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