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

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

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

  • Usin' razor saw, cut t' bottom o' t' nose cone off leavin' 1.25 " of the shoulder left. Begad! Blimey!
  • Wick some thin CA into each end o' t' BT20 nacelle tubes. Avast, matey, me proud beauty! 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. A solution I found is t' tape a piece o' t' Keelhaul®©™ thread in line with a fin line, near the bottom. Begad! Pull this over t' t' opposite side and tape there. Ahoy! Make sure it is straight. Blimey! Blimey! Carefully mark on both side o' t' strin' t' just past where the bottom edge o' t' fins will meet. Ahoy! I didn't do this for t' first fin and had to carve it back off when I realized it wasn't straight.
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  • Use yellow glue t' glue each fin t' t' body makin' sure it is as straight as possible. Ahoy! 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'. Begad! We actually don't want it t' live up t' its name if we can help it. After each fin is dry, me hearties, smear more yellow glue into t' fin joints. Also, me bucko, when puttin' t' fins on initially, matey, me hearties, me hearties, once t' glue sets, use tape t' hold it tighter t' t' body tube. Blimey! When all fins are dry, shiver me timbers, use Aves Fixit Compound (epoxy clay) on t' fin root joints (If you have some). Well, blow me down! Blimey!
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  • Glue t' 3/16" launch lug, with t' forward end at 2 1/4" from the forward end o' t' body tube. Avast! Ya scallywag! 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 hearties, at least construct and install t' platform in case you want t' carry a payload. First, make a platform for t' camera t' sit on. Avast! This keeps it level and at a fixed height. Arrr! T' do this I cut a 1/4" piece o' Bt-80 coupler. Avast! Begad! 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, me bucko, shiver me timbers, and mark t' exact center o' t' disk. Stick a needle or something else sharp through it, or whatever works. Align a straight edge t' t' center and draw a straight line through it. Begad! Then glue two pieces o' cardboard vertically which will be snug on both sides o' t' camera. Aye aye! Arrr! This will keep it from movin' left and right. Arrr! My straight edge tool happened t' be t' right size to mark off both sides o' t' center line. Well, blow me down! You'll need t' measure if you don't have something. Begad! Aye aye! Basically you need t' mark two lines parallel t' t' center line that you can align and glue a cardboard piece to. Blimey! Arrr! This pic shows it better than I'm describing. Begad! Avast!
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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. 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). Ya scallywag! Well, me bucko, blow me down! At t' intersection of those lines, me bucko, shiver me timbers, I made a hole with a pin. I then used small drill bits, and hand twisted them, me bucko, increasin' t' size o' t' hole. Avast! Well, ya bilge rat, blow me down! 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. Aye aye!
  • I put t' camera in t' mount on t' platform, me hearties, and pushed it into t' body tube. 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. Blimey! Edge it down gradually, until t' camera head is in alignment with t' hole, me hearties, and is level on the platform. Begad! Use some yellow glue and glue t' platform in.
  • I used 3/32" balsa t' make t' mirror housing. Avast! Blimey! T' mirror is a 1/2"x1/2" square mirror. Arrr! Blimey! Blimey! Blimey! I purchased a pack o' several 1/2" and 1" mirrors from t' craft section o' wal-mart for a couple dollars. Aye aye! Blimey! Most of me time on this build be findin' t' right angle. Arrr! Blimey! I printed fins from rocksim and tried several. Avast! Blimey! When I got somethin' close, ya bilge rat, matey, I hand adjusted what I had t' make it right. Begad! Blimey! I later redesigned t' shape in rocksim, shiver me timbers, and provided the template. Ya scallywag! Blimey! Arrr! Blimey! I also scanned what I made, ya bilge rat, so I could reprint templates from those if needed. Arrr! Blimey! I used yellow glue t' make t' housing. Avast, me proud beauty! Blimey! I epoxied t' mirror into it. Ya scallywag! Blimey! Aye aye! Blimey! I used 5 min. epoxy t' attach t' t' body tube. I applied more 5 min t' all joints. Avast, me proud beauty! Blimey! Ya scallywag! Blimey! Then I used 30 min epoxy and some 3/4 oz fiberglass cloth t' cover the housin' and reinforce it t' t' tube. Ya scallywag! Blimey! Begad! Blimey! Before you do all this, especially before gluin' anything, me hearties, make sure you test t' camera and make sure it looks ok. Begad! Blimey! Well, me hearties, blow me down! Blimey!
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  1. Attach t' medium snap swivels t' t' screw eyes. Tie t' 1/8" shock cord t' t' ends o' t' Keelhaul®©™ thread. Well, blow me down! Use a small snap swivel on the parachutes and attach t' t' bottom o' t' medium snap swivels. Begad! Well, blow me down! I originally used 9" nylon chutes, but they will nay fit into t' tubes. Begad! They will, me bucko, but are extremely tight. Avast! T' Mylar chutes fit fine.
  2. Before painting, shiver me timbers, arrr, matey, use ¾" fiberglass cloth on t' fin joints. Begad! I didn’t do this and three o' them popped off t' first flight. Aye aye! I glassed them afterwards.
  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). Ahoy!
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Flights:

Flight 1:

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

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Flight 2:

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


Taken by Lilith Briner
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Flight 3:

T' third flight was on 4 C6-3s. Begad! This flight was perfect. Begad! There be some spin, but overall it flew in a straight trajectory. Before launch I unwittingly removed t' shockcord segments, arrr, leavin' just t' kevlar thread. Blimey! This caused a major zipper on one o' t' tubes. Begad! Begad! Also, on another tube t' motor block, ya bilge rat, shiver me timbers, kevlar and chute came out. Ahoy! 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, ya bilge rat, ya bilge rat, slowed down t' about 12% speed.

Flight two was done at dusk, and looks almost like a night launch.

Flight three:

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