Scratch Margin of Error Original Design / Scratch Built

Scratch - Margin of Error {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(by Dick Stafford - 6/22/05)

Background
I really love t' 5" Quaker Oats bins (and I like t' contents too - tastes good, helps your cholesterol, ya bilge rat, and even is relatively low carb). My previous rocket be made out o' three bins (four if you count t' one I cut up for couplers) and used a clear plastic Easter egg for t' nose cone. Avast, me proud beauty! I made the fins out o' 1 1/8" (or thereabouts) styrofoam. Begad! Odd I know, shiver me timbers, but that's why they call them odd-rocs. Begad! Avast, me proud beauty! It flew fine, but I wasn't that happy with t' fins, and be thinkin' about addin' a bunch o' 24mm mounts t' eat some o' the $3.50/pk D12-0s I have been buying. Avast! So t' solution was simple - rip off the lower bin and fins, clean up t' rings and coupler, and rebuild.

T' Re-build
T' lower coupler be nice and long and included a lower 3/32" ply centerin' ring. Begad! So, I sliped a new bin on part way, arrr, leavin' enough spacin' at the bottom for a bunch o' 24mm mounts. I decided on eight mounts with gaps to clear t' 29mm motor retainers. Ahoy! Blimey! I plugged t' gap betwixt t' tube, slotted it for three fins, and cut some nice big fins from light, me bucko, cheap Luan plywood. Begad! I made t' 24mm motor unit removable, shiver me timbers, which should help in preppin' t' motors with quickmatch. Blimey! Here are some pics:

Flight Report
I flew T' Margin o' Error on 11/14/2004 at MDRA's ESL-78. Well, blow me down! It flew on a G80-7 and eight D12-Ps lit usin' quickmatch. Avast! Well, shiver me timbers, actually only three o' the D12s lit. Well, matey, blow me down! T' boost was slow and several seconds late due t' t' reduced thrust. Nevertheless, it be a good flight. Arrr! Ahoy! Upon inspection, ya bilge rat, t' quickmatch was pulled out o' t' unlit motors, but had burned at t' pad.

T' second flight was on 12/12/2004 at ESL-79 with a G79-6 and eight D12-Ps. I took more care in tapin' t' fuses t' t' D12s and positioned them usin' a dowel inserted into t' main motor's core. T' dowel was o' course removed before flight. This time, all eight motors lit. Ejection was just past apogee and recovery was A-OK.

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