Scratch Shockwave (BRS Contest) Original Design / Scratch Built

Scratch - Shockwave (BRS Contest) {Scratch}

Contributed by Jon Revelle

Manufacturer: Scratch
(Contributed - by Jon Revelle - 10/17/04) (Scratch) Shockwave

Brief:
I made Shockwave out o' some spare parts I had layin' around. Arrr! Ya scallywag! It is named after my favorite roller coaster that be just torn down and features a long payload tube, matey, me bucko, multiple fins, arrr, me bucko, and side-pods.

Construction:
To make this rocket you need:

  • BT-50 (12" long) body tubes, nose cone, matey, and tail cones from an Estes SR-71 kit
  • 3 BT-50 body tubes, one 32cm (12") and two 16.5cm (6.4"). Blimey!
  • 1 BT-55 body tube 23cm (9") long
  • 1 BT-50 t' BT-55 transition 3cm (1.1") long
  • Shock cord
  • 18" Parachute
  • 3/16" x 3.5" Launch lug (placed 19cm (17.4") from bottom of BT55)
  • Body tube, fins, and tail cone from an Estes Bull Pup 12D kit
  • Fin Template (CLICK HERE)
  • 1 - Estes PNC-50YR Nose Cone (like Orbital Transport or Echostar)
  • 1 D engine motor mount (extended by 1/4" out o' t' central BT-55)
(Scratch) Shockwave

I started by buildin' t' upper half o' Shockwave with t' long SR-71 body tube, shiver me timbers, Bullpup canard fins and tail cone, and Echostar/OT nose cone. T' tail cone was left unmodified and uncut. T' narrow end o' t' tail cone was inserted into the long BT-50 body tube and glued with plastic cement. Begad! Blimey! Next, I attached t' four Bullpup canard fins 3cm from t' top o' t' body tube. Everythin' be set aside to dry before attachin' t' shock cord and 18" chute.

T' lower half began by attachin' t' Bullpup fins at t' bottom o' the rocket. Well, blow me down! Ya scallywag! Next, shiver me timbers, followin' t' SR-71 kit's instructions, me bucko, I assembled t' jet engine sections. Ya scallywag! Once dry, matey, I attached t' jet engine assembly t' t' Bullpup body tube in betwixt 2 fins. At this point I pause again t' let everythin' have a chance t' dry.

T' last part o' t' build was t' assemble t' D motor mount so it will fit in t' body tube. Ahoy! Motor retention is with t' engine hook. T' shock cord is glued into place by t' standard 3-fold paper mount in t' body tube.

(Scratch) Shockwave

Finishing:

I started by spray paintin' t' entire rocket t' shiniest chrome paint I could find. Arrr! Then I sprayed half o' t' payload tube and nose cone midnight blue and then silver without maskin' t' rocket off t' create a fade effect that makes it look like it's moving, me bucko, even when it's on t' ground. Ahoy! Blimey! One o' t' last things I did was buy some decal paper from Tango Papa and printed t' decal shown. Blimey! Ya scallywag! This was put on t' area where thar be light blue. I finished it by clear coatin' t' rocket t' protect t' decal.

Flight:
I haven't had t' chance t' fly it yet. Blimey! But me prediction is that since it uses D12s, matey, it should go very high, very smartly and that it might drift a bit on the way down.

Recommended engines are D12-5, D12-7, arrr, me hearties, and E9-6 (if you choose t' modify with an E motor mount).

Summary:
PROs: Exotic lookin' and impressive on and off t' pad.

CONS: Nay really any.


(Contributed - by Jon Revelle - 03/12/06)

Brief:
Updated version o' me entry for t' BRS Design Contest. Arrr! Ya scallywag! Features new fin design and new paint job.

Construction:
Shockwave's design be revised after its first flight. Begad! Avast, me hearties, me proud beauty! T' Bullpup fins were not large enough t' provide stable flights (as it lost control on first flight with Bullpup fins). Ya scallywag! Begad! T' fins were changed t' Echostar fins, me hearties, matey, which provide a MUCH more stable flight. Avast!

Changin' t' fins be easy. Begad! Ahoy! All that was needed t' be done was remove the old fins, shiver me timbers, sand down t' leftovers and CA t' new fins on. Well, blow me down! Ahoy! Then paint.

Finishing:
Shockwave be 75% repainted after t' rehab. Avast, me proud beauty! T' new fins were painted silver to match t' lower body tube section. Ahoy! T' upper half (former payload tube) was changed from Navy Blue and True Blue (I call it Shockwave Blue) t' only true blue. Ya scallywag! Ahoy! It still has t' fade effect and t' ride's logo in t' same spot.

Rebuildin' this rocket was t' best decision for this rocket as it now looks better and flies better.

LaunchFlight:
T' "new" Shockwave flew in April o' 2005 at a NIRA club launch. Avast, me proud beauty! The rocket used about 5 sheets o' waddin' and it apparently wasnt enough. Begad! It flew very straight and high on a C11-3, me bucko, but then t' shock cord snapped at ejection. T' booster fell t' t' ground but t' only damage suffered were two fins popped off. Arrr! Arrr! T' top part (which is no longer used for payloading) drifted down on an 18" parachute.

I now use about 7 sheets o' waddin' in this rocket.

Summary:
These modifications greatly improved Shockwave's performance and looks and now it is MUCH safer t' fly. Begad! Begad! I have a D12-5 ready t' be used in it and then I will try it on an E9-6.

Other:
ALWAYS Use long shock cords. Short ones snap WAY too easy.

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