Just for the record: That's not the motor taking off. That's a wad of hot propellant shooting out the nozzle.
Here's a photo of the "engine" (brass plumbing fittings with an 1/8" nozzle of 4 #6 steel washers) and the little 4-gram, end-burning grain that was fired in the video. (The next grain was wrapped in masking tape and performed beautifully.) The engine was clamped on to the chair. (Another, identical brass end cap seals it.)
Propellant formula deleted I think this stuff would work OK just end-burning with no core.
I have no problem what-so-ever with people wishing to make their own motors/propellant as long as it is done properly. What I see in this picture is what could be construed as a PB, or nowdays IED by the authorities. I, me, myself, believe you 100%, that your intentions to make a rocket motor are genuine.
To make a properly functioning rocket motor involves a great deal of science/math. Simply forming a rough propellant grain and putting it in a metal pipe with an 1/8" hole is not what I would consider an honest attempt at making a true rocket motor.
Why am I so concerned about what I see?? Well first of all you are the one that asked what is wrong with the test firing. I've also "experimented" with sugar motors as well as zinc/sulfer, BP in the early 70's. There were a few of us guys that were involved with this for qiute a few years. We used very little science in the production of our motors. Trial and error was about it.
None of us had the "guts" to use metal casings (pipes). We used heavy walled cardboard tubes with plaster/water putty nozzles. What we were trying to do was to make large "Estes" type motors. We had more failures than success. All of our testing, flights, etc. were done on my Grandpa's farm well away from buildings and people. We were guilty of mixing up "stuff" at home (backyards) and lighting small samples.
For all the "experimenting" we did back then we were very fortunate in that only one of us was seriously injured. He was packing a BP motor that "went off", taking 2 fingers and half of his thumb with it. He also suffered a groin injurey on which I will not elaborate. Needless to say that incident ended our motor production.
Accident or not, we were coming to the conclusion anyway that we could not make consistant, reliable, safe motors. Now,commercial motors only for me, thank you, and things can "go wrong" with them also. That's why we have the safety codes.
Things have changed a heck of a lot since then. We were able to buy our supplies at the corner pharmacy. Implications of getting caught with the "stuff" back then were minor. I would never want to be caught with the item you have in your picture nowdays. You will be a terrorist and be treated as such until you prove otherwise.
Also now, for those that wish to "roll their own" there is a wealth of info out there, computer programs, experienced persons etc. to help in making/testing motors in the safest possible way.
Best wishes on your motor making, Be Legal, Be Safe!!!
