Scratch Raygun Gothic HoJo Original Design / Scratch Built

Scratch - Raygun Gothic HoJo {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 11/16/09)Scratch - Raygun Gothic HoJo

Brief:
This was the second rocket I built around the wooden birdhouses I found at Michael's. I decided the body of the birdhouse reminded me of a squatty version of the Honest John cone. This rocket is based on 3" tubing and flies on a cluster of four 24mm motors. Its name is also based on the Raygun Gothic Rocketship from Burning Man 2009.

Construction:
I found 3" tubing would fit the 'cone' perfectly and decided to use some Giant Leap tubing that I had around. I started construction with the cone. The fins on the birdhouse were held on with both glue and wire brads, but were easy to remove. A bulkhead was glued to the bottom of the birdhouse, the shoulder (Giant Leap coupler) was glued over that, and a 2nd bulkhead was glued to the end. A long eyebolt goes through both bulkheads.

I cut the centering rings and fins from 1/8" luan plywood. The rings were cut on buddy's router and the four 24mm holes with a hole saw. I cut the fins on a table saw. Because the four motor tubes were shorter than the fin root, the through-the-wall tabs had to be notched accordingly.

The shock tether is 1/8" Kevlar® attached to the motor mount. A bolt is attached in the center of the mount for motor retention. I recessed the mount so the rocket could sit flat on its end with the motors installed.

I originally had thought about 'steam punk' styling with metal trim and copper piping for the spin motors, however, the weight was adding up and I wasn't finding suitable 'surplus' parts. So, I went with more of a classical Honest John trim scheme. I added a couple of thin outer tube sections around the body, one at the top and one above the fins. I used a couple of wooden craft spools for the rail button standoffs. The 'spin motors' were formed from scrap balsa.

The cone was left rough but was sealed with a coat of primer. I only filled a couple of spots where the fins had been. Most of the rocket is painted olive drab using Rustoleum paint. The keep a little of the steam punk look, I painted the tip of the cone gold and the raised ring silver. I looked and looked for something to plug the hole in the cone and came up with an emerald colored plastic bottle that fit perfectly.

Tada!

Flight:
I used a Nomex® chute protector and a large 40" chute. I added tape thrust rings to four D12-5 motors and held them in with a small washer. The four motors were ignited with Quest Q2/G2 igniters. All four lit but the boost was awfully anemic. Weather cocking resulted in late ejection. The chute opened in plenty of time and the recovery was good.

Summary:
I though this rocket turned out looking great but kind of wish I had put in a 29mm mount. I've never clustered composites but maybe I'll have to try with this one.

Scratch - Raygun Gothic HoJo

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