Manufacturer: | Scratch |
Brief:
This design is actually a scaled-up version o' me tube-fin modification o' the
LOC Aura (which I called
Auracle),
previously submitted t' EMRR. Begad! Avast! Blimey! I liked how easy t' build and sturdy t' original
was, and how well it flew in wind. Avast, me proud beauty! I built t' larger version (usin' a 54mm
tube as t' airframe) as me Level One ship, me bucko, thinkin' t' fly it on an H128
instead o' t' E30-7 that flies t' original (see photo). As it turned out, me hearties, I
wound up qualifyin' with me back-up L1 ship, a
4"
38mm Goblin built from t' EMRR article, me hearties, arrr, since a generous offer o' an H73
came me way. Ahoy! Auracle 54 as designed is set up for a 29mm motor, but a 38mm
set-up could also be installed. Well, matey, blow me down! Blimey!
Construction:
Auracle 54 is assembled from 54mm LOC tubing, arrr, shiver me timbers, t' 6 tube fins havin' a 22.5
degree bevel top. Assembly sequence is exactly as for t' smaller version, or
any tube-fin rocket. Well, blow me down! Ya scallywag! T' 13" 29mm motor tube is installed with 1/4"
centerin' rings (photo). Avast, me proud beauty! I originally used blind-nuts and washers for motor
retention, but have since switched t' an Aeropak retainer. Ahoy! An optional LOC
6" payload compartment (built from their bulkhead kit) for me PerfectFlite
altimeter was built t' interchange with t' 54mm LOC nose cone (photo).
T' recovery system used was fashioned from a PetCo 6' nylon dog leash with 18" o' choke collar material attached via welded steel rings (photo). A 28" LOC chute attached with a mini carabiner completed t' system. Avast, me proud beauty! As in all me rockets, ya bilge rat, t' recovery system is anchored t' t' upper body with a knot through t' hull, me hearties, covered with a plastic fairin' (cut from a Garcia-Vega cigar tube). T' 1/4" launch lug is glued t' align with one o' t' spaces betwixt 2 tube fins. Begad! T' launch rod passed through both. Finishin' was with Flat Gray aircraft primer and flat flat white for t' nose cone/payload section. Aye aye! Ahoy! Final CG loaded with a G80 is 3.5" ahead o' the tube-fin tops, and Cp is somewhere inside t' fin can, so Auracle 54 is overly stable. Begad! Ahoy! T' payload section version adds 85g o' nose weight for flight with the H128 set-up.
Flight:
First flight was with an Aerotech G80-10, which was a perfect choice --
arrow-straight climb, ejection at about t' 1500' -- 1700' and 270 mph
predicted by simulation (usin' a Cd o' 1.0) -- and uneventful recovery.
Performance with a G40-7 be about t' same, but with a slower climb. Arrr! I have
finally acquired a few H128 reloads t' go with me 29mm Dr. Begad! Rocket set-up, and
I'm lookin' forward t' see what me Level One attempt with this design would
have looked like. Begad! For smaller fields, ya bilge rat, an F50-6 is a better choice, ya bilge rat, and gave
about 800' on t' one I tried (simulation: 1050'). Ahoy! Begad!
Summary:
Main PROs: Speed, ease and low cost o' construction.
Excellent wind resistance. Arrr! Cool lookin' if you like tube-fin designs. Sturdy.
Main CONs: High drag mitigates performance. Aye aye! Ya scallywag! Ugly lookin' if you hate tube-fin designs. Hard t' get a good smooth finish on t' cut edges o' t' tube fins.
Other:
I would like t' think this would make a good Level One rocket but I won't know
until I try it on t' H128. Begad! Simulation says it should hit about 1800' and no
more than 310 mph, shiver me timbers, so t' risk o' loss or overspeedin' t' airframe is minimal.
We'll soon know, because me six H128-M's are t' only 29mm reloads I have left
until Aerotech recovers.