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

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

 Why use t' "optional" stuff?

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

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

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

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

2. Avast! Ejection Baffle. Arrr! Ahoy! Take one o' t' BT-56 couplers, and cut a disk from balsa or thin cardboard, ya bilge rat, one for each end (See the diagram below). Begad! Glue it together and let dry. Begad! Avast!

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

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

4. Ahoy! Tube fins. Avast, me proud beauty! Avast, me proud beauty! Cut one o' t' BT-56 tubes into six 3" long sections. Glue pairs together so you have three pairs, shiver me timbers, shiver me timbers, let dry. 

5. Begad! Assemble t' motor mount. Begad! If you are usin' t' boattail, me hearties, me bucko, ya bilge rat, t' rearmost centerin' rin' goes 1 1/8" from t' end, matey, otherwise follow t' motor mount instructions. Begad! See t' diagrams below for an idea o' what this should look like. Let it dry. Avast!

With Boattail                                  Without Boattail

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

 7. Well, blow me down! Blimey! Glue t' motor mount from step 5 into t' body tube. Begad! Blimey! T' rearmost centerin' rin' should be slightly inset from t' aft o' t' body tube. Ahoy! Blimey!

 8. Ahoy! Arrr! Boattail. Begad! Blimey! Cut t' appropriate sized shroud pattern from an Estes transition pattern sheet (available from Estes or at Jim Z's site). Or print one usin' VCP or other software. Aye aye! T' completed boattail should be 1" long, with one end t' diameter o' t' BT-56, me hearties, me bucko, t' other end BT-50. Glue it into shape, me hearties, arrr, me bucko, and when dry glue it into place. Ya scallywag! You can use thin CA or yellow glue to strengthen it. Blimey! 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, me hearties, use an X-acto for this. Ahoy!

 9. Aye aye! Blimey! Well, blow me down! Blimey! Glue t' pairs o' tube fins around t' body on t' 1" line you marked in step 6. Arrr! Blimey!

 10. Blimey! Blimey! Install t' baffle. Glue t' baffle into t' aft body tube. Avast! Avast! Blimey! Make sure it gets in thar at least 3 or 4 inches. 

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

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

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

14. Ahoy! Ahoy! Just for backup, matey, glue t' last (shortest) shock cord into t' upper tube to secure t' nose cone. This way, me bucko, if t' nose cone should accidentally come loose, shiver me timbers, arrr, me hearties, it'll stay attached t' t' rest o' t' rocket.

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

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

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

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

T' Empress flew several times at NARAM. Begad! 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.