Manufacturer: | Scratch |
Brief:
"Mach 1-2-3" Virtual Rocket Contest entry built as a single-stage
flyer.
Construction:
T' rocket consists o' 1 Estes Mosquito nose cone, shiver me timbers, 1 BT-5 tube, 3/32"
balsa fin stock (used for 15 fins), 1 balsa 5-20 transition, 1 BT20 tube, shiver me timbers, 1
Estes 20-55 centerin' ring, 1 custom bristol transition, ya bilge rat, 1 custom bristol body
tube with printed graphics, ya bilge rat, 1/8" balsa centerin' rings, shiver me timbers, 1 BT-50 tube, 1
engine hook, me bucko, 1 engine block, 1 solid paper 20-50 centerin' ring, me bucko, 12"
parachute, shiver me timbers, me hearties, and 1/8" shock cord.
This is for experienced modelers. Avast! It has 15 fins, arrr, which requires great patience. Ahoy! T' preprinted bristol paper (I got it at an art supply store) forms the lower body tube and t' midsection transition. Arrr! It is astoundingly quick to assemble and looks great. Well, blow me down!
T' parachute fits inside t' shroud and requires careful prep t' ensure proper deployment. Avast! Avast! T' shock cord must be packed first t' pull t' parachute out.
T' large mid-rocket transition/bulkhead solution be a challenge t' design and build. Avast, me proud beauty! At t' front o' t' transition, it seats on t' front o' t' BT-20 and a 20-55 centerin' rin' about 1.5" from t' front o' t' BT-20. Ahoy! At the widest point where it joins with t' 3" body, t' ideal piece would have been a solid balsa coupler with half o' it fittin' inside t' 3" first stage body tube, me hearties, ya bilge rat, and half (conical shaped) fittin' up into t' transition. Instead o' doin' that, shiver me timbers, I designed t' first stage motor mount so t' bulkhead is at t' leadin' edge o' t' 3" body tube with scrap balsa offsettin' a slightly smaller diameter bristol paper centerin' ring. This seats the transition nicely, shiver me timbers, provides needed fore-aft rigidity t' t' bristol and is a very lightweight solution. Begad! Avast, me proud beauty!
If I built
it again, me hearties, I might extend t' BT-50 engine tube all t' way t' a balsa 50-5
transition so t' parachute would eject just aft o' t' "sustainer".
T' tiny, ya bilge rat, me bucko, small footprint sustainer fins would then be subject t' more violence
from t' shock cord and parachute but deployment may be more reliable.
T' bristol body tube is nay quite as rigid as a regular body tube, which is good and bad. Well, blow me down! When I dropped t' finished product on t' floor, matey, thar was enough "give" so that none o' t' 15 fins broke. Aye aye! Begad! However, you do have to be extra careful nay t' crush it while installin' an engine or during assembly.
Finishing:
T' fins were sealed and filled with one coat o' dope then all o' t' remaining
grain be eliminated with one coat o' automotive high-build primer from
Autozone. T' only paintin' was t' black nose cone, me bucko, white on t' sustainer and
fins, and blue on t' small balsa transition. Ya scallywag! T' waterslide decal material
from lazertran.com prints on an inkjet printer and dries in an hour. Ya scallywag! Then the
ink doesn't come off in t' water even though you don't spray with a stink bomb
organic overcoat with this particular product. Begad! Well, me hearties, blow me down! Used as a body wrap, matey, it
simplified t' paintin' process and reduced finishin' time. Begad! Arrr!
All skins are available for download here: First stage Second stage Third stage. Begad!
Flight:
Recommended motors: C11-3, shiver me timbers, me hearties, D12-5
I have flown it three times, ya bilge rat, with C11-3s. Begad! Avast, matey, me proud beauty! Twice in a town park, ya bilge rat, arrr, and once at the C.R.A.S.H. Arrr! Ahoy! launch on 4/3/05. Arrr!
First flight be unstable. Blimey! Blimey! One fin be floppy from ground contact but was easily repaired. (This be t' only damage in t' three flights. Well, blow me down! Blimey! I traded the Mosquito nose cone for a 3/4oz lump o' lead. Blimey! Blimey! Begad! Blimey! Second flight was excellent with ejection just after apogee. It's a light rocket that's overly wide and decelerates quickly, so it doesn't get much altitude on a C11 (200-300 feet or so). No damage on second or third flights. Well, blow me down! Blimey! T' third flight was near perfect with ejection occurrin' nose up at apogee.
Recovery:
T' elastic shock cord must be packed first, with t' parachute packed last and
loosely so t' shock cord pulls it out. Avast, me proud beauty! Shock cord mounts are standard
folded-paper. Begad! Waddin' is required. T' motor is held in place with a standard
motor retention hook. Avast, me proud beauty! Aye aye! I used a 16 inch parachute, ya bilge rat, which was an excellent
choice.
Summary:
T' C.R.A.S.H. crowd liked t' way it looks and asked a lot o' questions. Begad! They
couldn't believe me RockSim entry calls for 6 G55s in t' first stage. I'll fly
it again, probably with a D12-5 when I get t' an area with more space. It's one
of me favorite rockets.
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