And by “can” I mean is it legal, and can I do it with reasonable expectations of safety?
I’ve dabbling in model rocketry and while it’s fun, it can get expensive once you start firing F sized engines – which AFAIK – is the largest engine you can buy without special licensing. I’ve been designing and flying RC aircraft for years, and have recently started flying RC rockets – which are basically rockets on the way up and radio controlled gliders on the way down.
So, the engineer and scientist in me seems to think that a guy should be able to make his own sold fuel engines. I don’t need a delay, I don’t need the tracking trail, and I don’t need the ejection charge. All I need is something I can fire and launch a rocket to sufficient height to glide back down.
The problem is that it’s not something I can just google. Researching solid fuel rocket engines online does give me all kinds of answers, but nothing that I am going to blindly trust.
I do understand how the casing and nozzle work and am confident I could build those parts. It’s just the propellant that may be tricky. I have no problem getting gunpowder – smokeless or black – but I know that simply stuffing a pipe with gunpowder will not give me the result I’m looking for. I suspect that I’d need to mix something with the gunpowder to slow the combustion, but am not going to experiment based on the advice I’ve read in broken leet and text speak.
So, here’s the questions: Has anyone here built their own solid fuel rocket engines? Is it legal to do so? I don’t think TPTB would appreciate rocket recipes posted here in this thread so lets leave that part off. Just checking the feasibility at this point.
I don’t really know the details, since I’m not interested in pursuing the hobby that far, but a friend of mine was licensed up to N sized rockets. I’m not sure who he was licensed with, but the rockets he fired required FAA clearance as they would reach commercial airliner altitudes.
It could be that model rockets are insured under an organization like the AMA for RC planes. And that you have to be licensed under the rules for that organization for the insurance to be valid.
Not only can you reload your own rocket motors, but there are companies such as Cesaroni and Rouse-Tech that make reloadable motor casings and reloading components. You can also find complete buildup kits from sources like United Nuclear. However, you do not want to just attempt to pack gunpowder into a tube and ignite it. Before you start working with any pyrotechnics you need to thoroughly understand all the safety precautions and practical chemistry procedures involved in handling deflagrants. Unless you are prepared to spend some serious money in equipment, you will have to do only pressed grains, not cast or composite grains.
One pedantic point of note: although Estes refers to their solid propellent motors as “engines”, in the aerospace world we distinguish between solid propellant rocket motors and liquid propellant rocket engines. There seems to be some disconnect on how to refer to hybrids; for the most part the literature refers to them as hybrid motors (containing a solid fuel grain which is sprayed with liquid oxidizer), but the reality is that a hybrid is for all practical purposes a liquid engine with a large solid fuel afterburner, and suffers the deficiencies of both solids (low performance, chamber pressure variability throughout burn, limited throttleability) and liquids (mechanical complexity, combustion sensitivity of injector head configuration, thrust limitations), so the practical application for hybrids engines is pretty limited.
Well, yeah. Don’t store hundreds of tons of oxidizer in flammable plastic drums in your driveway. Over a gas main. And then weld next to it. On a building with a fiberglass roof.
The PEPCON disaster is a textbook example on why you should never depend on common sense to avoid catastrophe, especially when the responsibility is diluted by being distributed.
Well frack, there goes MY plan for my lottery winnings.
IIRC Scientific American had a book. It was a compilation of Amatuer Scientist columns. They had some nice articles on homebuilt rockets/rocket engines (big fuckers by todays model rocketry standards). They had a fuel mix that seemed pretty safe from a handling standpoint. You might want to look it up.
The also had articles on how to build cloud chambers, particle accelerators, X-ray machines, other cool shit, and my favorite, the Hilsch vortex tube. That book probably had a dozen different ways for the determined experimenter to end up maimed, dead, or in jail these days. Ahhh, the good ole days…
I remember the rocket. Steel tube with fins welded on. They guy that built it put a strobe light in the nose and flew it at night for one flight. Nice parabola. But very primitive. Stoichiometric mix of powders for fuel, just rammed into the tube. A mate of mine did a trial with a one foot length of plumbing pipe held in a large vice. Very satisfactory firework. The modern rocket motors are cast and have a shaped hollow core, so that the burning surface is both much larger than afforded by tube rammed full of powder, and can provide a controlled burn rate for best efficiency over the flight.