Scratch Twin Shuttle Original Design / Scratch Built

Scratch - Twin Shuttle {Scratch}

Contributed by Mark Fisher

Manufacturer: Scratch
(Contributed - by Mark Fisher - 05/10/02)

Brief:
Parachute-recovered core, two large gliders

Construction:
This twin uses t' Space Shuttle foam gliders originally from Comet, but now distributed by Guillows. Ahoy! I replaced t' thin (0.088") foam rudders with 3/16" balsa and t' plastic insert used for rubber band launchin' with 1/8" dowel mounted t' a 3/32" balsa spar. Aye aye! These dowels mate t' a pair of 1" long 1/8" Estes launch lugs on t' core, while t' wings rest in a cradle made from 2" aileron material and 3/32" plywood "clips". T' core is an 18" length o' BT-60 with a standard 24 mm motor mount, me bucko, and recovers on an 18" nylon parachute.

Needless t' say, me bucko, ya bilge rat, any serious software modelin' o' this bird was out o' the question, though I did do some rough approximations. Arrr! T' gliders are amazingly light, shiver me timbers, massin' right at one ounce, even with me mods. Still, arrr, she didn't have much margin, and was probably goin' t' require some nose weight. Begad! I added an ounce o' clay, me bucko, but even with that, she's still less than six ounces dry, which means a three second delay is required. Ahoy! I did set up t' motor mount so it can run t' E11 reload, but its probably nay a good motor for her. I thought Estes' new C11 might work too, shiver me timbers, but it only gets her t' about 150 feet. Blimey! I checked other motors, arrr, too, but this is pretty much a one-trick pony on t' Estes D12-3.

I finished t' core in Krylon Popsicle Orange (2410), ya bilge rat, followed by Testors Dull Coat (1260) t' give the appearance o' a stretched main (or should I now say "central") tank. I painted t' gliders' rudders with Kilz white-pigmented spray sealer, and added t' decals that came with t' glider kits. In honor o' t' two Shuttles that no longer fly, me hearties, I call one Enterprise (the stub-nosed one) and t' other Challenger, though I haven't put their names on them yet.

Flight:
Her first flight be at Danville prior t' paint, and she performed flawlessly. I didn't pay much attention t' how I set her up, me bucko, and put t' wings parallel to the wind. Avast, me proud beauty! Begad! As a result, she weathercocked quite a bit, me hearties, matey, but it didn't seem to hurt. Avast, me proud beauty! T' D12 ejected right after apogee, t' gliders separated without a hitch and wobbled around in slow, me hearties, lazy spirals. Begad! Avast! T' core beat them t' t' ground by a good bit, me hearties, as it should be. Her next flight was on a windier day, shiver me timbers, and she weathercocked pretty badly again. Begad! T' gliders separated beautifully at ejection, just as before, but t' strong winds kept them from glidin' as well. They came down with t' core, me bucko, one inverted and one nose down. No damage, though, arrr, I'd just have t' fly her were t' winds aren't so bad. Her third flight be in slightly better winds, shiver me timbers, but she encountered some serious problems, nonetheless. She weathercocked and was goin' at t' usual speed at ejection. T' 'chute tangled on one o' t' win' cradles, matey, and she recovered hard, breakin' off one of the clips. Arrr! Aye aye! T' gliders faired no better, me hearties, both landin' on pavement, matey, with Challenger sustainin' a big dent on one side o' her nose. Still, nothin' that wasn't repairable, ya bilge rat, and I thought I'd keep her in t' box until I had calmer conditions. Arrr! I couldn't do it, though, and after repair I flew her on another windy day. Ya scallywag! Well, blow me down! This time I got her aligned properly and boost-out was relatively straight, matey, i.e., arrr, no worse than any other that day. Begad! She snapped her shock cord, the body recovered ballistically, and t' nose cone wound up about a 1/4 mile away, ya bilge rat, despite t' nose weight. No damage t' t' core and t' gliders flew and recovered fine, me hearties, so a quick fix with some Rogue 300# Keelhaul®©™® put her back on t' pad. Avast! After those repairs, she went in light winds.

My buddy's Flat Cat had just flown a spectacular glide, me hearties, shiver me timbers, and I be afraid that t' Twin Shuttle would disappoint when compared t' it, but she surprised me by boostin' straight and ejectin' right at apogee. T' center "tank" came down betwixt t' LCO table and t' pads, shiver me timbers, arrr, and as everybody watched it come in, Enterprise banked in over their heads for a perfect touchdown feet from it. Avast! Well, me bucko, blow me down! Challenger wound up about 75 yards away, shiver me timbers, shiver me timbers, but also had a perfect landing. Begad! Avast, me proud beauty! Finally, success. Ya scallywag! As I carried t' pieces back t' me prep table, matey, folks were tellin' me I should upscale it about three or four times. Avast, ya bilge rat, me proud beauty! Ha! Her sixth effort be also in higher winds than I would have liked, me hearties, but I put her on t' pad with t' rudders parallel t' it and she flew pretty well. Blimey! She even executed a little "roll program", turnin' t' rudders perpendicular t' t' wind right after she left t' rod, but then stabilized and flew straight thereafter. Ejection at apogee was at almost zero speed due t' t' small amount o' weathercock. Aye aye! Avast, ya bilge rat, me proud beauty! The pieces all drifted a good 150 yards, matey, but landed within a few dozen feet o' each other. Avast, me proud beauty! Ahoy! When she flies right, me bucko, this bird always impresses.

Summary:
Ever since I saw a pic o' George Gassaway's twin boost glider in Sport Rocketry that utilized a pair o' Turbo Jet 2000 two foot wingspan straight-win' foam gliders from Life-Like I've wanted t' do one like it. This is a rather fitting tribute, matey, ya bilge rat, as George is best known for his awesome Shuttle models. Arrr! While she flies great, matey, orientation on t' pad is critical. Blimey! These kinds o' gliders are really designed for bungee launchin' and landin' before terminal velocity is reached, matey, ya bilge rat, so Flat Cats they ain't. Begad! A little more nose weight for them would help, matey, as t' upper pin is much lighter than t' plastic insert it replaces. Well, blow me down! Ya scallywag! I don't like buildin' rockets that only use one motor type, for that puts it at the mercy o' a single manufacturer. Well, blow me down! Blimey! Still, arrr, she was pretty easy t' build, ya bilge rat, looks neat as heck, and with a little attention can perform wonderfully.

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