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, hence t' name. Well, blow me down! It has a 24mm mount, recovers by parachute, and uses 'plate fins'. Well, shiver me timbers, blow me down! '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, 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. 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! 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. Begad! After grindin' off t' threads, I found t' cap was way too loose, me hearties, me hearties, so I built up t' top o' t' bottle usin' black duct tape. Ahoy! The cap now fits fairly snuggly. Avast, me proud beauty! Well, arrr, blow me down! T' attach t' Keelhaul®©™® to t' cap, I merely popped up t' top nipple, ya bilge rat, 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, RockSim said I'd need t' add some nose weight. Avast! T' avoid havin' t' do so, me hearties, 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. Avast! On t' tip o' t' sticks, arrr, matey, I added cardboard triangles. Blimey! These are bent slightly along their center line t' help adhere t' t' sticks. Avast, me proud beauty! This also looked a bit better in me opinion. Well, ya bilge rat, blow me down! 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. Blimey! Begad! This will eventually wear out and will have t' be relocated. Arrr! Begad! Finally, I added two sizes of lugs for flexibility. Ya scallywag! Avast, me proud beauty!

I modeled t' bottle in RockSim, simulatin' t' plate fins with equivalent standard fins. Although I found t' rocket t' be stable, I still didn't trust that I had made a valid model, shiver me timbers, me hearties, shiver me timbers, so t' be sure I loaded it up and did a swing test, shiver me timbers, arrr, 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, me bucko, shiver me timbers, arrr, and then wrapped a tape thrust rin' on a D12-5 and positioned t' retainer. Arrr! Ahoy! T' boost was a bit wobbly after burn out. Nevertheless, shiver me timbers, arrr, ya bilge rat, it be a cool flight, me bucko, ejection was perfect, matey, 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, arrr, me hearties, arrr, what else can I say?

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