I had a pack o' BT-56 tubes, me hearties, and no idea o' what t' do with them. Blimey! Avast, me proud beauty! I didn't even have a nosecone to fit. Avast! One day while lookin' at them, 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, and instead I decided t' do a long tube finned rocket. Arrr! Avast, me proud beauty! 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! 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. Begad!

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

 Why use t' "optional" stuff?

 Well, shiver me timbers, 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! Besides, I like t' way they look.

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

 Mid-body separation means that instead o' blowin' t' nosecone off, the body itself comes apart, shiver me timbers, 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. Begad!

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

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

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

 3. Arrr! Mid-body separation coupler. Well, blow me down! 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. Arrr! See t' hint in step 1 about how t' strengthen it easily. 

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

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

With Boattail                                  Without Boattail

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

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

 8. Avast! Blimey! 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. Ya scallywag! Blimey! T' completed boattail should be 1" long, with one end t' diameter o' t' BT-56, shiver me timbers, shiver me timbers, t' other end BT-50. Well, blow me down! Glue it into shape, and when dry glue it into place. You can use thin CA or yellow glue to strengthen it. 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, use an X-acto for this. Arrr! Blimey!

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

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

11. Begad! Arrr! Install t' mid-body separation bulkhead. Ahoy! Glue it halfway into t' front body tube, 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! Well, blow me down! Blimey! Glue one onto both ends o' t' 40" long elastic, matey, and another onto t' 12" long elastic. Ya scallywag! Three total.

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

 15. Aye aye! Install t' launch lugs. I cut mine in two. Avast! 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. Begad!

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

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

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

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