Wednesday, May 26, 2010

Launch Report #38: CATO 161

Yes, another late post. Oh well. I have no no time whatsoever lately.

The weather was great on Saturday - hazy but no wind. The only frustrating bits were that there were a lot of kids around - three school groups totalling almost 60 kids - and that a lot of rockets flew right into the sun and were hard to spot.

My first flight was the L-13 on a C6-3; simulated altitude 500 feet. It was a bit squirrelly and wobbled during boost; I'll add some nose weight before its next flight. It recovered nicely on a 15" chute (repaired from last month's launch).
Second flight was the Mach Goon on a G115WT reload. Simulated altitude 3500 feet; simulated velocity 1250 fps (Mach 1.1+). Way to high for this field, but I was asked to specially and I got permission. The motor ignited almost instantly, and it ripped off the pad:

It took a sharp turn east at a few hundred feet off the ground; perhaps a fin split off or it spit a chunk of propellant. Stability was marginal in any case. It roared off at ridiculous speed, and I heard a crack which may have been it breaking Mach for a moment. I never saw ejection despite the loads of tracking powder, and currently it's lost. I got in contact with the owners of a nearby farm field where it may have landed; they said they'd keep an eye out for it. Nice folks.

Final flight of the day was the Sudden Mach on an E18-4W, simulated altitude 1350 feet.

The drogue was a 6" nylon chute; the main was 15". Al Gloer helped me (a lot) with the charge, and I set the Minitimer 3 to 25 seconds - approximately 400 ft AGL at deployment.

It ripped off the pad rather nicely. I love the E18 reload.

It deployed the drogue right at ejection, but then the whole thing came apart, connected only by the Kevlar shock cord, and the charge never fired.

Turns out, it's hard to glue stuff to Blue Tube. The spacer rings had both stripped right off their couplers at ejection - easily repairable.

I'm not sure why the timer didn't fire the charge; perhaps it was mounted too loosely in the avbay. In any case, that's an investigation for another day, and I'll explain it further tomorrow.

Total was three flights, three rockets, three motors. Total of 188.4 Ns - one of my highest one-day totals.


DTH Rocket said...


I know how frustrating it is to lose rockets, but you have to expect that sort of thing with those minimum diameter high-performance high-thrust little guys.

Are you a little more nervous about the Sudden Mach now that you've lost Mach Goon?


The EGE said...

Eh, the Mach Goon was a one-shot rocket. Cheap to build, and the case was cheap.

The Sudden Mach is built stronger and saner; it's purpose-built as a recoverable, high-altitude and high-speed drag racer, rather than sticking a big motor in a little rocket. I'm not worried about recovery.