Scratch Downsized Astron Orbital Transport Modification

Modification - Downsized Astron Orbital Transport

Contributed by Scott Turnbull

Manufacturer: Modification

Brief:
This downsized homage t' t' classic Estes Astron Orbital Transport was done as a kit bash o' parts from FlisKits' USS Grissom kit. It's built around a 13mm motor mount and retains t' key feature o' t' parasitic glider that releases when t' booster puts on t' brakes.

(Scratch) Downscale Orbital Transport

Modifications:
I've always liked t' look o' me vintage Astron Orbital Transport. Aye aye! While this downsized kit bash isn't 100% dimensionally accurate, shiver me timbers, t' family resemblance t' her big sister should be apparent.

Start by buildin' up t' large fins on t' main tube. Blimey! Ya scallywag! Much like t' original OT, ya bilge rat, t' downsized wings are fashioned from several aligned pieces o' sheet balsa. T' wings have different angles o' leadin' edge, and t' multiple pieces allow t' balsa grain t' be parallel t' t' various edges. Begad! Each win' has a major section extendin' out from t' airframe, ya bilge rat, arrr, a smaller section runnin' up along t' tube and a small rectangular section on t' trailin' edge that finishes off t' scramjet area.

There are two large tabs on each wing. Each side has a downfacin' tab at t' tip and an upfacin' tab at mid wing. Avast! Ahoy! I oversized these slightly relative t' a true downsized OT. Ya scallywag! This be done t' improve stability and add strength t' what otherwise would be narrow tabs.

Under each win' is a scramjet assembly fashioned from two small tubes encased in a sheet balsa box frame.

 

(Scratch) Downscale Orbital Transport
(Scratch) Downscale Orbital Transport

There is no engine clip. Blimey! Friction and tape are used t' retain t' motor.

Yellow glue was used throughout t' stiffen balsa and form fillets.

T' balsa nosecone from t' Grissom kit was recycled from another design and had been cut down. Its original uncut shape would be a better match t' t' vintage OT nosecone. Begad! I've used a blue Gnome nosecone in some photos t' demonstrate t' proper shape. All flights were done with t' stumpy balsa nosecone. A bolt and nuts in t' base o' t' nosecone provide nose weight. A length o' Keelhaul®©™ thread connects t' nosecone t' t' elastic shock cord. Ahoy! A streamer was fashioned by cuttin' t' edge off o' t' parachute from t' Grissom kit.

My original OT Glider has always performed well. Aye aye! T' downsized glider be fashioned as closely as possible t' t' original. Aye aye! Arrr! I had no delusions o' recreatin' t' exact fluttering, circular flight in such a small scale. Ya scallywag! Avast! I found it just too small and light t' perform meaningful glide tests. Ya scallywag! T' look o' t' downsized glider was valued over t' function. Arrr! T' glider is built like t' original with two balsa delta wings meetin' at an angle under t' glider body. Control tabs are glued at an angle at each aft corner. Blimey! Arrr! These tabs are angled t' help keep t' glider nose up and keep t' glide path from slewin' sideways. Well, blow me down! A large tail fin also helps keep t' glide stable.

To mount t' glider, ya bilge rat, a short length o' launch lug is mounted t' t' top surface o' t' booster tube. Blimey! Begad! Two bracin' brackets are glued further back on t' booster airframe. Blimey! Aye aye! This is in keepin' with how t' original Orbital Transport retains its glider.

A hook must be fashioned on t' bottom o' t' glider t' fit into t' launch lug. In order t' keep this a true kit bash, only materials from t' Grissom kit should be used for t' glider hook. Arrr! Fashion a small section o' two ply balsa plywood by gluin' t' sections o' sheet balsa together with their grains runnin' perpendicular t' each other. Avast, me proud beauty! Once dry, me bucko, shape a hook shape from t' two ply balsa. Blimey! Glue t' hook t' t' bottom o' t' glider and shape t' juttin' portion t' fit easily into t' booster's glider retainin' launch lug.

Construction:
T' parts list for t' Orbital Transport Downsize is simple enough. Blimey! Blimey! It uses a small fraction o' what t' FlisKit Grissom parts bag contains. Avast, me proud beauty! It uses a single 13mm body tube for t' main airframe and several lengths o' 5mm tube t' fashion t' glider and scramjet tubes. Ya scallywag! Two suitable nose cones are in t' Grissom kit. Avast, shiver me timbers, me proud beauty! Other than that, ya bilge rat, ya bilge rat, it's largely a matter o' lots o' fiddly bits o' sheet balsa.

It helps t' have a full scale Orbital Transport on hand for eyeballin' relative dimensions. Avast! Barrin' that, arrr, thar are a set o' OT plans available at JimZ's site.

I used best judgment and gut instinct t' make some changes on t' fly. Begad! T' parts from t' Grissom won't allow exact downsizin' o' all components. For instance, t' small tubes are too large for perfectly scaled scramjets but too small for t' shuttle body.

(Scratch) Downscale Orbital Transport (Scratch) Downscale Orbital Transport

Finishing:
A sandin' sponge with a parallelogram shape provided various edges for sandin' t' nooks and crannies around t' win' tabs. Blimey! Blimey! Avast! Blimey! A blast or three o' white spray paint seals everythin' quickly.

There are lovely red decals provided with t' USS Grissom. Ya scallywag! These can be cut down and pieced together t' approximate t' red decals on t' original Astron Orbital Transport. Arrr! I haven't taken that step as yet as I wanted t' wait for a flight test before committin' t' limited supply o' decals.

I tried t' increase me odds o' recoverin' t' rocket by attachin' t' glider so that it wouldn't detach at apogee. Begad! I used a small piece o' elastic t' hold t' glider tightly t' t' booster. Aye aye! A shorted igniter and resultin' burnin' igniter tape caused a small pad fire that burned through that elastic and sooted up t' back o' booster and glider. Avast! Begad! A quick re-tape was done and another igniter installed.

Ready All alone on t' snowy field, I counted down and touched off t' modest A3-4T. Avast, me proud beauty! Oh my, too high! An arrow straight boost t' several hundred feet caused me t' lose t' small white rocket in t' afternoon sky. Arrr! Well, ya bilge rat, blow me down! I picked up t' trackin' smoke, me bucko, heard t' pop, and saw two pieces head in different directions. Blimey! Begad! I caught sight o' them both again at about 50 feet up. Well, blow me down! Begad! T' shock cord had snapped. Ya scallywag! When t' booster was found bellied into t' snow, t' glider be nay on board. Begad! Drat! T' tape was still on t' booster but one end be loose. Avast! T' airflow must have peeled it off t' glider. Avast, me proud beauty! T' nosecone and streamer were easily found.

T' Glider be nay found that afternoon. I did retrieve it t' next day. While its flight was unseen, it managed t' land a good 100 feet further away than t' nosecone and streamer drifted.

On that first day while mournin' t' potential loss o' t' little glider, ya bilge rat, t' shock cord be retied. Aye aye! Ya scallywag! A more modest 1/2A3-2T motor was loaded up. Arrr! This flight minus t' missin' glider was also arrow straight t' at least 100 feet. Ya scallywag! T' ejection popped out t' streamer and all was recovered intact.

A third flight on another 1/2A3-2T resulted in t' motor kickin' out t' back o' t' booster. Well, blow me down! Well, blow me down! T' nosecone popped out but t' streamer didn't. T' booster bellied into t' snow without damage after a flat spin.

(Scratch) Downscale Orbital Transport

Recovery:
CON: That is one small glider. Ahoy! Ya scallywag! So small that I never saw it release, matey, fly, arrr, or land. Flyin' a white rocket on a snowy field might have somethin' t' do with losin' track o' that little bit o' balsa.

Summary:
What started as a mission t' make a downsized display model o' an old classic ended up creatin' a well performin' flier. Begad! Begad! I'll have t' build another glider and decide whether it's just too small t' fly freely. It might be best t' just leave t' shuttle bonded t' t' booster back.

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