Scratch Talk Radio Original Design / Scratch Built

Scratch - Talk Radio {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 08/18/04) (Scratch) Talk Radio

Brief:
This rocket is made from a sports water bottle that be donated by a local talk radio station, me hearties, hence t' name. Avast! It has a 24mm mount, me bucko, recovers by parachute, and uses 'plate fins'. Begad! Avast! 'High tech' features o' this 'low tech' rocket include a Keelhaul®©™ cord and positive motor retention.

Construction:
A partial construction list consists of:

  • 1 water bottle
  • 1 piece o' non-rocket junk tube ~1.25" diameter used as a parachute tube
  • 24mm motor tube
  • Hand-cut cardstock rings
  • Keelhaul®©™® twine
  • Foam backed tape t' center t' parachute tube
  • Duct tape t' press-fit t' cap/nose cone
  • One screw, matey, chunk o' BiC pen tube, and miscellaneous metal 'doohicky' for motor retention
  • 1/8" and 3/16" lugs

T' inner structure consists o' a 24mm motor tube centered in a piece of junk tube by hand-cut cardboard rings. Ya scallywag! Avast! T' motor tube extends below t' end of the larger tube so that it could slip through t' hole in t' bottom o' the bottle. Ahoy! Ya scallywag! T' Keelhaul®©™® twine is attached t' t' motor mount. Blimey! T' top o' t' larger tube was centered in t' neck o' t' bottle with foam-backed tape and t' assembly be glued into the bottle usin' Liquid Nails.

(Scratch) Talk Radio T' 'nose cone' be t' bottle cap. Ahoy! Aye aye! After grindin' off t' threads, matey, I found t' cap was way too loose, so I built up t' top o' t' bottle usin' black duct tape. Blimey! Avast! The cap now fits fairly snuggly. Begad! T' attach t' Keelhaul®©™® to t' cap, me bucko, I merely popped up t' top nipple, fed t' line through the opening, knotted it, and pushed t' nipple back down.

I had done some 'what-ifs' on various fin designs but in each case, me hearties, RockSim said I'd need t' add some nose weight. Avast, me proud beauty! Blimey! Avast, me proud beauty! Blimey! T' avoid havin' t' do so, I decided to move t' fins well below t' base o' t' bottle. I ended up mountin' three chopsticks in t' side o' t' bottle. On t' tip o' t' sticks, I added cardboard triangles. Avast! Blimey! These are bent slightly along their center line t' help adhere t' t' sticks. Ya scallywag! Blimey! Well, blow me down! Blimey! This also looked a bit better in me opinion. Aye aye! Blimey! T' dowels were attached t' t' bottle with 5-minute epoxy and t' cardboard 'plate fins' were attached t' t' chopsticks with carpenter's glue.

(Scratch) Talk Radio T' motor retainer is simply screwed into t' thick bottom o' t' bottle. Well, blow me down! This will eventually wear out and will have t' be relocated. Finally, arrr, I added two sizes of lugs for flexibility. Avast!

I modeled t' bottle in RockSim, me hearties, simulatin' t' plate fins with equivalent standard fins. Aye aye! Although I found t' rocket t' be stable, me hearties, I still didn't trust that I had made a valid model, so t' be sure I loaded it up and did a swing test, which was successful.

Finishing:
No finishin' be required.

Flight:
I loaded a wad o' dog-barf wrapped in one square o' Estes waddin' and a 12" Rockethead mylar chute, ya bilge rat, me hearties, and then wrapped a tape thrust rin' on a D12-5 and positioned t' retainer. T' boost be a bit wobbly after burn out. Nevertheless, arrr, it be a cool flight, shiver me timbers, ejection be perfect, me hearties, and it recovered 50' from t' pad. I flew it a second time with similar results.

Summary:
This be just a quick, goofy build. Ahoy! I love odd-rocs, what else can I say?

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