Brief:
This is a basic "el cheapo" tube fin rocket inspired by BottleBat 3.0 by EMRR's latest featured reviewer, Larry Brand. Ahoy! Aye aye! 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. Avast! dead) rocket, which had a plywood bulkhead attached a few inches from its top. Avast! Well, blow me down! Prior to thinkin' about a BottleBat, me hearties, I had found that t' bulkhead was positioned perfectly such that when an Aquapod bottle be inserted, that t' widest point of t' bottle was right at t' top o' t' tube. Arrr! I decided that I'd form a short payload section from this tube. Ahoy! This method will only work if separation below the nose is desired. Well, blow me down! It does however, shiver me timbers, matey, me bucko, 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. I could buy another...or...I decided that I'd build t' fins from t' inner telescopin' tube. T' tubes I like from the Container Store have full-length inner telescopin' tubes. Avast! I never use all of the latter, so I always have a bunch around. Because o' t' smaller diameter, six rings o' inner tube would nay fit perfectly around t' section o' t' outer tube, ya bilge rat, however, me hearties, 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, shiver me timbers, 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, shiver me timbers, but as long as I had t' bottle modeled using the cap as t' nose cone and t' exposed body as an ogive transition, I was gettin' results that I didn't believe. Well, blow me down! Aye aye! T' CP was comin' up very close t' top of t' rocket and appeared t' be a bug in RockSim. Ya scallywag! After all, me bucko, I keep hearing about how stable tube fin designs are. Begad! Later, matey, when I modeled t' cone as a simple ogive, t' results were more in line with what I expected. Aye aye! Since I always believe in pickin' t' answer that I like, me hearties, 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 bucko, I envisioned some crunchin' goin' on. 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. Begad! After this was complete, I weighed t' rocket and found I still needed a little weight. Avast! So, 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. Avast, ya bilge rat, me proud beauty! I wasn't sure how this mix would look, arrr, but I am extremely satisfied with the results. Ya scallywag! 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. Well, blow me down! Well, arrr, blow me down! I tossed in a little dog barf just for good measures. A small F39-4 powered t' first flight. Avast, me proud beauty! 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 was quick enough although t' altitude was fairly low. Ahoy! Avast, ya bilge rat, me proud beauty! 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, and I love my version. Begad! I don't know t' actual cost o' materials, but t' airframe, fins, ya bilge rat, and cone were all leftovers/scrap. Ahoy! Well, blow me down! 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. Avast, me proud beauty! If I were t' do it over again, me hearties, I'd eliminate t' payload section in favor o' a longer main body. Blimey! If t' bottle were conventionally shaped, matey, I'd go with t' approach used on t' original BottleBat. Arrr! With an Aquapod, I'd fashion a shoulder usin' a short section o' tubin' and a inside tube/coupler as the shoulder.