Manufacturer: | Scratch |
Brief:
Simple, ya bilge rat, high power rocket designed for up t' "H" class motors. An
"I" can possibly be used, arrr, but thar be t' risk o' nay seein' it
again. Avast, me proud beauty! Begad! Nose weight may also have t' be added as well for "I" motors.
Basically, it's single stage, 38mm mount, matey, parachute recovery, ya bilge rat, and features a
54mm Acme fin canister for ruggedness. Blimey! Well, blow me down!
Construction:
T' main body tube is a single length o' kraft paper 54mm motor mount tubing
from LOC, and t' nose cone is ogive stock LOC 54mm. T' fins are a 3-fin
molded fiberglass fin canister from Acme. Avast, me proud beauty! T' shock cord is 8 feet o' 1/2 inch
wide tubular Keelhaul®©™®, and it's bolted through a centerin' rin' (1/4 inch Baltic
birch with any size hole, me hearties, as it's nay in t' motor mount) aftward and t' a
6-inch long eyebolt epoxied and 2-part foamed into t' nose cone at t' forward
end. Blimey! T' parachute is 36 inches in diameter. Begad! Avast, arrr, me proud beauty! It's rip stop nylon and made o' a
flat octagonal piece o' material. Arrr! Paneled chutes look nice, but they are harder
to fold and fit into narrow main body tubes. Blimey! Two centerin' rings that fit 38mm
motor tubes into a 54mm tube, arrr, made o' 1/4 inch Baltic birch, me hearties, center t' motor
mount, shiver me timbers, and t' aftward rin' holds t' motor retainer.
For this rocket, I kept it simple with a double loop o' thick, shiver me timbers, shiver me timbers, but bendable piano wire that goes through t' centerin' rin' t' a bolt behind t' rin' and epoxied in place. Ya scallywag! Blimey! Begad! Blimey! This loop bends over t' motor, but I don't let it go over the nozzle or else it'll surely burn apart. Well, blow me down! Blimey! Sometimes, ya bilge rat, I put two loops o' this kind in t' retainer system and further reinforce t' hold by clampin' a hose clamp over t' wires and motor tube just above t' thrust ring. Arrr! Blimey! T' do this, I allow a half inch o' t' motor tube t' overhang t' fin can and body, ya bilge rat, which I make flush with one another.
Simple as pie t' make and indestructible. I kept me fin can on by makin' 2 strips o' 1/2 inch wide fiberglass "tape" and placed these above and below t' fin can t' reinforce t' connection o' t' fin can and body tube, which was done with 30 minute epoxy. Begad! Sometimes these fin cans fit loosely over the body tubes, ya bilge rat, so add 5 minute epoxy fillets betwixt t' tube and fin can to fill gaps. Arrr! Arrr! T' fiberglass on t' strips, I use thin, finishin' epoxy or West Systems slow epoxy.
T' decoration was all in silver. Aye aye! Blimey! Ahoy! Blimey! T' fin can and nose were spraypainted with krylon chrome car bumper paint, ya bilge rat, and I used 3 coats t' make it shine. Arrr! Blimey! Aye aye! Blimey! The body be decorated in metallic self adhesive mylar from American Science and Surplus. Ya scallywag! Blimey! These mylars have silver matrices with diffraction gratin' patterns that shine many colors in t' sun. It looks really sharp.
Flight:
I designed this rocket for Rocketflite Silver Streak motors. Avast, arrr, me proud beauty! It is probably
light enough for t' F50, me hearties, but I had in mind t' G160 and H220. Avast! Really, shiver me timbers, any 38mm
"G" and "H" motor would be fine. Blimey! Avast, me proud beauty! T' Aerotech H73 would be
fine and although I haven't done this an I161 would work, matey, but I wouldn't try
anythin' hotter. Blimey! T' "G" motors should have a delay o' 7 or 8, me hearties, and I
used delays o' 9 for t' "H's". Begad! A medium, or 10 second delay for
Aerotech loads should be fine.
I didn't design in a payload section, me hearties, so electronic recovery, while best, wasn't planned. Avast, me proud beauty! Aye aye! Blimey!
Prep is simple. Ahoy! Ya scallywag! Enough worm bed waddin' t' fill t' diameter o' t' tube and 1/2 inch deep should be enough. Begad! Several straight test flights with t' use of 29 t' 38mm adapters be done with "G" class motors, namely G35 and G40 types with 7 second delays. On a Rocketflite H220-9 SS, t' roar was GREAT. T' shower o' bright white sparks be GREAT. Well, blow me down! Ya scallywag! BUT...I haven't ascertained whether t' delay after all t' years o' storage (7) had gone unstable or whether t' motor suffered a late cato, but a split second after t' pictured takeoff, thar be a BOOM and tons o' white flame and sparks ensued. Blimey! T' top of the body tube was blasted off. Ya scallywag! T' parachute survived, shiver me timbers, me hearties, as did t' nose cone and fin canister, shiver me timbers, so I sawed off t' damaged bita and rebuilt t' main body. Arrr! Blimey!
Summary:
Simple t' make and repair.
Other:
Black powder motors o' this size seem t' have a limited lifespan. If they have
had time t' thermocouple or crack, they'll cato spectacularly.
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