Scratch USPS Express Original Design / Scratch Built

Scratch - USPS Express {Scratch}

Contributed by Hans "Chris" Michielssen

Manufacturer: Scratch
(Contributed - by Hans "Chris" Michielssen - 06/27/09)

Brief:
This has been an interestin' year for me. Ya scallywag! I call it "Rocketry On A Budget". Well, blow me down! A box o' parts was donated by Jonathan Stewart from Plano Texas. Avast! I thank him for his generosity. Begad! I received me box on March 4, me bucko, me bucko, 2009.

Construction:
An inventory o' t' parts:

  • A) BT-5 12" long
  • B) BT-5 size 3-½" long party hornpipe tube
  • C) BT-20 14-½" long
  • D) BT-50 4" Clear Tube
  • E) BT-50 12-½" long
  • F) BT-55 14" long
  • G) BT-56 11" long
  • H) BT-55 12" long
  • I) BT-60 3" long
  • J) BT-60 10 ½" long
  • K) BT-80 15 long
  • L) 2 BT-5 "Pod" assemblies 5" long each (nose cones glued in each end)
  • M) 4 BT-5 Nozzles assemblies, ya bilge rat, ya bilge rat, 2-1/4" long each
  • N) 4 BT-3 Pod assemblies 2" long each
  • O) 20/50 Balsa Transition adapter
  • P) 55/60 Plastic Transition Adapter
  • Q) Balsa Conical Nose Cone for BT-5
  • R) Plastic Nose Cone for BT-55
  • S) Balsa Nose Cone for BT-20
  • T) 2 (Usable) BT-50 Balsa Blocks
  • U) 4 Engine Hooks (different sizes)
  • V) "Street Marker" Conical Cone, shiver me timbers, 2" at base
  • W) 1 Clear Plastic "Half" Bubble 2-½" long
  • X) 6 "Pre-cut balsa Fins
  • Y) 5 Launch Lugs 1/8" X 1"
  • Z) 1 Launch Lug 3/16" X 4"
  • AA) 4 Cardstock Tubes, me hearties, 3/16" X 5-½"
  • BB) 5 Popsicle Sticks
  • CC) 3 Golf Tees
  • DD) 2 Screw eyes
  • EE) 1 Bamboo Skewer 5-½" long
  • FF) 4 Black Plastic "Landin' Feet"
  • GG) 1 Yellow Plastic Dome 3" diameter
  • HH) Various Fiber Centerin' Rings
  • II) 2 Black Plastic "Angle" Pieces
  • JJ) 1 20 size Engine Block
  • KK) 10 Various Plastic "Tips, ends and points"
  • LL) Orange Plastic Streamer 54" X 2"
  • MM) 3/8" wide Black Shock Cord--long!
  • NN) 5 small plastic "Missiles"
  • OO) 4 White plastic Star Wars guns
  • PP) 8 small orange plastic "Tips"
  • QQ) 1 Plastic Candy Container
  • RR) 6 plastic "Plugs" Many holed
  • SS) 24" Nylon Parachute
  • TT) 36" Nylon Parachute
  • UU) 1 sheet Basswood 1/8" X 4" X 24"
  • VV) 1 sheet Basswood 1/8" X 4" X 16"

Some o' t' tubes have been pulled from older painted models. Ya scallywag! Blimey! There is some epoxy glue residue and paint. Avast! Blimey! I'll have t' cut off some o' t' rough edges and fill some imperfections. Blimey!

With so many small, arrr, arrr, decorative pieces sent, it made t' best sense t' build a sci-fi fantasy spaceship.

It seemed thar be too many parts in t' box! Rather than just gluin' everythin' t' t' main tube, me bucko, arrr, I'll try to combine as many (recognizable) parts into sub-assemblies and then attach them t' t' model.

Most all construction is documented on the PDF instructions and patterns. All parts listed above are referenced in t' file by t' same reference letter(s), shiver me timbers, too. Ya scallywag! Blimey! This PDF is the Assembly View

I had opened t' box when everythin' had first arrived. Begad! I was a little overwhelmed. Arrr! Well, blow me down! Blimey! I wanted t' incorporate as many interestin' parts as possible but t' try and do it with some sort o' consistent decorum. Well, blow me down! Begad! Blimey! I also had the "Surprise Items" t' consider. For instance, how do I add four popsicle sticks? They have t' be recognizable but still stay with t' flow o' t' design.

I visualized many o' t' body tubes and one adapter together on t' floor. From t' aft forward: T' large diameter BT-80 "engine compartment" (K) will connect t' t' trimmed Yellow Plastic Dome (GG). Well, blow me down! Larger coolant "vanes" (UU) will be cut t' fit t' dome and tube transition. This would continue t' t' BT-55 (F). Ya scallywag! Ahoy! Next is the Plastic 55/60 adapter.(P) T' ends will be trimmed and coated with epoxy t' protect t' plastic interior from the ejection charge. Arrr! T' adapter connects t' t' BT-60.(J) This tube is slotted. Arrr! I'll add 2 forward fins and "guns" (X) here. Avast, me proud beauty! T' "Street Marker Conical Cone" (V) will top off t' model. Aye aye! It'll require heavy fillin' and trimmin' t' work.

I re-drew t' model for t' third time. Blimey! Blimey! Avast, matey, me proud beauty! Blimey! I played with variations and came up with "Butterflied" rudder tips. T' wings would have down turned win' tips. Aye aye! Blimey! "Engines" (M, N, & A) will fit into t' angle formed by the win' tips.

A ram-jet style nose cone was made out off part Q. I cut ½" off t' tip with a razor saw then sanded t' cuts flat with a sandin' block. Ya scallywag! More sandin' followed until it achieved t' right visual balance. Begad! Arrr! This will be joined t' a shortened BT-5 (A) and be glued t' t' middle o' t' rudder's butterflied top. Aye aye!

T' balsa cone (S) be split down t' middle then sanded t' t' contour o' a BT-60. Arrr! Blimey! These would be used t' make side engine intakes on both sides o' t' rudder. Aye aye! Blimey! T' BT-20 (C) be split lengthwise down t' middle t' fit t' two sides from t' split nose cone.

1-1/4" was cut off t' BT-56 (G) t' make a coupler. Avast, me proud beauty! Ahoy! Blimey! It was split lengthwise and slid it into t' BT-55. Ya scallywag! Ya scallywag! Blimey! The overlap be marked then trimmed t' fit snugly. Ahoy! It took some "shimming" t' make these two (close diameter) tubes fit. Aye aye! T' butt-joint be hidden under t' aft tubing.

T' Red plastic Sanford Pen Casin' (KK) was cut into thirds. Ahoy! Begad! Two were centered in t' front o' t' win' engine assemblies. Well, blow me down! Avast, me proud beauty! T' remainin' third piece would go out t' end o' t' rudder tube.

T' 6-½" long BT-5 tube (A) was cut into equal thirds. Begad! I needed two win' "engine tubes" and one rudder ramjet tube.

I used t' four white plastic engine nacelles on either side o' t' engine tubes. Ahoy! T' front end was cut down, I didn't want an exhaust nacelle on t' front o' t' engine.

Centerin' rings were cut out o' t' shippin' box for t' stuffer tube inside t' aft BT-80 tube. Ya scallywag! T' interior BT-55 tube was offset t' t' top o' t' BT-80. Begad!

T' Stuffer tube was made out o' two pieces o' BT-55 and 56 (parts F and G) joined by a coupler made from a short piece o' t' supplied BT-55. Begad! Blimey!

T' engine will be a D12 fittin' into a BT-50 motor mount tube. Ya scallywag! (Part E). Arrr! Begad! A 3" piece o' BT-50 be cut for an engine mount. T' BT-50 was notched for t' suppled engine hook (U). T' end o' t' hook extended 1/4" beyond the engine mount tube. Begad! Begad!

There was plenty o' centerin' rings but no 50/55 rings. Avast, me proud beauty! Begad! From t' shippin' box, shiver me timbers, I made a 1" wide centering ring. Begad! Avast! I kept wrappin' t' cardboard strip round until it made a slip fit into t' BT-55 stuffer tube. Begad! I'll lay white glue t' plug t' open holes in t' corrugated cardboard.

There was no Keelhaul®©™®, so I made a standard Estes style tri-fold mount.

T' engine mount be glued inside t' shorter BT-55 tube until t' BT-50 engine tube was even with t' aft of the 55 tube.

It was obvious t' cut t' cone (V) down t' fit t' BT-60 upper tube. Begad! I decided t' cut it at an angle so t' tip would be angled down, me hearties, me bucko, much like t' old SST Jetliner when it be in flight. However, matey, after trimmin' it looked too saggy at t' front. I trimmed and sanded t' tip back at an angle. Well, blow me down! T' hole in t' nose cone tip be now an enlarged oval. I cut a piece o' scrap BT-55 (H) and CA'd it t' t' tip. Well, blow me down! Blimey! T' edges were sanded down t' match t' new conical shape. Begad! The nose cone adapter was easier than I would have thought. Aye aye! Aye aye! I took a piece o' BT-60 (I) and split it. It be set into the upper BT-60 and t' overhang "tab" was CA'd in place. Begad! Begad! T' adapter was simply glued t' t' cone edge, centerin' it all around. Begad!

T' transition dome (GG) be t' hardest t' cut out. Blimey! Even after cuttin' and makin' an inside transition angle, the match wasn't close enough for me. Aye aye! I built up t' open gaps with strips cut from scrap BT-55. Aye aye! I sanded t' fill pieces smooth with sandpaper wrapped around a BT-50 tube scrap.

T' form t' 55/60 plastic transition (P), t' original 3" long BT-60 was cut off t' transition piece. I coated t' inside with 15 minute epoxy t' protect it from t' ejection charge.

T' upper parachute tubin' (J) was a left over tube from a kit, already laser slotted for through t' wall fins. I'll have t' patch t' holes and fill t' seams. Begad! Ya scallywag! BT-60 scrap (I) be cut t' 1-½" t' make an inside tube coupler. This gives an inside wall t' glue t' patch pieces onto. Blimey! Aye aye! After t' coupler be glued in place, me hearties, scrap body tube strips were white glued in t' slots.

Three transitions vanes were cut from t' 1/8" basswood (UU). Aye aye! Two transitions had t' be matched, the curved aft dome (GG) and t' upper plastic transition.(P) Also, me hearties, me hearties, on t' two smaller outside vanes, t' dome angle had to be sanded t' an angle t' match t' curve. Blimey! This and t' dome were t' hardest parts o' t' build.

Two wings, me hearties, shiver me timbers, rudder, and win' tips were cut from t' 1/8" basswood. (TT)

T' black plastic angles (II) were used for t' win' cannon housings. I made "plugs" out o' laminated scrap 1/8" basswood. Well, blow me down! Well, blow me down! Blimey! T' white Star Wars "guns" (00) were shortened and glued into 1/8" holes drilled in t' plugs.

T' plastic candy package (PP) was sanded t' t' BT-80 body tube contour. I used only ½" o' two ends of t' BT–5 pod assemblies(L). Aye aye! They were both sanded t' t' BT-80 curve and t' flat front o' t' candy package. T' assembly was centered t' t' bottom o' t' BT-80 then super glued in place. Begad!

Finishing:
Finishin' t' rocket, I did t' best I could without too much complex masking. Avast, me proud beauty! Ahoy! Blimey! T' built rocket be painted gloss white, t' aft engine compartment painted black. Ahoy! T' popsicle stick vanes were first painted white, me hearties, me hearties, then glued onto the black engine tube.

I had plans for usin' many o' t' decals that were sent. Ahoy! While thar were plenty o' decals included, ya bilge rat, ya bilge rat, shiver me timbers, most all were older and unusable. Some rolled off t' paper onto themselves, others cracked. Avast! I know thar are decal solvents and repair solutions available, ya bilge rat, but I didn't have time t' order and fly t' model by t' deadline. Avast, me proud beauty! Avast, me proud beauty! I wanted t' use what was supplied. Ahoy! I did t' best I could without too much complex masking. Begad! I'm nay complaining, Mr. Stewart sent plenty o' parts for a fun build.

T' first time, I pieced together some yellow decal stripes on t' wings and rudder. Begad! Well, me bucko, blow me down! Others stayed together enough for t' rolled up edges t' be tacked into place with white glue. Well, blow me down! As t' decals dried, they pulled up on the edges. Avast! I tried re-tackin' them down again, but t' next day they lifted again. I let things sit for a few days while I tried t' think o' a solution. Well, blow me down! Well, shiver me timbers, blow me down! I removed most o' t' lifted decals.

On t' USPS Priority Mail Box were names and logos. Ahoy! I lightly scored t' eagle logo, names, and navy blue stripes with a razor blade. T' thin top layer o' paper was peeled off. Ya scallywag! Usin' t' USPS logos changed t' theme and back story of t' model.

I lightly wet t' peeled paper back with a sponge and carefully scraped off what be left o' t' brown cardboard layer and glue.

From thar be was pretty simple, arrr, a thin coat o' white glue and placement. Avast, me bucko, me proud beauty! I did lay some water on t' body tube where t' paper art was t' go. It helped with t' positionin' as I could slide t' glued paper into position. Well, blow me down!

Flight and Recovery:
T' first launch was scheduled for June 6, 2009. Blimey! Blimey! T' weather was clear, but t' launch area was waterlogged! Blimey! Many days o' rain in central Florida had left t' launch field too wet and unusable.

I usually don't fly with t' "Big Boys" in Bunnell, Florida, shiver me timbers, shiver me timbers, but I went t' t' NEFAR Half-Blast for the first flight on June 13. Blimey! Aye aye! I flew two small test models before t' Postal Express. T' loadin' was typical, me bucko, a D12-3 and wadding. Ya scallywag! I be nervous as it was a heavy build with lots o' nose weight.

Launch was show and straight maybe t' 350 feet. Ya scallywag! Blimey! I was concerned t' angled nose cone might effect t' vertical trajectory, matey, but it didn't seem t' affect it at all. Ya scallywag! Blimey! It slowed and blew it's chute just prior t' apogee. Avast, me proud beauty! Someone said there was a zipper. Well, blow me down! There couldn't be a zipper, ya bilge rat, thar wasn't any Keelhaul®©™® to cut through t' body tube. Begad! Blimey! Avast, arrr, me proud beauty! Blimey! Blimey! Blimey! T' shock cord was hangin' from about halfway down t' body, nay from t' nose. Arrr! Blimey! Begad! Blimey! Blimey! Blimey! It was hung up around t' toothpicks on t' center o' t' BT-55.

Upon landing, t' nose cone broke cleanly away from its adapter. Avast! One o' t' forward fins was gone, me hearties, broken above the fillet joint. Blimey! T' snap back o' t' ejection must have hit t' forward fin. Well, blow me down! Ya scallywag! Both are repairable, and I'll fly it again at t' June 27 R.O.C.K. Avast, me proud beauty! launch.

All repairs were made for t' local NAR, me bucko, matey, ROCK Section o' Orlando launch on June 27, arrr, arrr, 2009. Blimey! As always, I grabbed a smaller rocket and did a low level test flight t' get a feel for t' field and conditions. Arrr! I noticed t' plastic dome on t' Postal Express transition was loose, me bucko, arrr, and I hit it with a few drops o' CA glue. Ya scallywag! T' remembered t' earlier flight on a D12-3 thinkin' ejection be a hair early so I loaded up a D12-5.

Launch was slow and ejection occurred after apogee, ya bilge rat, on t' way down. Ya scallywag! T' chute ejected but was wrapped once around t' shock cord. Well, blow me down! It never fully opened but slowed t' descent with no damage.

A short rain held up launchin' for 15 minutes. Aye aye! I loaded up again, this time with a D12-3. Avast! This seems t' be the best available engine. Ya scallywag! If someone were t' make a D12-4 engine it would be close t' perfect. Begad! Arrr! This be t' best launch yet. Well, blow me down! Straight up, shiver me timbers, full parachute and no damage on landing.

Summary:
PROs: Lots o' fun buildin' with supplied parts. Arrr! Blimey! Avast, me hearties, me proud beauty! Blimey! Blimey! Blimey! Quite a learnin' experience. Ahoy! Blimey! When doin' an out-of-the-ordinary build, you change directions many times and pick up a few new techniques along t' way.

CONs: Some small parts break off. If I had t' resources, ya bilge rat, it would have flown higher with an E or F engine.

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