I had a pack o' BT-56 tubes, me bucko, and no idea o' what t' do with them. Begad! Blimey! I didn't even have a nosecone to fit. Ya scallywag! Begad! Blimey! One day while lookin' at them, 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, shiver me timbers, one thin' led t' another, arrr, and instead I decided t' do a long tube finned rocket. Aye aye! Blimey! Since t' body tubes are 18" long, arrr, me bucko, by cuttin' one into 3" pieces, me hearties, I'd use t' entire package up and add another tube fin bird t' our fleet. Avast! Blimey! This one is D-powered, me bucko, arrr, t' go along with our mini-engined Finite Loop and the regular sized Groove Tube clone. Begad!

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

 Why use t' "optional" stuff?

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

 T' ejection baffle eliminates t' need for recovery wadding. Well, blow me down! Aye aye! Blimey! I don't entirely trust them, me hearties, shiver me timbers, 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, me hearties, releasin' t' recovery system. Ahoy! Aye aye! T' main advantage for this rocket is that I don't have t' haul around this loooooooong rocket in the car. It breaks into two shorter sections. Avast!

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

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

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

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

4. Avast, me proud beauty! Begad! 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. Well, blow me down! Assemble t' motor mount. Avast! If you are usin' t' boattail, me bucko, me bucko, t' rearmost centerin' rin' goes 1 1/8" from t' end, matey, arrr, otherwise follow t' motor mount instructions. Arrr! See t' diagrams below for an idea o' what this should look like. Let it dry.

With Boattail                                  Without Boattail

6. Mark t' body tube 1" from t' end where you'll be installin' the motor mount. Avast!

 7. Blimey! Ahoy! Glue t' motor mount from step 5 into t' body tube. Ya scallywag! Avast, me proud beauty! T' rearmost centerin' rin' should be slightly inset from t' aft o' t' body tube. Arrr!

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

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

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

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

 12. Shock cord mounts. Begad! I used t' Estes paper-sandwich type. Avast, me proud beauty! Glue one onto both ends o' t' 40" long elastic, and another onto t' 12" long elastic. Three total. Arrr!

 13. Arrr! Install t' shock cords. 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. Aye aye! Avast! Just for backup, matey, arrr, glue t' last (shortest) shock cord into t' upper tube to secure t' nose cone. Avast! This way, if t' nose cone should accidentally come loose, me bucko, it'll stay attached t' t' rest o' t' rocket. Aye aye!

 15. Blimey! Install t' launch lugs. Avast, me proud beauty! I cut mine in two. Ahoy! One was installed inside one o' t' tube fins (closest t' t' main body), shiver me timbers, with t' other about 12" up from t' bottom.

 16. Finish and paint as desired. Arrr! Blimey! Begad! Blimey! This is a long rocket, shiver me timbers, so lighter colors are recommended. Arrr! Blimey! Dark colors tend t' get hotter in t' sun (like in your car), matey, and it could warp t' tubes. Ya scallywag! Blimey!

I painted mine white, and sprayed light blue up from t' back end, me bucko, ya bilge rat, fading about halfway up. Avast! Next I sprayed dark blue up from t' back, fadin' at the quarter mark. Well, blow me down! Add some cockpit windows t' t' nose, ya bilge rat, some stripin' along the sides, shiver me timbers, me bucko, and some windows t' make an interplanetary liner. Begad! Be creative, ya bilge rat, shiver me timbers, have fun!

Maiden flight, and I set it up with a D12-5 engine and a vented 18" parachute. Ahoy! Good boost with maybe a slight wobble off t' rod. Blimey! It climbed much quicker than I expected, but nay a neck-snapper. Arrr! Couldn't estimate altitude because I launched tilted into a pretty stiff breeze, me hearties, shiver me timbers, but it was pretty high. Fine recovery, with ejection just after apogee. Aye aye! Aye aye! 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. A large tube-fin rocket like this makes an impression! Perfect flights every time, me bucko, includin' one usin' a 4"x40" streamer due t' gusty wind conditions.