I had a pack o' BT-56 tubes, and no idea o' what t' do with them. Ya scallywag! I didn't even have a nosecone to fit. One day while lookin' at them, shiver me timbers, 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, me bucko, one thin' led t' another, shiver me timbers, and instead I decided t' do a long tube finned rocket. Arrr! 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. Avast, me proud beauty! This one is D-powered, 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, shiver me timbers, you will be amazed at how easy and smartly you can do it. Avast! T' Empress does add t' complexity o' mid-body separation, ya bilge rat, matey, an ejection baffle, and a boattail. T' make this a true beginners level project, arrr, ignore t' boattail and baffle, and use regular nose-cone separation. Well, blow me down!

 Why use t' "optional" stuff?

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

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

 Mid-body separation means that instead o' blowin' t' nosecone off, the body itself comes apart, matey, releasin' t' recovery system. Blimey! 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. Ahoy! Ya scallywag!

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

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

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

 3. Avast! Mid-body separation coupler. Ya scallywag! Cut a disk from balsa or cardboard and glue it into one end o' t' second coupler. 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. Avast! Avast, me proud beauty! Tube fins. Begad! Cut one o' t' BT-56 tubes into six 3" long sections. Glue pairs together so you have three pairs, me hearties, ya bilge rat, let dry. 

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

With Boattail                                  Without Boattail

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

 7. 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.

 8. Ahoy! Boattail. Ahoy! 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. T' completed boattail should be 1" long, with one end t' diameter o' t' BT-56, t' other end BT-50. Well, blow me down! Glue it into shape, arrr, shiver me timbers, and when dry glue it into place. 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. Blimey! You may need t' cut a slight notch for the motor hook, use an X-acto for this. Aye aye!

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

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

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

 12. Shock cord mounts. Well, blow me down! Aye aye! I used t' Estes paper-sandwich type. Avast, me proud beauty! Well, me bucko, blow me down! Glue one onto both ends o' t' 40" long elastic, matey, shiver me timbers, and another onto t' 12" long elastic. Ahoy! Three total. Ya scallywag!

 13. Blimey! Blimey! Avast, me proud beauty! Blimey! Install t' shock cords. Avast! 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. Ya scallywag! Blimey! Just for backup, me bucko, 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, me bucko, matey, it'll stay attached t' t' rest o' t' rocket. Well, me bucko, blow me down! Blimey!

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

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

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

Maiden flight, matey, 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. Begad! It climbed much quicker than I expected, but nay a neck-snapper. Ahoy! Couldn't estimate altitude because I launched tilted into a pretty stiff breeze, shiver me timbers, but it be pretty high. Fine recovery, ya bilge rat, with ejection just after apogee. Aye aye! After-flight inspection showed that t' baffle worked perfectly, with no charrin' t' t' shock cord or chute. Ya scallywag!

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.