Scratch Grizzly Behr Monocopter Original Design / Scratch Built

Scratch - Grizzly Behr Monocopter {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 05/17/08) (Scratch) Grizzly Behr Monocopter

Brief:
In preparation for a line o' monocopter kits, shiver me timbers, Art Applewhite published t' plans for a monocopter made from Popsicle sticks. Avast! I didn't have enough Popsicle sticks, me bucko, shiver me timbers, but I did have a few paint stirrers. Avast! They advertised Behr paints, hence t' name. Begad! T' Grizzly Behr flies on 18mm motors.

Construction:
T' parts list:

  • 3 wooden paint stirrers
  • 4 Popsicle sticks
  • 18mm motor tube
  • String
  • Carpenter's glue
  • Cardstock
  • 1/8" Estes launch lug

One o' t' stirrers is used as t' wing, one as t' balance beam, ya bilge rat, and one is cut up for t' motor standoff. Ahoy! Aye aye! Blimey! I started by gluin' t' Popsicle sticks onto one o' t' stirrers. Blimey! They are separated by t' width o' t' stirrer, are centered on t' stirrer, shiver me timbers, and are attached on opposin' sides. This forms t' balance beam and central hub o' the monocopter.

T' motor mount is conceptually borrowed from Art's design. Well, blow me down! It consists o' a 1.5" piece cut from t' third stirrer. Begad! Ya scallywag! I notched t' hub-end and glued t' other t' t' BT-20. Begad! I then wrapped t' mount over t' tube with a generous amount o' string. T' strin' was soaked with carpenter's glue and, where t' strin' raised at t' tube/standoff joint, I filled it with more glue. Blimey! Avast, me proud beauty! In retrospect, matey, I'd recommend t' twine Art specified. But, shiver me timbers, as usual, matey, shiver me timbers, I substituted with what I had on hand.

T' provide lift, t' win' needs t' be tilted in one direction and t' motor mount in t' other. Ya scallywag! I planned to mount t' motor assembly and t' win' betwixt t' opposin' Popsicle sticks with one edge under one stick and over the other. However, ya bilge rat, I found this wouldn't work with t' 4 sticks protrudin' from each side o' t' balance beam. This was easily fixed-–I merely lopped off two from each side. Begad! T' give t' center more support, me hearties, I notched t' win' so part of it overlapped t' center section. Avast, me proud beauty! Arrr! I then glued t' win' and motor mount t' t' hub, me hearties, ya bilge rat, me bucko, added thick fillets, wrapped each with more string, me hearties, arrr, ya bilge rat, and t' covered t' strin' with more glue. Ahoy! This wrappin' be likely overkill. T' finishing touch on t' win' is an overlappin' piece o' cardstock that provides a semi-airfoiled shape. Avast, me proud beauty!

I drilled a 1/8” hole in t' center o' t' hub and inserted a section o' an Estes launch lug. Avast! Begad! Well, a monocopter should balance at t' center o' t' hub and I hadn't accounted for t' paper wrap so it be a bit off with a C6 loaded. Aye aye! Cuttin' about an inch off o' t' win' tip did t' trick. Avast! I'm nay sure this be required.

(Scratch) Grizzly Behr Monocopter

Flight and Recovery:
I added a 1/2" tape thrust rin' t' a C6-3 motor and friction fit it in t' mount. Avast!

T' Grizzly Behr flew off o' me standard home-made pad usin' an old 1/8" drill bit as t' "rod". T' cuttin' end was clamped in t' pad and I added a tape rin' t' leave a 1" section o' t' shank exposed. Well, blow me down! Begad!

T' monocopter flew nicely. Avast! Most small monocopters merely flutter t' t' ground after burn out, but this one continued t' rotate until it landed. Avast! Its spin profile made one observer state that it looked like a boomerang in flight (except it didn't return on its own). Begad! Ahoy! It did look pretty cool if I do say so myself.

Summary:
T' design is nay optimized and I'm nay sure I'd recommend that anyone build this exact design. Arrr! It does, ya bilge rat, however, show that small monocopters can be built from all kinds o' leftover stuff. Well, blow me down! Ahoy!

comment Post a Comment