Looking to do mischief with foam and fibreglass one day…
I thought about making a lot of boards into 1 board.
Just a rounded shortboard mixed with a pin tail gun,
and with maybe a shortboard pintail and a rounded longboard added in.
Minimal volume in the pintail and lots more in the shortboards’ tail. And a lot of other variations too.
So what to do… maybe try something in a smaller version and build up.
Having a penchant,inclination, preference, perversion and a touch of fetish for the paipo at the moment, ( courtesy of a separated shoulder ) I found a start point.
Starting with the planshape. I thought of this…
A scalene triangle, rounded all round, but if you FLIP it, you get 4 different shapes.
Not overly pretty I admit, until you flesh it out with a few attractive curves and start turning a thought into an idea and then into a solid design. See next post…
Now its looking more organic, different WP’s,( as indicated), different widths,curves, math and science all the way 'round.
Accel. curves for manouverability, decreasing curves for hold,straighter lines for drive, same ~ area each side for lift taken from several angled midlines. And taking into account how the 3rd dimension will increase or decrease hold or release.
All the usual stuff but with more to come.
And I thought Id use the ply outline as more than a planshape and use it to make a HWS skin too.
The ply is beautiful Swedish aircraft ply that was used to make WW2 Spitfire planes, amongst others…
I bastardised the ply for my own gain and glued several slabs together but the details of that are boring. The important thing is that per sq. in., its twice as strong laterally, as longitudinally.
Surfoils-where did you get info about Ply being used in WW2 Spitfire planes?
The Spitfire(and all its variations) was built as an all alloy stressed skin monocoque-no wood in site!
Maybe your confused with the Mosquito twin engined bomber-that had incredibly strong plywood wings that coupled with its slippery shape was an incredibly fast aircraft. Its designers unknowingly at the time also created the first “stealth” bomber, as the wood did’nt reflect the the primitive German radar of the day!
Hey shifty, only source of info was the dudes at the lumber yard. They said it was for internal bracing/ bulkheads. Thanks for steering me straight tho, I hate being a source of mis info.
Anyway,sanded 2 outlines using all sorts of witchcraft and blasphemy til I was happy.
Every picture makes it look a different shape.
The intention is to have nil rocker but use the rail (outline/ planshape) as the rocker. So it should be as fast as possible in a straight line but with the exaggerated outline it should loosen it up.
Paipos are pretty manouverable anyhoo just because of their size so the outline design came back to being an exercise in blending different rails and tails.
So I sanded down a ply stringer, ~ 3in wide 7 ply, 3/4 in at the round end down to 1/4 in. ( At 3 inches wide and horizontal, is it still a stringer or a beam?)
Epoxied into place on one side.The shadow of the stringer shows the thickness variation.
So with the 2 skins separated by only the midline stringer, I taped off 2 in strips of carbon and cut down the centre of the tape so that the edges dont fray when I wet them out and lay them up.
The tape weighs nothing and I can sand it off later if its going to be seen.
Now with the ‘flipper’ on its edge, I laid 1 strip per side against the stringer. So with a strip either side the stringer became an " I " - beam, of sorts… or an H - beam…
The plan was to make both sides concave so I built a jig that held the board flat but allowed the sides to open and kept the ends flat. So where the blue is in the pic, I squirted in expanding foam. Maybe at this point you’ll be wanting me to return my Swaylocks key-ring…
I forgot to take pics of the jig.Sorry.
The foam is epoxy compatable, waterproof, sticks like the proverbial and shapes easily.
It filled in from the sides about 2~3 in or so, its not in any way exact but as its not going to be stood on, it’ll do fine.
After it set, I shaped the rails into a concave all the way 'round. It should have very little form drag. ( You know what I mean.)
And then I glassed over the concave rails with carbon and epoxy X 2.
So how to glass concave rails, I was going to do each side in turn, stick it in a plastic bag and immerse it into the water tank so it would get all-over pressure. Kinda like a vacbag but in reverse and energy efficient. But I didnt.
Instead I put strips of carbon over the rails and then covered it with Saran / Glad wrap / cling film.
Then I laid a rope of compatable diameter into the concave, with added pressure to conform to the curve.
And then gently paper-taped the Saran, the rope and the sides of the carbon down.
Yes , I know, its exactly what you’d see in any pro glass shop.
Bizarrely, when I unwrapped the thing , it was a 9.5… conformed to the concave and smooth.
I love it, especially those concave rails. What’s your reasons behind their design? Your template looks like the template of my new finless board that I have been working on. Thanks for posting, I also attached a pic of one of my old boards that I’ve posted before, it also had concave rails, probably for the same reason that you are seeking? -Carl
Carl ! Good to see youre doing something similar. I like the Red'n'White one!!
After coming up with all these great new theories and being quite proud of myself, I checked…
None of my ideas are new at all.
I even did the ‘holes thru the board’ back in the 70’s when I was a kid but itd already been done.
The good thing about my ‘new’ design ideas is that theyre new to me, I thought of them myself without knowingly copying anyones prior work. Is it the same for you Carl ?
As for the concave rails, there are several worthy reasons.
With a clean release along the bottom edge of the rails, the board will ride dependant on the outline. The effect of the outline on the performance should be obvious.
With no protruding foam rails, if I hit anything, theres the 2 skins and double carbon / epoxy wraps to take the impact.
Short of hitting a water buffalo, I shouldnt have to worry about minor cracks and dents etc…
With the carbon doubling back between the laps, it appears to give 4 layers of carbon around the rail, ( see blue line).
So like folding paper, it gives it strength by adding extra axises of ‘rigidity’ without adding extra material.
Man this is looking great! Finally some real expirementing and theory put into action! I can’t pretend to quite understand all the forces/tekniques at play here but it sure is looking good!