Brief:
Single-staged 15 x 29mm cluster rocket. Ahoy! Blimey! Thus far, matey, arrr, simultaneous ground ignition of (15) G35-7 motors was attempted. Ya scallywag! Blimey! Total thrust ends up in t' low K range if all t' ports are used, and with Econojet G motors. Ya scallywag! Blimey! Rocket can be flown on just one motor in t' central mount, ya bilge rat, and two at a time can be added symmetrically for other possible motor combinations. Ahoy! Blimey! Ya scallywag! Blimey! There are (7) mounts in t' main body tube and (8) outboards arranged with two at each fin, and these pods provide extra strength in t' fin attachment. Avast, me proud beauty! Blimey! 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, matey, 15 inches long and ogive. Avast! I'm not sure that this company still exists, arrr, ya bilge rat, but these great nose cones are obtainable on ROL auctions regularly. Begad! Avast, me proud beauty! They have a large base hole into which ballast is easily added. For this rocket, ya bilge rat, 6 ounces be added and foamed in place with 2-part polyurethane foam. Well, blow me down! Begad!

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, so they take on epoxies and fiberglass readily. Each length be 36 inches. Ahoy! These tubes are connected from t' motor mount t' t' parachute bay via Red Arrow Hobbies 4 inch phenolic couplers. Aye aye! 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. Ya scallywag! T' inner tubes consist o' (15) 12 inch lengths o' LOC 29mm motor tubing. Seven are inside the main airframe and eight are outboard pods each with a Rogue Aerospace balsa 29mm nose cone. Ya scallywag! Aye aye!

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. T' fins are epoxied t' t' main body tube with t' hypotenuse as the root edge against t' airframe. Aye aye! Then t' side pods further reinforce these connections with two per fin, me bucko, one on each side o' each fin. Aye aye! 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, ya bilge rat, arrr, which has a site on Rocketry Online. T' cord is attached t' a u-bolt in a 4 inch birch centerin' rin' (all centerin' rings came from Space Modelin' Solutions, which has a site on Rocketry Online) placed against t' motor mount tubes and linked with quick links, with one link betwixt t' two unlike materials in t' shock cord. Aye aye! 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, me bucko, thus allowin' t' rocket to separate in t' middle. Aye aye! Avast!

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

T' launch lugs are brass pipe cuttings, matey, 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. Arrr! T' epoxy used came from a boatin' store, and can also be obtained from West Systems, arrr, which has an online site. Ya scallywag! The result is a very sturdy, attention gettin' rocket. Avast, me proud beauty! This one was decorated in green, me bucko, blue and gold, me hearties, ya bilge rat, with metallic bands. Avast! 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. Aye aye!

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

To prep t' rocket, matey, I use worm bed waddin' and a Nomex®/Keelhaul®©™® chute protector. Begad! Blimey! Avast, shiver me timbers, me proud beauty! Blimey! 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, ya bilge rat, but some RSO's don't like that for safety reasons in dry fields and also the droppin' o' objects from high up, so either t' ejection charges can be removed from all outboards, arrr, arrr, or t' motors can all be arranged on a long shock cord with a chute. Arrr! Blimey! Well, blow me down! Blimey! I haven't designed that system yet, but have considered it.

All 15 motors (G35-7W) were simultaneously lit usin' Fire in t' Hole low current tungsten bridge igniters from Trailin' Edge Technologies. Avast! Oh, me hearties, 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. T' flight be straight with no spin. Avast! I loved t' roar o' a K equivalent motor with 15 nozzles. However, ya bilge rat, t' delay o' 7 is too short, me hearties, shiver me timbers, so t' parachute suffered damage from rapid deployment. Begad! But t' rocket survived intact and ready t' fly again.

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