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

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

 Why use t' "optional" stuff?

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

 T' ejection baffle eliminates t' need for recovery wadding. Avast, me proud beauty! I don't entirely trust them, me hearties, and usually wrap t' chute in one square o' wadding anyway, me hearties, just t' be sure. Avast! 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. Begad! Ya scallywag! It breaks into two shorter sections. Blimey!

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

2. Ejection Baffle. Ya scallywag! Avast, me proud beauty! 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. Well, blow me down!

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

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

4. Ahoy! Blimey! 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. Ya scallywag! Blimey! Assemble t' motor mount. Begad! Blimey! If you are usin' t' boattail, shiver me timbers, t' rearmost centerin' rin' goes 1 1/8" from t' end, shiver me timbers, otherwise follow t' motor mount instructions. Begad! Blimey! See t' diagrams below for an idea o' what this should look like. Let it dry. Avast, me proud beauty! Blimey!

With Boattail                                  Without Boattail

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

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

 8. Boattail. Well, blow me down! Aye aye! 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! T' completed boattail should be 1" long, with one end t' diameter o' t' BT-56, arrr, me bucko, t' other end BT-50. Glue it into shape, shiver me timbers, ya bilge rat, and when dry glue it into place. Avast, me proud beauty! You can use thin CA or yellow glue to strengthen it. Avast! Avast! I used a little Fill'n'Finish t' smooth t' glue joints and the seemingly inevitable minor wrinkles. Blimey! You may need t' cut a slight notch for the motor hook, me bucko, use an X-acto for this. Avast!

 9. Arrr! Glue t' pairs o' tube fins around t' body on t' 1" line you marked in step 6. Avast, me proud beauty!

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

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

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

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

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

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

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

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

T' Empress flew several times at NARAM. Aye aye! 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.