Scratch The Zorch Original Design / Scratch Built
Scratch - The Zorch {Scratch}
Contributed by Bill Eichelberger
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Brief
The Zorch is my personal version of the Estes S.P.E.V., having come to be as a result of a trip through the junk pile in my shop. It uses parts from one previously flown and damaged classic, from a never completed scale project, a damaged piece of tubing, and an orphaned nose cone. The only new parts in this bird are the Kevlar and the centering ring that I used to mount it.
Components
- BT-50
- BT-55
- PNC-55AC nose cone
- 5055 balsa transition
- launch lug
- 2050 centering ring
- 36" length of Kevlar
- 36" length of 1/4" sewing elastic
- 3/32" balsa fin stock
Construction
As I noted earlier, this project was literally a junkpile before I started construction. There's a very good chance that the only part of this bird to ever be used again would be the nose cone. I was in the midst of cleaning my shop and refurbishing some of the older members of my fleet. I had an Astron Avenger that I built back in 2001 after finding the transition in an Estes Designer's Special. The Avenger was a great bird, but was showing serious mileage. One particular area of concern was the BT-50 upper section that had been damaged by contact with a fin after one of the Estes shotgun ejection charges. Since the tube was glued to the transition and I was using a generic PNC-50 anyway, I opted to replace the entire payload section with parts I'd bought at NARCON from BMS. I almost threw out the old tube and transition, but realized that I could save a good portion of the BT-50 by cutting the damaged part away. I started trying to come up with another design for the shortened section before it occurred to me that with a touch o' the Dremel, it could be the lower section of a whole new bird. Looking around the shop I found a partially crushed length of BT-55, a PNC-55AC with no clear ancestry, and a set of fins that I'd misplaced after cutting them out for a project out of Peter Alway's Scale Bash. Putting all of this together resulted in the finished Zorch. All I had to do was sand the paint off of three spots on the old transition for the fins, hollow out the transition with my Dremel, and fit a 2050 centering ring at the old bottom/new top of the transition so that I'd have an anchor for a piece of Kevlar.
Finishing
I sprayed the completed rocket with a coat of Valspar primer, then gave the fins and upper section of BT-55 two coats of thinned Elmer's Fill & Finish. After sanding the rocket got another shot of primer. I settled for my fallback red, white and black color scheme, once again using Valspar paint that was left from other projects. I'll eventually print up a simple decal with the rocket name. I'd put a picture of a Zorch on it, but since as far as I know my Grandpa made the word up, I don't have any idea what it would look like. (The Zorch was somewhere in the human midsection, but Grandpa was always vague as to the exact location. Spleen, kidney, colon; all of them seem to be in the general area, but none would exactly look good as a rocket decal.)
Flight
I finally got this bird flown at NARAM 53 in Lebanon, Ohio. I was surprised to find that I had built this with the potential for E9 flights, but didn't have the nerve to try it on an E9 in front of a NARAM crowd. I went with a C11-7 and a spacer, which was just perfect for the field and conditions. The Zorch left the pad with authority and on a dead straight path. It arced over at apogee and was on the way down when the ejection charge fired, but it was still moving slowly enough to avoid a zipper. Recovery was handled by a parachute that I'd bought off of Ebay a long time ago. The black and white checked chute both looked and performed well, and I plan to keep it as a permanent part of The Zorch's recovery arsenal.
Summary
Pro's: Recycled parts design. Impressive performance.
Con's: Bears a resemblance to an FSI Sprint. Sue me. 
If I meant for it to be a Sprint clone, I'd have built a Sprint clone, as evidenced by the Viking 5 clone I had damaged by a CATO at NARAM.
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Flights
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Bill Eichelberger (May 9, 2013)
Grandpa would be proud. 
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Dick Stafford (August 4, 2011)
LOL, Zorch is the nickname of my best childhood friend.