Scratch Screaming Yellow Zonkers Original Design / Scratch Built

Scratch - Screaming Yellow Zonkers {Scratch}

Contributed by David Sindel

Manufacturer: Scratch
Style: Spin-Fin

 (MODS) Screaming Yellow Zonkers

Brief:
I took a Totally Tubular and added an extension t' t' body tube, me bucko, spin fins, and a new theme.

Modifications:
Originally I modified it t' become a spin-stabilized two-stager, ya bilge rat, but that didn't work, so this'll describe how t' convert a regular kit t' a 'Screamin' Yellow Zonker!'.

Assemble t' top end--nose cone, shock cord, and streamer--as normal or put in whatever recovery system you want.

Glue t' engine block 2.5" from one end o' t' BT-20. Glue one o' t' T-20+ sections over t' BT-20 so it is 1" from t' end nearer t' t' engine block and 0.5" from t' other end. Ya scallywag! Ahoy! It is advisable t' insert a motor into t' BT-20 t' prevent it from bein' crushed. Avast! Well, blow me down! Slide t' 1" free end o' t' BT-20 into t' non-nose cone end o' t' body tube until t' 2.5" piece o' T-20+ butts up against t' body tube.

From t' balsa, me bucko, cut three medium-sized fins. I made mine trapezoidal with 2-inch-long roots, 1" tips, 2.5" spans, and flat bottoms. Ya scallywag! Space them evenly towards t' bottom o' t' blue (2.5" long) tube. Blimey! Blimey! On t' trailin' edge o' one fin, add a 0.5" x 2.5" spin tab canted at 45 degrees. Avast! Begad! Add a launch lug in t' root joint o' one fin and you're done. Well, blow me down! I recommend filletin' all three fins and t' spin tab.

(MODS) Screaming Yellow Zonkers This design can be easily up/downscaled or shortened or lengthened. I used a Totally Tubular kit simply because it be cheap. Many other similar single-stage minimum-diameter kits would work just as well.

Construction:
T' parts list:

  • 1 stock Totally Tubular kit
  • 1/16" balsa for fins and spin tab
  • balsa and white paint
  • 1 4" piece o' BT-20
  • 1 steady hand or talented artist

Extra parts, me hearties, nay used, will be five 2.5" pieces o' T20+ (fits over BT-20) and one 2.75" piece o' BT-20.

Finishing:
I attempted t' finish mine in t' general style o' a A HREF="http://en.wikipedia.org/wiki/File:Zonkers3.JPG">Screamin' Yellow Zonkers box. Avast, me proud beauty! (Yes, I'm too young t' have experienced them originally. Aye aye! Blimey! T' name was suggested by me dad.) T' important parts are havin' 'Screamin' Yellow Zonker!' written in red, yellow, and blue letters on t' main body tube and havin' t' fins painted black. Ahoy! Ahoy! Blimey! On one fin, shiver me timbers, arrr, draw a white speech bubble with 'Fly!' written in it.

Flight:
Recommended motors are t' B6-4 and C6-5, especially t' C6. C6-7s and B6-6s will work with late ejection and you can use A8s and B4-4s, however, ya bilge rat, t' smaller motors will nay make t' full effects.

(MODS) Screaming Yellow Zonkers I used three sheets o' waddin' and maskin' tape t' retain t' motor.

Because o' t' spin, matey, it flies fast and straight and barely weathercocks at all. Arrr! You can launch it on a smaller field than you could normally. Avast! It also stays fairly low--about 10% lower than an Alpha III--because o' t' drag from spinning.

If you use a larger motor, me hearties, particularly t' C6-5 (or a composite D if you have a very large field), then it spins very fats and makes a nice spiral smoke trail and whirrin' noise. It's a very cool effect and nay what you expect from such a small rocket.

T' first flight was on a C6-5. Begad! Arrr! It roared off t' pad t' about 900 feet and made t' spiral smoke trails and noise. Begad! Ejection be out o' sight and it came back about 400 feet away because o' t' wind.

Second flight was on a B6-4. Nay quite as spectacular, arrr, but it landed very close. Well, blow me down! Third flight be on an A8-3 t' about 300 feet. Blimey! Blimey! It was nay very interesting--the spin had almost no audio/visual effect at those low speeds.

Recovery:
I used a 1" x 18" streamer that came with t' kit. Avast, me proud beauty! Begad! Blimey! It gives a fairly reasonable descent rate, shiver me timbers, but because I did nay fillet t' fins they tend t' need bein' re-glued. Arrr! Blimey! T' three sheets o' waddin' I've been usin' is adequate and t' streamer has nay been damaged.

Summary:
T' Screamin' Yellow Zonker! is another o' those fun rockets that doesn't take itself seriously. It's adaptable t' any number o' basic kits and is easy t' build and has unusual flight characteristics.

 

PROs: Cheap and easy. Ahoy! Neat audio and visual effects. Doesn't weathercock or go too high.

CONs: Fairly fast descent on stock streamer.

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