Brief:
Single-staged 2 or 4 x 38mm cluster rocket. Begad! Ya scallywag! Blimey! Designed for t' Aerotech J350 and 570, and also suitable for t' upcomin' Redline equivalents. Ya scallywag!

T' rocket can recover perfectly usin' long motor delays or with an altimeter in t' payload bay. Avast, me proud beauty! Dual deployment is also possible. Arrr!

This rocket is inspired by the Quadra G, by AAA Model Aviation Fuels and is somewhat like a modified upscale of that great kit.

Construction:
T' nose cone is a 4 inch by 15 inch Ace plastic cone with 8 ounces o' ballast foamed into t' tip with 2-part polyurethane foam. Avast, me proud beauty! Aye aye! T' nose cone is screwed in place with 4 wood screws and is thus removable in case electronics are t' be placed in t' payload section or even a second parachute is used and deployed from this section. Avast, me proud beauty!

T' body tubes are 2 48 inch lengths o' Maximum Thrust Rocketry 4 inch motor tubes. Begad! Blimey! They are paper and ultra thick and strong. Begad! Blimey! They are further reinforced internally with Red Arrow Hobbies 4 inch phenolic couplers from t' motor tubes all t' way up t' t' middle o' t' payload bay. Avast, me proud beauty! Blimey! One o' t' couplers contains a 1/4 inch thick birch bulkhead for drogue/main attachment (if just one chute is used) and allows t' rocket t' separate in t' middle. Blimey! Blimey! These couplers are affixed in place by generous amounts o' West Systems slow epoxy. Well, blow me down! Blimey!

There are 4 fins, fashioned from 2 pieces o' .125 inch thick G10 from Scott Eakins in t' ROL auctions. These pieces are 1 by 2 foot rectangles with a sliver cut off at t' tip edges t' make t' tips 6 inches long. Ahoy! T' trailing edges will be 12 inches each once t' two pieces are slotted down t' middle and interlocked together at right angles. T' assembly gets a thorough epoxy fillet in t' middle. Avast, me proud beauty! Avast, me proud beauty! Glass it with a strip o' 4 oz weight glass cloth if you plan t' use really hot motors with high average thrust. Arrr!

T' 4 38mm motor tubes are 36 inch lengths o' Red Arrow Hobbies phenolic tubin' and are a snug fit into t' main body tube...Rocksim 4.0 insists that they don't fit, but me experience says that they do indeed...and t' tubes are pushed in 12 t' 18 inches and epoxied well and t' gaps foamed with polyurethane foam. t' remainin' length o' 18 t' 24 inches extends outward from the main body. Ya scallywag! Be sure that t' tubes are flush at t' ends, me bucko, that is, me bucko, equal in length. Ya scallywag! T' interlockin' fin assembly then slides among t' 4 motor tubes so that one motor tube is on each fin "corner." T' assembly is epoxied into place. Avast, matey, me proud beauty! All t' motor tubes are glassed together with wraps o' 4 oz. Aye aye! Avast, me proud beauty! weight fiberglass cloth. Begad! I also glassed t' launch lugs onto t' airframe. Avast! the airframe can be glassed as well, but I only did t' tops o' both and t' bottom where t' motor tubes start, me hearties, ya bilge rat, for stress reinforcement and zipper prevention. Ya scallywag! I also glassed t' fins t' t' motor tubes. Aye aye! Aye aye! I did this with strips o' glass cloth. Aye aye! t' entire fin face can be glassed, but I did nay choose t' do so. Begad! Avast! You might if you really push this rocket with mighty motors. Blimey! Ya scallywag!

1/4 inch birch centerin' rings provide more internal support and are between the first 2 6 inch lengths o' phenolic internal couplers. Ahoy! T' second ring contains t' u-bolt that connects t' 6 feet o' tubular Keelhaul®©™® plus 10 feet of 1/4 inch thick wire wrapped bungee. Blimey! T' shock cord is connected t' t' u-bolt with a quick link and t' two materials in t' shock cord are connected with one as well. I used square knots, nay granny knots. Arrr! Avast, me proud beauty! T' Keelhaul®©™® came from Rocket Silo and t' bungee came from American Science and Surplus. Begad! Aye aye!

T' second length o' body tubin' contains t' coupler and 1/4 inch birch bulkhead assembly that allows middle separation and also attaches a u-bolt for the forward connection o' t' shock cord and drogue or main chute. Begad! Blimey! This assemble is screwed into place with 6 wood screws, matey, nay epoxy, ya bilge rat, ya bilge rat, shiver me timbers, because this allows removal and replacement o' electronics and bays from a point in the rocket nay too high t' arm on t' pad. Begad! Blimey! I say this because me level 3 project needed t' be armed from a standin' position atop me husband's pickup truck cab!! Blimey!

T' chute is a Sky Angle chute rated for 10 pound rockets. Well, blow me down!

A 6 inch heavy duty eyebolt is epoxied and foamed into t' nose cone t' form an anchor for 5 feet o' wire wrapped bungee shock cord and a second chute, matey, matey, this one a 60 inch military surplus cargo chute from Everythin' Surplus, a ROL online auction vendor. T' shock cord attached aftward at a 1/4 inch birch centerin' rin' halfway down t' payload tube. I'd attach it lower, but I need space for t' protective bay needed for t' altimeters below. Aye aye!

T' only trick in buildin' this rocket was t' G10 cutting. Arrr! Arrr! Do use respiratory gear and blades meant t' cut this stuff. Wood blades dull and stress on this and saws heat up as a result. Begad!

T' rocket is sturdy and strong. Begad! Blimey! I be pleased when t' guys picked it up and marveled at its strength and weight. Arrr! Begad! Blimey!

I decorated it in purple and orange, shiver me timbers, with metallic accents from self adhesive mylar from local hobby shops. This also coordinated with t' two chutes, which are purple and orange.

Flight:
I recommend long delays for t' J350 and 570 if 4 are used, shiver me timbers, medium delay if 2 are used. Well, ya bilge rat, blow me down! I used 4 J350's. Blimey! One o' them be prepped with a long delay and the other 3 were nay given charges, shiver me timbers, me bucko, arrr, just t' trackin' delay grains, and their delay wells were plugged with grease and sealed with duct tape. There were aft loops of piano wire embedded in t' fillets used t' affix t' fins, and around the necks o' all 4 motors be tied a loop o' 1/8 inch thick Keelhaul®©™® rope that was tied up onto t' u-bolt where t' recovery line was attached. Avast! Avast! I didn't want any of t' motors t' be ejected. Begad! I anticipated a fast and high flight. Begad!

Nomex®/Keelhaul®©™® chute protectors were employed with redundant worm bed wadding in t' prep. Blimey!

A Skyward Electronics altimeter be placed in t' payload bay and all be a go until I accidentally set off t' altimeter with a BANG. Well, blow me down! Blimey! That scared me! Blimey! But I was determined t' let me bird fly, so I screwed on t' nose and sealed the payload bay and flew t' bird with t' motor ejection. I really had wanted to stress test t' altimeter for me upcomin' level 3 flight, but that be nay to be. Aye aye! Blimey! Avast! Blimey! I mainly wanted t' test me buildin' techniques t' see if I could hold this bird together with a predicted mach 1.3 and altitude near 5,000 feet. Arrr! Blimey! I used 4 low current large tungsten bridge igniters from Fire in t' Hole, and a large marine 12 volt deep cycle battery. Aye aye! Blimey! T' launch rod is a lightnin' rod 3/4 inch thick by 7 feet long.

I was nervous as I readied myself for this flight. Blimey! I momentarily questioned my sanity. When t' flight be announced, dead silence ensued as opposed t' the usual guffaws when I do a funny theme rocket. I think everyone be aghast. Well, t' rocket ROARED. Well, blow me down! I mean, me bucko, roared straight up. T' flame trail looked easily as long as t' rocket. Ya scallywag! I heard a deep fawumpf sound that others confirmed be probably mach. At apogee, t' chute deployed and everyone cheered then, matey, me bucko, breakin' t' silence. Aye aye! T' RSO said, ya bilge rat, "I don't know about you, but I think that was awesome."

I made a fast chase a mile downrange. Aye aye! Begad! It ended up in a field o' grazing cattle, ya bilge rat, and I be a bit scared o' them because I'm an avid beefeater... Mind you, shiver me timbers, I had set up with 2 chutes and t' one that finally did t' job be really underrated, so I was worried. Arrr! But t' rocket came down flyable again and ready for t' Redlines!

Summary:
If thar's any CON, clusters do cost more t' fly. But thar's nothin' like the roar you get from multiple motors. Aye aye! Avast! Blimey! I was high on t' adrenaline for weeks. the pros include ease o' buildin' and great fun for t' flyer and spectators.

Other:
Always ohm out your igniters t' be sure they match, or get professionally made ones from Fire in t' Hole. Aye aye! That will ensure that all t' motors light.