Author Topic: Geezer Foil 2  (Read 1346 times)

PonoBill

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Geezer Foil 2
« on: March 15, 2017, 06:05:02 PM »
So,GF2 needs to be a lot stiffer, a lot stronger. Two ways to do that--1. use very strong materials, or 2. use a strong structure. I'm going mostly with 2 with a bit of 1 tossed in.

The front foil will be boxed, the rear, i'm not sure yet.

Here's the start of building the box and a new connector foil. There will be two fences coming down to the joint of the main wihng, and a brace across the top that the board connects to.



Here's the wing and center foil pieces. I cut through the top of the wing sections, leaving the aluminum intact, then flexed the pieces into this position






Glued with Gorilla glue



Added carbon strips to reinforce the joints,



Good start I think. I'm not going to try bagging this. the center foil is going to be a wet layup. I'm thinking a thin skin of spruce ply on the top of the wing, glued in place, and then carbon. The fences reinforcing the joints are going to be thin plywood with carbon on each side--a thin sandwich, but it should be strong. Top piece probably plywood with fiberglass over it.  Maybe some carbon too--why not. I have a lot of 10oz scrap.

Total width is 29 inches. the center foil is 22"X8" The angle wings are 13" X8". I'm fudging a bit on the foil coefficient, but according to my calculations the full wing (center and angled wings) gives 240# of lift at 4mph. The coefficient might be better, we'll see. There's nearly 200# of righting force available if the foil tilts 30 degrees at 5mph. Lots 'o fudging in those numbers.
« Last Edit: March 15, 2017, 06:17:45 PM by PonoBill »
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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.

Ichabod Spoonbill

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Re: Geezer Foil 2
« Reply #1 on: March 15, 2017, 06:41:38 PM »
I'm amazed you can actually do the math on that. I'm definitely not that kind of nerd. Mucho respect.
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PonoBill

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Re: Geezer Foil 2
« Reply #2 on: March 15, 2017, 08:47:54 PM »
Water makes it easy since the density parameter factors out to 1, so you can ignore it,  and I'm doing a very simplified calculation assuming zero degree AOA.
Ponohouse is for sale: http://www.ponohouse.com
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.

blackeye

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Re: Geezer Foil 2
« Reply #3 on: March 15, 2017, 11:15:30 PM »
I like the new names: GF1 and GF2. Sounds a bit more hip than the original. Perhaps Admin can rename the thread.

I look forward to having a GF experience someday soon.

surfcowboy

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Re: Geezer Foil 2
« Reply #4 on: March 16, 2017, 12:39:26 AM »
This is a great design evolution.

What's the back again? Same apparatus or a single winglet on a fin?

Admin

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Re: Geezer Foil 2
« Reply #5 on: March 16, 2017, 02:16:46 AM »
Cool.  Are you going to router the board to recess the top brace? 

stoneaxe

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Re: Geezer Foil 2
« Reply #6 on: March 16, 2017, 06:08:05 AM »
Very cool bro. I can't wait to move...so stoked about having a real workshop finally. Glad you'll have some of the experimenting out of the way. I was thinking about that board I want to build last night and it occurred to me that I should install a tuttle box in it. Now I'm thinking it would be good to also build in some hard points for mounting a GF2...or maybe that will be GF3.... :)
Bob

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PonoBill

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Re: Geezer Foil 2
« Reply #7 on: March 16, 2017, 07:47:23 AM »
Cool.  Are you going to router the board to recess the top brace?

No, that's too much like work. I already have through bolt sleeves installed in the 11'11" SIC. I'm just going to bolt it to the bottom. We can do pretty later.

The tail will be a T wing in place of the fin. I think the standard fin fox will do for testing since there won't be that much weight on it. I'd have to go to Tuttle for serious use, through it might need a rudder.

A version of this design would be good for the boat idea you had Admin.
Ponohouse is for sale: http://www.ponohouse.com
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.

surfcowboy

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Re: Geezer Foil 2
« Reply #8 on: March 16, 2017, 07:50:55 AM »
I'd like to maybe get a thread going on putting in hard mount points. I'm starting a new board soon (that cabin is almost done!) and I'd like to add a Tuttle and/or a 4 point mounting plate into it. I keep thinking the 4 point is easier than a Tuttle overall. Of course I could be wrong but then again, so could the industry. Lord knows once the tooling is made it's near impossibile for people to switch to a better way. Ask Larry A about that.

I'll see if I can get us started. I'd like a few camera mounting options as well.

Admin

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Re: Geezer Foil 2
« Reply #9 on: March 16, 2017, 08:05:34 AM »
A version of this design would be good for the boat idea you had Admin.

It sure could.  I am envisioning a little steeper and deeper for the angled members with very minimal verticals (possible just mounting stubs) and a reduced length of the horizontals.  Less chord as there would be two.  One of these Flat V-foils just inside the fore and aft confines of the rider cockpit (3 feet apart-ish?).  In my mind the mid points of the angled members would about 16-18 inches apart on each.  Mine can be a lot less stable than yours.  I don't need to stand on it.

I like how low you will be riding.  How tall is your total foil?
« Last Edit: March 16, 2017, 08:36:02 AM by Admin »

PonoBill

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Re: Geezer Foil 2
« Reply #10 on: March 16, 2017, 09:56:32 AM »
19 inches.
Ponohouse is for sale: http://www.ponohouse.com
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: Geezer Foil 2
« Reply #11 on: March 16, 2017, 04:01:11 PM »
More progress. The goofy eye problem seems to be helping me focus. Little pun there.




Wing with top carbon. I glued an aluminum brace to the bottom that supports the wing joints and then glassed over it. Then did carbon on the top. I'll do one layer of carbon on the bottom and one more on top



I think I'll bondo the thing before I do the next layer of carbon.



Top brace and mount,



I wrapped to top brace with peel ply to try to get some kind of wrap over the edges. Probably won't work. I should have tapered the edge.



Vertical gates that brace from the top plate to the wing joints. I'll cut two out of this. It's 1/8 spruce ply wrapped in two layers of carbon.
« Last Edit: March 16, 2017, 04:12:05 PM by PonoBill »
Ponohouse is for sale: http://www.ponohouse.com
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.

Admin

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Re: Geezer Foil 2
« Reply #12 on: March 17, 2017, 02:36:00 AM »
You are a rapid prototyping machine!

Are the gates needed?  It looks strong as is.

US fin box mounts is a great idea for your T foil and would be cool for GF3 for the Flat V.  I am thinking of doing that for both of the flat V's on my Swell Sled.  Two plates in each box.  4 boxes.  Maybe a foot of combined fore/aft adjustment with long boxes. 

« Last Edit: March 17, 2017, 06:17:06 AM by Admin »

DW

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Re: Geezer Foil 2
« Reply #13 on: March 17, 2017, 03:58:44 AM »
Hey Bill, have you been following where kite foils are going?  The latest is trying to get foils to carve turns off the back foot, instead of pivot turning between your feet. It's all about getting true surfboard feel. Within two years, what we have today will be no more, I think.

They are getting there by reversing the foils, bigger in back. Canard like setup. Zeeko has it in production. Back yard guys are just swapping wings. Some are getting it to work.

surfcowboy

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Re: Geezer Foil 2
« Reply #14 on: March 17, 2017, 08:01:23 AM »
DW, that's so funny. I was thinking of putting a forward canard on my bodyboard by mounting a fuselage backwards as a test. I was thinking it was too weird but I guess the rules are all thrown out these days lol.

I'll totally play with that.

 


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