign, but how can random perversity in motors be avoided? I can guess that scrupulously protecting grains from humidity and oil might be a good idea. I've seen some encourage doubling up igniters. I was unaware of the connection to a specific propellant. It would be great to know when the factory seal was broken on motors and how they'd been stored between then and launch. Honestly though, I can see in a video that a motor does not light cleanly, but it would be tough to work out the effect on the thrust curve (vs nominal) during the critical period from when thrust balances weight and the rocket leaves the rail. Most chuffing motors fly OK.
24" scratch build, flight card lists an E26-10W but does not state the rocket weight.
View attachment _Chuff.mp4
I believe this is one of those things that resist exact science and thereby keep the hobby interesting.
We can choose to fly when wind is benign, but how can random perversity in motors be avoided? I can guess that scrupulously protecting grains from humidity and oil might be a good idea. I've seen some encourage doubling up igniters. I was unaware of the connection to a specific propellant. It would be great to know when the factory seal was broken on motors and how they'd been stored between then and launch. Honestly though, I can see in a video that a motor does not light cleanly, but it would be tough to work out the effect on the thrust curve (vs nominal) during the critical period from when thrust balances weight and the rocket leaves the rail. Most chuffing motors fly OK.
24" scratch build, flight card lists an E26-10W but does not state the rocket weight.
View attachment _Chuff.mp4
I believe this is one of those things that resist exact science and thereby keep the hobby interesting.