CERG June 2005

Date 06/25/05

Well several Ex'ers decided to get together and fly a couple of rockets and test a few motors before the next CEG launch. So we packed up and headed out to one of our launch sites. The day started out with some very high broken clouds, a slight breeze and nice warm (not to hot) morning due to the sun being behind the clouds. After arriving at about 8:20 am, a couple of guys were already out and had a rocket ready to fly. We got out the cameras and starting filming.

The button was pushed and away Kimble’s rocket went. There was an "N" class motor that had a beautiful boost. Just as the motor was burning out something happened to the rocket and it folded over and broke apart. We helped by picking up all the pieces we could find and got ready for the next launch. Jack’s rocket was loaded onto the rail and everyone was ready... 3...2...1... We heard the igniter pop, saw a little smoke and then a flame. The next 1/10 of a second there was a big kaboom. The rocket was blown apart in a split second. We walked around and picked up all the pieces of the rocket and motor we could find. We did find one complete grain that got ripped in half. Upon looking at the grain, we saw many voids and small air pockets. It looks like gas built up during the cure of the grain.

After that, Don and Ed's hybrid rocket was prepped for flight. After fixing various issues and one miss fire, they got it off the ground. The rocket went up towards the sun at which point I lost sight of it with the camera. Congrats Don, you finally got to fly your bird and your engine. I was able to static test 3 different motors including MBR's Purple Nurple, my new purple formula. The camera of course makes it look pinker that it really was, but it is coming along nice. Due to some thrust stand difficulties, I was not able to capture all the data I was looking for. I had many more motors to test that day, but I wanted to collect the proper data, so I only fired the three. The burn time on the blue two grain 38mm motor was 1.42 seconds with a peak case pressure of 572 psi. The 38mm four grain purple motor had a burn time of 2.9 seconds and the 54mm Purple had a burn time of 4.33 seconds.

Preston also test fired several small motors of which still need a little work with several cato’s. The 29mm motors seemed to have lots of thrust, but without the test stand working correctly, we were not able to get any good data.

Videos from our day.

First Rocket - Great boost, then something happens. (mpeg1 2.0 meg)
Second Rocket - 3...2...1... where did it go? (mpeg1 .7meg)
Don's Rocket - Great hybrid flight. Don's first hybrid engine and it was a success. (mpeg1 2 meg)
MRB Purple Nurple - This is my new purple formula 54mm 5 grain K600ish motor with a 4.3 second burn along with a smoke/tracking grain. (mpeg1 3.4meg)