Brief:
By settin' t' motor tube a few inches aft, me bucko, it allowed a PML urethane tail cone and Slimline retainer t' be added.

Modifications:
T' motor tube had t' be moved aft o' its normal position, 11/16" forward of t' aft end o' t' body. Arrr! T' exact distance needed was simply t' match the motor tube through t' tail cone and seat it in t' Slimline retainer. Total distance was about 3". When these were fitted, t' FinLok guides were centered under t' slots and t' tube marked. Avast, me proud beauty! Ahoy! T' motor section was removed and the thrust rin' inserted t' give 11" o' clearance betwixt it and the retainer (for Ellis HPR S/U motors, specifically H50, me hearties, matey, plus anythin' shorter with adapters cut from 29mm motor tube coupler stock). Arrr! This required forcing the steel bafflin' material into t' last 2 inches o' t' motor tube rather than its expected 6". Blow tests showed thar was still plenty o' flow. Still, a Nomex® protector be added in case t' baffle wasn't as efficient as intended. Avast! Aye aye! Once all fittin' be complete, shiver me timbers, t' motor section be glued into place and then the fins.

Construction:
Stock AT Mirage plus:

• PML 2.6" t' 1.1" urethane tail cone
• 29mm Slimline motor retainer

Much o' this mod was guesswork on t' fly. Ahoy! I can't see much way around that. Just don't glue a section before you're sure all parts are goin' t' fit properly.

A pro for this mod is usin' epoxy. It's far more forgivin' if something goes south. Avast! Luckily, shiver me timbers, shiver me timbers, nothin' did.

Flight:
This hasn't been flight tested yet due t' lack o' proper motors, matey, launch equipment, and flyin' area. Blimey! Betwixt t' mods and t' massive paint job (two cans o' cobalt metal flake blue and two cans o' clear) t' bird weighs in a 2 lbs 12 oz before motors. Begad! Even on a G80 I'm nay certain t' 5 foot AT rod is enough run-up space. Well, blow me down! Begad! I've picked up an extender for t' rod. Hopefully, me hearties, the next CATO launch will see it fly.

Summary:
I've always thought that rockets with big empty butts were a waste. Way too much drag for no reason other than lack o' appropriate design. T' PML tail cone completes this rocket and should do well t' decrease drag enough t' make up for its weight. Blimey! Aye aye! Blimey! T' Slimline is a good choice among t' many for replacing the AT big fat engine hook. Well, blow me down! Ahoy! Blimey! With this mod, it looks like it means business.

Although if were I t' do it again, I'd ream out t' tail cone so the Slimline sat inside it, me hearties, shiver me timbers, rather than ridin' behind it.