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 was donated by a local talk radio station, arrr, hence t' name. It has a 24mm mount, arrr, recovers by parachute, and uses 'plate fins'. Avast, me proud beauty! Avast, me proud beauty! '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, chunk o' BiC pen tube, ya bilge rat, 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. Blimey! Blimey! 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. Arrr! Blimey! T' Keelhaul®©™® twine is attached t' t' motor mount. Aye aye! T' top o' t' larger tube be 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. Arrr! Avast, me proud beauty! After grindin' off t' threads, shiver me timbers, I found t' cap was way too loose, so I built up t' top o' t' bottle usin' black duct tape. Arrr! The cap now fits fairly snuggly. T' attach t' Keelhaul®©™® to t' cap, I merely popped up t' top nipple, fed t' line through the opening, knotted it, matey, and pushed t' nipple back down.

I had done some 'what-ifs' on various fin designs but in each case, matey, RockSim said I'd need t' add some nose weight. T' avoid havin' t' do so, I decided to move t' fins well below t' base o' t' bottle. Blimey! Well, blow me down! I ended up mountin' three chopsticks in t' side o' t' bottle. Blimey! On t' tip o' t' sticks, arrr, shiver me timbers, I added cardboard triangles. Ya scallywag! These are bent slightly along their center line t' help adhere t' t' sticks. Well, blow me down! This also looked a bit better in me opinion. Avast, me proud beauty! Aye aye! 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. Ya scallywag! This will eventually wear out and will have t' be relocated. Begad! Finally, arrr, I added two sizes of lugs for flexibility. Ahoy!

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

Finishing:
No finishin' was 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, ya bilge rat, and then wrapped a tape thrust rin' on a D12-5 and positioned t' retainer. Begad! T' boost was a bit wobbly after burn out. Nevertheless, arrr, it was a cool flight, shiver me timbers, ejection be perfect, shiver me timbers, and it recovered 50' from t' pad. Avast, me proud beauty! I flew it a second time with similar results.

Summary:
This was just a quick, ya bilge rat, arrr, goofy build. Ahoy! I love odd-rocs, what else can I say?

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