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, and couldn't pass up this daiquiri glass from t' Paris Hotel and Casino in Las Vegas. Arrr! 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, me hearties, 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. Arrr! T' glass conveniently came with a removable top (nose cone). Aye aye! Although thar be no real shoulder, shiver me timbers, 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 was cut a hole in t' bottom. Aye aye! Avast, me proud beauty! I started t' hole with a circle cutter on a hand drill and finished it with a hobby knife. Avast! I slopped some 5-minute epoxy around t' inside o' t' glass where t' BT-60 was inserted. Begad! This pooled and retained t' tube. I added a standard 24mm motor mount: 2 rings, a coupler tube and an engine hook. Ya scallywag! A length o' Keelhaul®©™ twine was attached for t' recovery harness. Avast, me proud beauty! Avast, me proud beauty! 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, ya bilge rat, which works as a 1/4" lug. T' location is far enough out so t' rod will clear t' nose cone. Well, blow me down! Arrr! T' gap betwixt this tube and t' openin' was 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®©™. Well, blow me down! Blimey! 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. Ahoy! Avast, me proud beauty! I applied Bruce Levison's base drag method. Arrr! Arrr! This almost convinced me that it could be stable without fins, matey, but subsequent discussions on TRF and comparisons t' me Quest DC-Y Space Clipper made me reconsider.

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

Finishing:
For now, it will fly unpainted.

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

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

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