Saturday, August 15, 2009

Certification

I brought my Nike-Apache all nice and shiny new to the field. I found a CATO member willing to sponsor me, and I assembled the motor and got it ready for flight. Hangar 11 was out of H128s, so I used an H165-M Redline with a deliciously loud roar. I got it RSO approved, on the pad, and ready to go:












Unfortunately, the first flight was a failure. The following is my best forensic explanation of the observed events. The motor ignited and burned fine, bringing the rocket up to speed and producing a loud roar. Due to the loose fit of the transition section, the lead weight and its high momentum pulled the Apache and transition right up off the high-drag Nike body at burnout - approxiamtely 600 feet and 600 fps. The chute, well built and packed to open quickly, did. The thin elastic shock cord snapped on both sides of the parachute loop, leaving the parachute, Nike body, chute protector, and Apache / transition coming down in 4 separate pieces. Oh snap.

I walked out to inspect the damage. Despite the high-speed deployment, the 28" nylon chute was in perfect condition, as of course was the Kevlar chute protector. I found the Nike body next. As do many rocket bodies (like the Bullpup) with large fins and a motor in back, it had glided down and came back undamaged. This meant at worst, I could buy a new 2.6" nose cone and try again sometime with a non-scale rocket, or perhaps a Nike Smoke.

Finally, I found the Apache, or part of it anyway. The heavy nose weight and fins and transition in back had made it perfectly stable coming in. Absolutely perfectly stable. It was buried so that only half was sticking out, and I could not pull it out with my bare hands. Fortunately, Bob from Hangar 11 was kind enough to lend a shovel. After loostening the sod around it, I first pulled up the body, sans nose cone. After a bit more digging, I found the cone. Except for flattened antennae and the covering of dirt they looked... remarkably undamaged. Thank goodness for the soft dirt of the sod farm.

After conferring with the ridiculously helpful Al Gloer, I set to work. He mixed some 5-minute epoxy and I scraped off the nose cone, then glued it back on and set it out to dry. He gave me a 5-foot piece of 1/4" kevlar, with loops sewed on both ends and for the chute. The kevlar would withstand more forces, he said, and could have survived the premature separation. I straightened the antennae and bought a pair of quick-links (one for attaching the other end of the kevlar to the rocket, and one because they were $2.50 and ridiculously useful), and made a small vent hole to prevent air pressure differences from contributing to another premature separation, located based on the advice of a flier I picked out at random in the RSO line who was more than happy to explain to me what to do.

Finally, I entrusted my 29/180 case to Carson's Motor Cleaning, a NERRF / METRA institution. Carson is a maybe 13-year-old kid who cleans your motor cases for you - 2 bucks for a 29mm case, 3 for a 38mm case, and up to 6 bucks for a whole 98mm case - and does it well. In ten minutes, I had a conveniently clean case.

Under Mr. Gloer's guidance, I assembled another H165R-M load, including Gary Tortora's handy tape trick which keeps all the ejection charge in. He then showed me how to put lots of tape on the transition so it wouldn't drag-separate. Patrick McConnell managed to dredge up another set of Jr. Cert forms and I was ready to go.












This time, it leaped off the pad after a single igniter chuff, and held together all through ascent. It arced over at a simmed 1700 feet, then ejected about 3 seconds past apogee due to the slightly long delay. A moment of smoke, then this glorious sight:












After about a 2-minute descent, which was very slow - about 15 fps due to the large chute - it finally landed. The cone stuck on landing, but amazingly, for the second time that day, did not break. I picked it up very carefully and carried it back for post-flight inspection.












Al Gloer and another flyer checked the rocket for damage - none - and signed off on the forms. I was offically Jr. L1 certified! Now all I need to do is photocopy the documents and send them off to the NAR HQ for offical filing and a new NAR member card with my new cert level.

I'd like to thank a few people:
My dad, for taking a whole day to be bored while I drove, bored while I prepped rockets, taking awesome pictures, bored while I was the pad manager, bored looking for my rocket, and bored driving home again, all for my benefit.
Al Gloer, for being a huge help with repairing the Nike-Apache, for witnessing my cert flight, and for getting me going again after my embarrassing failure.
Gary Tortora, for various help during motor assembly.
Pat McConnell for the form.
Several other CATO members, for various help along the way.
Bob from Hangar 11, who helpfully had all the parts I needed.
And last but not least Carson, for the very helpful service of motor cleaning.

2 comments:

Dick said...

Sound like you learned a lot from the first flight. Congrats on the L1!

Sascha Grant said...

Congratulations!