I had a pack o' BT-56 tubes, matey, and no idea o' what t' do with them. Avast! I didn't even have a nosecone to fit. One day while lookin' at them, me bucko, matey, matey, tryin' t' figure out how I could get rid of the things, I started playin' with t' idea o' buildin' a Mean Machine clone. Well, matey, one thin' led t' another, matey, and instead I decided t' do a long tube finned rocket. Avast! Since t' body tubes are 18" long, by cuttin' one into 3" pieces, me hearties, I'd use t' entire package up and add another tube fin bird t' our fleet. Ya scallywag! Ya scallywag! This one is D-powered, t' go along with our mini-engined Finite Loop and the regular sized Groove Tube clone.

 If you've never built a tube fin rocket, you will be amazed at how easy and smartly you can do it. Begad! T' Empress does add t' complexity o' mid-body separation, me hearties, an ejection baffle, and a boattail. Well, blow me down! Well, blow me down! T' make this a true beginners level project, ignore t' boattail and baffle, and use regular nose-cone separation. Well, blow me down!

 Why use t' "optional" stuff?

 Well, t' boattail will allow t' rocket t' go higher. Begad! There's a whole lot o' complicated mathematical formulas that explain why in aerodynamic terms, but it's all pretty much beyond me. Ahoy! Besides, matey, I like t' way they look. Aye aye! Arrr!

 T' ejection baffle eliminates t' need for recovery wadding. I don't entirely trust them, and usually wrap t' chute in one square o' wadding anyway, just t' be sure. Well, blow me down!

 Mid-body separation means that instead o' blowin' t' nosecone off, the body itself comes apart, ya bilge rat, releasin' t' recovery system. Ya scallywag! T' main advantage for this rocket is that I don't have t' haul around this loooooooong rocket in the car. Begad! Begad! It breaks into two shorter sections. Arrr!

 Yellow glue is plenty strong enough for this rocket. Begad! I used Elmer's Fill'n'Finish for fillets betwixt t' tube fins and t' smooth the boattail. Well, blow me down!

2. Avast, me proud beauty! Ejection Baffle. Take one o' t' BT-56 couplers, arrr, and cut a disk from balsa or thin cardboard, one for each end (See the diagram below). Well, blow me down! Begad! Glue it together and let dry. Begad!

hint: if you use thin cardboard, me hearties, try sandwichin' 2 layers together and soak them in CA (superglue) t' toughen them up. Blimey! Blimey! Coat Balsa with yellow glue t' add stiffness. Ya scallywag! Blimey! Ahoy! Blimey!

 3. Avast, me proud beauty! Avast! Mid-body separation coupler. Aye aye! Cut a disk from balsa or cardboard and glue it into one end o' t' second coupler. Don't put any holes in this one, it's a solid bulkhead. Avast, me proud beauty! Aye aye! See t' hint in step 1 about how t' strengthen it easily. 

4. Ahoy! Aye aye! Tube fins. Cut one o' t' BT-56 tubes into six 3" long sections. Glue pairs together so you have three pairs, let dry. 

5. Assemble t' motor mount. Well, blow me down! Ahoy! If you are usin' t' boattail, t' rearmost centerin' rin' goes 1 1/8" from t' end, shiver me timbers, matey, otherwise follow t' motor mount instructions. Well, blow me down! Begad! See t' diagrams below for an idea o' what this should look like. Let it dry. Aye aye! Begad!

With Boattail                                  Without Boattail

6. Begad! Mark t' body tube 1" from t' end where you'll be installin' the motor mount. Ya scallywag! Aye aye!

 7. Blimey! Glue t' motor mount from step 5 into t' body tube. Begad! T' rearmost centerin' rin' should be slightly inset from t' aft o' t' body tube. Aye aye!

 8. Avast, ya bilge rat, me proud beauty! Boattail. Avast, me proud beauty! Cut t' appropriate sized shroud pattern from an Estes transition pattern sheet (available from Estes or at Jim Z's site). Well, blow me down! Or print one usin' VCP or other software. Avast, arrr, me proud beauty! T' completed boattail should be 1" long, with one end t' diameter o' t' BT-56, me bucko, me bucko, t' other end BT-50. Avast, me proud beauty! Ahoy! Glue it into shape, arrr, matey, and when dry glue it into place. Begad! Begad! You can use thin CA or yellow glue to strengthen it. Well, blow me down! I used a little Fill'n'Finish t' smooth t' glue joints and the seemingly inevitable minor wrinkles. Ya scallywag! You may need t' cut a slight notch for the motor hook, me bucko, use an X-acto for this. Ya scallywag!

 9. Begad! Ahoy! Blimey! Glue t' pairs o' tube fins around t' body on t' 1" line you marked in step 6.

 10. Avast, me proud beauty! Install t' baffle. Arrr! Begad! Glue t' baffle into t' aft body tube. Begad! Begad! Make sure it gets in thar at least 3 or 4 inches. 

11. Install t' mid-body separation bulkhead. Glue it halfway into t' front body tube, me bucko, shiver me timbers, with t' solid end closest t' t' nosecone. Blimey! This be t' coupler that holds t' two body tubes together!!! Make sure you glue it in straight. Begad! Arrr!

 12. Well, blow me down! Blimey! Shock cord mounts. I used t' Estes paper-sandwich type. Glue one onto both ends o' t' 40" long elastic, ya bilge rat, and another onto t' 12" long elastic. Ahoy! Blimey! Begad! Blimey! Three total.

 13. Avast, me proud beauty! Install t' shock cords. Ya scallywag! Glue one end o' t' 40" shock cord into t' bulkhead coupler, and t' other end into t' lower body just above the baffle. 

14. Well, blow me down! Just for backup, ya bilge rat, glue t' last (shortest) shock cord into t' upper tube to secure t' nose cone. Arrr! Arrr! This way, matey, if t' nose cone should accidentally come loose, shiver me timbers, it'll stay attached t' t' rest o' t' rocket.

 15. Install t' launch lugs. Blimey! I cut mine in two. One be installed inside one o' t' tube fins (closest t' t' main body), ya bilge rat, with t' other about 12" up from t' bottom. Arrr!

 16. Ahoy! Arrr! Finish and paint as desired. Well, blow me down! Well, blow me down! This is a long rocket, so lighter colors are recommended. Ya scallywag! Dark colors tend t' get hotter in t' sun (like in your car), ya bilge rat, and it could warp t' tubes.

I painted mine white, and sprayed light blue up from t' back end, fading about halfway up. Begad! Blimey! Next I sprayed dark blue up from t' back, fadin' at the quarter mark. Ya scallywag! Add some cockpit windows t' t' nose, some stripin' along the sides, and some windows t' make an interplanetary liner. Be creative, have fun!

Maiden flight, matey, shiver me timbers, and I set it up with a D12-5 engine and a vented 18" parachute. Begad! Good boost with maybe a slight wobble off t' rod. Aye aye! It climbed much quicker than I expected, but nay a neck-snapper. Ya scallywag! Aye aye! Couldn't estimate altitude because I launched tilted into a pretty stiff breeze, but it was pretty high. Fine recovery, with ejection just after apogee. Avast, me proud beauty! After-flight inspection showed that t' baffle worked perfectly, with no charrin' t' t' shock cord or chute. Arrr!

T' Empress flew several times at NARAM. Ahoy! A large tube-fin rocket like this makes an impression! Perfect flights every time, includin' one usin' a 4"x40" streamer due t' gusty wind conditions.