|Fat Fat Boy||
||24" nylon parasheet||Estes D12-7 core, 3x Quest C6-0 outboards, airstarted with Jet-X wick||The previous flight with this setup was so successful I wanted to try
it again, so I prepped the model the previous day again, as I had before,
with a D12 core and C6 outboards. This time, I set up to ignite all
motors with the Jet-X wick, which was ignited by a Quest Tiger-Tail igniter
external to the motors. This would reduce the delay between core
and outboard ignition both by shortening the Jet-X run to each outboard,
and by inserting a delay of approximately 1 second before core motor ignition.
With the rocket on the pad and ready to fly, I check range and sky, counted down, and pressed the launch button. The Jet-X flared up immediately, momentarily engulfing the base of the rocket in its flame before the core motor ignited and began to lift the rocket off the pad. The attempt to shorten the delay before outboard ignition was successful, with the outboard motors beginning to ignite when the rocket was 10 to 20 feet up.
Unfortunately, one of the outboards apparently suffered a debond between the propellant and the case, leading to a CATO. Even worse, in a plugged (or even vented) tube, a roman candle type failure is a Very Bad Thing.
In this case, the force of the ejecting propellant tore the forward centering ring loose from the body tube, and the propellant slug found its way into the ejection bay. While the nose cone and recovery system were ejected, they were slow enough getting out of the way that the shock cord was burnt in four places, and the parachute was badly toasted; in addition, the inner layer of the body tube was delaminated, and a hole burned completely through the side of the recovery bay.
Lower down, the motor mount was buckled and torn open, a hole knocked in one of the fin tabs (this rocket has six fins, and the outboard mounts are between the fin tabs), and the body tube in that bay torn completely away.
The only salvageable items were the nose cone, motor hook, and some of the snap-swivels from the recovery system.
Fortunately, Quest was very cooperative with warranty service, and didn't even ask that I mail in the failed motor before arranging to ship a pack of replacement motors and a replacement kit -- I opted for a Big Betty, currently their largest kit, comparable to a Big Bertha.
||18" nylon parasheet||North Coast F62-6 Dark Star||This flight was completely nominal -- except that I'd never been this
close to an F62 at ignition before. The Monroe field, where I usually
fly, has the 3/16" and larger rods 100 feet from the launch table; at Kent,
there's only 30 feet of clearance. Makes a big difference with a
motor in this thrust range!
Recovery, unfortunately, was a little more exciting; the rocket descends quite slowly under the 18" parachute, and the wind had started to pick up by this time; the rocket made it all the way to the Green River, which runs along the west end of the recovery area. I had been walking as it drifted, and was close enough to see exactly where it landed -- except I couldn't tell for sure whether it went into the river, or across. When I got to the bank, I didn't see a parachute in the water or on either bank.
As I was looking, I noted another rocket descending into a construction site across the river. I started back to the launch area, intercepted the flier whose rocket I'd seen (I recognized it, a BT-50 2-stage set up for D12 motors in both stages, though flown with a C6 in an adapter in the upper stage for this first flight). We both got into my car and drove to the bridge, crossed, and got as close to the construction site as we could, then walked in. I directed him to the top of a ramp embankment where I'd seen his rocket land, and then started looking on the river bank for my Spike -- and found it, less than six feet from the top of the bank, hidden from view from the launch side by a blackberry bramble.
||12" plastic parasheet w/ spill and vents||Estes C6-5||This was a ho-hum perfect flight -- as usual for this rocket -- and, with more practice angling the rod for motors in this class, I was able to land the rocket just twenty feet or so from the pads. Unfortunately, after this flight, I had to leave the field in order to be at work on time.|