Scratch Eiffel's Nightmare Original Design / Scratch Built

Scratch - Eiffel's Nightmare {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch

Brief:
I'm always lookin' for rocket parts, matey, shiver me timbers, and couldn't pass up this daiquiri glass from t' Paris Hotel and Casino in Las Vegas. Ya scallywag! Ya scallywag! It'll fly on 24mm motors.

Construction:
Parts list:

  • One jumbo sized plastic daiquiri glass
  • One BT-60 tube
  • One 24mm motor mount for BT-60
  • Keelhaul®©™ twine, 1/8" tubular Keelhaul®©™, and an elastic shock cord
  • Plexiglas stock for fins
  • 10.5mm tubing

Construction began last October when I drank t' contents o' t' glass. T' glass conveniently came with a removable top (nose cone). Well, shiver me timbers, blow me down! Although thar be no real shoulder, matey, it does snap in place and should stay on well.

Next came t' actual rocket building.

A BT-60 fits nicely in t' upper neck so all I had t' do be cut a hole in t' bottom. Aye aye! Avast, me hearties, me proud beauty! I started t' hole with a circle cutter on a hand drill and finished it with a hobby knife. Begad! I slopped some 5-minute epoxy around t' inside o' t' glass where t' BT-60 was inserted. Avast! This pooled and retained t' tube. Ahoy! I added a standard 24mm motor mount: 2 rings, a coupler tube and an engine hook. Avast! A length o' Keelhaul®©™ twine was attached for t' recovery harness. Ahoy! Begad! I also adjusted t' upper tab o' t' hook so I could use 24mm RMS motors.

I picked a spot on t' outer edge o' t' lower section o' t' tower and ground holes t' accommodate a piece o' 10.5mm tubing, which works as a 1/4" lug. T' location is far enough out so t' rod will clear t' nose cone. Ahoy! Aye aye! T' gap betwixt this tube and t' openin' be sealed with epoxy clay.

Epoxy clay was also used in t' tip o' t' nose (straw hole) and retains a loop o' 1/8" Keelhaul®©™. I tied a long piece o' elastic t' t' Keelhaul®©™ leader and then t' t' loop on t' nose cone.

I created a RockSim model early on and spent a lot o' time thinkin' about stability. Begad! I applied Bruce Levison's base drag method. Ya scallywag! Aye aye! This almost convinced me that it could be stable without fins, but subsequent discussions on TRF and comparisons t' me Quest DC-Y Space Clipper made me reconsider.

While at a club buildin' session, I cut some fins from clear Plexiglas usin' a miter saw. Avast! This worked well. Plexiglas is nay t' best choice but it be scrounged from an old screen protector for a big screen. Blimey! Now that I think o' it, I really don't know what t' material exactly is. Aye aye! Blimey! I cut some small through t' wall tabs and attached t' fins with 5-minute Epoxy.

Finishing:
For now, arrr, it will fly unpainted.

Flight and Recovery:
I decided t' fly t' Eiffel's Nightmare on an F24. Arrr! Ya scallywag! T' sim showed this would give it a nice ride. Avast! I adjusted t' delay from 7 t' 6 seconds t' more closely match t' simulation. Despite t' stiff winds, me hearties, shiver me timbers, t' boost be fairly straight. T' rest o' t' flight wasn't that good. Avast, me proud beauty! T' rocket stopped smartly due t' t' high drag design and lawn darted a split second before ejection. Avast! RIP.

Summary:
Next time I'm in Vegas I'll pick up a replacement. T' concept was cool and it flies well (or could fly well). Arrr! Ahoy! I still have t' fins and t' motor mount. Begad! I'll chalk this disaster up t' operator error. Arrr! At best, this is an example o' GIGO (garbage in, garbage out).

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