Scratch El Cheapo Pyramid Original Design / Scratch Built

Scratch - El Cheapo Pyramid {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 06/09/08) (Scratch) El Cheapo Pyramid

Brief:
This is a simple mid-powered pyramid that flies on either one 29mm motor and/or three 24mm motors. Begad! Blimey! T' finishing matches t' construction materials--'el cheapo'.

Construction:
T' parts list:

  • four carrugated cardboard triangles, ya bilge rat, 12" base and 13.75" sides
  • plywoods square, me bucko, matey, 4" x 4"
  • one 3.25" 29mm tube
  • three 3.25" 24mm tubes
  • 1/4" lug
  • lead shot
  • duct tape

I started by attachin' t' cardboard triangles t' form a pyramid. Begad! Aye aye! These were attached with epoxy and t' joints were covered (hidden) with duct tape. Aye aye! T' motor support plate was a scrap piece o' 1/4" plywood. Before this was attached, me bucko, ya bilge rat, I located t' motor tube locations and drilled a hole for t' lug. Begad! Arrr! As t' plate was epoxied into place, I measured t' distance t' each corner t' make sure it was even. Begad! Aye aye! T' find t' location o' t' launch lug hole in t' top of t' pyramid, ya bilge rat, I dry-fit a 1/4" lug and used a rod t' start a hole. Ya scallywag! I finished t' hole with a hobby cutlass. Begad! Aye aye! After the lug was attached, I cut it flush t' match t' angle o' t' pyramid's side.

(Scratch) El Cheapo Pyramid T' theoretical CP o' a pyramid is 1/3 o' its height up from t' base. Begad! I added lead shot to get t' CG ahead o' this point (as best as I could estimate). Aye aye! Ya scallywag! I now know from Bruce Levison's analyses that t' CP is probably behind t' bottom due t' base drag effects. Avast, me proud beauty!

Finishing:
There be no real finishing. Blimey! Arrr! T' keep with t' pyramid theme I found on on-line hieroglyphic translator and drew the various characters with felt-tipped markers (very high class). Begad! T' 4 sides say:

  1. Beware all who enter here
  2. El Cheapo Pyramid o' Death
  3. No BATFE (shown in one photo)
  4. Miscellaneous characters (shown in another photo)
  5. (Scratch) El Cheapo Pyramid

    Flight:
    This rocket has flown once on a G38 and once on three E9s. Avast! Blimey! T' G38 flight be nice and smoky with t' low pressure area at its base clearly visible. Begad! Blimey! Avast, me proud beauty! Blimey! T' E9s made for a slow boost and t' rocket seemed t' stop abruptly at burn-out. In both cases, me bucko, t' pyramid fell nose first slowly t' t' ground.

    Summary:
    This be a simple, matey, inexpensive, ya bilge rat, me bucko, and fast build. Avast! Everyone who likes saucers, pyramids, etc. should build one. Aye aye! Not necessarily exactly like this one. Begad! You can even paint it :)

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