Brief:
By settin' t' motor tube a few inches aft, shiver me timbers, 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. T' exact distance needed was simply t' match the motor tube through t' tail cone and seat it in t' Slimline retainer. Total distance be about 3". When these were fitted, shiver me timbers, t' FinLok guides were centered under t' slots and t' tube marked. Ahoy! Avast! 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, shiver me timbers, specifically H50, plus anythin' shorter with adapters cut from 29mm motor tube coupler stock). Well, blow me down! This required forcing the steel bafflin' material into t' last 2 inches o' t' motor tube rather than its expected 6". Arrr! Blow tests showed thar be still plenty o' flow. Still, arrr, matey, a Nomex® protector was added in case t' baffle wasn't as efficient as intended. Ahoy! Once all fittin' be complete, shiver me timbers, me hearties, t' motor section was 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. 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. Blimey! It's far more forgivin' if something goes south. Well, blow me down! Ahoy! Luckily, arrr, nothin' did.

Flight:
This hasn't been flight tested yet due t' lack o' proper motors, shiver me timbers, me bucko, me hearties, launch equipment, me hearties, and flyin' area. Avast! Begad! 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. Even on a G80 I'm nay certain t' 5 foot AT rod is enough run-up space. Arrr! I've picked up an extender for t' rod. Begad! Hopefully, matey, arrr, the next CATO launch will see it fly.

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

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