Monday, January 31, 2011

Scratch: G125

Basically, this is G125 motor with fins and a nosecone. Would your RSO let it fly?

I guess I'll fess-up now - this was not my idea, nor is it a ‘live' G125. A year or so ago I ran across a picture of a rocket, whose body was a spent motor casing. Being a wise-#@!, I thought it would be fun to build one to get a rise out of my RSO/LCOs. Using my Dremel with various cutting wheels and grinders, I managed to ream out the casing from a spent G125 motor. I cut some G10 fins and some brass lugs, and attached them with epoxy. I made fillets out of epoxy clay. A piece of 24mm tubing fit nicely inside and I added some Kevlar® twine for a shock cord. When I went to search for a nose cone, I found that I didn't have any junk nose cones that were suitable. I was going to have to add a lot of nose weight to offset the heavy casing, fins, and fillets. I had recently bought a PML resin cone, but the shoulder was obviously the same diameter as the OD of the motor tube. Since I didn't want to sacrifice this fairly expensive cone by grinding the shoulder down, I cut a 1 ½" piece of 29mm tubing to ‘adapt' the cone to the body tube/casing. I attached it to the cone with a tiny screw, forming a reverse shoulder that overlaps the body tube rather than fitting inside.

To complete the effect, I removed the nozzle from another spent casing. It sits in the end of the rocket and, along with a protruding Copperhead, completes the effect of a motor with fins glued on. I also added some red/white checkerboard tape to the small piece of 29mm tubing. The rest is unfinished.

I first took this rocket to a NAR launch. I was sure to get some raised eyebrows there, since the G125 isn't even a legit motor at that site. Well, I neither got the desired effect or did I launch it (I can't remember why). At the next high-power launch, I again pulled it out. There, people see odder things and didn't have much reaction. Oh well. I guess a gag is all in the presentation?

I used a small plastic chute (8"?) and some Estes wadding. The boost on a D12-5 was a little wobbly, but not too bad. The chute was under sized and the cone embedded itself in the relatively soft dirt.

So far, I have not been able to convince myself to expend an E15 or E30 on this little rocket. It will probably just sit in my fleet until I re-use the nose cone.

Update: Well, I reused the cone so it hasn't flown again.