PGerringer
Ruler of Heck
- Joined
- Jul 12, 2001
- Messages
- 1,778
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I'm sorry we missed the WELD launch held at Whitakers this past weekend. I hear there were some spectacular shows. This is reprinted with permissing from Jeff Taylor who did the original report. I thought you guys would like to see it.
The adrenalin has finally worn off to the point where I can write a partial launch report for this past weekend's WELD (Whitakers Experimental Launch Days). Three days of experimental high power rocketry.
Friday: the Thunderflame class, taught by guest instructors Alan Whitmore and Ben Russell, was about all that happened. I think Alan launched one rocket to test the launch system. Students mixed and cast propellant for 38mm motors.
Saturday: Overcast at about 5,000 for much of the day, which kept it cool. The winds were light and blowing in the good direction ( from the SW ). The most awesome flight of the day was Steve Krall and Ed Rowe's tremendous Standard Arm. They didn't have time to paint it, but it was still a work of art. The Standard Arm flew on a central 75mm 7600 N-s red motor, with 4 38 mm outboards. The core motor ripped the rocket off the pad and the outboards air started as planned. Unfortunately, Steve in his excitement, turned off the altimeter before counting the beeps so we don't know how high it went.
As the day progressed we all watched the construction of Kelly and Mark's "Bigger Dawg" out at the reallyreallyfuckinfaraway cell. This rocket was not to be believed, by far the largest launch attempt east of the Mississippi. An up scaled version of the Estes rocket, this one was 24" in diameter, about 15 feet tall, and weighing in at 646 lbs. Yep, that's 646 lbs. You read it right, SIX HUNDRED AND FORTY SIX pounds. Yikes! The boys had a single 8" diameter motor designed for a full 80,000 N-s. As the rocket grew on the launch pad you could feel the electricity building long the flight line. Yowza, these crazy fools were really gonna try and fly that thing! Then a dull thump was heard and smoke rising from the partly assembled rocket spelled bad news. An ejection charge had fired prematurely during the preflight electronics test. No one was hurt and the rocket, which was still horizontal at the time, was not damaged. That did end the chances of flying that day, however.
The first of the Thunder flame class motors lifted off with a really
shocking amount of power. It was a super fast .6 second burn, and it was instantly clear that the students had mixed some very hot stuff. The next two class motors proved just how close to the edge the first one was, by blowing up. There were a couple more successful class motor flights, and then a third motor over pressurized. At this point the students decided that discretion was the better part of valor, and the remainder of the class motors were not flown. The final consensus was that the AP used for the class propellant had a higher content of sub 200 mic particles than previous supplies. It was a tough lesson for the class, but in my opinion a trial by fire (so to speak) is the best way to learn.
Sunday: Near perfect weather. I rushed out to the pads and had the first flight of the day with my 9" diameter V2 rocket. I used a 98 mm loaded with blue propellant for a total of 5000 N-s, a full L. A great boost, if I do say so, but at apogee the nose cone broke its 600 lb rated quick link and plummeted to its death (8 lbs of lead in the nose). The rest of the rocket recovered as planned and I'll have a new cone ready in no time. Mark and Kelly were hard at work prepping the Bigger Dawg again and this really added excitement to the whole day. I mean you'd be prepping a rocket and you'd look up and there was this HUGE thing taking shape way way way out there in the field. It was a bit surreal. Steve Krall, not satisfied with the previous day's success, loaded up his original level 3 rocket with a 75 mm 6000 N-s M motor using the "slow" version of his white flame ropellant.
All I can say is that I hope to never see the "fast" version of this! The rocket ripped off the pad and at about 200' turned to confetti with a tremendous BOOM. Everyone was sure the motor had catoed, the boom, the fluttering pieces, what else could it be? Well the motor didn't cato, it was just the most massive shred I have ever witnessed. The BOOM apparently was the Rocketman R14 chute opening at Mach 2 (no it didn't survive). Afterward, Steve said, "maybe I should have glassed that one."
At this point the Bigger Dawg had begun its trip from horizontal to
vertical. This was a slow trip that took several minutes. Once vertical, we all turned off our FRS radios and cell phones before Mark climbed up and armed the electronics (better safe than sorry). There were launch officials (!) stationed at strategic locations to stop traffic and the one and only Whitakers cop car (betcha didn't know they had one) was on hand to fight back the crowds. With the radios off it was kinda hard to communicate with the reallyreallyfuckinfaraway cell. Kelly was to flash the lights on his truck, but it was so far away I couldn't see the lights. Didn't matter. I could sure as heck see that rocket when it started to move. It moved right off the pad with no hesitation and climbed to about 400' before disaster struck. The motor's forward closure let go and it all came crashing back to earth.
Well not all, the forward section of the rocket was not damaged by the motor failure and it deployed its chutes as intended, recovering without damage.
Ben Russell's O motor flight seemed almost routine after that excitement. Ben made the 'up' part look easy with a perfect burn from his 25,000 N-s 6" diameter O motor. However, with big rockets 'up' is usually the easy part and this flight was no exception. To me it looked like a classic drag separation of the nose at burnout, but others heard the altimeters fire and this was clearly seen on the video tape. No clue why both altimeters fired early. The rocket went splat. (On my soapbox) Folks get this straight, barometric altimeter cannot be trusted. Never ever buy one and you'll be much happier. (Ok, off my soapbox).
There were many other good flights that I haven't detailed here, and there are so many new EX fliers that I haven't learned their names yet.
Oh yea, there is one more flight that I do remember....Dave Muesing's orange rocket. Dave brought three of his latest AN motors out to the launch (down Bruce!, down! AN is ok, really!) Dave decided to static test the first motor. 2.5" in diameter and about 12" long this thing looked serious. AN doesn't light quickly, an so there was lots of smoke before any fire emerged from the nozzle. The initial thrust was very low (see that smoke plume
leaning over in the breeze?) but it increased as the burn progressed, with much popping and choppiness. Just when I was starting to wonder if it was going to hold together, it burned out, about 6 or 8 seconds of burn I guess. Dave decided to fly the next motor.
"Dave," I said, "is that thing going to have enough thrust to get off the pad?"
"Well sure, this grain is 30% longer!" said Dave, confidently.
The burn was exactly the same as the first one. About two thirds of the way through the rocket slow slid up to the top of the rod, leaned over and flew horizontally for a few yards, and crashed.
Out of rockets, Dave decided to static fire the third motor. It performed consistently with the first two. Consistency is important and I'm sure Dave will put these test data to good use.
That's it for now, see ya'll next time.
- Jeff Taylor
PS- Buy Loki Research!
