Brief:
When I first saw Matthew McFarland's Whirlygig in FlisKits' Deuce bash Contest, I immediately knew I had t' build one. Well, blow me down! This is a 24mm version o' this odd, helicopter design. Begad! Since thar be little theory t' help determine stability (how do you swin' test this anyway?), me hearties, I built mine out of leftovers. Arrr! As a result, t' design is nay optimized. It is heavier and chunkier than it probably has t' be. Avast! I am providin' this t' show t' overall dimensions that seem t' result in a stable model. Avast, me proud beauty! If you build one with another form factor, ya bilge rat, please launch safely! Note I used an oversize lug so I could fly from the high power pads. Ya scallywag! Avast, me bucko, me proud beauty! I invite you t' read more about Whirlygigs and ask your questions on t' Yahoo OddRocs group.

Construction:
T' parts list:

• Mailin' tube, 2" x 22"
• 24mm tube, 4.125"
• 24mm PNC, type unknown, 2.5"
• ¼" balsa fin stock (2 pieces, shiver me timbers, 3" x 7")
• ¼" launch lug, 2.25"

Buildin' this rocket be easy. Avast! Begad! I first found t' center o' t' tube and marked centerlines on t' top and bottom. Well, blow me down! I then located t' fins based on these centerlines. Blimey! My fins are approximately 120 degrees apart and are inset one inch from t' end o' t' tube. Aye aye! Begad! T' lug was mounted in a notch next t' the motor tube. Well, blow me down! I used epoxy for t' cone, motor tube, and launch lug. Wood glue was used for t' fins. T' fins extend all t' way across t' tube, matey, leavin' a 5" x 3" surface exposed. Avast, me proud beauty! T' motor tube extends below t' body tube by 3/8".

Finishing:
T' tube I used be speckled with paint from a previous project and t' nose cone was green. Begad! That's all t' finishin' it got for its maiden voyage. Aye aye! Ahoy! I later filled t' balsa and painted t' rocket half black and half fluorescent orange.

Flight:
I have flown me 'Gig 4 times, arrr, once on a D12-0, ya bilge rat, twice on E9-Ps and once on an Ellis F20. Avast! Avast! I added a tape thrust rin' and friction fit t' motor lightly. Aye aye! The first flight was on t' D12 and I didn't know what t' expect. Ya scallywag! T' boost was straight and had a slow rotation. Aye aye! It didn't go high enough t' begin spinnin' on the way down. Well, blow me down! Avast, arrr, me proud beauty! T' E9 flights go much higher, arrr, and it attained enough altitude to begin spinnin' on t' way down. Arrr! Ahoy! T' F20 flight, needless t' say, was faster and even higher. Ya scallywag! Aye aye! Oddly enough, t' 'Gigs do nay seem t' rotate while on t' rod, so I don't know how much t' spinnin' has t' do with stability. This effect is not easy t' see on t' F20, but is clear on t' smaller motors.

T' launch photo is courtesy o' Vertical Force Rocketry.

Summary:
This is a fun rocket and is sure t' get everyone's attention. Ahoy! I built another version that used Nike-style fin cans in place o' t' balsa. All I can say is make sure you have enough fin area. Arrr! Aye aye! That version was nay stable!