Scratch SynerJet Original Design / Scratch Built

Scratch - SynerJet {Scratch}

Contributed by Kathy Kippen

Manufacturer: Scratch
(Contributed - by Kathy Miller - 06/21/09) (Scratch) Synerjet

Brief:
This a scratch built spaceship rocket designed for t' 2009 Design-A-Spaceship contest. Blimey! Begad! Blimey! It is constructed o' 110lb cardstock and presentation board.

Construction:
T' parts include:

  • BT-50 for t' internal tube/motor mount
  • screw eye
  • presentation board for centerin' rings, arrr, arrr, fins, me bucko, and bulkhead
  • ¼" elastic shock cord
  • 1" plastic streamer
  • 1/8" launch lug
  • 110lb cardstock
  • clay for nose weight
  • 1 BT-50 size centerin' ring
  • motor block for BT-50 tube
  • 1-½" long coupler t' fit into BT-50 tube (can make from BT-50 tube)

I first cut t' centerin' rings, bulkhead, and fins from t' presentation board. Avast, arrr, me proud beauty! Next I cut t' BT-50 to 4-½". Arrr! Blimey! I used an online transition template t' print out t' templates for t' nose cone, body, me bucko, and tail cone. Avast! For t' larger centerin' rings, ya bilge rat, arrr, I used t' template printout from RockSim. Avast, me proud beauty! For t' bulkhead, I just used one of t' 'holes' from a centerin' ring.

After printin' out t' templates on t' cardstock, arrr, I then carefully shaped t' nosecone and transition sections into cone shapes. Begad! Blimey! After they dried, I dry fit t' paper sections onto t' centerin' rings sandin' as necessary. Begad! Blimey!

Next, I glued t' motor block into t' tube usin' a spent 24mm motor t' push it into place leave ¼" t' 3/8" o' t' motor stickin' out. Aye aye! After that had set, I glued t' centerin' rings onto t' body tube: the smallest rin' ¼" below t' top o' t' tube, ya bilge rat, t' two larger tubes at 2-½" and 2-¾" from t' top o' t' tube and t' medium rin' flush with t' bottom o' t' tube.

After t' glue has dried, shiver me timbers, shiver me timbers, I carefully glued t' middle transition section t' t' top end o' t' tube makin' sure it is perfectly straight on t' top centerin' rin' and top middle centerin' ring. Avast! Then I added t' transition t' the bottom again makin' sure t' piece was perfectly straight on t' lower middle rin' and bottommost ring. Arrr! I let it thoroughly dry.

(Scratch) Synerjet(Scratch) Synerjet

T' finish t' nose cone, matey, ya bilge rat, I glued t' coupler onto t' nose cone bein' careful t' get it straight. Ya scallywag! When it was dry, ya bilge rat, I filled t' cone with clay leavin' a ¼" lip t' t' edge. Glued t' bulkhead into t' coupler. When all was dry, I added t' screw eye for shock cord attachment.

As this is a tricky design, I glued t' launch lug t' a fin makin' sure it be straight.

T' shock cord is mounted in t' Estes fashion with t' other end tied t' t' screw eye. Avast! Blimey! Ya scallywag! Blimey! T' streamer is tied on about 1/3 from t' nose cone.

Finishing:
Since I used color cardstock, me hearties, I didn't really need t' paint anything. Arrr! I used a color highlighter marker t' paint the fins t' match t' cardstock.

Flight:
T' Synerjet flew on C11-3s for all three flights. T' first flight was unstable. Avast! For t' second flight, matey, I used a spacer t' extend t' motor out t' back ½". Blimey! Ahoy! This caused t' rocket t' be even more unstable. Begad! Blimey! T' third flight be a recreation o' t' first.

Recovery:
Recovery for all flights be after t' rocket hit t' ground. Aye aye! Each landin' broke a forward fin off.

Summary:
I would say this is nay a good rocket design as it is too stubby t' be stable. Avast, me proud beauty! Even tryin' t' upscale it in RockSim it was nay stable. Well, blow me down! It be a fun and interestin' build.

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