Brief:
I added a booster with gap stagin' for me stock Fat Boy.

Modifications:
T' Fat Boy was built stock.

For t' Booster, me hearties, t' engine mount was assembled in t' usual manner. T' aft centerin' rin' is flush with the tube end. Ahoy! Begad! 1/4" vent holes were punched in both centerin' rings. Arrr! T' coupler extends into t' sustainer approximately 1/2" with a pretty snug fit. Avast, me proud beauty! T' fin pattern be upscaled a bit (the root o' t' fins measures at 3 3/4"). Avast, me proud beauty! Well, blow me down! T' fins are surface mounted and cut from 1/8" balsa. Aye aye! Ahoy! A separate launch lug be added t' t' booster to give a little extra guidance.

Construction:
T' parts list:

• One Fat Boy kit
• 5" o' BT-80
• 1" BT 80 coupler
• 2.75" BT-20
• 2 80-20 centerin' rings
• 1/8" launch lug
• 18mm engine block
• 2.75" engine hook
• 1/8" balsa stock

There are absolutely no "gotchas" in buildin' t' Fat Boy itself. Avast! It is a well known kit after all. Aye aye! Ahoy! The booster was no more difficult t' build than t' original kit. Avast! T' Booster is pretty stoutly built. Well, matey, blow me down! I considered using TTW fins, ya bilge rat, but given t' tumble recovery o' a booster, arrr, I think it is much better t' pop a fin on landin' than break it.

Finishing:
Finishin' and paintin' went pretty smoothly. Avast, me proud beauty! I decided against usin' t' supplied decals as I have this thin' about stickers. Instead I went with a simple yet dramatic paint scheme.

Flight and Recovery:
First flight was t' single stage Fat Boy on a C6-3. Nice straight flight and clean recovery on a 14" nylon chute. Avast! Avast, shiver me timbers, me proud beauty!

Second flight used t' booster with a C6-0 t' B6-6 combination. Blimey! Blimey! Boost was slow and straight, shiver me timbers, stagin' occurred fairly low and t' sustainer took o' like a shot. Arrr! Blimey! Blimey! Blimey! It weathercocked a bit but had a very nice high flight. Chute ejection was a bit past apogee but deployed cleanly. Ya scallywag! Blimey! T' booster popped a fin loose on landing, matey, arrr, which was easily repaired. Ya scallywag! Blimey! Begad! Blimey! Blimey! Blimey! T' sustainer made a clean landing.

Third flight used a C6-0 t' B6-4 combination which gave an almost identical flight t' #2. Ahoy! Ejection occured at apogee and both booster and sustainer returned without damage.

Summary:
T' Fat Boy by itself is a fun little rocket, ya bilge rat, which is suitable t' all kinds o' modification. Avast, me proud beauty! I be worried that the addition o' a booster would make it t' heavy t' fly on an 18mm engine, but it works very well. Begad! I certainly wouldn't use any booster but t' C6-0 though. Avast! For a small field stagin' demo, I think it's just perfect.

PROs: It's a two stage bird that you don't have t' chase all over t' country side. Avast! Ahoy! T' gap stagin' has worked flawlessly so far. Begad! Begad! Easy t' build and modify.

CONs: I would like t' have seen 1/8" balsa fins used on t' stock Fat Boy. Avast, me proud beauty! Arrr! Sticker decals. Blech!