www.pulse-jets.com

You'll find that you can't really predict with any level of accuracy what your burn rate coefficient and burn rate exponant are without some sort of experimentation. Even the pro's that I know can't predict these values. If you stick with the formulas that Richard has provided, including things you ...

I haven't totally given up. The issue is that when the motor burns out there is a deceleration that is significant, at least 2 g's. That deceleration will ALWAYS trigger a gravity type device, whether it is mercury or a steel ball bearing, ALWAYS. You could use this event to trigger a timer, or anot...

I have to agree that in general hybrids are much safer than "conventional" rocket motors. I've seen enough of those in rapid disassembly mode to have a healthy respect for the kind of power they can generate. I have a buddy that does experimental hybrids very successfully. I've never seen any of his...

another problem with fuses, they light the motor from the bottom. You want to light a motor from the TOP.

They are used sometimes in air starting rocket motors in clustered rockets...they usually put them in a teflon tube to ensure they light the motor from the top.

To the best of my knowledge: When the sugar is melted is coats the potassium nitrate, which is key in proper kn ratios. Black powder is similar, as the potassium nitrate is coated with charcoal and then mixed with sulfur, gound for a long time. Sugar cannot coat the potassium nitrate like charcoal,...

If you had read the site as I directed, you would have discovered your problem. If you read the site, read it again. Specifically what when wrong? You overpressurized the motor casing. More specifically, you exceeded the material strength of the CPVC "casing" you had. I'll bet it was a hoop failure....

Start here . Read the whole website, understand it, then come back to ask the questions that you still have. Something that I posted to another person in the forum, it bears repeating... You'll find that people are a lot more helpful about sharing knowledge with you if you ask intelligent questions....

I would agree that it was a detonation as opposed to an overpressurization. I've seen both, this is far and away the most significant CATO I've seen to date...and I've seen some big ones. When I talked with him last he was using HTPB rubber for the grains...I guess some of his grains are PVC. All ar...

I'm familiar with the Motor system. No one way valve anywhere in the system. Link to their website. This is the motor I believe was used in the photo.

Can you explain why you believe it blew up?

Some CATO pictures from LDRS. This was a Contrail Rocketry Hybrid "O" class motor... Rocket reduced to confetti. My hypothesis? The grain collapsed, plugged the nozzle. Chamber pressure rose over the nitrous tank pressure. Flame got stuffed into the nitrous tank...the nitrous went MonoProp and deton...

I made an end burner motor(4 inches) using epoxy as fuel, threw a flame 6 inches long behind it but it didn't produce much thrust.Maybe I was using the wrong type of epoxy(steel).But the 6 inch long flame indicates there was a good pressure buildup in the motor. I would expect that if you wanted to...

I would expect that a solid booster has more vibration than a liquid fueled one. Voids/micro voids, and just particle size differences would account for some instability in the burn. Don't forget the aerodynamic effects of the boosters and when they drop away you are shedding 2/3 of your total thrus...

Look here.

If that doesn't cover it fully, try re-reading the thread...all the info you are requesting is there...

It seems that on this forum there is a stong push to "do it yourself", I like that, but I tend to focus on certain aspects of the hobby to do it myself. I am an Electrical Engineer, and could certainly design, and test my own altimeters and timers, but I choose not too. I do that kind of work all da...

Could be a solution to begin a timing event. I think it could work well for that. You could do the 555 timer as you suggested, but the battery would need to be at least a 9V or something that will deliver a couple of amps of current for a second or two. Most e-matches, christmas tree bulbs, flash bu...