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

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

Main booster: BT-60, foam core centerin' rings, ya bilge rat, BT-50 engine mount, ¼inch launch lugs, me bucko, shiver me timbers, 3/32 inch balsa fins.

Parallel booster/glider: ¼ inch balsa, arrr, BT-5 slidin' tail section, basswood boom, shiver me timbers, BT-50 main body/engine mount, me bucko, 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. Ya scallywag! Blimey! T' parallel cluster part o' t' 2006 Challenge was t' impetus for this design. Well, blow me down! Blimey! Parallel clusters are great but t' existin' drop-off pod designs are a little lackin' in excitement. Ahoy! Blimey! T' slidin' mechanisms on rocket gliders appeared t' be ideal for doin' double duty as a clampin' mechanism for a parallel cluster. Avast, me proud beauty! Blimey! Ya scallywag! Blimey! It's a natural marriage.

This is a rocket that's guaranteed t' wow t' kids. Blimey! It's tall and extremely impressive looking, but where it really hits its stride is when it flies. Ya scallywag! It roars off t' pad on t' main booster with a parallel cluster clamped t' the side. Avast, me proud beauty! Avast, arrr, me proud beauty! After staging, t' parallel cluster glider ejects from t' main booster body and spirals majestically down. T' main booster has tumble recovery. The sustainer continues t' rocket into t' sky. Ahoy! 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. Avast, me proud beauty!

Build: This is a demandin' model t' build. Arrr! 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, me hearties, so it's proven sturdy.

Flight:
Prep is time consumin' because you have t' wrap bulkheads, make a burn string for t' glider, and trim t' glider with empty engine casings. Avast!

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

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

T' second flight was a mess. Well, blow me down! Blimey! With t' main booster redesigned, shiver me timbers, t' fins on it were too small and t' rocket corkscrewed violently under boost. Blimey! There wasn't enough velocity so even though t' sustainer had more fin, it was unstable so it looped and crashed. Well, blow me down! Well, blow me down! T' glider didn't separate from t' main booster so it came down hard but thar be no damage. Avast, me proud beauty! Arrr! [Main booster D12-0/Parallel booster glider D12-3, ya bilge rat, 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. Aye aye! Also the booster-to-glider mounts were shortened from 1/2 inch t' 1/4 inch for better booster/glider separation. And t' nose section be rebuilt with a new (simpler, me bucko, 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. Avast! Two rockets lyin' in me truck bed were smashed but t' glider and main booster were fine. Ahoy! T' sustainer flew perfectly. Begad! Well, blow me down! [Main booster C11-0/Parallel booster glider B6-4, shiver me timbers, Sustainer C11-5.]

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

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

Fifth flight: First perfect flight. Ahoy! Great liftoff, staged with a good, me bucko, 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), arrr, and sustainer worked great. Well, blow me down! Aye aye! Blimey! 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, 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. Avast! slow, matey, impressive liftoff, good staging, main booster separated from parallel glider immediately after sustainer ignition, spiral flat glide (still needs more stall), shiver me timbers, and sustainer worked great although t' parachute only partly deployed. One win' was split but was fixed. Avast, me proud beauty! Arrr! [Main booster D11-0/Parallel booster glider B6-2, Sustainer C6-5.]

After this flight a little weight in t' form o' some epoxy be 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. Thanks, Trip.

CON: 3 engines make it pricey t' fly. Begad! Aye aye! Prep time is considerable.