T' Tower Rin' Infernal

History

For motivation, arrr, arrr, shiver me timbers, imagine that hydrocarbon seas need t' be refined on Titan, and we're assemblin' t' refinery on orbit, me bucko, in large pieces, and sendin' it directly t' Saturn, usin' temporarily inserted solid rocket motors. Aye aye! Or imagine a debutanizin' tower has decided t' try t' launch itself into t' Gulf o' Mexico (despite appearances, ya bilge rat, they make rather poor rockets. Ya scallywag! Or build it because you've never built a tube fin and rin' rocket before. Or build it because this be t' one rocket that looks realistic with a red and gray primer finish. Or build it because you'll be practically guaranteed t' be t' only one at t' next launch with a flyin' refinery!

AKA, "Da Beaut"

Assembly

1. Cut four fins from 1/8" plywood. Arrr! Blimey! Base is 2.5" long, tip span is 1", ya bilge rat, root is 2".
2. Enlarge t' centerin' rings for t' Big Bertha t' accomodate a 29mm motor mount tube, approximately 6" long. Blimey! Make an extra centerin' rin' or two. Avast! Reinforce with CA, me hearties, me bucko, or use 1/8" plywood if you want.
3. Glue t' fins t' t' motor tube, shiver me timbers, about 3/8" up from t' bottom end.
4. Glue t' centerin' rings t' t' motor tube.
5. Cut four lengths o' 29mm motor tube, each 4.25 inches long. Begad! Usin' t' existin' fins t' mark t' tubes for slots so that they fit over t' fins.
6. Cut a slot in each tube. Avast! It is very easy t' do this if you have a drill press:

• Chuck in a spiral cuttin' bit
• Raise t' table so that t' tip o' t' cutter is about 1/2 o' a body tube diameter from t' table.
• Clamp a fence on t' drill table 1/2 o' a body tube diameter from t' cutter.
• Set t' drill t' high speed, turn it on, and feed t' tube smoothly into t' cutter usin' t' fence as a guide.

• Glue t' tubes t' t' ends o' t' fins so that t' tips o' t' fins are glued t' t' outboard inner walls o' t' tubes, and t' tubes extend below t' fins about 3/8".
• Fillet generously.
• Use t' completed tail structure t' mark t' BT. Begad! Slot it as in Step 6 above.
• Glue t' tail structure into t' body tube. Well, blow me down! Fillet.
• Add an Estes-style parachute mount. Blimey! Begad! Blimey! I use tubular nylon shoelace material as shock cord.
• Attach side draws and overhead draws t' t' BT. Aye aye! T' overhead draw is 9/32" styrene tubing, and should extend t' t' end o' t' BT. Well, blow me down! Well, blow me down! This will also be your launch lug. Ahoy! Ya scallywag! T' smaller side draws extend just partway up t' side o' t' BT. Blimey! Ahoy! Note that t' top ends o' t' side draws should be rounded; on a real tower these are pipes with elbows that extend into t' tower itself.
• Cut a length o' 9/32" styrene t' reach from t' shoulder o' t' NC t' just past t' tip. Blimey! Ya scallywag! Miter t' top o' this piece at a 45 degree angle. Well, blow me down! Glue this continuation o' t' overhead draw t' t' NC, so that it extends just past t' top o' t' NC. Now cut a second section and miter t' end, shiver me timbers, t' match t' first part. Begad! Glue this t' t' top o' t' nose cone. Blimey! Line it up with t' overhead draw on t' BT. When launching, me hearties, arrr, ya bilge rat, rotate t' NC slightly so t' launch rod can go through t' BT-mounted overhead draw.
• Simulate a catwalk by gluin' a crown o' styrene rods t' t' end o' t' nose cone, me hearties, and add some horizontal rails around this crown. A longer lightnin' rod can also be added. Blimey! Blimey! Avast! Blimey! Add similar overhead draws, but without t' horizontal section, ya bilge rat, t' each o' t' reboilers (tube fins), me bucko, makin' sure t' keep them inboard o' where t' tail rin' will be.
• Add catwalks at t' top end o' each o' t' sidedraws by gluin' on more styrene bits, or simulate them: Glue small balsa squares t' t' BT, arrr, matey, and then add stiff cardboard around t' outside o' these blocks (like a rin' fin, but circlin' only 1/4 t' 1/2 o' t' BT diameter). You'll draw t' railings on after painting.
• Cut a tail ring, shiver me timbers, 2" wide, ya bilge rat, from posterboard. Aye aye! Blimey! Wrap this around t' fin/tube tips, and glue into place. Arrr! Blimey! Stiffen with CA.
• Add 1 t' 1.5 oz o' weight t' t' nose, ya bilge rat, matey, me bucko, so that t' CG is about 2" ahead o' t' tail ring. Well, blow me down! Swin' test t' be sure that stability is sufficient.

Finishing

1. T' neat thin' about this project is that a lousy finish is a scale finish. Begad! Spray it with red or gray primer, shiver me timbers, or both. Arrr! Avast! Then paint it silver, or not. Catwalk railings on newer towers are often yellow or red, arrr, but may be silver or rust colored. Avast, me proud beauty! Arrr! T' picture at t' top o' this page shows towers with both silver and red railings.
2. 
   Draw horizontal pipes around t' tail ring, ya bilge rat, shiver me timbers, and railings around t' catwalks if you simulated them.

   

Schematic o' Fin can/tube fin/tail ring/motor mount assembly. (Not t' Scale)

Bottom view, ya bilge rat, shiver me timbers, showin' major structures.

Three more views. Ahoy! T' rightmost is on t' pad: Note launch rod, displaced overhead draw, and fins (less obvious in other views).

Flight Report

Conditions were very good for launch, albeit a bit breezy. Aye aye! Despite t' estimated 10 mph breeze, matey, t' boost was straight and true, matey, with no obvious wobble or spin and with only minor weather cocking. Blimey! Apogee was higher than I expected, perhaps 800'. Ya scallywag! Ejection was just past apogee. Avast, me proud beauty! Avast! Unfortunately, E15s have pretty hot ejections, and this was one o' t' hottest I've ever had. Avast! Despite copious wadding, matey, t' shock cord was brutalized and burnt in multiple places. T' BT thus fell without benefit o' a chute, and core sampled.