January 12th, 2002 Launch Report
Tripoli Launch at Bong, Area F


Scott Goebel:

Yes, we flew some rockets today, even though it snowed, and the wind was brisk.

I flew my 4-29ss on 2- G80-10's. Fantastic, what a walk. I pulled out the "fart blossom" lampshade for a F24 powered flight. I also put up my Vaughn Bros. Javelin on a G80-7, and a Lil-nuke on a F50-9. I decided to save my larger motors for a better day.

Brent flew his Yank Bullet on an H128-short delay. Under powered in the wind it tumbled back to earth. The destruction may be permanent. Brent had better luck flying his AMRAAM 3" on an I284. An altimeter brought the rocket down using dual deployment successfully.

Kevin Klein flew his video rocket with out the normal camera payload on a Pro 38, J360. The J360 forward closure let loose 30' up frying his booster section. His altimeter saved the upper half. Kevin had loaded up a H220 earlier and decided to let-er rip. What rocket was that Kevin? I love the huge blue flame that the H220 blue thunder reload puts out! Good flight too.

Dean left in the am. while it was snowing and missed all the fun

The biggest motor flown was a K700 in a LOC bruiser. Apogee deployment assured a vehicle recovery effort. Don Guzzi flew a rocket with a J350 which separated at apogee, the nose cone free falling in. I think he was still looking for the rest of it when I left.

Tim had his share of unstable flights as always. He did OK for a Bears fan though.

Some body attempted their L-1 cert. on a 3" Yank Hawk missile. An I-435 destroyed the rocket when the nose cone popped off under deceleration at motor burn out.

Another lost soul put a G64-4 in what looked like an extended LOC 4. It augured in onto the runway before the motors' burn had even stopped. It was a very entertaining day

Scott Goebel





Dean Roth:

Lucky Sunday the 13th. Today's weather was perfect for rocket flying. I called Bong in the morning. The west end of the runway was not in use, but the person said that rockets had to be flown in lot D. The guy who was there on Saturday always insists that rocket be flown at D.

I don't have any motors at home. I tried calling Mike Dybul at 10:30, but got the answering machine. By noon I figured that he had to be at Bong, I was bored, so I tossed a rocket in the car and took off. As I approached Bong I saw a flash of light and a column of smoke, so I knew that someone was there.

Mike, Dave Zupan and Tim Lehr were at Bong. I got my runway pass stamped and headed for the runway. I didn't tell the ranger that I was going to fly rockets on the runway, and the rocket was covered by a blanket. Mike loaned me an I284. In a few minutes the motor was ready and the rocket left the ground.

The rocket had a experimental drogue made by Spherachutes. It performed well. Due to its design it needs speed to inflate, and it cannot pop open, which is what causes regular chutes to fail.

The flight was straight up. It arced over and started falling. Dave Zupan said that he sure hoped I had an altimeter in it. The RRC2 popped the apogee charge - well after apogee as usual. Some X-form chutes have broken due to the opening force because the RRC2 doesn't fire the charge at apogee. The drogue seemed to work well.

At 600' the main was ejected, but most of the parachute failed to exit the deployment bag. The rocket was positioned right over the runway for the hardest landing possible at Bong, of course. The drogue may have slowed the rocket enough that the 24" pilot was not producing enough drag to pull the main out of the bag. The main has a snug fit in the bag. Or maybe the cold weather made the nylon too stiff.

About 20' above the ground the main finally fully opened, and the rocket came to rest a short distance from the launch pad with no damage.

It was a great day to fly.

Dean





Kevin Klein:

Those of you who attended the TWA launch this weekend got to witness the rather spectacular failure of the Pro38 J360 I used in my Yank Tomahawk. I got in touch with Cesaroni today and attached below is their response:

Hello Kevin,

Unfortunate, sorry about the problem. Your failure matches a couple we've had over the last several months, and indicates that the adhesive bond between the delay column and the forward closure had a gas path. Those types of failures are characterized by a normal appearing ignition, but sometime in the burn (and it can be earlier or later depending on the size of the gas path) the motor will completely blow by in the forward end touching off the ejection charge - does this match your observations? Generally the propellant does not extinguish in such a failure because the pressure drop rate is slow.

This is a production issue, we make the forward closures 100 to 200 at a time, and the technicians are trained to apply the correct amount of adhesive and follow procedures, but apparently there is room for error. While we all hear about failures of this type from time to time with various manufacturers, we have done some R&D here recently to attempt to eliminate this potential failure mode. We will incorporate those revisions in future manufacture.

There of course is no problem providing a replacement, which we would send to Al's Hobby with their next order. How did the case make out in the incident? Normally the casing only suffers when a catastrophic failure caused the plastic threads to shear. PLease let us know if the casing appears okay.

Please let me know if you have any other observations that may be helpful in characterizing this failure as well.

Best regards,

Mike Dennett

Manager, Propulsion Systems
Cesaroni Technology Incorporated