ROCstock XIX Report and Photos

Reported by Robert H. Brigham
All photos by Jeff Stai

Page 7

Five rockets with less than M-class impulse nosed above the standard waiver using more than one motor. In other words, they did it the hard way. Dave Flynn, Eric Pyne and Andrew Tryon did it by staging.

After a successful flight on Friday with an I375/I161 combination, Dave flew his two stage “Omega 4” on Saturday with a J800/J135 motor set. Booster recovery, staging, and sustainer recovery all worked perfectly. Peak velocity at sustainer burnout was 790ft/sec. Apogee, 7,778’, was reached 15 seconds later. After a perfect dual parachute deployment, the main brought the bird down at 20ft/sec with no damage. Total flight time, 3 minutes.

Eric Pyne’s staging attempt was partially successful. He used his scratch built rocket as a test bed for an interstage coupler design, and it worked. Eric employing the less conventional combination of an Aerotech I161 sustainer sitting atop a Hypertek J330 powered booster. Upon ignition, the hybrid blatted it’s way aloft, then successfully handed things off to the composite-powered sustainer which finished the job, taking the rocket to an estimated 10,000’. The coupler system worked. Recovery was problematic. Using the onboard RocketHunter, Eric successfully tracked the signal to 2 gentlemen who had strapped the rocket to the back of their ATV and were ready to depart with it. They rapidly relinquished their trophy. Later inspection suggests the rocket may have stripped it’s chute and, once on the ground, been run over. It’s a jungle out in the desert!

Andrew Tryon had even less luck with his staging attempt. Late Saturday he launched his PML Quantum Leap neé “Red Baron” on a J460 staging to a J415. During post-mortem there were indications that the second stage igniter slide back during first stage boost, delaying second stage pressurization. By the time the J415 came alive, the sustainer was no longer pointed skyward. This is not a recipe for success. The electronics did their best to compensate by duly detecting apogee and deploying the parachutes, but in retrospect, this was not a good thing. As flight crew member Dave Echkart put it, “All parts were recovered on the lakebed proper with the exception of the altimeter itself. [Andrew] was unable to find it. [“The Red Baron”] will be repaired and fly again.”

Sorry - this is Gary Bitterman's Magnum
with a J415 and no airstarts.
We're really very very sorry that we
missed Rick's flight, but we did get to
see Gary's!

The two remaining complex high altitude attempts used air starts. The first was Dave Sparks who started up his “Dark Star” on a K550. The plan was to airstart pairs of I211’s and G35’s, but only 1 of the 4 airstarts lit (the “Dark Star” stayed, well, mostly Dark), taking the bird to only 5200’. The second was performed by the club master of airstarts, Rick Magee. He put up his stretch Magnum on a K700, followed by a single pair of I200’s, followed by two successive pairs of H180’s. When that many motors work perfectly, it can only be described as a work of art. Thanks for the show Rick.

So, try to imagine a flurry of airstarts...

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