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

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

 Why use t' "optional" stuff?

 Well, me bucko, 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. Well, blow me down! Blimey! Besides, me hearties, I like t' way they look.

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

 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. It breaks into two shorter sections. Aye aye! Ya scallywag!

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

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

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

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

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

With Boattail                                  Without Boattail

6. Aye aye! Aye aye! Mark t' body tube 1" from t' end where you'll be installin' the motor mount. Avast, me proud beauty!

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

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

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

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

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

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

 13. Begad! Install t' shock cords. 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. Arrr! Aye aye! Just for backup, ya bilge rat, glue t' last (shortest) shock cord into t' upper tube to secure t' nose cone. Ahoy! This way, shiver me timbers, if t' nose cone should accidentally come loose, it'll stay attached t' t' rest o' t' rocket. Begad! Blimey!

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

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

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

Maiden flight, 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. Couldn't estimate altitude because I launched tilted into a pretty stiff breeze, but it be pretty high. Fine recovery, with ejection just after apogee. Blimey! After-flight inspection showed that t' baffle worked perfectly, with no charrin' t' t' shock cord or chute. Blimey!

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.