Monday, May 20, 2013
Friday, May 17, 2013
I started on the nozzle ring this morning. I drilled out the center, starting with a center bit and working up to a 1" diameter bit. The larger drill bits remove a lot of material quickly, but an inch is about the limit for my lathe. Next I'll bore out the center to the right diameter. Then I'll face it, cut the relief that the divergent section fits into, and index the holes for the six screws that hold the two sections together. Then I'll flip the piece. Once flipped I can finish it off to the correct diameter and cut the convergent section. Lastly I'll add the o-ring gland and index the twelve screw locations for the screws that hold it in the casing.
Thursday, May 16, 2013
The aluminum tube for the DSS-TM-3 SStS motor arrived yesterday. I'm just indexing/drilling the screw holes so not much work for me. DSS TM-3 motor? OK, it's getting tough to keep track of all the motors as there are more than a few in varies stages of construction and testing. The motor is a single burn (half of the dual phase concept) that is intended to serve as a flight motor for the avionics package once successfully tested. The design calls for approximately 90 lbs (41 Kg) of propellant. Hopefully that flight will occur later this year. As always, check the weekly reports on the Sugar shot to Space site for more detailed information.
Charles M. Parkin, Jr. as he is described in the book:
Rocket expert, U.S. Army Engineer, Research and Development Laboratories, Fort Belvoir, Virginia; Founder of Youth Science Corps; President, American Rocket Society, Washington D.C. chapter.
In the later chapters of the book, he describes a small rocket which utilizes a sugar based propellant. I've often thought that it would be fun to build that rocket exactly to the specification in the book and then actually fly it.
Maybe I will do that some day...
Wednesday, May 15, 2013
With this drawing, I now pretty much have all the drawings that I need to begin cutting metal in earnest. I plan to go back and update these drawings. I don't really need a drawing for the bulkhead as it's identical to the nozzle ring in thickness, o-ring gland placement, and retaining screw locations.
Monday, May 13, 2013
ULINE mailing tube as the casting tube/inhibitor for this motor. This particular tube has a wall thickness of 0.080" and allows for a bit of insulation to fit between the propellant segments and the casing wall. The motor is designed to use a propellant grain consisting of six segments. Each segment should weigh approximately 4.75 lbs (2.15 kg) for a total propellant load of approximately 28.5 lbs (13 kg).
It been almost exactly one year since I started this motor...far too long. SStS has been going very slowly and in spite of some recent progress, I suspect that the the way forward will continue to be a slow progression. Back when I started getting really involved with amateur rocketry thirteen years or so ago, I was designing, making, testing, and flying much more frequently. I think in those early days, once I joined the Reaction Research Society there was so much excitement in going to the launches. The first event that I went to included zinc/sulfur, LOX/kerosene, HTPB, and sugar . Within the next few months I saw many more of those and added steam, HTP, and a variety of hybrids, good times. I don't know that I can get back to that level of activity anytime soon, but Theo definitely enjoyed the desert, the rockets, and the people so we should make a point to go more than once a year. With that in mind I'm making a conscious effort to finish the TR-1 motor ASAP.
Here is the next part to be made.
This is a fairly heavy motor, but it won't matter. With 1000 lbs of thrust there is no doubt in my mind that it will get itself off the ground when it's time to. The purpose is to build something relatively simple and at low cost, and to sharpen my skills before moving on to a larger project that I've been toying with for the past 10 years or so. There is some excess material in this design, so the part could go through a weight reduction process, but there is really no point for a static test.