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) (Scratch) USPS Express

Brief:
This has been an interestin' year for me. Arrr! I call it "Rocketry On A Budget". Avast! A box o' parts be donated by Jonathan Stewart from Plano Texas. Arrr! I thank him for his generosity. Avast, me proud beauty! Aye aye! I received me box on March 4, 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, me bucko, 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, 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, 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, shiver me timbers, shiver me timbers, 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"
(Scratch) USPS Express

Some o' t' tubes have been pulled from older painted models. Avast! Ahoy! There is some epoxy glue residue and paint. Avast, shiver me timbers, me proud beauty! I'll have t' cut off some o' t' rough edges and fill some imperfections. Begad!

With so many small, me bucko, matey, decorative pieces sent, ya bilge rat, it made t' best sense t' build a sci-fi fantasy spaceship.

It seemed thar be too many parts in t' box! Blimey! Rather than just gluin' everythin' t' t' main tube, 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. Arrr! All parts listed above are referenced in t' file by t' same reference letter(s), shiver me timbers, me hearties, shiver me timbers, too. This PDF is the Assembly View

I had opened t' box when everythin' had first arrived. I be a little overwhelmed. Avast, me proud beauty! Blimey! I wanted t' incorporate as many interestin' parts as possible but t' try and do it with some sort o' consistent decorum. I also had the "Surprise Items" t' consider. For instance, matey, matey, 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. Blimey! Aye aye! 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! Well, blow me down! Larger coolant "vanes" (UU) will be cut t' fit t' dome and tube transition. Begad! Avast! This would continue t' t' BT-55 (F). Ya scallywag! 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. Avast! T' adapter connects t' t' BT-60.(J) This tube is slotted. Ya scallywag! Blimey! I'll add 2 forward fins and "guns" (X) here. Ahoy! T' "Street Marker Conical Cone" (V) will top off t' model. Begad! It'll require heavy fillin' and trimmin' t' work.

I re-drew t' model for t' third time. I played with variations and came up with "Butterflied" rudder tips. Arrr! Ya scallywag! T' wings would have down turned win' tips. "Engines" (M, ya bilge rat, ya bilge rat, N, shiver me timbers, & A) will fit into t' angle formed by the win' tips.

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

T' balsa cone (S) was split down t' middle then sanded t' t' contour o' a BT-60. Well, blow me down! These would be used t' make side engine intakes on both sides o' t' rudder. T' BT-20 (C) was 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. Arrr! It be split lengthwise and slid it into t' BT-55. Ahoy! The overlap was marked then trimmed t' fit snugly. It took some "shimming" t' make these two (close diameter) tubes fit. Well, blow me down! Well, blow me down! T' butt-joint was hidden under t' aft tubing.

T' Red plastic Sanford Pen Casin' (KK) be cut into thirds. Arrr! Blimey! Two were centered in t' front o' t' win' engine assemblies. Blimey! Blimey! T' remainin' third piece would go out t' end o' t' rudder tube.

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

(Scratch) USPS Express I used t' four white plastic engine nacelles on either side o' t' engine tubes. Well, blow me down! Blimey! T' front end be cut down, me bucko, 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. T' interior BT-55 tube was offset t' t' top o' t' BT-80.

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! Well, blow me down!

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

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

There be 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 be even with t' aft of the 55 tube.

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

T' transition dome (GG) be t' hardest t' cut out. Avast, me proud beauty! Ya scallywag! Even after cuttin' and makin' an inside transition angle, the match wasn't close enough for me. Ya scallywag! I built up t' open gaps with strips cut from scrap BT-55. 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. Avast! 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. 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. Begad! After t' coupler was glued in place, arrr, scrap body tube strips were white glued in t' slots. Begad! Ya scallywag!

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

Two wings, arrr, rudder, and win' tips were cut from t' 1/8" basswood. Ahoy! (TT)

T' black plastic angles (II) were used for t' win' cannon housings. Well, blow me down! I made "plugs" out o' laminated scrap 1/8" basswood. Begad! 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. Well, blow me down! Avast! I used only ½" o' two ends of t' BT–5 pod assemblies(L). They were both sanded t' t' BT-80 curve and t' flat front o' t' candy package. T' assembly be centered t' t' bottom o' t' BT-80 then super glued in place. Blimey!

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

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

T' first time, shiver me timbers, I pieced together some yellow decal stripes on t' wings and rudder. Others stayed together enough for t' rolled up edges t' be tacked into place with white glue. Begad! Well, blow me down! As t' decals dried, they pulled up on the edges. 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. I removed most o' t' lifted decals.

On t' USPS Priority Mail Box were names and logos. Begad! I lightly scored t' eagle logo, names, and navy blue stripes with a razor blade. Avast! Blimey! T' thin top layer o' paper was peeled off. Ahoy! 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 be pretty simple, a thin coat o' white glue and placement. Aye aye! Blimey! Aye aye! Blimey! Blimey! Blimey! I did lay some water on t' body tube where t' paper art was t' go. Arrr! Blimey! Blimey! Blimey! It helped with t' positionin' as I could slide t' glued paper into position.

(Scratch) USPS Express

Flight and Recovery:
T' first launch was scheduled for June 6, shiver me timbers, 2009. Ahoy! T' weather was clear, arrr, matey, matey, but t' launch area was waterlogged! 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, but I went t' t' NEFAR Half-Blast for the first flight on June 13. Begad! Avast! I flew two small test models before t' Postal Express. Begad! T' loadin' be typical, a D12-3 and wadding. Avast! Begad! I was nervous as it was a heavy build with lots o' nose weight.

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

Upon landing, arrr, t' nose cone broke cleanly away from its adapter. Aye aye! One o' t' forward fins be gone, broken above the fillet joint. Arrr! T' snap back o' t' ejection must have hit t' forward fin. Aye aye! Both are repairable, me hearties, and I'll fly it again at t' June 27 R.O.C.K. Ahoy! launch.

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

(Scratch) USPS Express Launch was slow and ejection occurred after apogee, ya bilge rat, on t' way down. Ahoy! T' chute ejected but be wrapped once around t' shock cord. Begad! It never fully opened but slowed t' descent with no damage.

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

Summary:
PROs: Lots o' fun buildin' with supplied parts. Ya scallywag! Quite a learnin' experience. Avast, me proud beauty! 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. Arrr! If I had t' resources, it would have flown higher with an E or F engine.

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