Scratch Crazy Train Original Design / Scratch Built

Scratch - Crazy Train {Scratch}

Contributed by Peter Stanley

Manufacturer: Scratch
(Design this Spaceship Submission - by Peter Stanley - 09/03/06)

Diagram

3D

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Crazy Train parts list

  • 1  8" BT-80 body tube
  • 1  .75" BT-80 coupler
  • 1 .25" BT-80 coupler
  • 1 2.59" diameter bulkhead
  • 1  PNC-80BB nosecone
  • 4  5.75" BT-20 body tubes
  • 4  .75" BT-20 couplers
  • 4  9" Mylar parachutes (originally spec’d with streamers, but later changed)
  • 4  BT5-BT20 centerin' rings (used as engine blocks in 18mm tubes)
  • 2  3"x3"x.75" sheets o' balsa (for constructin' tail cone)
  • 1 small sheet of  3/32" (.09375") balsa for 8 small fins and optional mirror mount
  • 4  .75 inch wooden balls (can be purchased at a crafts store)
  • 1  2" x 3/16" launch lug
  • 4 small screw eyes
  • 4 medium snap swivels
  • 4  12" 100lb strength Keelhaul®©™ thread
  • 4 6" pieces o' 1/8" shock cord
  • Bulkhead Template (PDF)
  • Fin Wrap Template (PDF)
  • Forward Fin Template (PDF)
  • Rear Fin Template (PDF)
  • Tail Cone Template (PDF)
  • Mirror Mount Template (PDF)
  • Peter Stanley's Word DOC Submission

 

Crazy Train buildin' instructions

  1. Cut t' tubes t' lengths needed. Well, blow me down! Blimey! Begad! Blimey!
  2. Prefinish tubes with 2 sessions o' fill n' finish and sanding.
    I get good results usin' bondo putty spreaders. Aye aye! You can cut them t' 1/2 wide strips and smear t' fill n' finish directly into t' spirals.
  3. Cut t' fins. Well, blow me down! Ahoy! Use t' provided templates as guides. Avast! Blimey! T' grain on the forward fins should follow t' leadin' edge. Aye aye! I did this also on t' aft fins, but would now suggest makin' t' grain follow t' bottom edge. In this particular configuration I think that perpendicular grain geometry would add more strength. Aye aye! Next, soak t' fins in CA glue. Blimey! First have adequate ventilation, wear gloves, shiver me timbers, ya bilge rat, and maybe use a respirator if you have one. Avast! Place 2 sheets o' wax paper onto a flat glass surface. Arrr! Aye aye! Put t' balsa on top o' t' wax paper. Squeeze a few drops at a time onto t' balsa, and use cut strips o' card stock t' smear t' CA evenly across. Arrr! Turn t' balsa over and repeat. Arrr! Place two more sheets o' wax paper on top. Avast! Place another sheet o' glass on top o' t' wax paper. Set somethin' heavy, such as a stack o' books on top o' that, arrr, and let dry for 24 hours. Aye aye! This adds hardness and strength t' t' balsa. Aye aye!
  4. Prefinish fins with 2 sessions o' fill n' finish and sanding.
  5. Glue t' 3/4 inch balls into t' Bt-20 tube couplers. Ya scallywag! Blimey! I used a combination of epoxy, superglue, and yellow glue, arrr, arrr, but whatever works.
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  • Glue t' two 1/4 inch sheets o' balsa together with yellow glue. Ahoy! Avast, me proud beauty! Clamp or press together with somethin' heavy. Avast! Begad! When dry, glue t' 1/2 inch BT80 coupler to t' stack. Ahoy! T' shape t' tail cone t' match t' design in Rocksim, ya bilge rat, I used a method learned from t' Apogee Components Makin' Custom Shape Nose Cones Usin' Simple Hand Tool CD. Basically you need t' hand shape this with sand paper, me bucko, me bucko, usin' t' rocksim tail cone template as a guide. You'll need t' buy t' CD t' get t' detailed procedure, me hearties, or figure out a method that works for you. Arrr! Once t' tail cone is finished, me bucko, glue into t' bottom o' the main BT80 tube.

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  1. Make a straight line down each o' t' BT-20 tubes. I use aluminum angle for this, ya bilge rat, but use whatever works for you.
  2. Use the fin wrapper guide t' make four lines on t' main BT80 tube. Aye aye! Aye aye! Blimey! At t' middle point where t' wrapper edges meet, draw an additional line for t' launch lug.
  3. Tie a piece o' Keelhaul®©™ thread t' each BT20 centerin' ring. Begad! Avast, me proud beauty! Push t' thread thru each tube and make sure t' centerin' can slide in. Avast! Spread some yellow glue 2.5 inches into a tube. Mark an engine spacin' tube, or spent (or not) 18mm Estes motor 1/4 inch from t' end. Ahoy! Then and push the centerin' rin' in, leavin' t' 1/4 inch overhang. Repeat for t' other three tubes. Aye aye!
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  5. Glue t' forward fin t' t' end o' each nacelle tube. Avast! Blimey! Refer t' t' 2D image for placement. Arrr! Avast! Glue t' aft fin t' each nacelle tube, ya bilge rat, makin' sure it is in perfect alignment with t' forward fin. Begad! T' back side o' t' fin should be 1 inch from t' bottom o' t' tube. Refer t' t' 2D image for placement. Ya scallywag! I used Apogee's Epoxy Clay for t' fin fillets. This will add strength. Begad! It's actually Ave's Fixit Compound, arrr, but it's t' same price whichever place you buy it. Begad! Begad!

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  • Drill a 1/16" hole into each 3/4 inch ball on t' side that's inside the coupler. Blimey! Usin' needle nose pliers, twist a tiny screw eye into each hole, and remove. Ahoy! Blimey! Put a drip o' glue o' your choice into each hole and replace screw eye. Begad!

  • Usin' razor saw, arrr, cut t' bottom o' t' nose cone off leavin' 1.25 " of the shoulder left. Begad!
  • Wick some thin CA into each end o' t' BT20 nacelle tubes. Well, blow me down! Blimey! This will help prevent zipperin' on t' forward ends and reduce possible damage on t' rear ends.
  • It is easy t' get t' bottom o' t' fins out o' alignment. Aye aye! A solution I found is t' tape a piece o' t' Keelhaul®©™ thread in line with a fin line, shiver me timbers, near the bottom. Ahoy! Arrr! Pull this over t' t' opposite side and tape there. Begad! Make sure it is straight. Aye aye! Carefully mark on both side o' t' strin' t' just past where the bottom edge o' t' fins will meet. Aye aye! I didn't do this for t' first fin and had to carve it back off when I realized it wasn't straight. Aye aye!
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  • Use yellow glue t' glue each fin t' t' body makin' sure it is as straight as possible. Arrr! This rocket as it's designed has a high probability o' becoming unstable due t' t' increased chance o' asymmetric and off-axis thrust, hence the name 'Crazy Train'. We actually don't want it t' live up t' its name if we can help it. After each fin is dry, matey, smear more yellow glue into t' fin joints. Also, shiver me timbers, when puttin' t' fins on initially, me bucko, once t' glue sets, use tape t' hold it tighter t' t' body tube. Well, shiver me timbers, blow me down! When all fins are dry, use Aves Fixit Compound (epoxy clay) on t' fin root joints (If you have some). Aye aye!
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  • Glue t' 3/16" launch lug, me bucko, with t' forward end at 2 1/4" from the forward end o' t' body tube. Arrr! Blimey! If you're usin' t' recommended 2" lug, the bottom edge should be t' CP location.
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  • Optional mirror mount instructions (for wireless Boostervision camera): If you don’t use a camera, me bucko, at least construct and install t' platform in case you want t' carry a payload. Avast, me proud beauty! Blimey! First, make a platform for t' camera t' sit on. This keeps it level and at a fixed height. Arrr! Blimey! Arrr! Blimey! T' do this I cut a 1/4" piece o' Bt-80 coupler. Begad! Blimey! Begad! Blimey! I made a cardboard bulkhead from a priority mail box. See my article here on how t' do this. Print and cut out another bulk template, matey, me hearties, and mark t' exact center o' t' disk. Arrr! Stick a needle or something else sharp through it, or whatever works. Arrr! Align a straight edge t' t' center and draw a straight line through it. Ya scallywag! Then glue two pieces o' cardboard vertically which will be snug on both sides o' t' camera. This will keep it from movin' left and right. Begad! My straight edge tool happened t' be t' right size to mark off both sides o' t' center line. You'll need t' measure if you don't have something. Begad! Basically you need t' mark two lines parallel t' t' center line that you can align and glue a cardboard piece to. Ahoy! This pic shows it better than I'm describing. Aye aye! Begad!
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  • Make a hole for t' camera eye. Begad! I first made a vertical center line between two fins opposite t' side o' t' launch lug. Aye aye! I then made a horizontal line between t' top o' t' tube and t' point where t' top fins attach (approximate 1 5/8" from t' top o' t' tube). At t' intersection of those lines, arrr, ya bilge rat, I made a hole with a pin. I then used small drill bits, and hand twisted them, me hearties, increasin' t' size o' t' hole. Arrr! I eventually had t' improvise and twist a knife into in. Later I used a wooden dowel with sand paper. Begad! I enlarged it until t' camera head would poke through.
  • I put t' camera in t' mount on t' platform, and pushed it into t' body tube. Aye aye! Blimey! This is tricky, and you'll want t' test this a little before hand, because with t' bottom sealed off it's hard t' pull it back if you go too far. I had t' cut a hole in t' platform t' pull mine back some. Avast! Blimey! Edge it down gradually, arrr, arrr, until t' camera head is in alignment with t' hole, ya bilge rat, and is level on the platform. Arrr! Blimey! Use some yellow glue and glue t' platform in. Ya scallywag! Blimey!
  • I used 3/32" balsa t' make t' mirror housing. Ya scallywag! T' mirror is a 1/2"x1/2" square mirror. I purchased a pack o' several 1/2" and 1" mirrors from t' craft section o' wal-mart for a couple dollars. Arrr! Most of me time on this build was findin' t' right angle. Avast! I printed fins from rocksim and tried several. When I got somethin' close, ya bilge rat, I hand adjusted what I had t' make it right. Avast, me proud beauty! I later redesigned t' shape in rocksim, and provided the template. I also scanned what I made, so I could reprint templates from those if needed. Begad! I used yellow glue t' make t' housing. Avast! I epoxied t' mirror into it. I used 5 min. Blimey! epoxy t' attach t' t' body tube. I applied more 5 min t' all joints. Arrr! Begad! Then I used 30 min epoxy and some 3/4 oz fiberglass cloth t' cover the housin' and reinforce it t' t' tube. Begad! Before you do all this, matey, especially before gluin' anything, make sure you test t' camera and make sure it looks ok.
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  1. Attach t' medium snap swivels t' t' screw eyes. Begad! Ahoy! Tie t' 1/8" shock cord t' t' ends o' t' Keelhaul®©™ thread. Ahoy! Use a small snap swivel on the parachutes and attach t' t' bottom o' t' medium snap swivels. Blimey! I originally used 9" nylon chutes, but they will nay fit into t' tubes. They will, but are extremely tight. T' Mylar chutes fit fine.
  2. Before painting, me hearties, use ¾" fiberglass cloth on t' fin joints. Blimey! I didn’t do this and three o' them popped off t' first flight. Avast, me proud beauty! I glassed them afterwards. Well, blow me down!
  3. For finishin' I used a combination o' spray enamel(main body color), brushed on acrylic (for t' orange balls and light blue bands) and vinyl adhesive (for t' red stripes). Avast, me proud beauty! Avast, me proud beauty!
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Flights:

Flight 1:

I first flew this on 4 A8-3’s. Arrr! One o' t' motors didn’t ignite, and t' launch controller wire remained attached. It went about 7 feet and fell over. Begad! Even on 3 motors it seemed t' have a straight boost. On t' first flight I used 4 9" nylon chutes. Ya scallywag! Aye aye! These chutes were too tight and I think contributed t' t' damage from t' motors tryin' t' eject. Arrr! Two fins broke off durin' motor ejection. Avast! Begad! A third broken upon landing. Avast! I glued these back on, and then fiberglassed them with ¾ oz glass. Blimey! I also changed t' chutes to 9" mylar which fit much better.

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Flight 2:

T' second flight was on 4 B6-4's. Ya scallywag! Blimey! This flight be great, matey, and t' rocket suffered no damage. Aye aye! Blimey! Avast, me proud beauty! Blimey! It did arch over slightly, but seemed mostly stable. Begad! Blimey! Begad! Blimey! One of the nosecone/parachutes came off because t' shockcord burned through. Well, me hearties, blow me down! Blimey! I lauched this right as it be gettin' dark, me hearties, so t' onboard video is nay that great. T' altimeter reported 161 feet.


Taken by Lilith Briner
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Flight 3:

T' third flight be on 4 C6-3s. Arrr! Ya scallywag! This flight was perfect. Ya scallywag! Begad! There was some spin, but overall it flew in a straight trajectory. Before launch I unwittingly removed t' shockcord segments, leavin' just t' kevlar thread. Begad! Ya scallywag! This caused a major zipper on one o' t' tubes. Arrr! Also, on another tube t' motor block, kevlar and chute came out. Well, blow me down! Blimey! I should have used epoxy on those instead o' yellow glue. T' alimeter reported 566 feet.

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Flight one is in extremely slow motion, slowed down t' about 12% speed.

Flight two be done at dusk, me bucko, matey, and looks almost like a night launch.

Flight three:

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