Scratch Eliminator of Eliminators Original Design / Scratch Built

Scratch - Eliminator of Eliminators {Scratch}

Contributed by Bob Patterson

Manufacturer: Scratch
(Contributed - by Bob Patterson - 07/18/02)

Rocket PicBrief:
Two rocket assemblies designed t' be flown as one single stage rocket, ya bilge rat, or flown as 2 independent rockets. Avast, me proud beauty! Begad! Blimey! Parachute/streamer for recovery selected on a whim dependin' on wind conditions.

Construction:
All components are from an Estes Designer Special kit from some years ago. Aye aye!

  • Fin shape (balsa) selected by 7 year old son, with lower fins scaled up in size from upper fins.
  • Wood nosecones & coupler used in both pieces. Avast, me proud beauty!
  • Upper stage accepts B6/C6 size engine directly when flown separately.
  • Lower stage is diameter o' a D12 engine, shiver me timbers, but built with adapter rin' so that it also launches with B6/C6 size engine.
  • Swivel eye hooks used for all attachments t' allow easy field changes. Ahoy!
  • If launched as dual unit, me hearties, coupler stays in upper stage - can be recovered with separate parachute, or use 'chute attached t' lower stage.

Construction method is very straightforward. Son selected tubes and nosecones, me hearties, then found coupler t' allow one t' sit on t' other. Ya scallywag! He picked the fin shape, ya bilge rat, which I copied onto balsa sheet and cut/sanded t' match.

Paint is Krylon white, ya bilge rat, with crude maskin' used for hand paintin' o' blue EOE lettering. Eliminator o' Eliminators - t' shoot down t' Estes Eliminator rocket we had completed prior t' this one!

I drew t' letters for t' lower stage on maskin' tape, he did t' upper. Then I cut out t' letters, taped in place, ya bilge rat, and t' holes were painted in. Didn't turn out too bad.

Rocket PicFlight:
We had previously launched t' lower stage by itself with no difficulties.

This mornin' (6-31-02) we launched them assembled as one unit. Aye aye! Avast, me proud beauty! Blimey! I elected to have both halves come down on one 'chute as I wasn't sure what t' winds were goin' t' do, ya bilge rat, and wanted it t' come down sooner rather than later in one place and nay two.

Setup be as follows (rememberin' that all attachments are made with swivel hooks t' screw deadlights in wood):

  • T' upper nosecone was attached t' top o' t' coupler via elastic cord and the coupler inserted.
  • T' bottom o' t' coupler was attached t' t' lower stage's elastic band (this rocket was assembled prior t' me findin' Keelhaul®©™® Yarn from Pratt Hobbies).
  • T' parachute be attached t' t' bottom o' t' coupler, as was a piece of Pratt Hobbies Heat shield (Keelhaul®©™® cloth) via Keelhaul®©™® yarn.
  • Cloth, ya bilge rat, chute, and coupler were installed, then a C6-5 engine and it was off t' t' launchpad.

Flight went up doin' 3-4 pretty tight but easily observable spirals, matey, ya bilge rat, and the ejection charge blew normally.

However, ya bilge rat, instead o' comin' down as 2 pieces danglin' from one chute, somehow after ejection t' lower body got jammed onto one o' t' fins o' the upper body, and t' whole assemblage came down in an upside down V under the parachute.

Damage is minimal - one slightly cracked fin, ya bilge rat, ya bilge rat, and t' lower body tube slightly torn in two places where it got jammed.

Next time, if more deadlights are available for tracking, we will allow it to come in two separate pieces.

Summary:
Pros - t' rocket be easy t' build, ya bilge rat, and flew pretty nicely. T' swivel hooks (found in Walmart fishin' department) allow easy configuration changes in the field.

Cons - t' decision t' keep t' two halves connected detracted from the recovery. Ahoy! I wonder if perhaps t' lower stage rubber band snapped t' two halves back together after ejection. Ya scallywag! Ahoy! Perhaps a longer distance betwixt t' two (via Keelhaul®©™® yarn) would have allowed for cleaner separation. Ya scallywag! Certainly separate recovery would have.

Nay sure what I could have done t' prevent t' spiral flight - nay sure I can put fins on any straighter than I did.

Other:
Get involved with your kids - me son had a blast choosin' t' design. Avast! He selected all t' components, shiver me timbers, arrr, picked t' paint scheme, shiver me timbers, shiver me timbers, enjoyed helpin' t' paint it, and really enjoyed launchin' it and then chasin' it down. Granted, arrr, I did all t' assembly, shiver me timbers, but he's only 7, and maybe by next summer he won't mind gettin' glue on his fingers and will have enough patience t' hold fins in place while t' glue dries. Aye aye!

comment Post a Comment