TR-1 MOTOR UPDATE

I didn't get much time at the lathe this weekend, just enough to face the divergent side of this piece and cut the relief that the other half of the nozzle fits into.  I need to index the screw locations, then I can flip the piece and finish it off.  I did realize during the weekend that I didn't have a complete set of drawings for this motor.  It had been so long since I designed this motor and I was incorrectly thinking that I had designed this piece to work with another nozzle divergent piece that I had already fabricated.  You can see that nozzle here, it's the one on the right.  At one point this weekend I saw the two motor casings sitting next to one another and immediately thought "wait a second, that other motor is way bigger...that nozzle piece can't work with the TR-1 motor!"  After checking my earlier designs I realized that I had drawn a preliminary version of the needed part.  I double checked everything, made some minor adjustments to the design of both pieces and now have a full set of drawings for this design.

I may still decide to take some excess weight out of the nozzle ring as it's heavier than it needs to be.  Then again, it doesn't really matter for the static test so I may just get the important stuff done then move onto the next piece. It would be beneficial to remove weight from the aft end of the rocket before the flight so I'm sure I'll do it before then.   I'm machining the nozzle ring out of 1018 which is noticeably tougher to machine than the 12L14 that I'll be using for the divergent piece.  Once you've machined 12L14 steel, all other steel seems like a chore!

TR-1 MOTOR UPDATE

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.

SStS MOTOR CASING (DSS TM-3)

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.

I've collected a lot of rocketry stuff over the years, maybe none as cool as this book.  The Rocket Handbook for Amateurs by Lieutenant Colonel Charles M. Parkins.  I saw a copy of this book sell on ebay claiming to be a first edition.   Maybe it was...maybe it wasn't.  The listing included numerous photos of the book, but suspect is the fact that the copyright page had the lower third cut off, right were mine clearly states that its a "second impression".  I don't really care that mine is a second edition, but I paid WAY less that buyer of the other book paid.  I bought the book for the information it contained and maybe a little for the nostalgia of being able to read a book from the golden age of amateur rocketry.  In any case my copy has something even better than being a first edition, an inscription from the author.  It looks to me like the inscription is to someone with the initials H.C. I'd love to know who that is.

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...

TR-1 MOTOR CASING

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.

TR-1 PROPELLANT SEGMENT DESIGN

I plan to use a 4" 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).

TR-1 ROCKET MOTOR UPDATE

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.