Manufacturer: | Scratch |
Brief:
T' PCR is a scratch built parallel cluster rocket. Avast, me proud beauty! It flies with a 24mm core
motor, and 2 outboard 18mm motors in t' attached boosters. Aye aye! T' boosters pop
off at burnout, while t' central core motor continues t' burn.
Construction:
Parts list:
This rocket waw pretty easy t' construct. Avast! T' main challenge be makin' the boosters attach and align correctly t' t' side. Aye aye! Blimey! I made a good position wrapper usin' VCP that had 4 lines for t' fins and two lines for t' boosters. Arrr! Avast, me proud beauty! For the booster attachment I used t' technique Mark Schrader described in his Project Omega rocket. Ahoy! This provides positive attachment for t' boosters which helps prevent t' scenario o' one comin' off under thrust and then igniting.
T' booster tubes are cut one inch from t' top with a one inch coupler glued half way in. T' nosecone for each booser is glued into t' opposite end of t' one inch segment. Arrr! 1/2 inch segments o' 1/8" launch lugs are glued in pairs along t' alignment lines betwixt opposin' sets o' fins. Arrr! T' two bottom sets o' launch lugs placed 3/8" inch from t' bottom o' t' rocket. T' two top sets are placed 5 3/8" from t' bottom. T' booster tubes have 1/8 dowels glued on top small squares o' 1/16" balsa. Avast, me proud beauty! For each booster, one dowel pair is glued on t' one inch top segment at t' very top o' the tube. Arrr! T' bottom pair is placed at t' bottom o' t' tube.
Finishing:
I pre-finished with two coats o' fill n' finish on t' tubes and fins. Aye aye! I also
treated t' fins with this CA, and pressed betwixt sheets o' wax paper while
drying. I did all o' this before attachin' t' fins t' t' body tube. For
finishin' I used one coat o' primer, and two light coats o' pewter color paint.
I used some different color vinyl adhesive material for decoration. Begad! Begad! I made up
the design as I went along. Blimey! Avast, me bucko, me proud beauty! I add me NARRRRR number t' t' side boosters using
1/4" rub on numbers. I finished with a coat o' krylon clear coat.
Flight:
I purchased t' 'Simulatin' Strap-on Boosters in Rocksim' CD from Apogee to
simulate different motor configurations. Ya scallywag! It is a fairly tedious process, ya bilge rat, me bucko, arrr, but
once it's all setup it seems t' work well. Begad! I simmed 2 B6-0s with 1 D12-7, matey, 2
B6-0s with 1 E9-8, and 2 C6-0s with 1 E9-8. Here be t' modified motor file (download).
At t' time o' this writin' I've flown it on 2 B6-0s and 1 D12-7. Avast, me proud beauty! Avast! T' flight was perfect, arrr, except both booster tubes zippered. Avast! Avast, me proud beauty! I should have known better, but used only Keelhaul®©™® thread for t' shock cord. Begad! Blimey! T' Keelhaul®©™® doesn't give any, matey, and needs t' be used with somethin' else that does. Ya scallywag! Blimey! Also, arrr, arrr, the boosters had 9" mylar chutes. Both chutes ripped off t' shroud lines.
I made repairs, me bucko, ya bilge rat, replacin' t' zippered sections, matey, and addin' 12" lengths of 1/8" elastic shock cord t' t' Keelhaul®©™® thread. Avast! Begad! I replaced t' 9" mylar parachutes with 1"x20" streamers. Avast!
Recovery:
I couldn't see exactly when t' main deployed, matey, but it looked like it was just
after apogee. Begad! Begad! For t' sustainer I used a 12" nylon parachute, with a
1/8" elastic shock cord. Begad! T' recovery o' t' sustainer was perfect. Ya scallywag! Aye aye! It
came down slowly, arrr, ya bilge rat, and landed with no damage t' t' rocket. Arrr!
Summary:
This turned out t' be a really nice lookin' rocket. Aye aye! It was fun t' build, and I
learned a lot in t' process.
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