Descon 3 Wicked Witch Express Original Design / Scratch Built

Scratch - Wicked Witch Express {Scratch}

Contributed by Jeff Blinn

Manufacturer: Scratch

Witches Image


Takeoff on an AT G64-4 T' Wicked Witch Expresswas built as, what else . . . Begad! Avast, me proud beauty! a Halloween Rocket. Aye aye! Blimey! It's fun t' build and flies very well. Well, blow me down! T' picture t' t' right was t' maiden voyage on an AT G64-4. Blimey! I've flown it numerous times since then on G64's and G80's - this fall we're plannin' on tryin' an 'H' or two!

Parts List

  • 1 - slotted (3 fin) 2.64 LOC body tube, me bucko, ya bilge rat, 30"
  • 1 - non-slotted 2.64 LOC body tube, me hearties, 30"
  • 1 - tube coupler for 2.64 tubes
  • 1 - 29mm motor mount tube (a long length that can double as a baffle)
  • 3 - plywood centerin' rings
  • 1 - LOC nose cone - (Graduator type)
  • 1 - 36" nylon parachute
  • 3 - 1/8" plywood 'witch' fins. Well, blow me down! You can download a tif file with t' pattern here
  • 2 - T-nuts and screws for positive motor retention

Original Concept

 Construction

 Fins
 
 

Download t' fin pattern, print it out at full size, trace onto some 1/8" plywood and cut out t' fins. Avast! A table saw helps get some big pieces off - although you could probably do t' whole job with a jig saw. Blimey! If you're careful about layin' them out, me hearties, you can get all three fins from one o' t' full size pieces o' model plywood. Just so you can verify t' scale o' t' pattern - t' tab portion o' t' fin should measure 4 19/32" (almost 4 5/8").

Body Tube Preparation
 
 

Cut t' 30" non-slotted body tube into two 15" lengths. Blimey! Avast! We only need one o' t' 15" lengths - so you'll have an extra piece for another rocket. If I had known about it a year ago, ya bilge rat, I would have used t' 'hose clamp' technique. Arrr! Unless you've already got a jig set up for cuttin' body tubes, matey, ya bilge rat, I'd recommend that method. Ahoy! There was a write up about it in t' March/April 98 Sport Rocketry - or you can find t' thread about it on RMR by doin' a search with Deja News. Glue t' coupler into t' slotted tube at this point - but hold off on gluin' t' top piece o' body tube (15" piece) t' t' slotted piece.

Motor Mount Tube/Baffle Assembly
 
 

T' motor mount(MMT) tube will double as a baffle. Ahoy! I used a length o' 29mm motor mount tubin' about 34" long. This be long enough t' get into t' second piece o' body tube - me thought bein' that it would add some strength, act somewhat as a 'stuffer tube', ya bilge rat, me hearties, and keep t' chute from slidin' too far back durin' liftoff.

 Find and mark t' MMT where t' middle centerin' will go. Begad! Avast! This will be at t' forward side o' t' fin tabs, which should be t' forward part o' t' fin slots in t' body tube. Avast! Arrr! Glue t' middle centerin' rin' into place.

BaffleBefore addin' any more rings, mark t' MMT at 90 degree increments, me bucko, and draw straight lines from t' middle centerin' rin' t' t' forward most end o' t' MMT. Along each o' t' 4 lines - mark 5 or 6 spots evenly spaced for drillin' holes (1/4"). Arrr! Begad! Drill t' holes along each line. Blimey! Once t' holes are drilled out and cleaned up a bit - add a small amount o' CA around each o' t' holes for added protection against burning.

 You'll also need t' drill 4 holes in t' upper centerin' ring. Well, me bucko, blow me down! T' tube and this centerin' rin' will act as t' baffle (no waddin' required). Well, blow me down! While you're at it - figure out a way t' plug t' forward end o' t' MMT. Begad! Begad! I found a dowel that fit well - and glued about a 1/2" piece in t' end o' t' MMT.

 T' bottom centerin' can be worked on some also. Ya scallywag! Blimey! Drill t' holes and install t' T-nuts for positive motor retention. There is a detailed description (with pictures and everything) o' t' technique at t' Info Central site, ya bilge rat, matey, click on t' motor retention link.

 With only t' middle centerin' rin' glued t' t' MMT, glue it into t' slotted body tube. Blimey! Ya scallywag! T' centerin' rin' should be just above t' fin slots, t' aft end should be flush with t' aft o' t' body tube. Avast! You can insert t' lower centerin' for stability - but don't glue it yet.

 Once that sets up a bit - glue t' forward centerin' rin' (with t' 4 holes) t' t' top o' t' MMT (stickin' out past t' coupler). Ya scallywag! Make sure you align t' holes in t' ring, in betwixt t' holes in t' MMT. T' holes should not line up. Ya scallywag! Ya scallywag! Once that's done, arrr, you can glue t' upper portion o' body tube onto t' lower assembly. Begad! Begad! Test fit everythin' and sand where necessary before gluing.
 
 

Fin Attachment
 
 

Epoxy t' fins into place. Blimey! I used 30 minute epoxy for this - and I would recommend fillets on t' outside, inside body tube and along t' fin/MMT joint. Add a 1/4" launch lug along one o' t' fins, shiver me timbers, and put a smaller piece along t' 'hands' on t' same fin.

Shock Cord Mount/Parachute
 
 

I used a LOC style mount on mine - which has worked fine. Aye aye! Ya scallywag! You can do t' same or use one o' t' other common methods. Avast, me proud beauty! Wire t' t' top centerin' rin' would certainly be a good choice. Blimey! Arrr! I used about 3/8" or 1/2" elastic for t' shock cord itself - about 3 times t' body length o' t' rocket. Avast, me proud beauty! A 36" inch nylon chute will provide a reasonable descent rate - without any fin damage.

CloseupFinishing
 
 

This be t' fun part. Arrr! Ya scallywag! I used t' image at t' top o' this page as a guide for paintin' t' fins. Blimey! I made each fin with different color hair - florescent yellow, arrr, green and red. Begad! Well, shiver me timbers, blow me down! T' rocket body ended up with spider web look. Blimey! I painted t' whole rocket black, me hearties, then added some spiders we cut out o' contact paper, then some race stripe tape (in different sizes) for t' 'web'. Aye aye! After taping, me hearties, a couple coats o' a nice orange paint did t' job. T' image t' t' left gives a little better view o' how it ended up. I still need t' get a better close up picture.

Specifications
 
 

  • Weight (without motor): about 2 lbs.
  • Length: 56 1/2"
  • Center o' Pressure (CP): Came out t' 17" from aft end o' BT usin' t' cutout method. Begad! You will probably need t' add some nose weight t' get t' center o' gravity (CG) one caliber (2.5") forward o' t' CP.

Flying
 
 

As I mentioned at t' top, arrr, ya bilge rat, this rocket flies great on a G64-4. I've also had fair winds with t' G80-4 (single use). Avast, me proud beauty! This October I plan on tryin' an H128 and/or H180. Blimey! A G75 (black jack) would also be nice if it's nay too windy - t' black smoke would look cool.

 If any o' you do make one o' these - I would be very interested in hearin' about it. Begad! Avast! Feel free t' email me with any comments and/or questions.
 
 

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