Brief:
This is another simple, "el cheapo" tube fin rocket based on me tube can concept. A tube can is a fin can with tube fins o' course, built usin' t' telescopin' inside tube from a Container Store mailin' tube. Arrr! 'Real' rocket coupler tubes can also be used.

Construction:
T' parts list:

• 4" mailin' tube (~13.25) and liner (~26")
• one 4" nose cone (in this case recycled from a grounded HPR bird)
• plywood centerin' rings (2)
• 29mm motor tube
• 3' o' thin wire rope and two crimp terminals
• heavy Keelhaul®©™ twine
• buttons from railbuttons.com
• one FirstFire tube
• 2 small nylon rivets from Giant Leap
• chute and protector t' be selected on t' field

I cut t' six tube fins from t' mailin' tube liner and attached them t' a longer piece o' that tubin' usin' carpenter's glue. Avast! Well, blow me down! Blimey! A 29mm motor tube is mounted betwixt two plywood centerin' rings on t' ends, me hearties, formin' a fin can. Ahoy! Blimey! T' fin can slips into a short body tube that I liberated from me daughter (it held a bottle o' wine) and is connected t' t' body tube by t' lower rail button and a nylon pop rivet.

T' recovery harness is a long piece o' thin steel cable mounted through t' top rin' and a longer piece o' thick Keelhaul®©™ twine. Blimey! I forget where I came across t' wire, me bucko, but it was found, nay bought. Begad! Ya scallywag! It is held in place by two crimp terminals (these were bought). Begad! I don't know if I have t' right term, me hearties, but you slide them on t' cable and crimp them on (read: beat them with a big hammer).

For motor retention, me hearties, I mounted a thin aluminum tube through t' two rings. Blimey! A hook made out o' a coat hanger is then run through this tube. Well, blow me down! On t' top, ya bilge rat, a bend in t' wire keeps it in and on t' bottom it is bent t' mate with t' motor. Aye aye! This be t' same technique I used on me Fat Boy 3x4. Ahoy! Begad! T' hook pivots t' allow t' motor t' be inserted and removed and maskin' tape is used t' keep it in t' locked position.

Finishing:
I finished mine in a camo style usin' Model Master dark tan and medium green that be left over from me AquaBottleBat. Well, blow me down! Aye aye! T' cone was previously painted black and I left it that way.

Flight and Recovery:
I used a chute protector and a 48" chute for recovery duties. Well, blow me down! I also added just a tad o' dog barf as usual. Ya scallywag! Begad! T' motor o' choice was a G64-7W with t' delay drilled down t' 4 seconds. When I installed t' motor, matey, I found that, since me wire retainer was custom made for t' 29/120 casing, it didn't mate properly with t' 29/40-120 hobby line case. Avast, me proud beauty! I smartly fashioned a spacer from a tube that, me bucko, if me memory is correct, came with a pack o' G20s. I used a few wraps o' maskin' tape t' hold this spacer tight against t' motor and ensure t' retainer stayed in place.

T' El Tubo Loco flew nicely, shiver me timbers, however, t' delay seemed closer t' t' original 7 seconds than t' desired 4. Arrr! Aye aye! Nevertheless, me hearties, it call came down undamaged. Avast, me proud beauty! Begad! This rocket would fly really nicely on a 29mm H, shiver me timbers, but for now that ain't happening.

Summary:
I like cheap rockets. Ya scallywag! I liked t' idea o' usin' up t' extra tubin' that I had layin' around. Begad! And I'm now likin' tube fins. Nay much else t' say...