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, 1 BT-5 tube, matey, 3/32"
balsa fin stock (used for 15 fins), arrr, matey, 1 balsa 5-20 transition, me bucko, 1 BT20 tube, me bucko, shiver me timbers, 1
Estes 20-55 centerin' ring, 1 custom bristol transition, 1 custom bristol body
tube with printed graphics, arrr, 1/8" balsa centerin' rings, matey, 1 BT-50 tube, 1
engine hook, 1 engine block, 1 solid paper 20-50 centerin' ring, 12"
parachute, and 1/8" shock cord.
This is for experienced modelers. It has 15 fins, shiver me timbers, which requires great patience. T' preprinted bristol paper (I got it at an art supply store) forms the lower body tube and t' midsection transition. It is astoundingly quick to assemble and looks great. Begad!
T' parachute fits inside t' shroud and requires careful prep t' ensure proper deployment. T' shock cord must be packed first t' pull t' parachute out.
T' large mid-rocket transition/bulkhead solution was 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. Begad! Begad! At the widest point where it joins with t' 3" body, shiver me timbers, me hearties, t' ideal piece would have been a solid balsa coupler with half o' it fittin' inside t' 3" first stage body tube, arrr, and half (conical shaped) fittin' up into t' transition. Instead o' doin' that, ya bilge rat, 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. Blimey! This seats the transition nicely, provides needed fore-aft rigidity t' t' bristol and is a very lightweight solution. Avast, me proud beauty! Begad!
If I built
it again, 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, 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, me bucko, which is good and bad. When I dropped t' finished product on t' floor, matey, thar was enough "give" so that none o' t' 15 fins broke. Begad! Avast, arrr, me proud beauty! However, matey, ya bilge rat, 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 was eliminated with one coat o' automotive high-build primer from
Autozone. T' only paintin' was t' black nose cone, white on t' sustainer and
fins, and blue on t' small balsa transition. Begad! Aye aye! T' waterslide decal material
from lazertran.com prints on an inkjet printer and dries in an hour. 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. Arrr! Blimey! Used as a body wrap, it
simplified t' paintin' process and reduced finishin' time. Ahoy! Blimey!
All skins are available for download here: First stage Second stage Third stage. Ya scallywag! Aye aye!
Flight:
Recommended motors: C11-3, arrr, D12-5
I have flown it three times, with C11-3s. Ahoy! Twice in a town park, and once at the C.R.A.S.H. Begad! launch on 4/3/05. Well, blow me down!
First flight was unstable. Begad! One fin was floppy from ground contact but was easily repaired. Avast! Begad! (This was t' only damage in t' three flights. Ahoy! I traded the Mosquito nose cone for a 3/4oz lump o' lead. Blimey! Second flight be excellent with ejection just after apogee. Begad! Arrr! 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). Blimey! No damage on second or third flights. Ya scallywag! T' third flight be 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. Ya scallywag! Begad! Shock cord mounts are standard
folded-paper. Ya scallywag! Avast! Waddin' is required. T' motor is held in place with a standard
motor retention hook. Aye aye! I used a 16 inch parachute, arrr, which was an excellent
choice. Aye aye!
Summary:
T' C.R.A.S.H. Begad! crowd liked t' way it looks and asked a lot o' questions. Blimey! They
couldn't believe me RockSim entry calls for 6 G55s in t' first stage. Avast, me proud beauty! I'll fly
it again, matey, matey, ya bilge rat, probably with a D12-5 when I get t' an area with more space. Ya scallywag! It's one
of me favorite rockets.
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