Brief:
For completion o' her NARTREK Sliver cluster flight requirement, I suggested t' me wife that we rebuild t' stock 18mm engine Estes Bullpup with a cluster o' four 13mm A3-4T motors. She had already built one Big Bertha and didn't feel like buildin' another 3-motor version (Astron Ranger) that NARRRRR recommends for this task. So we tried this.

Construction:
T' stock Estes Bullpup kit be built accordin' t' t' plans, except t' stock 18mm motor mount and thrust rings were omitted entirely.

Modifications:

1. 5-minute epoxy was used, me hearties, since sims predicted a 200 mph, 26G climb out
2. Recovery system: 9" nylon parachute on 18" o' 3/8" elastic
3. Boattail was omitted t' accommodate t' 4 motor cluster
4. Four 3" lengths o' 13mm Estes tubin' glued together in a 2x2 square array were used instead and slid into t' aft body tube after slatherin' with ample 5-minute epoxy.

Approximately 1/4" o' t' cluster array was left protruding. No motor stops or motor hooks were used; retention was by friction fit usin' bits o' maskin' tape and by wrappin' t' protrudin' aft 1/4" o' t' motors and protrudin' aft 1/4" o' t' motor tubes with maskin' tape before launch.

It is important t' seal t' five open spaces betwixt t' motor tubes and t' hull with bits o' cotton soaked in wet epoxy t' insure ejection charge pressurization. Avast, ya bilge rat, me proud beauty! For balance, ya bilge rat, t' nose cone had 25g o' epoxy and fishin' sinkers added as ballast at t' tip--don't omit this step!!

Use plenty o' extra waddin' (or better yet, me bucko, a small Nomex pad) when flyin' t' protect that chute from t' heat o' 4 ejection charges!! Final flyin' weight is 85g.

If desired, both t' scale and cluster requirements o' t' NARTREK Silver program can be satisfied with this rocket (separate flights needed) by finishin' in scale colors and usin' t' kit decals; for maximum scale points, shiver me timbers, t' boattail can be loosely attached over t' 4-13mm motor cluster for "judging". Ahoy! All in all, this is about t' cheapest, me bucko, arrr, me hearties, simplest and fastest buildin' 4-motor cluster model that I know of. Begad! It easily goes together in less than an hour with epoxy and includin' painting. Begad! Well, blow me down! O' course its main reason for bein' built is t' fly t' NARTREK Silver requirement (a cluster rocket havin' 3 or more motors). Besides, shiver me timbers, thar just aren't any inexpensive kits o' this type available nor few scratch cluster designs that qualify (a few are me "2BZ", shiver me timbers, "Funnel Vision" and "Cheap Dumb Rocket" on this website). Aye aye! Altitude performance is identical t' t' stock C6 powered Estes Bullpup, 700' or so, although t' "C12-4" powered "Silver Bullpup" sure gets thar a lot faster!!

Finishing:
Model was finished with a single coat o' silver spray paint.

Flight:
T' ship is designed exclusively for A3-4T motors and it should fly well even on only two o' these. Avast, me proud beauty! I don't recommend substitution o' A10-3 motors (equivalent t' a C40-3!) unless you want t' see a shred. Begad! Ignition be done with a clip whip--it works every time and you can check continuity on each motor with this setup.

First flight be perfect: straight, arrr, shiver me timbers, incredibly fast boost t' 600-700', me bucko, and with ejection right at apogee.

Recovery:
Despite lots o' extra wadding, matey, me wife's brand-new, me hearties, shockin' pink 9" Top-Flite chute was scorched black and holed by t' ejection blast.

Summary:
PROs:

• This be t' fastest kit t' build that can be used for t' NARTREK Silver badge.
• Small 13mm motors make this good for junior flyers and/or small fields.
• Good flyin' qualities

CONs:

• Added complexity o' cluster flight
• No real advantage over t' great-flyin' stock Estes Bullpup (except you can toast a C6-powered Bullpup in a drag race)