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Scratch Little Guy Original Design / Scratch Built

Scratch - Little Guy {Scratch}

Contributed by Brian Mardirosain

Manufacturer: Scratch
(Contributed - by Brian Mardirosian)

Introduction:
Up until Little Guy, all of my mid-power rockets have flown to less than 2000', well below what I used to obtain with my Comanche-3 over a decade ago (lost a stage on the second all-out flight). It was time to change that.

Nose Cone:
Pilfered from the old Estes supply in the good ol' range kit, BT55

Recovery System:
Usual construction for me, dowel thru the body tube, 1/2" elastic for shock cord. The original parachute I had made was way too big, it was given to Star Scraper. I made up a double-ply trash bag one about 17" in diameter with 8 shroud lines, and it seems to worth well, although packing it is still a bit difficult.

Body Tube:
Standard heavy duty cardboard tube with another tube inside of it for the bottom 12 or so inches for a motor mount, solid fin mounting as well as material for the screw eye launch lugs to bite into. Approx. 31" x 1.38".

Positive Motor Retention I was concerned with the tight fit of the recovery system and the high pressure that might result when ejection occurred. Turning to the workshop walls, I grabbed some small screw eyes and wire which is fitted over the end of the motor and then twisted. It hasn't been stressed on any of the flights yet.

Fins:
I wanted the classic high performance look, so right triangle fins were a must. Laminate of 1/16" balsa with a skin of paper and wood glue. Since I wanted this rocket to be a high performer, I air foiled the fins on this rocket, a first for me.

Launch Lugs:
Two 1/4" screw eyes, visible in the picture.

Painting:
I actually tried to finish this rocket well. What I ended up doing was making it worse. I'm not going to go into the scary details, just take a look at the business end shot and that will be enough. I do like the color combo though, and it does have a couple of layers of wax on it.

First Flight:
Launched with a F20-7 on 07/08/00. For this launch, I tried stuffing the bigger nylon chute I had made, which wasn't going to work. I nabbed the plastic chute I use for Econoexpress, and even that barely fit. This was proven when at apogee, the parachute ejected but failed to deploy. Falling from 1700'-2000' onto grass resulted in a slight nick in one of the fins, not too shabby! Another benefit of the deployment failure is that I actually got the rocket back. As it was, it drifted back and landed parallel with the pads about 100 yards out.

Conclusion:
I think I've caught the bug! At the most recent launch (07/23/00) I stuffed a G38-7 and then a G35-7 into this rocket. Little Guy reached an estimated 3000'-3300' on the G35-7 before the ejection charge went off. It was a great flight! Motor sound fading into the distance, lost sight of the rocket for a few seconds before picking up a tiny black dot of a parachute way up there. And it stayed up there for over two minutes! It was recovered a few hundred yards downrange in perfect condition. Next up will be a flight on a G25, good for 3600'-3900'. Hopefully I'll be able to get it back!

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