I had a pack o' BT-56 tubes, matey, and no idea o' what t' do with them. Aye aye! Aye aye! I didn't even have a nosecone to fit. Arrr! Ya scallywag! One day while lookin' at them, me hearties, tryin' t' figure out how I could get rid of the things, me hearties, I started playin' with t' idea o' buildin' a Mean Machine clone. Well, me hearties, shiver me timbers, one thin' led t' another, matey, and instead I decided t' do a long tube finned rocket. Arrr! Begad! Since t' body tubes are 18" long, matey, 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, t' go along with our mini-engined Finite Loop and the regular sized Groove Tube clone. Ahoy!

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

 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. Besides, I like t' way they look. Avast, me proud beauty!

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

 Mid-body separation means that instead o' blowin' t' nosecone off, the body itself comes apart, matey, 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. Arrr! It breaks into two shorter sections. Begad!

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

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

hint: if you use thin cardboard, arrr, 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. Ya scallywag! Blimey!

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

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

With Boattail                                  Without Boattail

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

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

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

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

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

11. Ahoy! Install t' mid-body separation bulkhead. Avast! Glue it halfway into t' front body tube, me hearties, 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. Avast, me proud beauty!

 12. Blimey! Avast! Shock cord mounts. Ya scallywag! I used t' Estes paper-sandwich type. Avast! 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! Well, blow me down! Glue one end o' t' 40" shock cord into t' bulkhead coupler, ya bilge rat, and t' other end into t' lower body just above the baffle. 

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

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

 16. Avast, me proud beauty! Well, blow me down! Finish and paint as desired. 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, ya bilge rat, me bucko, and sprayed light blue up from t' back end, matey, fading about halfway up. Next I sprayed dark blue up from t' back, me hearties, fadin' at the quarter mark. Avast, me proud beauty! Add some cockpit windows t' t' nose, some stripin' along the sides, shiver me timbers, arrr, and some windows t' make an interplanetary liner. Be creative, have fun!

Maiden flight, arrr, ya bilge rat, 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, but nay a neck-snapper. Ahoy! Begad! Couldn't estimate altitude because I launched tilted into a pretty stiff breeze, but it was pretty high. Fine recovery, arrr, me hearties, with ejection just after apogee. Blimey! Well, arrr, blow me down! After-flight inspection showed that t' baffle worked perfectly, me bucko, shiver me timbers, with no charrin' t' t' shock cord or chute.

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