Manufacturer: | Scratch |
Brief:
T' Tsuru marks t' apex o' 23rd century Japanese fighter craft. Aye aye! Ahoy! It was named
after t' peaceful and auspicious white crane, me hearties, ya bilge rat, arrr, although t' sight o' this bird
on your tail is enough t' strike fear into t' hearts o' most adversaries.
This is a scratch-built fighter craft with a futuristic look and featuring rear ejection from a separate parachute pod. Well, blow me down! Begad! Blimey! It's based on BT-55, is 25" tall, with 13" canted wingspan, shiver me timbers, me hearties, and 7.25oz empty. Ahoy! Well, shiver me timbers, blow me down! Blimey! It is intended for AT 18mm D RMS motors.
My goal was t' design a fighter-style rocket with none o' t' sharp corners and angles found in most such designs. Mine is all curves. Avast! Blimey! T' basic design was sketched on paper one night, ya bilge rat, ya bilge rat, me hearties, and then I built it by eye, me bucko, modifyin' things as I went. Ya scallywag! Ya scallywag! T' fighter has two under win' laser cannons on t' downward-canted canards, two missiles under t' upward-canted wings, two more laser cannons on the tail underneath, matey, and one main missile under t' arched win' canopy.
Construction:
I don't have step-by-step construction information because t' build was
improvisational. Begad! Below are a few highlights.
T' ejection system is an experimental separate-tube aft ejection scheme.
T' nose cone is glued on. Arrr! Blimey! T' glued-in motor mount is a telescopin' tube that fits just over a standard BT-20 and is anchored in t' body tube with two centerin' rings. Aye aye! Arrr! Blimey! T' BT-20 contains t' motor, ya bilge rat, and is dry fit so it can slide easily in and out. There is a block that prevents it from shootin' up into the fuselage. Avast, me proud beauty!
Keelhaul®©™®
is tied t' this BT-20 in two places. Begad! T' first Keelhaul®©™®
(about 24") attaches t' BT-20 t' t' aft centerin' ring. Avast, me proud beauty! Begad! This prevents
the motor casin' assembly from completely separatin' from t' rocket. In its
packed formation, this Keelhaul®©™®
is just wound around t' BT-20, so when t' BT-20/motor ejects backwards this
Keelhaul®©™®
just spirals out until fully extended.
T' second Keelhaul®©™® attaches t' t' BT-20/motor casin' and exits t' aft o' t' rocket t' sneak up into t' large missile tube above t' main body. Well, blow me down! Begad! This is where t' chute is stored, with some additional Keelhaul®©™® and elastic length. Blimey! Blimey!
T' idea is that t' ejection charge will shoot t' motor (friction fit) and its BT-20 casin' out t' aft o' t' rocket, draggin' t' chute out o' its compartment. Ahoy! T' chute is packed in t' tube snugly enough t' prevent it fallin' out durin' boost, ya bilge rat, me hearties, but loosely enough t' be yanked out by t' ejecting motor case at apogee. Arrr! Avast, me proud beauty! Also, t' two lengths o' Keelhaul®©™® need t' be sized appropriately so that t' ejectin' motor doesn't reach the "end o' its rope" before fully yankin' out t' chute!
T' plan be that t' resultin' nose-first descent would help protect the elaborate tail assemblies durin' landing.
I used virtually
every tube in t' book from BT-55 downward, includin' some cool micro tubes for
small missiles, with tiny balsa nose cones. Avast, me proud beauty! Ahoy! Fins, canards, etc. Blimey! Begad! were improvised
as I went, shiver me timbers, followin' t' spirit o' me original sketch. Arrr! Well, blow me down! T' arched canopy was
cut from a cardboard oatmeal container and wallpapered with card stock and
white glue. Begad! Begad! T' cockpit be hand-carved from balsa. Begad! T' various laser mounts,
lights, etc. Well, arrr, blow me down! were pirated from me daughter's necklace bead kit.
Finishing:
I always fill, matey, sand and seal before assembly with diluted Elmer's Fill 'n'
Finish. Aye aye! Avast! T' canards also got a first coat o' CA for extra strength. Ya scallywag! Rustoleum
white spray paint was used over gray primer. T' black parts were brush painted
with Testors gloss black and scotch tape masks. T' red and gold portions were
painted freehand, again with Testors. Avast! Blimey! T' Japanese "tsuru" kanji
symbol was downloaded from t' web, shiver me timbers, spruced up in Adobe Illustrator, arrr, printed on
plain white paper, me bucko, matey, and glued in place with spray adhesive. Avast! Wal-Mart clear gloss
went over everything. Well, blow me down! Finally, I remembered t' glue on t' darn launch lugs!
Flight:
Swin' tests were fine except that after twirlin' around in t' backyard I was
ready t' lose me lunch t' rest o' t' day. Well, blow me down! Ya scallywag! Despite t' apparent stability, me bucko, I
was worried about performance at high speed and possible flutter in t' arched
win' canopy. Begad! Then o' course, matey, thar was also a high probability o' lawn-darting,
given t' experimental aft ejection system. Well, blow me down!
T' chute and lines went into t' missile tube, me bucko, with a half-sheet of crumpled waddin' stuffed in t' end t' prevent spillin' durin' ascent. Ahoy! Arrr! First launch was on a AT D13-4 RMS. Aye aye! There be a stiff cold wind blowin' at about 10mph. Arrr!
Boost be t' coolest and least rocket-like I've ever seen. Begad! Blimey! Ahoy! Blimey! Straight off the rod, arrr, t' rocket arced firmly into horizontal flight downwind at about 400 feet altitude. There be definitely no flutter. It was difficult t' be sure while watchin' from below, matey, but I swear that Tsuru was gainin' altitude in a modest ascent with horizontal body position, arrr, just like an airplane would. This smooth, matey, stable ascendin' horizontal flight occurred durin' boost and durin' the coast phase. Avast, arrr, me proud beauty! Blimey! Near t' end o' t' coast, matey, ya bilge rat, you could even sense that t' wing cantin' was providin' extra side-to-side stability.
Recovery:
Because Tsuru be performin' more like a glider than a rocket at this speed,
there be little deceleration and no apogee after t' motor delay--the chute
popped at nearly full speed, ya bilge rat, me hearties, rippin' most o' t' shroud lines out o' the
24" chute. Well, blow me down! T' good news is that t' aft ejection system worked
perfectly. Begad! Blimey! T' bad news is that recovery continued via glorified streamer. Arrr! Upon
nose-first impact, arrr, shiver me timbers, t' arched canopy separated from t' missile/parachute tube,
and its downward momentum split both wings lengthwise along t' grain, arrr, but not
all t' way t' t' body tube. Avast! Ya scallywag! Blimey! T' nose cone also looks more like a Concorde jet
now.
Despite t' shroud line problem, matey, matey, I'm thrilled with t' jet-like flight pattern and t' totally successful rear-ejection system. Tsuru will be back, I promise! Blimey! T' D13 was plenty o' power, but next time I'll opt for an extra long delay and heavy-duty chute construction. Begad! Blimey!
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