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

Modifications:
T' Fat Boy was built stock. Well, blow me down!

For t' Booster, matey, matey, t' engine mount be assembled in t' usual manner. Avast! T' aft centerin' rin' is flush with the tube end. Avast! 1/4" vent holes were punched in both centerin' rings. Avast! Aye aye! T' coupler extends into t' sustainer approximately 1/2" with a pretty snug fit. Well, blow me down! T' fin pattern was upscaled a bit (the root o' t' fins measures at 3 3/4"). Blimey! T' fins are surface mounted and cut from 1/8" balsa. Ya scallywag! A separate launch lug was 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. It is a well known kit after all. Ahoy! Avast, me proud beauty! The booster was no more difficult t' build than t' original kit. Well, blow me down! T' Booster is pretty stoutly built. I considered using TTW fins, me bucko, 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! 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 be t' single stage Fat Boy on a C6-3. Aye aye! Nice straight flight and clean recovery on a 14" nylon chute. Avast!

Second flight used t' booster with a C6-0 t' B6-6 combination. Avast, me proud beauty! Boost was slow and straight, ya bilge rat, stagin' occurred fairly low and t' sustainer took o' like a shot. Well, blow me down! It weathercocked a bit but had a very nice high flight. Arrr! Chute ejection be a bit past apogee but deployed cleanly. Blimey! T' booster popped a fin loose on landing, arrr, which was easily repaired. Aye aye! T' sustainer made a shipshape landing.

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

Summary:
T' Fat Boy by itself is a fun little rocket, arrr, me bucko, which is suitable t' all kinds o' modification. I was worried that the addition o' a booster would make it t' heavy t' fly on an 18mm engine, matey, but it works very well. Well, blow me down! Blimey! I certainly wouldn't use any booster but t' C6-0 though. Arrr! For a small field stagin' demo, matey, ya bilge rat, 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. Aye aye! Begad! T' gap stagin' has worked flawlessly so far. Well, blow me down! Easy t' build and modify.

CONs: I would like t' have seen 1/8" balsa fins used on t' stock Fat Boy. Begad! Blimey! Sticker decals. Blech!