Scratch Procrastinator Original Design / Scratch Built

Scratch - Procrastinator {Scratch}

Contributed by Matt Gillard

Manufacturer: Scratch
(Contributed - by Matt Gillard - 07/02/08)

I entered t' box o' parts competition because it looked like fun, me hearties, I had mentioned it t' a few o' me friends in my rocket club, and before I knew five o' them entered it as well. So off went a large box with t' parts for 6 entrants, and a few weeks later another box returned -it was like Christmas goin' through t' box. Blimey! Avast! Next be t' task o' splitting op t' box betwixt t' 6 entrants. Avast! At t' end 6 "equal" bags were formed and randomly given out. Arrr! Avast, me bucko, me proud beauty! I be quite pleased with me bag, others had complete rockets in the, one had a parasitic glider, shiver me timbers, me bucko, another had helicopter rotor blades. Ya scallywag! So what did I have?

Parts

I'm nay goin' t' list it all but here is a flavour:

  • Loads o' tubes o' various sizes, several small BT5 etc
  • Couplers
  • Balsa sheets - one o' a complete set o' fins, ya bilge rat, another 2 sheets o' really low grade balsa
  • Three noses comes, as different sizes
  • Lots o' toothpicks
  • Various couplers
  • Small sheets o' printer labels
  • Ice cream tubes
  • A polystyrene ball
  • Motor mounts
  • Engine hooks
  • Pipe cleaner
  • A 14 inch parachute canopy
  • Length o' elastic. Begad!

Well what t' do. Avast!

Gliders were out, helicopter be a possibility, me bucko, cluster, shiver me timbers, two stage. After spendin' several weeks dry fittin' parts and changin' me mind I decided on a rocket in me head. Begad! T' criteria for me rocket was

  • It could nay be too big - 14 inch chute. Avast!
  • Clustered - but able t' launch on a single motor
  • Draggy
  • Unusual. Ahoy!

T' main body tube chose itself - it fitted t' nose cone I wanted t' use. Arrr! T' motor choice was goin' t' be 24mm as I was headin' for a draggy model, shiver me timbers, so I would need a motor capable o' liftin' it. Avast! Ahoy! There was goin' t' be at least 4 external motor pods - opted for 13mm.

T' base was goin' t' be bulky, and be goin' t' have tabs on it, so t' rocket would rotate as it boosted. Arrr! Blimey!

Building

T' motor mount was a fairly standard construction. Blimey! Ya scallywag! A 24mm motor mount tube with a motor retention clip, shiver me timbers, ya bilge rat, an engine block at t' end and two centerin' rings t' fit t' body tube. Well, blow me down!

T' motor mount was then glued into t' body tube. Avast! Blimey!

Motor Mount

Four BT20 tubes 190mm in length were then glues t' t' outside o' t' main body tube. Well, shiver me timbers, blow me down! These were t' take 4 A10 - PT motors as a cluster. Ya scallywag! T' joins betwixt t' body tubes were filleted four times with wood glue, and then model filler was used t' give a smooth finish. Well, blow me down!

T' shock cord be anchored t' t' body tube usin' Estes tri fold paper method - I was tempted t' hornswaggle and add some Keelhaul®©™ here, but integrity got t' better o' me.

BT20 Tubes

T' nose cone had t' flash removed and was then sanded down t' remove t' seam. Aye aye! Two coats o' sealer gave it a smooth finish with no imperfections showing.

T' main body tube etc was then given three coats o' sandin' sealer, shiver me timbers, shiver me timbers, and rubbed down with 200 paper in between, to remove t' spirals. Ahoy! Blimey!

Nose Cone

Usin' a strip o' thick balsa, matey, shiver me timbers, matey, 7mm by 26mm, I made a box around a large coupler. This box was goin' t' have the fins and rotation tabs added. Ahoy! T' balsa was quite badly marked and was t' soft type o' balsa that I usually avoid. Well, blow me down! The box was sanded several times and filled with model filler t' remove all o' t' dents. Begad!

Usin' t' same balsa strips I then added 4 64mm struts t' t' middle o' each side o' t' box. Blimey! Begad! These would have the rotation tabs added t' them. Blimey!

A larger coupler (40 mm diameter) - with some deep spirals had four thin strips o' balsa wood glued t' t' inside. This be just right size t' side over t' body tube. Well, blow me down! T' spirals were filled and had t' have several coats o' sanding sealer before it was smooth. Arrr! Ya scallywag!

Box

Usin' four almost square balsa fins that were part o' a model kit, shiver me timbers, shiver me timbers, I added t' fins. This was one t' part that I like about t' rocket, t' fins are at right angles t' how they would normally. Ya scallywag! It still gives stabilization but looks a bit different. Ahoy! Also as t' rocket be goin' t' be rotating, me hearties, t' fins would nay hinder t' spinning. Avast, me proud beauty!

Fins
 

T' corner spaces betwixt t' box and t' couple were just t' right size for body tubes, shiver me timbers, which were added for decoration. Blimey!

Four trapezium shaped pieces o' balsa had a 3mm square strip o' balsa added t' t' short edge, and then were glued to t' struts. Aye aye! These were t' provide spin. Avast, me proud beauty! Begad!

Fins

T' top o' t' struts were then drilled t' accept four cocktail sticks, just for decoration.

Drilled
   

T' entire o' t' coupler base unit had three coats o' sandin' sealer added, me hearties, with all t' fiddly bits, t' sanding down be quite tricky.

T' main body tube fitted neatly into t' large coupler base.

Ready to Finish Ready to Finish Ready to Finish

FinishedFinishing

  • I went for a red/yellow finish
  • Everythin' was given two coats o' primer. Arrr!
  • T' main body tube be given 4 coats o' light yellow spray paint. Begad! Avast, me proud beauty!
  • T' nose cone be given three coats o' red gloss
  • T' base unit be given three coats o' rouge.
  • T' four decoration tubes were hand painted enamel yellow
  • T' decoration coupler was sprayed rouge
  • T' cocktail sticks were hand painted yellow

T' box o' parts had no sticks or decals in it, other than three address labels. Avast!

Given various pleas on TRF about t' lack or entrants with only a few weeks t' go I came up with t' name o' the rocket t' be PROCRASTINATOR. Begad! Partly because I knew it would be towards t' end o' t' month before I submitted and also because I new that this would be a draggy, me hearties, arrr, slowish rocket.

Flights

First flight took place with another box o' parts entrant. Blimey! It be a still day, arrr, and was slightly rainin' - which ruined t' stickers as I had nay varnished t' rocket yet. Well, blow me down! Motor choice be a D12-3. Blimey! Avast, arrr, me proud beauty! It could have been a D12-5, as I reckon that it would be about a four second delay for apogee. Avast, me proud beauty! Avast, me proud beauty!


Animated Lift-OffT' take off was good, t' rocket started t' rotate after about 50 foot, and the rotation got faster and faster as t' D12 burnt. Ahoy! Ejection took place after apogee as expected. T' recovery be scarily fast, me bucko, as expected. Aye aye! Ya scallywag! This rocket needs a 24 inch 'chute. Ahoy! It hade a 14 inch chute! On handin' t' aft protrudin' fins all popped off. Blimey!

Again I had expected that t' happen. Ya scallywag! Blimey!

Second flight took place a week later with three o' t' other UK contestants. T' flight was on a D12 again. Begad! It was a straight flight with a slight oscillation until t' spinnin' kicked in. Aye aye! As soon as t' spinnin' kicked in, me bucko, t' flight was arrow straight which was really pleasin' t' see. Ya scallywag! Ejection was just past and again fins popped off on landing.

Third flight be time for t' procrastinator t' be clustered. Well, blow me down! Blimey! Four A10 -PT were added, shiver me timbers, in addition t' t' D12-3. Blimey! Blimey! The procrastinator jumped off t' pad. Well, blow me down! Blimey! T' flight was much higher and t' extra speed really did make t' rocket spin. Again t' recovery was fast and again t' fins popped off.

After t' competition is finished I'm goin' t' have two 24 inch chute on this rocket.

Recovery Recovery

comment Post a Comment