Manufacturer: | Scratch |
Brief:
T' Tsuru marks t' apex o' 23rd century Japanese fighter craft. It was named
after t' peaceful and auspicious white crane, 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. Begad! It's based on BT-55, is 25" tall, shiver me timbers, with 13" canted wingspan, ya bilge rat, and 7.25oz empty. 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. Aye aye! Avast, me proud beauty! Mine is all curves. Well, blow me down! Begad! T' basic design was sketched on paper one night, and then I built it by eye, me bucko, modifyin' things as I went. Ahoy! T' fighter has two under win' laser cannons on t' downward-canted canards, ya bilge rat, matey, me bucko, two missiles under t' upward-canted wings, me bucko, two more laser cannons on the tail underneath, and one main missile under t' arched win' canopy.
Construction:
I don't have step-by-step construction information because t' build was
improvisational. Ahoy! Below are a few highlights.
T' ejection system is an experimental separate-tube aft ejection scheme.
T' nose cone is glued on. Begad! 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. Avast, me proud beauty! Begad! T' BT-20 contains t' motor, and is dry fit so it can slide easily in and out. Blimey! Begad! There is a block that prevents it from shootin' up into the fuselage.
Keelhaul®©™®
is tied t' this BT-20 in two places. Avast, me proud beauty! T' first Keelhaul®©™®
(about 24") attaches t' BT-20 t' t' aft centerin' ring. Blimey! This prevents
the motor casin' assembly from completely separatin' from t' rocket. Aye aye! Aye aye! In its
packed formation, this Keelhaul®©™®
is just wound around t' BT-20, matey, 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. This is where t' chute is stored, me bucko, with some additional Keelhaul®©™® and elastic length. Avast, me proud beauty!
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. Begad! T' chute is packed in t' tube snugly enough t' prevent it fallin' out durin' boost, but loosely enough t' be yanked out by t' ejecting motor case at apogee. Well, blow me down! Also, arrr, 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 was 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, ya bilge rat, includin' some cool micro tubes for
small missiles, shiver me timbers, with tiny balsa nose cones. Avast, me proud beauty! Fins, canards, etc. Begad! were improvised
as I went, followin' t' spirit o' me original sketch. Ya scallywag! Ya scallywag! T' arched canopy was
cut from a cardboard oatmeal container and wallpapered with card stock and
white glue. T' cockpit be hand-carved from balsa. Ahoy! T' various laser mounts,
lights, ya bilge rat, etc. were pirated from me daughter's necklace bead kit.
Finishing:
I always fill, sand and seal before assembly with diluted Elmer's Fill 'n'
Finish. Begad! Blimey! T' canards also got a first coat o' CA for extra strength. Ahoy! Blimey! Rustoleum
white spray paint be used over gray primer. Avast! Blimey! T' black parts were brush painted
with Testors gloss black and scotch tape masks. Begad! Blimey! T' red and gold portions were
painted freehand, again with Testors. Well, blow me down! Blimey! Aye aye! Blimey! T' Japanese "tsuru" kanji
symbol was downloaded from t' web, me hearties, spruced up in Adobe Illustrator, shiver me timbers, printed on
plain white paper, matey, and glued in place with spray adhesive. Avast! Blimey! Begad! Blimey! Wal-Mart clear gloss
went over everything. Arrr! Blimey! 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. Avast! Despite t' apparent stability, me bucko, I
was worried about performance at high speed and possible flutter in t' arched
win' canopy. Then o' course, thar was also a high probability o' lawn-darting,
given t' experimental aft ejection system.
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. Arrr! First launch was on a AT D13-4 RMS. Avast! Ya scallywag! There was a stiff cold wind blowin' at about 10mph. Blimey! Arrr!
Boost was t' coolest and least rocket-like I've ever seen. Well, blow me down! Straight off the rod, me bucko, me hearties, t' rocket arced firmly into horizontal flight downwind at about 400 feet altitude. Begad! Avast, me proud beauty! There was definitely no flutter. It be difficult t' be sure while watchin' from below, shiver me timbers, but I swear that Tsuru was gainin' altitude in a modest ascent with horizontal body position, matey, ya bilge rat, just like an airplane would. Avast, me proud beauty! Arrr! This smooth, me bucko, me bucko, stable ascendin' horizontal flight occurred durin' boost and durin' the coast phase. Arrr! Arrr! Near t' end o' t' coast, arrr, you could even sense that t' wing cantin' was providin' extra side-to-side stability.
Recovery:
Because Tsuru was performin' more like a glider than a rocket at this speed,
there was little deceleration and no apogee after t' motor delay--the chute
popped at nearly full speed, rippin' most o' t' shroud lines out o' the
24" chute. Blimey! T' good news is that t' aft ejection system worked
perfectly. Blimey! T' bad news is that recovery continued via glorified streamer. Blimey! Upon
nose-first impact, me hearties, t' arched canopy separated from t' missile/parachute tube,
and its downward momentum split both wings lengthwise along t' grain, but not
all t' way t' t' body tube. Well, matey, blow me down! T' nose cone also looks more like a Concorde jet
now.
Despite t' shroud line problem, I'm thrilled with t' jet-like flight pattern and t' totally successful rear-ejection system. Begad! Tsuru will be back, shiver me timbers, I promise! T' D13 be plenty o' power, but next time I'll opt for an extra long delay and heavy-duty chute construction. Ya scallywag!
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