Scratch - Crazy Train {Scratch}

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

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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

Cut t' tubes t' lengths needed.
Prefinish tubes with 2 sessions o' fill n' finish and sanding.
I get good results usin' bondo putty spreaders. Arrr! Begad! Blimey! You can cut them t' 1/2 wide strips and smear t' fill n' finish directly into t' spirals. Avast!
Cut t' fins. Use t' provided templates as guides. T' grain on the forward fins should follow t' leadin' edge. Ahoy! 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. Aye aye! Next, soak t' fins in CA glue. First have adequate ventilation, me hearties, wear gloves, me hearties, ya bilge rat, and maybe use a respirator if you have one. Well, blow me down! Place 2 sheets o' wax paper onto a flat glass surface. 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. Turn t' balsa over and repeat. Ya scallywag! Place two more sheets o' wax paper on top. Avast, me proud beauty! Blimey! Place another sheet o' glass on top o' t' wax paper. Set somethin' heavy, me hearties, such as a stack o' books on top o' that, and let dry for 24 hours. This adds hardness and strength t' t' balsa. Ya scallywag! Well, blow me down!
Prefinish fins with 2 sessions o' fill n' finish and sanding.
Glue t' 3/4 inch balls into t' Bt-20 tube couplers. Blimey! Blimey! I used a combination of epoxy, superglue, matey, and yellow glue, arrr, me hearties, but whatever works. Avast! Blimey!

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Glue t' two 1/4 inch sheets o' balsa together with yellow glue. Avast! Clamp or press together with somethin' heavy. Begad! Aye aye! When dry, matey, glue t' 1/2 inch BT80 coupler to t' stack. Ya scallywag! 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, me bucko, arrr, shiver me timbers, 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. Once t' tail cone is finished, glue into t' bottom o' the main BT80 tube. Begad!

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

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

Usin' razor saw, cut t' bottom o' t' nose cone off leavin' 1.25 " of the shoulder left. Arrr!
Wick some thin CA into each end o' t' BT20 nacelle tubes. Well, blow me down! 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. Begad! Begad! A solution I found is t' tape a piece o' t' Keelhaul®©™ thread in line with a fin line, shiver me timbers, arrr, near the bottom. Avast, me proud beauty! Well, me bucko, blow me down! Pull this over t' t' opposite side and tape there. Avast! Aye aye! Make sure it is straight. Ya scallywag! Carefully mark on both side o' t' strin' t' just past where the bottom edge o' t' fins will meet. Begad! I didn't do this for t' first fin and had to carve it back off when I realized it wasn't straight. Well, blow me down!

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Use yellow glue t' glue each fin t' t' body makin' sure it is as straight as possible. Avast, me proud beauty! Well, blow me down! 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. Blimey! After each fin is dry, smear more yellow glue into t' fin joints. Also, when puttin' t' fins on initially, once t' glue sets, me hearties, use tape t' hold it tighter t' t' body tube. Well, me bucko, blow me down! When all fins are dry, use Aves Fixit Compound (epoxy clay) on t' fin root joints (If you have some). Arrr!

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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. Ya scallywag! 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, at least construct and install t' platform in case you want t' carry a payload. Ahoy! First, shiver me timbers, make a platform for t' camera t' sit on. Arrr! Avast, me proud beauty! This keeps it level and at a fixed height. T' do this I cut a 1/4" piece o' Bt-80 coupler. Begad! 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, and mark t' exact center o' t' disk. Stick a needle or something else sharp through it, or whatever works. Avast, me proud beauty! Arrr! Blimey! Align a straight edge t' t' center and draw a straight line through it. Then glue two pieces o' cardboard vertically which will be snug on both sides o' t' camera. Ahoy! This will keep it from movin' left and right. Avast, me proud beauty! Blimey! My straight edge tool happened t' be t' right size to mark off both sides o' t' center line. Ya scallywag! Begad! Blimey! You'll need t' measure if you don't have something. Aye aye! Blimey! Basically you need t' mark two lines parallel t' t' center line that you can align and glue a cardboard piece to. Arrr! This pic shows it better than I'm describing. Blimey! Avast, me proud beauty! Blimey!

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Make a hole for t' camera eye. Begad! Arrr! 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). Avast! At t' intersection of those lines, I made a hole with a pin. Well, blow me down! Ahoy! I then used small drill bits, ya bilge rat, and hand twisted them, increasin' t' size o' t' hole. Aye aye! Begad! I eventually had t' improvise and twist a knife into in. Avast, me proud beauty! Later I used a wooden dowel with sand paper. Ahoy! I enlarged it until t' camera head would poke through. Ahoy!

I put t' camera in t' mount on t' platform, matey, and pushed it into t' body tube. Avast! Blimey! This is tricky, me hearties, 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. Well, blow me down! Blimey! Begad! Blimey! Edge it down gradually, until t' camera head is in alignment with t' hole, and is level on the platform. Avast, me proud beauty! Blimey! Use some yellow glue and glue t' platform in.
I used 3/32" balsa t' make t' mirror housing. Ya scallywag! T' mirror is a 1/2"x1/2" square mirror. Aye aye! Aye aye! I purchased a pack o' several 1/2" and 1" mirrors from t' craft section o' wal-mart for a couple dollars. Avast! Ya scallywag! Most of me time on this build was findin' t' right angle. Well, blow me down! Aye aye! I printed fins from rocksim and tried several. Ya scallywag! Ya scallywag! When I got somethin' close, matey, me bucko, I hand adjusted what I had t' make it right. Arrr! Avast! I later redesigned t' shape in rocksim, matey, and provided the template. Blimey! I also scanned what I made, so I could reprint templates from those if needed. Begad! I used yellow glue t' make t' housing. Begad! Avast, me bucko, me proud beauty! I epoxied t' mirror into it. I used 5 min. Arrr! Aye aye! epoxy t' attach t' t' body tube. I applied more 5 min t' all joints. Then I used 30 min epoxy and some 3/4 oz fiberglass cloth t' cover the housin' and reinforce it t' t' tube. Well, blow me down! Before you do all this, especially before gluin' anything, make sure you test t' camera and make sure it looks ok. Begad! Begad!

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Attach t' medium snap swivels t' t' screw eyes. Avast, me proud beauty! Tie t' 1/8" shock cord t' t' ends o' t' Keelhaul®©™ thread. Use a small snap swivel on the parachutes and attach t' t' bottom o' t' medium snap swivels. Ya scallywag! Ahoy! I originally used 9" nylon chutes, but they will nay fit into t' tubes. Blimey! Begad! They will, but are extremely tight. Well, blow me down! Ya scallywag! T' Mylar chutes fit fine. Arrr! Aye aye!
Before painting, use ¾" fiberglass cloth on t' fin joints. Ya scallywag! I didn’t do this and three o' them popped off t' first flight. Begad! I glassed them afterwards. Avast!
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). Aye aye!

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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. It went about 7 feet and fell over. Arrr! Arrr! Even on 3 motors it seemed t' have a straight boost. Begad! On t' first flight I used 4 9" nylon chutes. Well, blow me down! Arrr! These chutes were too tight and I think contributed t' t' damage from t' motors tryin' t' eject. Two fins broke off durin' motor ejection. A third broken upon landing. Arrr! I glued these back on, ya bilge rat, ya bilge rat, and then fiberglassed them with ¾ oz glass. Begad! 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. Aye aye! This flight was great, and t' rocket suffered no damage. Begad! Begad! It did arch over slightly, me bucko, but seemed mostly stable. Avast! One of the nosecone/parachutes came off because t' shockcord burned through. Avast! I lauched this right as it was gettin' dark, shiver me timbers, so t' onboard video is nay that great. Well, blow me down! T' altimeter reported 161 feet.

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Flight 3:

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