April 18, 1997 - Launch Report
The derelict Big Bertha that had been given to us was repaired with improvements. I had installed a 3-deflector baffle comprised of offset half-circles according to a recent posting that I now cannot find to give proper credit. You know who you are and thanx for the idea. The Estes paper SC mount was removed. Since I couldn't get at the top of the motor mount tube, I epoxied in a LOC-style loop SC mount. Lastly it was given a nice flat-black paint job and looks as good as new.
The whole family piled into the Aerostar and headed for our nice big field at the college. Uh-oh. It's covered in soccer players! We hemmed and hawed about a long, narrow corridor that was open between two of the soccer fields that even coincided with the prevailing breeze. But reason kicked in and reminded me that the Big Bertha was a bit of an unknown quantity. The reconstruction had gone well and I didn't think its stability had been anything but improved. But just in case it acted squirrely on launch, I didn't want to be standing in the middle of a crowd. So we drove about 10 miles to a fairly large yard shared by two schools.
This field was mostly deserted, only a few families there playing ball and such. I don't think anyone noticed while we were setting up the launchpad. The Big Bertha was prep'd with a B6-4 for its comeback flight. I threw in one sheet of wadding, just to backup the baffle system. It was getting dusky, a little cool and just a slight breeze.
"5-4-3-2-1" Whoosh!
I like the Big Bertha! It didn't go very high on the B6, but I saw the
motor flame-out and then a red glow at the base of the soaring black
bodytube. That was neat!
I heard one small boy across the field exclaim, "Whoa, what was THAT?"
"BIG BERTHA!" shot back my son Kyle.
Bertha had just nosed over when the NC ejected, right on cue. The 18" x-form (garbage bag) chute deployed without a hitch and brought her down only about 50' away. 100% success and much cheering and jumping about by the peanut gallery.
This was cause for a victory re-launch! We got Bertha ready again, except of course we had to step up to a C6-5. The sheet of wadding from the first launch was still in the tube, and very brown on one side. The baffle was working fairly well, but it looked like it was a good thing that I had put the sheet of wadding in there. This time I added another sheet, just for good measure with the more powerful C6.
All the other kids at the field have stopped to watch. They see we are ready again and begin a countdown for us. "10-9-8..." Hmm, no continuity light on the controller. Remove safety key and go back to check the ignitor, but it looks okay. Bend the leads apart very gently just to make sure they're not shorted. Connect the clips to the leads while the ignitor is out. Go back and check but still no continuity.
One boy from the spectator's section is dragged by his mother into a car. "No - we can't stay any longer. We're late as it is!" He is not happy and neither am I.
Hmm. Take key out, clip one alligator directly to the other. Recheck with key, still no continuity. Okay, it's either the controller or the wires, not the rocket. Opened the controller and there was the problem. The battery holder was sprung. Amanda must have dropped it after the first launch. Bend it back and put the controller back together. Now we have continuity! Take out key, go back and put ignitor back in rocket, put Bertha back on the launchpad. The count from the spectators begins again.
"10-9-...-3-2-1" Nothing... rats!
Grrr, take the back off the controller again and bend the metal clip further
to hold the batteries tighter. Put the cover back on and reinsert key.
Alright, a noticeably brighter continuity light.
Our countdown. "5-4-3-2-1" Whooooosh!
Bertha was away! She arc'd a little into the breeze, (a good thing too)
but climbed beautifully without any rotation at all that I could see.
I think she reached around 500' before turning back toward the ground.
This time the NC ejected well after apogee but not too bad. This was the
first 'C' launch my wife Teresa had seen, and she was impressed by the
altitude. So were the spectators, several "oohs" and "wows" wafted our
way. Yeah, Bertha's up there... and drifting. Even on the x-form. There
must be a stronger breeze up there. She drifted all the way across the
field (some 300') and touched down just short of some trees at the far
side.
Quite a crowd accompanied Kyle as he carried Bertha back. While he was on his way, I started prepping the SuperShot for the last launch of the evening. I thought about showing Teresa just how high the SuperShot can go on a C6, but the distance that Bertha drifted talked me out of it. I dug out another B6-4 and put it in. Kyle and his entourage got back with Bertha just as I was connecting the ignitor clips. Once everyone had cleared away, we were ready.
"5-4-3-2-1" Whooosh!
Another nice liftoff for the SuperShot that ejected right on time.
But I'm still having trouble with the chute deployment. This time, my
kevlar backup line to the SC tangled around the chute. Good thing the
SuperShot is a tough bird. It did a poor imitiation of streamer recovery
with the ball of plastic garbage bag that was supposed to be a parachute.
The SC shows no sign of scorching thanks to the steel leader, so I think
I'm gonna remove that kevlar backup line. With this small bodytube, it's
just too hard to get the parachute, SC and kevlar line stowed properly.
Not a great ending, but we were extremely pleased with Big Bertha. Both sheets of wadding from the second launch were still in the tube and looking very scorched and brown. I think my next baffle unit will be solid disks with non-aligning holes. The half-circles seem to let too much hot gas past.
Still working on "The Shadow" project. I'm waiting for some mailorder parts to complete the first motor mount unit for dual 'D' operation.