Kurt Gugisberg holding his rocket, Black Rock Desert

Kurt Gugisberg holding his rocket, Black Rock Desert. The Big Purple rocket was created as a multipurpose booster for various configurations. It has a six-inch diameter airframe with a single 75 mm motor mount. The fins are 1/8" G 10 fiberglass and a direct rip off of the PML Pterodactyl design. I'm sure there is a name for the shape, modified clipped delta or something like that. The airframe is phenolic tubing with one layer of 6 oz. fiberglass. The booster electronics bay is located in the coupler with access through the upper bulkhead. In it's original design, the upper section housed a dual deployment set up. A coupler with bulkheads on either side holds the electronics and access is through a hatch on the side of the airframe. The booster electronics are not used in this configuration. The upper electronics bay usually will have two Altacc altimeters for deployment, with room for additional timers or altimeters if needed. After two successful flights as a dual deploy sport rocket, I installed a video camera payload section. With this modification, I also installed a three chute parachute harness which provided a very stable decent. I would deploy the chutes at apogee to get the longest hang time as possible. Some of these videos are featured in Giant Leap's video "Onboard Rocketry". Bigger Purple: The next step in the program was to use the Big Purple booster in a two-stage configuration. I needed to build the sustainer. I had a fiberglass fuel transit pipe that someone gave me and it was the perfect length for the project. It's inside diameter was slightly more than 4" so I needed to make a transition from the six-inch booster to the odd sized sustainer airframe. I used hand made 6" to 4" centering rings to center a section of 4" airframe inside a 16" section of 6" airframe. Then I fashioned the sloped transition section from Styrofoam. I wanted this section to be extremely strong so I used a Kevlar sock purchased from Giant Leap to cover the section. Using epoxy resin, I coated the phenolic and Styrofoam and rolled the sock down, pulling it tight to remove the wrinkles and to stretch the material to make as thin as possible. It still was rather bulky compared to fiberglass cloth but the extra thickness was perfect for the 4" section that was to fit inside the sustainer's tail end. This transition would also house the parachute for the booster. In the sustainer, I recessed the rear bulkhead far enough for the transition coupler to clear, about 5". The 3" motor tube was fiberglassed for added strength since it was hanging free. I ran two brass tubes up to the electronics bay, which was just ahead of the forward motor tube centering ring/bulkhead. These tubes hugged the motor tube and allowed the igniter wires from the timer to reach the motor without interference from the transition coupler. For recovery, I am using dual deployment. However, both chutes will exit from the top of the airframe. The main chute is packed below the drogue chute and ejection charge. Hopefully the main will stay in place when the drogue is ejected. This has worked well with smaller models, at least 90% of the time. On it's maiden flight, Bigger Purple flew on a L1120 staging to a K560 at El Dorado Lake during Springfest 2002. Onboard was Joe Mullin's Rocket Hunter tracking transmitter. I set the first channel of the sustainer's Blacksky Timer 2N to blow a small charge to separate it from the booster at one second after burnout. I set the second channel of the timer for one second later to ignite the K560. All went well. The boost was virtually straight up, separation occurred right on time, sustainer motor fired perfectly. At apogee, a glint of light off of the fins signaled the rocket's nose over. After that, there was nothing. It was heard coming in ballistic, someone heard a loud pop, and some one said they saw a chute on the horizon. I thought all was lost. We had no signal from the transmitter. Later, Joe picked up the transmitter's signal. As we pulled up to the area, we saw the sustainer lay on the ground in one piece as if nothing had happened. However, the main chute was a hundred feet away in one direction, the transmitter was off in another direction, the nosecone, in a third. Our summation was that the rocket came in ballistic until the main charge went off at approximately 500 feet altitude, the main popped out and instantly broke it's shock line, but the rocketman ballistic drogue was enough to slow it down and turn it around so it hit motor first in the dirt. The drogue's line pulled through the fiberglass, a 6" long zipper but everything else was fine. Even the main chute didn't shred. It was an 8' diameter Spherachute. In the end, the problem was a too small of an ejection charge for the drogue. With two nylon shear pins, the 2.5 gram charge didn't do the job. Altitude reached was 16,763 feet. For XPRS I will be using a M1315, staging to a L1120. Expected altitude will be near 25,000 feet. Epilog: At XPRS, Black Rock, Nevada, September 28, 2002, The Bigger Purple launched successfully to an altitude of 25,244 feet above the lakebed. The launch, boost, separation of stages, ignition of sustainer, and recovery of both, the booster and sustainer with no damage, was picture perfect. September, 2002.