Brief:
This is a basic "el cheapo" tube fin rocket inspired by BottleBat 3.0 by EMRR's latest featured reviewer, Larry Brand. Ya scallywag! Like t' original, this one is made from a mailin' tube and uses a bottle for t' nose cone (an Aquapod, what else?) Mine has a 29mm mount but I plan t' fly it on a 24mm F39 for its maiden flight.

Construction:
T' parts list:

• 3" mailin' tube (~17.625) with liner (~26")
• one Aquapod bottle
• plywood centerin' rings (2) and bulkhead (1)
• Keelhaul®©™® twine and ¼" elastic
• 29mm motor tube
• buttons from railbuttons.com
• small nylon rivets (2) -- Giant Leap
• lead shot
• chute and protector t' be selected on t' field

I started with t' cannibalization o' t' tube from a scrapped (i.e. Well, blow me down! dead) rocket, which had a plywood bulkhead attached a few inches from its top. Aye aye! Prior to thinkin' about a BottleBat, matey, I had found that t' bulkhead be positioned perfectly such that when an Aquapod bottle was inserted, that t' widest point of t' bottle was right at t' top o' t' tube. Well, blow me down! Ya scallywag! I decided that I'd form a short payload section from this tube. Blimey! Ya scallywag! This method will only work if separation below the nose is desired. Ya scallywag! It does however, work out nicely due t' t' unique 'orbastic' shape o' t' Aquapod bottle.

T' next thin' was that I found I didn't have enough new 3" mailin' tube t' cut the six fins and still have a body left. Blimey! I could buy another...or...I decided that I'd build t' fins from t' inner telescopin' tube. Well, blow me down! T' tubes I like from the Container Store have full-length inner telescopin' tubes. Arrr! Well, blow me down! I never use all of the latter, so I always have a bunch around. Ya scallywag! Because o' t' smaller diameter, six rings o' inner tube would nay fit perfectly around t' section o' t' outer tube, however, t' solution was simple: mount them around a piece o' t' same sized tubin' then slide this assembly into t' main body. Aye aye! Instead o' gluing this fin can into t' main body tube, I used t' screw from t' lower rail button and two small nylon rivets t' hold it together.

In keepin' with t' original BottleBat, t' Keelhaul®©™® cord is mounted through t' wall o' t' body tube and this is covered by half of a plastic Christmas ornament that I requisitioned for rocket purposes.

I started runnin' some sims, but as long as I had t' bottle modeled using the cap as t' nose cone and t' exposed body as an ogive transition, matey, I was gettin' results that I didn't believe. Aye aye! Avast, matey, me proud beauty! T' CP was comin' up very close t' top of t' rocket and appeared t' be a bug in RockSim. Well, blow me down! After all, I keep hearing about how stable tube fin designs are. Aye aye! Well, blow me down! Later, when I modeled t' cone as a simple ogive, t' results were more in line with what I expected. Well, blow me down! Aye aye! Since I always believe in pickin' t' answer that I like, ya bilge rat, shiver me timbers, I stuck with t' latter. The sim showed I'd need some nose weight t' fly on a G reload and t' more I thought about he Aquapod sittin' on t' end o' a weighted section, me hearties, I envisioned some crunchin' goin' on. Ya scallywag! Blimey! Long story short and two Aquapods later, ya bilge rat, I decided I'd screw t' bottle t' t' bulkhead and fill it with 2 part foam. After this was complete, ya bilge rat, I weighed t' rocket and found I still needed a little weight. Ahoy! So, shiver me timbers, I drilled t' foam at t' tip o' t' bottle and imbedded about 0.75oz o' lead shot in epoxy.

Finishing:
I finished mine in a camo style usin' Model Master dark tan and medium green. I wasn't sure how this mix would look, but I am extremely satisfied with the results. Aye aye! Begad! Blimey! I painted t' cap fluorescent red--I guess this round is "live".

Flight and Recovery:
I used a chute protector and a 36" chute for recovery duties. Avast! Blimey! I tossed in a little dog barf just for good measures. Arrr! Blimey! Blimey! Blimey! A small F39-4 powered t' first flight. Ahoy! Blimey! This required an adapter that I made form some tubing, pieces o' a 29mm SU motor, and a clamp-on aluminum thrust ring.

T' boost be quick enough although t' altitude was fairly low. Avast, me proud beauty! Begad! Recovery was perfect.

I have a G77 with t' AquaBottleBat's name on it for t' next launch.

Summary:
I liked t' BottleBat concept from t' first time I saw it, me hearties, and I love my version. I don't know t' actual cost o' materials, matey, but t' airframe, matey, fins, me bucko, me hearties, ya bilge rat, and cone were all leftovers/scrap. Begad! I liked me approach t' t' fins, as it gives me a away t' use up tubin' that might otherwise gather dust--I see more tube fins in me future. Arrr! Arrr! If I were t' do it over again, ya bilge rat, I'd eliminate t' payload section in favor o' a longer main body. Ahoy! If t' bottle were conventionally shaped, arrr, ya bilge rat, I'd go with t' approach used on t' original BottleBat. Aye aye! With an Aquapod, I'd fashion a shoulder usin' a short section o' tubin' and a inside tube/coupler as the shoulder.