An unhappy Endeavor...

The Sunburn rocket has been put on hold, not indefinite, but on hold for now. The upper section is complete for the most part, the chute still needs to be made and a couple of ejection tests to make sure everything is working properly will complete the work on the rocket.

In between the build of the Sunburn and now I have been trying to get some of my other rockets in the air. Back at the end of July I was able to finally Cert 1 on a nice H motor, although it took me three hours to find the rocket that cleverly disguised it self as a fence post! Before that launch though my lovely wife procured a nice Cesaroni K500 motor for my next launch. A very, very nice gift for Father's Day!

I decided to use this motor for my level 2 certification and decided to use my very first rocket I had ever built, but never flown. The PML Endeavor kit is a really nice kit and I had recently rebuilt it with some of the newer techniques I have learned and was confident that it would survive a launch. A friend also gave me a nicely machined aluminum tail cone that fit nicely on the aft of my Endeavor. Here she is on the launch pad all majestic and gleaming in the Saturday morning sun...

A few minutes later, after a couple of succesful launches of smaller rockets by fellow rocketeers the announcement for my rocket came up. I had a feeling in the back of my mind that something was not right, there was something I had missed. I attributed this feeling though to the fact that the rocket was built over a decade ago and had never flown before. Oh, how wrong I was! I had my video camera going, but the film is so blurry that it is hard to see. So I have drawn out the best I could the flight path of my Endeavor.

As you can see the flight went out of control at about 75 to 100 feet or approxiamately two seconds after lift off. After further examination of the crashed remains it was concluded that the aluminum tail cone added on after the rocket was built moved the CG of the rocket and hence moving the CP further down and making the rocket unstable. OOPS! When I added the tail cone I forgot to recalculate both of those numbers and look what I did. Fortuanately I during my rebuild of the rocket last December I built it to last and the only damage done to the rocket was a minor damage to the airframe. The following is a "how to fix and Endeavor when you fail to calculate the CG and CP of a rocket!"

The Damage...
As the picture shows the rocket is now in three distinct pieces. The little red part just aft of the silver section is supposed to be attached to the red section. Not sure when this broke off, but the rocket did seperate on the ground when the ejection charge went off. More than likely the airframe was damaged right there on landing and then the stress of the ejection charge was just a bit much for it. Never the less it is definitly repairable. Some menetioned to basically cut the damaged section off and shorten the rocket. I didn't like this option, I like big rockets, the bigger the better. I thought about putting a small section inbetween, but then realized I would need a coupler tube...this rocket has a piston ejection system. The coupler tube would get in the way! Argh. Then came the bright idea of laminating the outside and inside of the rocket with epoxy, sanding till the cows come home, and proceeding from there. Almost worked...almost...until I tried to put the payload section back in and it got stuck and broke the repair I just made. So I finally made my mind up and went the route of something I truly had never done before. Fibreglass. Making a special trip out to the local hobby store and picked up some 3/4oz light fibre glass and using the epoxy I already know how to use went about the repair. The following is a picture show of the process...mostly...hard to take pictures when your hands are covered in epoxy...

The first picture is of the epoxy applied to the tube, and the second is of the two layers of fibreglass applied. Had to change locations fairly quickly due to the fact that some rain clouds started move in. Once applied I had to wait it for it to cure. Now is a good time to go have a conversation with your wife about finances, keep it civil though! The reason I choose finances? It usually takes a while to has out all the needs and necessities. More than enough time to allow the epoxy to cure. Now comes the extrememly fun part of the ENTIRE process. Sanding. Make sure you have something good to listen to or a decent enough football game to watch and you will be done in no time. Using 60 grit to really tear into the epoxy/fibreglass was more than satisfying. Finishing it off with 100 grit or higher is recommended to get a nice finish. And here is the repaired body frame...

Primed and painted, the white is primer. The Endeavor is ready to fly again! Now to get a motor...