Classes are out but design team work goes on. Steel Bridge is in Provo, Utah, and June has Robotics in Michigan, FSAE to Toronto and Lincoln, Nebraska, Formula Electric also at Lincoln, and AAVG Rocket and Mars Rover events just an hour away from each other in the Eastern Utah desert. Each of those events validate a year of design, build, test, and repeat.
The AAVG HPER rocket team has one of the more interesting challenges; they manufacture their own motor casings and solid propellant, so if things go wrong they really go wrong, just as they did in the early years of NASA’s existence.
Chief rocket scientist Jill Davis’ team has done things right. They learned just how many threads to cut in aluminum so that tube holds together under propellant pressure. They also learned that if your propellant isn’t cured properly the motor casing can vaporize in an instant, spewing aluminum shrapnel in all directions.
Sunday they fired their smaller Helios to nearly 10,000 feet in a complete systems test powered by a commercial ($$) motor. All that was left was to validate the home-built propulsion system. With the IREC competition less than three weeks away yesterday’s rocket motor test was critical.
They’d bolted a heavy test stand to the ground in a distant corner of S&T’s experimental mine, just yards from where they mixed the fast-burning chemical components. Safety is paramount; nothing happens until blasting gurus DeWayne Phelps or Jimmie Taylor give the all clear.
Planning is essential. NASA often refers to a “launch window” when launch parameters are met for a successful launch. In the case of Josh and Terry the test “window” was a gap in a series of thunderstorms sweeping across central Missouri. The ignition wire, along with the steel barriers behind which they hide during the test, could be the perfect place for a lighting strike. And that would skew the test data beyond use. And melt your boots.
“Fire In The Hole!” x 3, then ”3…2…1…GO!” Terry pushed the launch button and was rewardedwith a tiny puff of smoke from the rocket’s tail. And nuttin’; no fire, noise or anything. Crap, a misfire! Safety protocol says don’t approach the device for 30 minutes, and then with the utmost care. Half an hour of sitting in the rain, listening to thunder before Josh Lewis and Terry McGarvey carefully removed the burnt igniter that failed to start the reaction. They changed their system by doubling the electrical triggers and wrapped them in pieces of leftover fuel (the aerospace equivalent of a bigger hammer) and got the results they wanted.
A puff, a small flame, then a long hissing roar that seemed to go on for minutes. Burn time was probably just 10-15 seconds but for these rocket scientists it was an eternity, since a fatal (to the motor) aberration might occur in the next ¼ second.
And then silence.
For a moment Josh and Terry looked at each other then started screaming “YES!” and dancing through the mud and rock. That meant they could go ahead and build the actual competition motor for the Utah launch. These S&T rocket scientists could now add “chemist” to their resumes.
Epilogue: Rocket motors burn fast and hot, and remain too hot to touch for some time. During the cool-down wait we noticed Matt Fogle’s name written on the cylinder. Explained Terry “Matt is definitely the “Godfather” of this project. He was the one who first started researching all about making solid rocket fuel, and the motor designs are his designs. So Josh Lewis and I signed the case and did it for Matt, since he is one of our best friends and without him none of this would be possible.”
Now that’s classy.