Author Topic: Wing Board Tail Rocker - Thoughts  (Read 32556 times)

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #60 on: June 15, 2022, 10:50:36 PM »
I was fiddling with Tre Hendrix's Kalama E3 today trying to figure out some of the issues he's having with it (mostly just tuning the foil to be parallel to the board and shimming the tail a little). I put my 6 foot level on it and was surprised to find there's a fair bit of rocker on the bottom.
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 #61 on: June 16, 2022, 01:42:21 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.

I gave this serious consideration when I built mine. But you need a 65mm hole and then each time you disassemble the setup you have to remove the motor from the mast. Not so practical. So I have built a carbon recess with a small self draining hole. The wire will still be exteriorised for practicality. The board has enough volume it will not end up underwater

Slyde

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Re: Wing Board Tail Rocker - Thoughts
« Reply #62 on: June 16, 2022, 01:45:32 AM »
and from the bottom...

Dwight (DW)

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Re: Wing Board Tail Rocker - Thoughts
« Reply #63 on: June 16, 2022, 03:14:54 AM »
Looks good Slyde. That’s my Fall project. A foildrive specific board.

dns

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Re: Wing Board Tail Rocker - Thoughts
« Reply #64 on: June 16, 2022, 10:06:05 AM »
Very nice Slyde.  8) Pretty much exactly what we were envisioning. Good point about the wire routing, hadn't considered that.

kwhilden

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Re: Wing Board Tail Rocker - Thoughts
« Reply #65 on: June 16, 2022, 10:24:45 AM »
Nice board. Is the hole for water drainage, wire routing or both?
Sustainable Surf

Slyde

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Re: Wing Board Tail Rocker - Thoughts
« Reply #66 on: June 16, 2022, 11:44:39 AM »
Nice board. Is the hole for water drainage, wire routing or both?
drainage. The wire cannot be disconnected. It would be perfect if it had a waterproof plug for the battery box. But i think there might be an issue with the amount of current needed for a waterproof plug, but dont quote me on that.

juandesooka

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Re: Wing Board Tail Rocker - Thoughts
« Reply #67 on: June 16, 2022, 02:10:26 PM »
Nice board. Is the hole for water drainage, wire routing or both?
drainage. The wire cannot be disconnected. It would be perfect if it had a waterproof plug for the battery box. But i think there might be an issue with the amount of current needed for a waterproof plug, but dont quote me on that.
I have half-heartedly looked into removable connections and people in DIY community have discussed options.  There are various 3-pin connectors that seem like they'd work, either connecting the motor and esc along the wire somewhere convenient, or installing a waterproof boat-deck mount in the box.  However, these options wouldn't work well for you, as you'd have to make the through hull hole quite big to accommodate the plug.  Or maybe getting crazy with it: the hole through the board has a has a deck mount on board bottom that the motor wire plugs into, then on board top another deck mount that the box wire connects to.  That's two connections to manage but nicely sleek compared to a wire over the tail.

Wave Chaser

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Re: Wing Board Tail Rocker - Thoughts
« Reply #68 on: June 16, 2022, 06:10:40 PM »
PonoBill, I hate to trouble you, but since this is the "tail rocker" thread, and since you already have your straight edge out, could you please let us know how much the E3 has and which model you are looking at?  I don't know if this is the most useful way, but I like to put the straight edge flush with the tracks down the center-line and then measure how much tail kick (in this case, to the pointy release edge,) and how much at the board's midpoint (at the center-line).

Thanks!
Age:  61
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140lbs / 63kg
Axis HPS 830, Ultrashort fuse, P350 tail, 86cm carbon mast, 45l Axis Froth board

burchas

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Re: Wing Board Tail Rocker - Thoughts
« Reply #69 on: June 17, 2022, 07:05:20 AM »
PonoBill, I hate to trouble you, but since this is the "tail rocker" thread, and since you already have your straight edge out, could you please let us know how much the E3 has and which model you are looking at?  I don't know if this is the most useful way, but I like to put the straight edge flush with the tracks down the center-line and then measure how much tail kick (in this case, to the pointy release edge,) and how much at the board's midpoint (at the center-line).

Thanks!

Images of earlier production Kalama E3 boards showed the rocker Bill mentioned,
as seen in the picture below. Can you confirm Bill?
in progress...

Dontsink

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Re: Wing Board Tail Rocker - Thoughts
« Reply #70 on: June 17, 2022, 01:50:34 PM »
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.

I do not understand this.
Why would zero rocker at the foilbox give a nose down attitude in flight?.
Most modern  foils are designed to fly level on flat boxes, and if this is not the case you can always shim the mast plate.

juandesooka

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Re: Wing Board Tail Rocker - Thoughts
« Reply #71 on: June 17, 2022, 02:16:01 PM »
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.

I do not understand this.
Why would zero rocker at the foilbox give a nose down attitude in flight?.
Most modern  foils are designed to fly level on flat boxes, and if this is not the case you can always shim the mast plate.

On a short board (under 6') with minimal nose rocker, adding some tail rocker it will make it feel "nose up" when it rides. 
Alternatively, no tail rocker, the flat red line on the kalama board above, will not give this "nose up" feel -- and in some situations that can feel "nose down", like dropping into a steep wave it feels like your board is beyond neutral and actually pointing into the wave -- versus the nose up feeling of a surfboard or a snowboard in powder. 
The added blue lines illustrate how the tail rocker makes the board in front angle up, the nose rides is an inch or two higher than it be if no tail rocker. 
And yes, you can achieve the same thing with mast shims, either adding more rocker effect or removing it entirely.  (unless you have a tuttle mount)
Early sup conversions we found the boards had way too much tail rocker, which caused the foil to be pointing downward when paddling, really bad for paddling power and glide getting into waves.
The tail rocker thing is more pronounced on prone surf foils and shorter wing boards -- eg the sky 5' had a lot of tail rocker. So does the new FG Armstrong boards.


« Last Edit: June 17, 2022, 02:19:52 PM by juandesooka »

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #72 on: June 18, 2022, 07:11:33 AM »
The board is a prototype of the E3 (I probably should have mentioned that). I have the level handy, but not the board.

I think the radical changes Dave pioneered are driven by the changes in foil design and how people are using them. Moving to higher aspect foil or small foils means board speed becomes important. A high aspect, thin foil section wing that's under 1000sq cm is going to need some speed to get my fat ass off the water. Both flat bottoms, tails that flow, and minimum rocker or kick are all ways to get that speed.

Early on I thought the only thing a board needed to do was float me long enough to get off the water. After that I wanted it to mostly disappear. That works when you're riding a big, thick foil that can lift 200 pounds at 3 mph. I calculated that the 999 Axis wing generates 80 pounds of lift at 3 mph. Of course, my calculations are always open to question, I've been known to lose a zero or forget to carry the one, but I think that's close.
« Last Edit: June 18, 2022, 07:53:21 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.

PonoBill

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Re: Wing Board Tail Rocker - Thoughts
« Reply #73 on: June 18, 2022, 07:21:06 AM »
Nice board. Is the hole for water drainage, wire routing or both?
drainage. The wire cannot be disconnected. It would be perfect if it had a waterproof plug for the battery box. But i think there might be an issue with the amount of current needed for a waterproof plug, but dont quote me on that.
I have half-heartedly looked into removable connections and people in DIY community have discussed options.  There are various 3-pin connectors that seem like they'd work, either connecting the motor and esc along the wire somewhere convenient, or installing a waterproof boat-deck mount in the box.  However, these options wouldn't work well for you, as you'd have to make the through hull hole quite big to accommodate the plug.  Or maybe getting crazy with it: the hole through the board has a has a deck mount on board bottom that the motor wire plugs into, then on board top another deck mount that the box wire connects to.  That's two connections to manage but nicely sleek compared to a wire over the tail.

I'm using bullet connectors that are about the same diameter as the wire. After I solder the wire in place I cover the connector and the wire end with copious dielectric grease and shrinkwrap a cover onto it. I'll probably need to refresh the grease on the connectors themselves fairly often, but no big deal. The slim connectors mean I can remove the motor when I choose to--which won't be often, both of the boards I'm modifying will be dedicated to this use--a SIC Manta that I never really warmed to, and a hollow board Mark Raaphorst gave me that he rejected for quality reasons (one the internal braces pulled loose during molding).

There are 3-pin waterproof connectors that can handle 50+ amps, but they are bulky and stupid expensive (I was considering one for $273, but decided that was nuts). The bullet connectors I'm using are rated for 100 amps. The big problem with individual connectors is that it's easy to get the wires swapped, which often means the motor runs backward. Line tags or color-coded shrink wrap resolves this issue.

The board with the Faux Drive also has a 3D printed pass-through gland that clamps the wires to the hull. The gland is also filled with grease. The board with the huge motor and gearbox has the wired going through the mast and passes into the board through a short bit of carbon tube that I glassed into the board. My first thought was to make a compression fitting to seal the wares in place, but I wound up just pumping the tube full of caulking compound.

Both projects have been ignored for the past few weeks because I've been either wingfoiling or working on motorcycle projects and/or fixing my 3D printers. The ones I shipped from Maui had a rough trip, disassembled in flat-rate boxes. I have everything necessary to finish these foil projects and get them on the water. I just need to get off my ass and finish them.

« Last Edit: June 18, 2022, 07:42:31 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.

kwhilden

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Re: Wing Board Tail Rocker - Thoughts
« Reply #74 on: June 18, 2022, 08:03:38 AM »
Hi Ponobill.. thanks for the update. 

I've ordered a Foil Drive because I don't have the time to build my own.  There's a significant learning curve I would need.   

However I'm going to build a new wingboard soon designed to use the foil-drive assist. 

What I would like to do is cut the stock cable on the foildrive, and put in a quick-connect like you mentioned.  So it's easy to build a through-hull fitting for the cable in my next board. 

Can you post some pics of your connectors?

Sustainable Surf

 


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