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

Modifications:
T' Fat Boy was built stock. Aye aye!

For t' Booster, me hearties, t' engine mount was assembled in t' usual manner. Begad! T' aft centerin' rin' is flush with the tube end. Ya scallywag! 1/4" vent holes were punched in both centerin' rings. Avast! T' coupler extends into t' sustainer approximately 1/2" with a pretty snug fit. Aye aye! T' fin pattern be upscaled a bit (the root o' t' fins measures at 3 3/4"). T' fins are surface mounted and cut from 1/8" balsa. Well, matey, blow me down! 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. Well, blow me down! Arrr! It is a well known kit after all. Begad! The booster be no more difficult t' build than t' original kit. Avast, me proud beauty! T' Booster is pretty stoutly built. Begad! Blimey! I considered using TTW fins, ya bilge rat, but given t' tumble recovery o' a booster, me bucko, I think it is much better t' pop a fin on landin' than break it.

Finishing:
Finishin' and paintin' went pretty smoothly. Begad! I decided against usin' t' supplied decals as I have this thin' about stickers. Aye aye! 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. Well, blow me down! Nice straight flight and clean recovery on a 14" nylon chute. Begad!

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

Third flight used a C6-0 t' B6-4 combination which gave an almost identical flight t' #2. Avast, me proud beauty! Blimey! 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! I was worried that the addition o' a booster would make it t' heavy t' fly on an 18mm engine, matey, shiver me timbers, but it works very well. Avast! Well, blow me down! I certainly wouldn't use any booster but t' C6-0 though. 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. T' gap stagin' has worked flawlessly so far. Well, matey, 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. Avast! Blimey! Aye aye! Blimey! Sticker decals. Avast, me proud beauty! Blimey! Blech!