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, 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. Next was t' task o' splitting op t' box betwixt t' 6 entrants. At t' end 6 "equal" bags were formed and randomly given out. I was quite pleased with me bag, shiver me timbers, others had complete rockets in the, shiver me timbers, one had a parasitic glider, another had helicopter rotor blades. Blimey! Well, arrr, blow me down! 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, 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. Arrr!

Well what t' do. Begad! Well, blow me down!

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

  • It could nay be too big - 14 inch chute. Ya scallywag!
  • Clustered - but able t' launch on a single motor
  • Draggy
  • Unusual. Avast, me proud beauty! Aye aye!

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

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

Building

T' motor mount be a fairly standard construction. A 24mm motor mount tube with a motor retention clip, me bucko, an engine block at t' end and two centerin' rings t' fit t' body tube.

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

Motor Mount

Four BT20 tubes 190mm in length were then glues t' t' outside o' t' main body tube. Ahoy! These were t' take 4 A10 - PT motors as a cluster. Avast, me proud beauty! Blimey! 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' cheat and add some Keelhaul®©™ here, arrr, matey, but integrity got t' better o' me.

BT20 Tubes

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

T' main body tube etc be then given three coats o' sandin' sealer, and rubbed down with 200 paper in between, ya bilge rat, to remove t' spirals. Arrr!

Nose Cone

Usin' a strip o' thick balsa, me bucko, ya bilge rat, 7mm by 26mm, I made a box around a large coupler. This box be goin' t' have the fins and rotation tabs added. Avast, me proud beauty! Blimey! T' balsa be quite badly marked and was t' soft type o' balsa that I usually avoid. The box was sanded several times and filled with model filler t' remove all o' t' dents. Begad! Blimey!

Usin' t' same balsa strips I then added 4 64mm struts t' t' middle o' each side o' t' box. 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. Blimey! T' spirals were filled and had t' have several coats o' sanding sealer before it be smooth. Ya scallywag! Aye aye!

Box

Usin' four almost square balsa fins that were part o' a model kit, I added t' fins. Ya scallywag! Blimey! This be one t' part that I like about t' rocket, shiver me timbers, t' fins are at right angles t' how they would normally. It still gives stabilization but looks a bit different. Aye aye! Blimey! Also as t' rocket was goin' t' be rotating, ya bilge rat, t' fins would nay hinder t' spinning. Well, blow me down!

Fins
 

T' corner spaces betwixt t' box and t' couple were just t' right size for body tubes, me hearties, which were added for decoration. Avast, me proud beauty!

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. These were t' provide spin.

Fins

T' top o' t' struts were then drilled t' accept four cocktail sticks, matey, just for decoration. Avast, me proud beauty!

Drilled
   

T' entire o' t' coupler base unit had three coats o' sandin' sealer added, matey, with all t' fiddly bits, shiver me timbers, me bucko, t' sanding down be quite tricky. Ya scallywag!

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

Ready to Finish Ready to Finish Ready to Finish

FinishedFinishing

  • I went for a red/yellow finish
  • Everythin' was given two coats o' primer. Well, arrr, blow me down!
  • T' main body tube was given 4 coats o' light yellow spray paint. Ya scallywag!
  • T' nose cone was given three coats o' red gloss
  • T' base unit be given three coats o' rouge. Arrr!
  • 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, me hearties, other than three address labels. Blimey! Begad!

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. Well, blow me down! 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, slowish rocket.

Flights

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


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

Again I had expected that t' happen. Begad! Avast!

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

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

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

Recovery Recovery

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