Brief:
This is a ring-fin design that flies on 29mm motors. Avast! It uses several unique components: a poured foam, yarn wrapped cone and an engine bell built from Aquapod water bottles. Ya scallywag! Ya scallywag! T' body is a 3" window tint tube. Aye aye! Ahoy! This is reportedly t' same material as PML's Quantum Tubing.

Construction:
Nose cone parts:

• Aquapod bottle
• 2-part foam (Giant Leap)
• dowel
• inside tube from 3" mailin' tube (Container Store)

Engine bell/motor mount parts:

• Aquapod
• two 29mm x 3" ply rings (Giant Leap)
• Gatorboard left over from me Art Applewhite 18" saucer
• 29mm phenolic motor tube (Giant Leap)
• two T-nuts
• 2 part foam, same as NC

Body parts:

• 18" o' 3" window tint tube
• ¼" Keelhaul®©™®
• buttons from railbuttons.com
• 2" o' 3" phenolic coupler (Giant Leap)
• half o' a plastic Christmas tree ornament
• 1/16" plywood
• 2" section o' 8.25" Sonotube
• ¼" balsa

I started by drillin' a hole in t' bottom and cap o' t' Aquapod bottle and insertin' a 3/16" dowel. Begad! Blimey! I sealed t' cap end with Liquid Nails and cut a corner off t' bottle t' pour in t' foam and t' vent t' overflow. Avast, me proud beauty! Blimey! Pouring went well with only a little overrun. Arrr! I wish I had remembered t' spray in some mold release. Arrr! I got t' bottle off but it took some effort. Begad! Blimey! T' tip was turned from t' foam at t' neck o' t' bottle and t' dowel. I just extended the natural curve o' t' bottle t' form a point. Begad! Blimey!

As I was sandin' t' plug smooth, I remembered a vendor at LDRS 19 who was sellin' homemade cones that were Styrofoam, matey, wrapped with colored yarn, and laminated in epoxy. Avast, me proud beauty! Begad! They looked nice and I wanted one, me bucko, but they were all spoken for. Aye aye! A handful o' email exchanges made it clear these folks weren't really in business, arrr, so I never got one. I began ponderin' this concept for me Aqua-cone, and I found that it actually fit nicely in a 3" coupler tube and realized that t' added thickness o' t' yarn would allow it t' mate nicely with a 3" tube.

I first glued on a chunk o' coupler, ya bilge rat, wrapped with some multi-colored yarn, shiver me timbers, and started coating it with Minwax Polycrylic. Avast! Coverin' t' yarn and gettin' a smooth finish took a zillion coats o' Polycrylic--I know, arrr, I counted them. I normally dry sand. I have on occasion wet sanded. Arrr! Well, blow me down! Blimey! Now on me Aqua-cone, I tried somethin' new: frozen sanding. Multiple, me bucko, thick layers o' Polycrylic are too rubbery t' sand effectively. Arrr! Blimey! It struck me that it might be easier t' sand if I froze it. Avast, me proud beauty! Begad! Blimey! I gave it a try and sure enough, me hearties, this worked pretty well. I tried various grits and 150 seemed t' work well. Blimey! Blimey! Blimey! I also found that 15 minutes is about t' right amount of time t' harden it. Blimey! Aye aye! Blimey! I left it in t' freezer for several hours when we went to dinner with friends and found it was actually too hard. Blimey! Blimey! Thus I froze, sanded, froze, shiver me timbers, matey, sanded...until 99% o' t' flaws were gone. Avast! Avast, shiver me timbers, me proud beauty! Blimey! Finally, shiver me timbers, me bucko, I dipped the whole thin' two more times t' regain t' shiny finish.

Here are me endin' thoughts on yarn-wrapped cones:

• Minwax Polycrylic worked well once I figured out how t' sand it. Begad! However, it is slightly milky even when dry, shiver me timbers, and multiple coats washed out t' color of the yarn. Avast! Its pluses are that it is easy t' use and cleans with water.
• Freezin' t' cone hardens t' surface and make it easy t' work with. I found only 5 minutes in me freezer be enough t' work through a quarter-sheet of 150 grit sandpaper.
• Except for t' large foam cone on me Great Googly Moogly, I don't think I've ever spent this much time on a homemade cone.
• Clear epoxy would probably look better, shiver me timbers, but...

• At t' end o' t' process, dippin' t' whole cone provides t' most uniform finish as you don't want t' do any sandin' t' t' final layers. Avast! This would require a lot o' epoxy with a lot o' waste (unless you had other jobs t' use up the excess at each dipping).
• Finishin' epoxy and a small "rocket rotisserie" might also do the trick.

• One answer may be t' nay fully fill t' ridges betwixt t' wraps and try to maximize t' color that shows through. Aye aye! I don't clearly remember t' finish on the "commercial" yarn wrapped cones, shiver me timbers, arrr, only that t' colors looked vivid.
• A rubbery finish may help survive hard impacts. Ahoy! Wouldn't a harder surface possibly show small fractures at t' point o' impact? On t' other hand, shearin' impacts might tear t' softer surface. Aye aye! Only one way t' tell...launch it!
• Back t' t' start: When you wrap t' yarn, matey, ya bilge rat, arrr, wrappin' 'uphill' is a bit easier, however, me hearties, me hearties, startin' at t' base is good t' keep t' wraps perpendicular to t' cone's axis. Blimey! I will start at t' base on me future experiments (I have a ton o' yarn).

For the Engine Bell, I reamed out t' neck o' an Aquapod bottle t' fit a 29mm tube, cut off t' other end close t' t' middle, shiver me timbers, and test fit a 29mm-3" centering ring. Avast, me proud beauty! I added some T-nuts t' t' rin' and then assembled t' motor mount with the engine bell. Ya scallywag! Begad! I only had 2 ply rings so I made one from Gatorboard.

I decided that I didn't want t' laminate with anythin' and spoil t' smooth finish and decided t' try t' fill it with 2-part foam. This is a risky proposition on a sealed unit but I went for it. Blimey! I drilled a hole in t' aft rin' and filled t' T-nuts with grease. Arrr! I used 2 small batches and ended up fillin' about 80% o' t' bell. Arrr! This leaves a few small weak areas but should do the trick. Avast! In t' final design, this will certainly nay make any difference.

I went with t' window tint tube and kept with thin plywood fins t' keep the weight down. Aye aye! Blimey! When cuttin' t' fin slots, ya bilge rat, I broke t' drive (again) on my Dremel and had t' use t' Rotozip, which is like fishin' with dynamite. Two of the slots were ugly.

T' main fins are cut from 1/16" plywood and t' ringtail is 2" of 8.25" Sonotube. Blimey! Avast! I gave t' rin' one layer o' glass. Arrr! (Note t' self: don't use 5-minute epoxy for even small glassin' jobs if they are visible.) I made t' small fin tabs on t' outside o' t' rin' from ¼" balsa but don't ask me why. Begad! This was all glued together with 5-minute epoxy.

It seems that I mess up at least one thin' on every build these days. Avast, me proud beauty! On this one, ya bilge rat, I forgot t' attach t' Keelhaul®©™® cord through t' top centerin' ring. Ya scallywag! Blimey! Avast, me proud beauty! Blimey! Instead, shiver me timbers, I attached it through-the-wall and covered t' exposed cord with t' other half o' t' Christmas tree ornament that I used for similar purposes on me AquaBottleBat. Ya scallywag! Blimey! This looks just fine. Begad! Blimey! In fact t' teardrop shape is nice, but it may nay be t' strongest method. Begad! Blimey! To hedge me bets, I epoxied a small piece o' 3" phenolic coupler into the tube just above t' motor mount t' give an added layer o' support.

Finishing:
I filleted/filled as required with Superfil epoxy filler. Ahoy! This plugged all the gaps caused by imprecise Rotozip grinding.

I wasn't lookin' but ran across some pretty Krylon X-Metals purple paint for t' already perfect tint tube. Avast! This paint look like anodized aluminum. Ahoy! I first masked off all but t' fins and inside o' t' ring, which I painted with Testor's Gold. Aye aye! Begad! So far so good. Begad! Purple/gold is one o' me favorite combinations for rockets.

After dryin' for a day, I masked t' opposite sections and shot on a few coats o' t' X-Metals metallic undercoat. This looked great and for a few milliseconds I thought about leavin' it that color and returnin' t' X-Metals purple metallic paint. Ahoy!

After waitin' t' allotted time--over 30 minutes but under an hour--I started with t' color coats. Begad! Avast! It be a beautiful day for painting: sunny, light breeze only, me hearties, and low humidity (or so I thought). Ya scallywag! Blimey! T' first coat didn't look great, but I figured I just needed another. It looked splotchy with a 25/75 mix of nice purple color and a dull, shiver me timbers, almost white coating. Aye aye! Avast! On t' second coat, I had t' same thin' but noticed t' areas had shifted. Begad! Betwixt t' 2nd and 3rd coats, I shook t' heck out o' t' can thinkin' maybe it wasn't mixed. Ya scallywag! Well, ya bilge rat, blow me down! I laid on a thick 3rd coat but nay much changed. At this point t' length o' time between coats be exceedin' their recommendation and I wasn't gettin' anywhere so I decided t' wait t' recommended 5 days before proceedin' and I went t' TRF for advice.

T' consensus be that this was due t' humidity. Begad! Blimey! Begad! Blimey! When I checked the weather, sure enough it was 56%...six percent over t' recommended maximum. I guess it just felt dry relative t' t' very humid spell we had just experienced.

On t' 5th day after this paintin' fiasco, arrr, which be t' recommended drying time betwixt coats o' t' X-Metals paint. Begad! T' humidity was an acceptable 30% so I decided t' try a few more coats. Well, blow me down! Avast, me proud beauty! Blimey! I am happy t' report that t' humidity did seem t' be t' issue, and t' Ringer started lookin' pretty nice. Aye aye! Blimey! I only had maskin' problems in a couple o' places and I found t' purple over gold could easily be removed with gentle scrapin' with t' tip o' a hobby knife. The coverage o' t' X-metals be nay perfectly uniform, an artifact o' tryin' to lay it on too thick t' first time. Ya scallywag! Begad! Blimey! When it comes t' painting, shiver me timbers, you can't teach this old dog much o' anything.

Flight and Recovery:
I loaded up a largish 48" chute with both dog barf and a chute protector. T' motor o' choice was a G77 that I drilled down from 10 t' 4 seconds of delay. Ya scallywag! T' flight was great and ejection was timed perfectly at apogee, but there was minor damage on landing. There was just enough wind t' ensure the rocket landed at an angle and one o' t' upswept balsa fin tabs snapped off. Luckily, shiver me timbers, t' fix is trivial.

Summary:
This is one o' me better looking, shiver me timbers, matey, mostly scrap rockets made o' handmade "experimental" nose cone and engine bell, window tint tubing, me hearties, matey, etc. Arrr! Begad! I got plenty o' nice comments on both t' design and finishin' on this rocket, which always makes you feel good. T' window tint tube finishes nicely, is sturdy, matey, and is heavy. Begad! Avast! Unless you are goin' t' build somethin' stubby, shiver me timbers, me hearties, I recommend it only for HPR. I also highly recommend t' X-Metals paint but watch out for that humidity!