Author Topic: Wing Board Tail Rocker - Thoughts  (Read 32560 times)

JohnnyTsunami

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Re: Wing Board Tail Rocker - Thoughts
« Reply #45 on: June 08, 2022, 11:55:46 AM »
JohnnyTsanami- How much you weigh? What 600 and 800 cm2 foils are you using?

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MikeLima

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Re: Wing Board Tail Rocker - Thoughts
« Reply #46 on: June 08, 2022, 05:28:37 PM »
Since I have Armstrong boards I’d previously thought about how they and the kalama shape are different ways to achieve the same ends. Moving the tracks forward allows the tail rocker to be gentle enough to not grab the water when touching at speed like a flat tail, but still get near or at the surface when slogging, so you aren’t making an eddie. I’ve never sup’d either or used a kalama so idk how they compare in either respect. I’m sure the kalama is a faster paddler…. Although I think if I made a kalama rip off I’d fade in a release edge (maybe 0.5cm deep) towards the back end, so water really can’t get sucked around the angle when touching.
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cnski

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Re: Wing Board Tail Rocker - Thoughts
« Reply #47 on: June 08, 2022, 05:38:17 PM »
ML- ya that's what I thought. 800 and 600 is all the buzz right now in the Mike's Lab world. Are you using that super tiny stabilizer? I think it's too small. At least for me. Makes the foil feel really unstable and porpoises. Wonder why they came up with that size? 32 cm. It's smaller than the stabilizer on my Bullet 3 kitefoil. And I wish they would make a big brother to the 800 for light wind course racing with a 100cm wingspan. That would be really great. Sorry off topic but relevant.

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #48 on: June 08, 2022, 09:00:12 PM »
Dave started building those boards for prone foiling and then started doing a lot of wild variations to test the concepts. He made a ridiculous number of prototypes, some of them very strange--like the super-ling prone barracuda-skinny board he was playing with probably around January. Then a couple of people tried them wingfoiling, and then incredibly quickly--it seemed like less than a week or so later there were all kinds of Kalama weird tail, skinny boards winging and surf foiling or doing the flatwater pop-up classes with Jeremy Riggs. They multiplied like bunnies on Maui. I've only seen a few downwind foiling here in the Gorge.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

burchas

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Re: Wing Board Tail Rocker - Thoughts
« Reply #49 on: June 09, 2022, 07:32:13 AM »
Tail-rocker is a conundrum - to get up on foil your actually want a displacement design which is always more efficient with some rocker and once you are up on foil you want the slippery, skippery feel of a planing hull for touchdowns. I agree with Jondrums observations except that a flat rocker board launches quicker when winging - that I find only potentially true on shorter sub 5'0ft wing boards. On longer wingboards the same trouble Jondrum describes becomes apparent - especially if you are trying to pump board up.

Kalama's board have zero rocker from what I can see along the centerline from the middle back - he solves the conumdrum with his extreme V in the tail which gives plenty rocker along the outline.

My take is that you need some rocker, especially on SUP's and the reason people think flat rockers work on wing boards is because the power on hand allows you to overcome the initial tail drag apparent when you try and pump up - once you overcome this drag (with the help of the wing) the board releases quickly and pops up on foil - it feels efficient, but it actually isn't.



I think your analysis makes most sense. It's certainly consistent across the board and not necessarily following trends:

My 5'10 is pretty much straight tail - zero rocker with small cut away last 2inches. I don't like the no rocker feeling, a 5'10 board paddles slow as is, and when tail get's lifted by wave for take off, it's sticky, sticky, sticky, until all hell breaks loose and the flat rocker makes the board feel like it's on roller-bearings and you take off. The straight tail pushes the nose down so you have to counter that by sinking tail a bit adding to the stickyness. I prefer a more progressive acceleration and I feel the board needs a much steeper wave than what a narrower longer board would. The E3 solves the flat rocker issue by the triangular chimes in back

Trying 3 different variations of the Kalama concept including my own, I had few observations. Volume and maybe more important, surface area at the tail seems to dictate how effective is the concept when it comes to winging.
I can see how the concept addresses the water flow and release but for pumping the wider kalama tail didn't seem to offer advantage over straight tail for similar volume except for the super narrow Barracuda tail
That said, pintail for a wing board wouldn't be my choice (maybe for sinker) which bring me back to the rocker.

Reading through these comments was a throwback to the sup days when I compared the SIC Bayonet Vs Naish Maliko, continuous rocker vs 2 stage planing rocker or progressive acceleration vs explosive take-off.
The Maliko tail rocker is not completely flat but it is minimal. I think that incorporating this kind of tail rocker on a short wing board might prove more effective when initiating a pump over a dead flat section yet still effective
for touchdowns.
in progress...

Slyde

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Re: Wing Board Tail Rocker - Thoughts
« Reply #50 on: June 10, 2022, 02:54:47 AM »
Ha ha, looks like I'm not the only one convinced by Kalama's thought processes. This is my new SUP in progress too. No tail rocker and kalama tail for a SUP that needs boardspeed to get on foil. The tradeoff is a nosedown attitude in flight. I still think a wingboard needs some tail rocker for better flight characteristics but If the SUP proves to be what people are saying I will try a rockered kalama tail on my next wing board.

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #51 on: June 10, 2022, 08:37:15 AM »
Interesting observation Slyde, do you use footstraps? I can see how that reduced tail volume would demand that you be standing a bit forward when you're floating, and if you can't shuffle back a bit you'll be nose down. You could tune the foil position to flatten the trim, or perhaps experiment with your foil or stabilizer angles, but everything is a compromise since we don't have any active trim capability other than body weight position relative to the foil. The Kalama tail is designed first and foremost to move through the water easily. The really long versions made that goal clear--they comprised foiling agility greatly in favor of gaining speed quickly in a wave.
« Last Edit: June 10, 2022, 08:39:44 AM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Wave Chaser

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Re: Wing Board Tail Rocker - Thoughts
« Reply #52 on: June 10, 2022, 10:01:03 AM »
Do any of the E3 sizes have tail rocker along the center line?

I agree with Slyde that, "I still think a wing board needs some tail rocker for better flight characteristics..."
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Slyde

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Re: Wing Board Tail Rocker - Thoughts
« Reply #53 on: June 10, 2022, 01:42:35 PM »
Interesting observation Slyde, do you use footstraps? I can see how that reduced tail volume would demand that you be standing a bit forward when you're floating, and if you can't shuffle back a bit you'll be nose down. You could tune the foil position to flatten the trim, or perhaps experiment with your foil or stabilizer angles, but everything is a compromise since we don't have any active trim capability other than body weight position relative to the foil. The Kalama tail is designed first and foremost to move through the water easily. The really long versions made that goal clear--they comprised foiling agility greatly in favor of gaining speed quickly in a wave.
Well actually this SUP will be for a foil drive so I  won’t be using straps for that at least to begin with as there is quite a lot of weight movement required as you foil up. I may add a front strap as I get experienced. The design philosophy here is to have a SUP that will foil up with the least effort so that I can ride non breaking swells at my local beach on no wind days. The sandbar disappeared after the council modified some groynes so now there are no breaking waves that can be paddled in to, but the swells are still there begging to be ridden. Hence the foil drive. It seems the Kalama tail will be the best way of getting a board of this size up to foiling speed.  Itching to get it on the water to try.

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #54 on: June 10, 2022, 08:42:04 PM »
I'm building my own foil drives. I'm at V 2.2 right now. I just blew my most recent folding prop into shrapnel--I need to start armoring up before I test these things--I had a chunk of the prop hit me square in the breastbone. It left a small cut and a big-ass bruise but didn't wind up stuck in my chest so I got that going for me. Time to get the props printed at shops that can do more exotic stuff, though my latest modification to my Ender printers pushes deep into exotic extruded plastic.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Slyde

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Re: Wing Board Tail Rocker - Thoughts
« Reply #55 on: June 11, 2022, 01:07:50 AM »
I'm building my own foil drives. I'm at V 2.2 right now. I just blew my most recent folding prop into shrapnel--I need to start armoring up before I test these things--I had a chunk of the prop hit me square in the breastbone. It left a small cut and a big-ass bruise but didn't wind up stuck in my chest so I got that going for me. Time to get the props printed at shops that can do more exotic stuff, though my latest modification to my Ender printers pushes deep into exotic extruded plastic.
Thats above my pay grade.
Ill stick to carbon , foam and epoxy.  ;)

dns

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Re: Wing Board Tail Rocker - Thoughts
« Reply #56 on: June 15, 2022, 10:21:01 AM »
I'm building my own foil drives. I'm at V 2.2 right now.

Funny, I was just talking about this at the beach yesterday. We were discussing putting a hole all the way through  the deck and mounting the battery pack longitudinally right above the foil. Heat sink would be exposed on the bottom of the board.  That would make it nice and low profile and mitigate the heat and swing weight issues.

juandesooka

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Re: Wing Board Tail Rocker - Thoughts
« Reply #57 on: June 15, 2022, 11:08:12 AM »
Funny, I was just talking about this at the beach yesterday. We were discussing putting a hole all the way through  the deck and mounting the battery pack longitudinally right above the foil. Heat sink would be exposed on the bottom of the board.  That would make it nice and low profile and mitigate the heat and swing weight issues.

[sorry for full-on thread hijack]

I am on diy foil drive v2.1. (aka Faux Drive)

The foil drive is designed to be an add-on to an existing board/foil.  The system works but the wires and box are cumbersome. If building a board from scratch, you could definitely do better.  That's a really interesting idea about installing on the bottom....the worry is your water proofing has to be 100% of you're screwed.

For installing on board top, having the wire come through the board would be an improvement -- best in show would be efoil style with a hollow mast and the wire running under the mast plate. Another option is a through hull handle like the new armstrong boards use, with wire through that. 

For the battery and electronics, you could have the box sit in a recessed area in deck, ideally flush with board deck, still use the waterproof box.  Next level up from there is to build a hatch in the board like efoils. I am not sure if the heat sink inside that hatch would provide enough cooling, or you'd need to expose it, or use water cooling.   

I have found my FD is fun in surf ... only had chance to try it twice. Flat water, mixed results. I am skipping the middle man and building a full efoil next, as it's the same everything just bigger. Going bigger! :-)  What changed my mind was seeing my buddy ripping around way outside on a big day, picking off bombs on the shoulder.  I picture leaving port to travel 5km to chase ferry and freighter wakes, no tow boat or wind assist required.  Not quite the same as unassisted wave foil riding...but I am sure it will be lots of fun in its own different way.

juandesooka

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Re: Wing Board Tail Rocker - Thoughts
« Reply #58 on: June 15, 2022, 12:56:49 PM »
PS in case mods or admins are reading this...I moved my reply above to an earlier Foil Drive thread....but can't figure out how delete it. I guess the Modify button is time limited? As it doesn't show as available.

JohnnyTsunami

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Re: Wing Board Tail Rocker - Thoughts
« Reply #59 on: June 15, 2022, 01:00:53 PM »
New rocker template on top of my older template so the foils are in the same place. The addition of some tail rocker will make the board ride nose up at slow speed and flat at high speeds (hopefully).

Imagine a stall situation where the old rocker submarined the new rocker should bounce back. It’s funny that many brands are straight in the back half and others have tail rocker. Length helps and these are under 5’ so it’s critical

 


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