Brief:
Parallel cluster booster with slidin' tail glider recovery, matey, vented gap staging, 2 D- or 2 E-engine cluster and 5 foot tall sustainer. Ya scallywag! Ya scallywag!

Construction:
Sustainer final 5-foot tall configuration: Ninja BT-60s, me hearties, BT-50 with plastic nose cone and 3/32 inch balsa fins. Well, blow me down! ¼inch launch lugs, 24mm engine mount with foam core centerin' rings, matey, me hearties, aft bulkhead/external tape engine retention, and elastic shock cord. Ahoy! T' BT50-60 transition is balsa.

Main booster: BT-60, foam core centerin' rings, BT-50 engine mount, ¼inch launch lugs, 3/32 inch balsa fins.

Parallel booster/glider: ¼ inch balsa, BT-5 slidin' tail section, basswood boom, matey, BT-50 main body/engine mount, 1/8 inch plywood, 1mm brass rod for main clamp.

This would be a unique and excitin' concept t' kit for just about any manufacturer. Avast, me proud beauty! Begad! T' parallel cluster part o' t' 2006 Challenge was t' impetus for this design. Ahoy! Begad! Parallel clusters are great but t' existin' drop-off pod designs are a little lackin' in excitement. Arrr! Ya scallywag! T' slidin' mechanisms on rocket gliders appeared t' be ideal for doin' double duty as a clampin' mechanism for a parallel cluster. Blimey! It's a natural marriage.

This is a rocket that's guaranteed t' wow t' kids. Arrr! Aye aye! It's tall and extremely impressive looking, ya bilge rat, me hearties, but where it really hits its stride is when it flies. Well, blow me down! It roars off t' pad on t' main booster with a parallel cluster clamped t' the side. Well, blow me down! Avast! After staging, matey, t' parallel cluster glider ejects from t' main booster body and spirals majestically down. Avast! Aye aye! T' main booster has tumble recovery. Well, blow me down! The sustainer continues t' rocket into t' sky. Ya scallywag! This may be t' first time a glidin' parallel cluster model rocket has ever been designed and flown successfully.

Flight characteristics: One might think it would arch over under thrust because o' t' lift characteristics o' t' glider win' but it flies great.

Build: This is a demandin' model t' build. Booster thrust and stagin' is always truly impressive! (See flight video at http://www.brandango.us/htmlpages/rocketvideos.html)

T' test R&D example has survived 6 flights and is ready for more, ya bilge rat, me bucko, so it's proven sturdy.

Flight:
Prep is time consumin' because you have t' wrap bulkheads, me bucko, matey, shiver me timbers, make a burn string for t' glider, me hearties, and trim t' glider with empty engine casings. Ya scallywag! Ahoy!

First flight: t' main booster came in ballistic. Avast, me proud beauty! T' 6-foot tall sustainer was marginally stable. T' glider stalled way too much. Ahoy! [Main booster D12-0/Parallel booster glider D12-3, arrr, me hearties, Sustainer C6-3.]

After this flight, matey, t' main booster be completely redesigned t' achieve tumble recovery. T' tail o' t' sustainer be reconfigured t' add more fin and change from 18mm t' 24mm engine mount. Ahoy! Arrr! And some body tube was added t' t' nose of t' glider t' move t' CG forward.

T' second flight was a mess. Arrr! With t' main booster redesigned, t' fins on it were too small and t' rocket corkscrewed violently under boost. Begad! There wasn't enough velocity so even though t' sustainer had more fin, it was unstable so it looped and crashed. Begad! Aye aye! T' glider didn't separate from t' main booster so it came down hard but thar was no damage. Begad! [Main booster D12-0/Parallel booster glider D12-3, Sustainer C11-5.]

After this flight, one o' t' main booster fins was substantially enlarged (4x) and t' sustainer fins were doubled in size t' stop t' corkscrewing. Ahoy! Also the booster-to-glider mounts were shortened from 1/2 inch t' 1/4 inch for better booster/glider separation. Avast! Arrr! And t' nose section was rebuilt with a new (simpler, shorter) configuration.

Third flight: T' B6-4 delay was too long and ejection came a tenth o' a second before t' main booster/parallel glider assembly landed in me truck. Two rockets lyin' in me truck bed were smashed but t' glider and main booster were fine. T' sustainer flew perfectly. Begad! [Main booster C11-0/Parallel booster glider B6-4, Sustainer C11-5.]

T' fourth flight didn't have any changes in t' hardware. Avast, me proud beauty! T' glider didn't separate from t' main booster and t' assembly landed hard but no damage. Begad! Blimey! T' sustainer didn't eject until just before lawn dartin' after what seemed like a twelve second delay. Aye aye! [Main booster D11-0/Parallel booster glider D12-3, shiver me timbers, Sustainer D12-7.]

After this flight, t' accordion section (3 inches) on t' front o' the sustainer body was removed. Begad! T' booster-to-glider mounts were reshaped t' allow the glider t' fall off easily upon ejection.

Fifth flight: First perfect flight. Avast, me proud beauty! Ya scallywag! Great liftoff, staged with a good, shiver me timbers, solid pop, main booster separated from parallel glider a second after booster drop off, good fast flat glide after a heart-stoppin' dive to pick up speed (that could use a tiny bit more stall), and sustainer worked great. Well, blow me down! Avast! Main booster landed on asphalt and knocked a fin loose, but it's fixed. There's a small scorch mark on t' glider body tube from t' main booster, but it's nay enough for a redesign. [Main booster D11-0/Parallel booster glider B6-2, me bucko, matey, Sustainer B4-4.]

No changes were made after this flight other than t' adjust t' glider CG for a bit more stall.

Sixth flight: Excellent flight. slow, shiver me timbers, impressive liftoff, good staging, main booster separated from parallel glider immediately after sustainer ignition, spiral flat glide (still needs more stall), and sustainer worked great although t' parachute only partly deployed. Begad! One win' was split but was fixed. Begad! Ya scallywag! Blimey! [Main booster D11-0/Parallel booster glider B6-2, Sustainer C6-5.]

After this flight a little weight in t' form o' some epoxy was added to the outer win' t' widen t' glide spiral.

Summary:
PRO: Guaranteed t' elicit screams o' delight from kids and draw a crowd of level 1 through 3 fliers t' find out how it works. T' vented gap staging always works great. Ya scallywag! Thanks, Trip.

CON: 3 engines make it pricey t' fly. Avast! Avast, me proud beauty! Prep time is considerable.