Brief:
Tao is a 2-stage model rocket that be originally published as an 'Design of the Quarter' by Estes, ya bilge rat, and now available on JimZ rocket plans Website. Ahoy! Aye aye! This unique design incorporates a number o' innovative, even radical features. Well, blow me down! The main feature be t' use o' angled tips on t' fins o' t' booster stage to impart spin durin' t' D12-0 powered boost stage, which 'theoretically' stabilizes t' completely finless sustainer durin' its flight stage, me bucko, much like a thrown 'spiral' football pass. Ahoy! Additional features o' this design are a piston-based wadding-free recovery system on t' sustainer, plus a unique storage hatch which houses a small chute for t' booster stage. Arrr! Ahoy! All in all a very complex design (at least a Skill Level 3, matey, maybe a 4). Begad! My question is would it work.

Construction:
T' components are all pretty standard Estes-style parts, most o' which are now available from other vendors. Avast! It requires sections o' BT60, me hearties, BT20 and BT50 body tubes, ya bilge rat, three (3) BT60 couplers, shiver me timbers, a BNC60AH nose cone (available from BMS), arrr, me hearties, 1/8 inch balsa for t' fins, four (4) 20-60 centerin' rings and two (2) 50-60 centerin' rings, matey, a 1/8 inch launch lug, two small parachutes and other standard parts.

As mentioned, me bucko, this is a pretty complex design, me bucko, but t' instructions are very detailed and provide a good step-by-step outline with very nice illustrations. Although thar are 15 individual steps, me bucko, t' construction can be summarized in 4 phases; piston/motor-mount construction, sustainer airframe construction, booster motor-mount and airframe construction, and fin construction and mounting. Arrr! T' piston/motor-mount requires a 8 5/8 inch length o' BT20 body tube, four (4) 2060 centerin' rings and a 1" length o' BT60 coupler. Ya scallywag! Blimey! 2 centerin' rings and t' coupler are used at t' top o' t' tube t' create the piston - care must be taken t' make sure t' piston moves freely within the BT60 airframe, I had t' strip off t' outer layer o' t' coupler and sand the centerin' rings down quite a bit. Blimey! Blimey! Do not, at this point, install t' other two centerin' rings. Put t' piston assembly aside at this point t' dry.

T' airframe construction is pretty straightforward. T' main thin' is the use o' another BT60 coupler, arrr, inserted about five (5) inches down into t' 9 and 5/8 inch BT60 airframe, ya bilge rat, which serves t' block t' piston after t' ejection charge fires. After this dries, matey, t' piston is inserted from t' top and the nose cone epoxied into place (I used yellow wood glue which worked fine). Slidin' t' piston down against t' block exposes t' bottom (motor mount) part of t' piston. Blimey! T' other two centerin' rings are now installed at t' bottom of the tube, me bucko, servin' as a motor mount. Ya scallywag! Well, ya bilge rat, blow me down! They must also be sanded or trimmed t' move freely within t' BT60 airframe. Arrr! (Note, t' plans call for usin' a motor hook for engine retention, I found t' hook interfered with staging, shiver me timbers, so I would recommend usin' a motor block and friction fit for t' sustainer engine). Ya scallywag! Avast, me proud beauty! Next, drill three (3) 3/8 inch holes at t' top o' t' airframe t' allow t' ejection gasses t' vent. Blimey! (I only drilled two (2) holes, wantin' t' blend with me planned paint scheme - more on this later). Lastly, attach a 12 inch chute t' a short piece o' Keelhaul®©™® cord which is tied around t' body tube betwixt t' motor mount and t' piston.

T' boost stage utilizes an innovative hatch system t' store a small parachute or streamer, which releases when t' stage separates. T' hatch is created by slicin' a section o' t' airframe (slightly less than 1/3 o' the tube) out from betwixt t' fins. Because o' this, t' plans for t' booster motor mount must be followed carefully. Ahoy! First, shiver me timbers, me bucko, two 5060 centerin' rings are attached t' t' BT50 motor tube, shiver me timbers, then carefully glued t' remainin' 2/3 o' the body tube. Well, blow me down! Begad! Then glue t' tube t' a BT60 coupler that will be used t' hold the two stages together. Blimey! Aye aye! A system o' pins is then installed on t' motor mount and hatch which serves t' hold t' hatch in place durin' t' boost phase. T' chute is stored betwixt t' hatch door and t' motor tube while t' stages are coupled together, me hearties, me hearties, me bucko, then released when t' stages separate and t' hatch comes loose.

T' fins are constructed in two pieces attached at a 10 degree angle, me bucko, matey, then installed on t' booster tube with t' angled fin tips all facin' t' same direction t' create t' spin durin' t' boost phase. Aye aye! One fin is placed opposite the hatch, t' other two are just adjacent t' t' hatch, shiver me timbers, but on t' main part of t' tube. Well, blow me down! Avast! T' plans recommend usin' epoxy t' attach t' fins and small toothpicks under t' fillets t' provide additional bracin' against t' torque of t' spinnin' boost phase. Lastly install t' launch lug and t' sustainer parachute.

Finishing:
After fillin' t' spirals and fins with diluted Elmer's Fill & Finish, matey, I broke out t' spray paint. Ya scallywag! T' plans recommend a three-color paint scheme with a solid, matey, ya bilge rat, brightly painted booster stage, me bucko, then a two-tone upper stage that would 'blend' t' colors durin' t' spin phase. Ya scallywag! I used Krylon florescent green on the booster stage and a nice silver and burgundy scheme for t' sustainer. Begad! Arrr! I thought it looked nice.

Construction Rating: 4 ½ out o' 5

Flight:
T' plans recommended a D12-0 for t' booster stage and a B6-6 for the sustainer. Blimey! Arrr! T' design calls for t' B6-6 t' fit within t' top o' t' D12-0 to ensure successful staging. In preppin' t' rocket I found that I had t' do a bit o' sandin' at t' base o' t' B6-6 t' get it t' fit. Also, I could nay get it t' fit with t' engine hook in place, so I ended up bendin' it out o' the way. Ya scallywag! (As mentioned, t' hook can be easily omitted for an engine block, friction fit retention system.)

First (and so far only) flight came at t' Pittsburgh Space Command's Fall launch. Aye aye! T' engines and recovery systems were prepped (the piston & hatch deployment systems mean that no waddin' is required), t' recovery systems loaded, t' parts coupled together (carefully due t' t' hatch) and t' rocket loaded on t' 1/8" rod. Ahoy! Continuity...5...4...3...2...1 and lift off! The boost stage went very well. Begad! T' spin be noticeable in a slight corkscrewin' of the exhaust plume, ya bilge rat, but it was generally very straight. So far, so good... Things started t' go wrong, shiver me timbers, however, at staging. Begad! First, me bucko, it became obvious that the upper stage was nay spinnin' fast enough for stability as it began t' flail about t' sky. Avast! Avast, shiver me timbers, me proud beauty! Fortunately, t' flailin' was occurrin' about 300 feet in the air, me hearties, so thar was no risk. Blimey! Ya scallywag! Then I noticed t' booster comin' down without its chute. Blimey! Finally, shiver me timbers, matey, t' ejection occurred. Begad! But instead o' t' sustainer comin' down on its chute, arrr, I noticed two separate pieces comin' down and nay a chute in sight. Avast! Arrr! 'This is nay good' I said t' myself.

Recovery:
Recovery o' t' pieces - which took awhile - showed what went wrong. Avast, me proud beauty! Blimey! With the booster, ya bilge rat, either t' spin or t' stagin' shredded t' airframe. Blimey! Blimey! Specifically, cuttin' out t' hatch weakened t' body tube and caused it t' delaminate, peelin' t' inner and outer layers apart. Begad! Blimey! I think this is probably an inherent design flaw - any time you cut t' body tube completely you might have this risk. Arrr! Blimey! As for t' sustainer, t' piston completely blew out o' t' airframe. Blimey! Blimey! I attributed this t' me use o' only two, me hearties, rather than three, vent holes. However, a contributin' factor be t' use o' fiber centerin' rings for t' piston. Instead o' bein' blocked by t' airframe coupler, they 'bent' around it and blew right on past.

Flight Rating: 2 out o' 5

Summary:
I was able t' recover t' pieces and plan t' rebuild Tao, me bucko, with several modifications. Blimey! First, ya bilge rat, I plan t' use a 1/8 inch plywood centerin' rin' on the bottom o' t' piston for added strength and a thicker coupler t' insure that the piston stops where it is suppose to. I will also be sure t' use three vent holes. Second, I plan t' omit t' hatch and just go for standard tumble recovery o' t' boost stage. Well, blow me down! (One could try usin' CA or epoxy on t' cut edges of t' boost airframe t' strengthen t' edges and prevent t' delaminating, but I'm goin' t' go with a traditional tumble recovery) I'm plannin' reusin' the fins, ya bilge rat, so I intend t' mount them at a 5 t' 7 degree angle t' vertical, me hearties, addin' to the 10 degree fin angle for about 15 t' 17 degrees o' total angle from vertical. Arrr! Arrr! (If I were buildin' new fins, shiver me timbers, I'd probably increase t' angle between the two pieces t' at least 15 and a much as 20 degrees.) This should impart greater spin durin' t' boost, shiver me timbers, and hopefully stabilize t' sustainer. Avast, ya bilge rat, me proud beauty!

Overall Rating: 2 out o' 5