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

1
Click for Larger Pic

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

3 4 5
<--- Click on Any t' Enlarge --->

  1. Make a straight line down each o' t' BT-20 tubes. I use aluminum angle for this, but use whatever works for you. Begad! Begad! Blimey!
  2. Use the fin wrapper guide t' make four lines on t' main BT80 tube. Arrr! At t' middle point where t' wrapper edges meet, draw an additional line for t' launch lug. Begad!
  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. Spread some yellow glue 2.5 inches into a tube. Well, me hearties, blow me down! Mark an engine spacin' tube, shiver me timbers, or spent (or not) 18mm Estes motor 1/4 inch from t' end. Arrr! Then and push the centerin' rin' in, leavin' t' 1/4 inch overhang. Repeat for t' other three tubes.
  4. 6
    Click for Larger Pic
  5. Glue t' forward fin t' t' end o' each nacelle tube. Refer t' t' 2D image for placement. Aye aye! Glue t' aft fin t' each nacelle tube, ya bilge rat, makin' sure it is in perfect alignment with t' forward fin. Ahoy! T' back side o' t' fin should be 1 inch from t' bottom o' t' tube. Ahoy! Refer t' t' 2D image for placement. I used Apogee's Epoxy Clay for t' fin fillets. Avast! This will add strength. Well, blow me down! Avast! It's actually Ave's Fixit Compound, but it's t' same price whichever place you buy it. Well, ya bilge rat, blow me down!

7
Click for Larger Pic
  • Drill a 1/16" hole into each 3/4 inch ball on t' side that's inside the coupler. Ya scallywag! Usin' needle nose pliers, arrr, me hearties, twist a tiny screw eye into each hole, and remove. Blimey! Put a drip o' glue o' your choice into each hole and replace screw eye. Ya scallywag! Begad!

  • Usin' razor saw, shiver me timbers, cut t' bottom o' t' nose cone off leavin' 1.25 " of the shoulder left. Ya scallywag!
  • Wick some thin CA into each end o' t' BT20 nacelle tubes. 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. Begad! A solution I found is t' tape a piece o' t' Keelhaul®©™ thread in line with a fin line, near the bottom. Aye aye! Pull this over t' t' opposite side and tape there. Blimey! Make sure it is straight. 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.
8
Click for Larger Pic
9
Click for Larger Pic
  • Use yellow glue t' glue each fin t' t' body makin' sure it is as straight as possible. This rocket as it's designed has a high probability o' becoming unstable due t' t' increased chance o' asymmetric and off-axis thrust, arrr, hence the name 'Crazy Train'. Well, blow me down! Ahoy! We actually don't want it t' live up t' its name if we can help it. After each fin is dry, smear more yellow glue into t' fin joints. Also, shiver me timbers, when puttin' t' fins on initially, arrr, once t' glue sets, ya bilge rat, use tape t' hold it tighter t' t' body tube. Avast, me proud beauty! When all fins are dry, matey, matey, use Aves Fixit Compound (epoxy clay) on t' fin root joints (If you have some). Blimey!
10
Click for Larger Pic
11
Click for Larger Pic
12
Click for Larger Pic

  • Glue t' 3/16" launch lug, with t' forward end at 2 1/4" from the forward end o' t' body tube. If you're usin' t' recommended 2" lug, the bottom edge should be t' CP location.
13
Click for Larger Pic
  • 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, me hearties, make a platform for t' camera t' sit on. Ya scallywag! Blimey! This keeps it level and at a fixed height. Arrr! Blimey! T' do this I cut a 1/4" piece o' Bt-80 coupler. 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 bucko, and mark t' exact center o' t' disk. Blimey! Stick a needle or something else sharp through it, me bucko, or whatever works. Ahoy! 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. Arrr! This will keep it from movin' left and right. Well, blow me down! Begad! Blimey! My straight edge tool happened t' be t' right size to mark off both sides o' t' center line. Well, ya bilge rat, blow me down! Blimey! You'll need t' measure if you don't have something. Basically you need t' mark two lines parallel t' t' center line that you can align and glue a cardboard piece to. Avast! This pic shows it better than I'm describing.
14
Click for Larger Pic
  • Make a hole for t' camera eye. Blimey! 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). Ahoy! At t' intersection of those lines, I made a hole with a pin. Aye aye! Arrr! I then used small drill bits, ya bilge rat, and hand twisted them, increasin' t' size o' t' hole. Arrr! Avast, arrr, me proud beauty! I eventually had t' improvise and twist a knife into in. Well, blow me down! Ya scallywag! Later I used a wooden dowel with sand paper. Begad! I enlarged it until t' camera head would poke through. Avast!
  • I put t' camera in t' mount on t' platform, and pushed it into t' body tube. Ya scallywag! This is tricky, me bucko, 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. Edge it down gradually, until t' camera head is in alignment with t' hole, me bucko, matey, and is level on the platform. Well, blow me down! Use some yellow glue and glue t' platform in. Arrr!
  • I used 3/32" balsa t' make t' mirror housing. Ya scallywag! Arrr! T' mirror is a 1/2"x1/2" square mirror. Begad! I purchased a pack o' several 1/2" and 1" mirrors from t' craft section o' wal-mart for a couple dollars. Blimey! Most of me time on this build be findin' t' right angle. I printed fins from rocksim and tried several. Begad! When I got somethin' close, me bucko, I hand adjusted what I had t' make it right. Ahoy! Arrr! I later redesigned t' shape in rocksim, and provided the template. Avast! I also scanned what I made, so I could reprint templates from those if needed. I used yellow glue t' make t' housing. I epoxied t' mirror into it. Avast! I used 5 min. Blimey! epoxy t' attach t' t' body tube. Ya scallywag! 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. Before you do all this, arrr, especially before gluin' anything, ya bilge rat, make sure you test t' camera and make sure it looks ok.
15
Click for Larger Pic
16
Click for Larger Pic
17
Click for Larger Pic
18
Click for Larger Pic
19
Click for Larger Pic
  1. Attach t' medium snap swivels t' t' screw eyes. Avast, me proud beauty! Blimey! Tie t' 1/8" shock cord t' t' ends o' t' Keelhaul®©™ thread. Avast, me proud beauty! Blimey! Use a small snap swivel on the parachutes and attach t' t' bottom o' t' medium snap swivels. Aye aye! Blimey! Avast, me proud beauty! Blimey! I originally used 9" nylon chutes, arrr, shiver me timbers, but they will nay fit into t' tubes. Arrr! Blimey! They will, ya bilge rat, but are extremely tight. Avast, me proud beauty! Blimey! Well, ya bilge rat, blow me down! Blimey! T' Mylar chutes fit fine.
  2. Before painting, use ¾" fiberglass cloth on t' fin joints. Begad! I didn’t do this and three o' them popped off t' first flight. Well, blow me down! 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). Aye aye! Blimey!
20
Click for Larger Pic
20
Click for Larger Pic

Flights:

Flight 1:

I first flew this on 4 A8-3’s. Well, blow me down! One o' t' motors didn’t ignite, and t' launch controller wire remained attached. Ya scallywag! It went about 7 feet and fell over. Avast, me proud beauty! Begad! Even on 3 motors it seemed t' have a straight boost. On t' first flight I used 4 9" nylon chutes. 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. Aye aye! Begad! A third broken upon landing. Avast, me proud beauty! I glued these back on, matey, and then fiberglassed them with ¾ oz glass. Blimey! I also changed t' chutes to 9" mylar which fit much better.

22
Click for Larger Pic
23
Click for Larger Pic
24
Click for Larger Pic

Flight 2:

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


Taken by Lilith Briner
Click for Larger Pic (Picture taken by Lilith Briner)

Flight 3:

T' third flight was on 4 C6-3s. This flight was perfect. Arrr! 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. Ahoy! Arrr! This caused a major zipper on one o' t' tubes. Arrr! Also, matey, me hearties, on another tube t' motor block, kevlar and chute came out. Begad! I should have used epoxy on those instead o' yellow glue. T' alimeter reported 566 feet.

25
Click for Larger Pic
26
Click for Larger Pic
27
Click for Larger Pic
28
Click for Larger Pic

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

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

Flight three:

comment Post a Comment