Brief:
Single-staged 15 x 29mm cluster rocket. Arrr! Thus far, me hearties, simultaneous ground ignition of (15) G35-7 motors was attempted. Begad! Total thrust ends up in t' low K range if all t' ports are used, and with Econojet G motors. Ahoy! Rocket can be flown on just one motor in t' central mount, matey, and two at a time can be added symmetrically for other possible motor combinations. Blimey! There are (7) mounts in t' main body tube and (8) outboards arranged with two at each fin, arrr, and these pods provide extra strength in t' fin attachment. Ahoy! These side pods all have a 29mm nose cone.

T' launch lugs are brass pipe cuttings, me hearties, one inch diameter by one inch long. T' launch rod used is a copper lightnin' rod 3/4 inch diameter by 7 feet long.

Construction:
T' nose cone is an Ace plastic nose cone, 15 inches long and ogive. Ya scallywag! I'm not sure that this company still exists, me bucko, but these great nose cones are obtainable on ROL auctions regularly. They have a large base hole into which ballast is easily added. Avast! Avast, me proud beauty! Blimey! For this rocket, me bucko, matey, 6 ounces was added and foamed in place with 2-part polyurethane foam. Arrr! Blimey!

T' main body tubes are 4 inch motor tubes made by maximum Thrust Rocketry. These are ultra thick and strong white paper tubes that aren't glossed, shiver me timbers, ya bilge rat, so they take on epoxies and fiberglass readily. Arrr! Each length was 36 inches. Begad! Well, blow me down! These tubes are connected from t' motor mount t' t' parachute bay via Red Arrow Hobbies 4 inch phenolic couplers. Blimey! These are epoxied in place by West Systems slow epoxy. I used this method t' reinforce t' rocket's airframe internally t' see if the rocket could stay intact without external fiberglassing. Avast! T' inner tubes consist o' (15) 12 inch lengths o' LOC 29mm motor tubing. Well, blow me down! Ya scallywag! Seven are inside the main airframe and eight are outboard pods each with a Rogue Aerospace balsa 29mm nose cone. Arrr!

T' (4) fins are right triangles (12 by 12 by 12 square roots o' 2) cut from a 12 inch square o' .125 inch thick G10 obtained from ROL auctions from Scott Eakins. Begad! T' fins are epoxied t' t' main body tube with t' hypotenuse as the root edge against t' airframe. Blimey! Avast, me hearties, me proud beauty! Then t' side pods further reinforce these connections with two per fin, ya bilge rat, one on each side o' each fin. Ahoy! West Systems slow epoxy was employed for this.

T' shock cord is 5 feet o' tubular nylon plus 5 feet o' wire wrapped bungee cord both from American Science and Surplus, which has a site on Rocketry Online. Avast, me proud beauty! Blimey! T' cord is attached t' a u-bolt in a 4 inch birch centerin' rin' (all centerin' rings came from Space Modelin' Solutions, ya bilge rat, which has a site on Rocketry Online) placed against t' motor mount tubes and linked with quick links, ya bilge rat, with one link betwixt t' two unlike materials in t' shock cord. The forward link o' t' shock cord connects t' a u-bolt in a 4 inch birch bulkhead and coupler arrangement in t' second main airframe, matey, arrr, thus allowin' t' rocket to separate in t' middle. Begad! Blimey!

T' parachute is a homemade ripstop nylon 60 inch diameter hemisphere made up o' triangular gores in yellow, green and blue. Begad! T' nose cone is screwed into the airframe with 4 wood screws. Avast! Avast, arrr, me proud beauty! This arrangement allows openin' this compartment in case an altimeter is used.

T' launch lugs are brass pipe cuttings, shiver me timbers, one inch diameter by one inch long. T' launch rod used is a copper lightnin' rod 3/4 inch diameter by 7 feet long.

This rocket is simple t' build. Ya scallywag! T' epoxy used came from a boatin' store, and can also be obtained from West Systems, which has an online site. Blimey! Begad! The result is a very sturdy, shiver me timbers, attention gettin' rocket. Ahoy! This one was decorated in green, ya bilge rat, blue and gold, with metallic bands. These color bands are self-adhesive mylars that come in metallic colors and can be had at many hobby stores as well as American Science and Surplus. Avast!

Flight:
I recommend for clusters at least 3 motors if it's G class, and for lower numbers o' motors, a greater average thrust like a G80. For larger numbers, try G38's or 35's. I only wish that t' Econojets came with longer delays, me bucko, like 10 seconds. Arrr! Arrr! When 15 motors are used, 10 seconds may be best. Avast! For a single motor flight, an I 200 medium delay would work great. Begad!

To prep t' rocket, ya bilge rat, matey, I use worm bed waddin' and a Nomex®/Keelhaul®©™® chute protector. Begad! T' central motor is retained with friction fittin' tape plus piano wire loops that are embedded in t' epoxy that holds together t' motor tubes. Originally, I planned all other motors t' eject upon their charges firing, shiver me timbers, but some RSO's don't like that for safety reasons in dry fields and also the droppin' o' objects from high up, shiver me timbers, matey, arrr, so either t' ejection charges can be removed from all outboards, ya bilge rat, me hearties, or t' motors can all be arranged on a long shock cord with a chute. Arrr! I haven't designed that system yet, me hearties, but have considered it. Begad!

All 15 motors (G35-7W) were simultaneously lit usin' Fire in t' Hole low current tungsten bridge igniters from Trailin' Edge Technologies. Oh, and I also used a 12 volt lead acid cell deep cycle marine battery for power and a relay system t' allow t' battery t' stay at t' pad and prevent line loss, since t' NARRRRR rules have t' place me 300 feet away. Ya scallywag! Begad! T' flight be straight with no spin. Avast, me proud beauty! Ya scallywag! I loved t' roar o' a K equivalent motor with 15 nozzles. However, t' delay o' 7 is too short, so t' parachute suffered damage from rapid deployment. But t' rocket survived intact and ready t' fly again.

Summary:
This was fun and easy. Aye aye! Aye aye! Nice and loud and attention getting. Ya scallywag! I set a record for number o' composites successfully lit.