Author Topic: Geezer Foil  (Read 3967 times)

PonoBill

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Geezer Foil
« on: July 17, 2016, 09:02:14 AM »
Back to work on the geezer foil. I was preparing to wire cut some foam for the wings, I laid out the airfoils shape for every 10 inches and planned to make plywood templates for each end to guide the wire. Just before I started cutting I found a foam glider wing in the hobby shop here in Hood River with almost the exact shape and dimensions. Saved me a lot of time. I decided to back the wing with aluminum for the layup. I'm using thin aluminum and I rolled in some corrugations at the dihedral curve so it would holed the rocker under bagging pressure. I bagged up the wings when I glued them to the aluminum with Gorilla glue that I prewet by mixing in water.











I'm finding quite a few timesaving bits that should move this project along. I'm on a one week surf safari so everything is on hold until next week, but I think I'm only a few weeks away from trying this.
« Last Edit: July 17, 2016, 09:08:00 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.

blackeye

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Re: Geezer Foil
« Reply #1 on: July 17, 2016, 10:05:59 AM »
What is your technique for the layup? Do you wrap cloth around the edges? If not, how do you get top and bottom layers to join?

I draped a single piece of cloth over the leading edge so that both top and bottom foil surfaces were covered and intended to have the two layers meet to form a sharp trailing edge. 

One foil worked but the other slipped in the bag and I had a wrinkly mess on the leading edge. And I sanded the trailing edges too much such that they didn't meet anymore. My fix was to lay a piece of carbon over the leading edge much like making carbon rails on a board. For the trailing edge I glued in a strip of cedar and trimmed it. Next time I will plan a wood or carbon flat stock trailing edge and sand it to shape before layup.

PonoBill

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Re: Geezer Foil
« Reply #2 on: July 18, 2016, 05:31:54 PM »
I did a quick try of vacuum bagging on a layer of carbon on the top. The stiffness of the carbon made it impossible to wrap the trailing edge. Leading edge not so bad. I put on a layer of peel ply to see if I could pull the carbon hard enough across the trailing edge to make the turn and then tape it. Worked OK on the leading edge, made a mess on the trailing edge. I didn't get much adhesion to the aluminum or the foam so ripping off the peel ply delammed the carbon in a lot of places. So I slit it all up with a vibrating balde and peeled it off. Try two will be more like making a paddle blade. I'll wrap the leading edge and do top and bottom at the same time, squashing the top and bottom layers together and trimming back to leave a half inch margin.

I like your solution though. Might try that if #2 doesn't work well.

I need to prep the foam better. Probably has mold release on it from beeing molded.
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
« Reply #3 on: July 18, 2016, 08:40:08 PM »
I've never worked with carbon I didn't realize it was so hard to bend th heavy stuff. This wing building method seems to be a great way to get a mock up built. We need  somebody with a mill that we can get to cut us a few plywood wing forms without the grinder session.

Arany

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Re: Geezer Foil
« Reply #4 on: July 18, 2016, 10:17:17 PM »
Is ther connections  between  the carbon and the aluminum  do they touching one the other.thanks

DavidJohn

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Re: Geezer Foil
« Reply #5 on: July 19, 2016, 03:29:07 AM »
Check this out Bill..

http://youtu.be/Q7HzOgAoTH4

PonoBill

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Re: Geezer Foil
« Reply #6 on: July 19, 2016, 07:48:27 AM »
That's pretty cool. My original design was a surface-piercing box, but when I did the math I discovered I'd have to really fudge on the lift to keep it in the water. Either make the foil very flat or make the aspect ratio ridiculously high. You can see in your video how small that lifting foil is. I want to do surface piercing for the inherent stabilty. I'm trying to size the wings so the foil will bank, but the righting force will be substantial.
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.

Subber

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Re: Geezer Foil
« Reply #7 on: July 19, 2016, 08:09:35 AM »
Check this out Bill..

http://youtu.be/Q7HzOgAoTH4

Shark mouth bi-plane.

Looked very stable.

Cool.
Jimmy Lewis Black & Blue Noserider 10'1"x31"x4.25," 164 liters, 24 lbs, 1 box
Pearson Laird Surftech Longboard 10'6"x23"x29.75"x18"x4.375," 154 liters, 24 lbs, 3 boxes
Takayama Ali'i II Surftech 11'x21.375”x28.5”x17.25”x 4.25,” 162 liters, 26 lbs, 3 boxes

PonoBill

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Re: Geezer Foil
« Reply #8 on: July 23, 2016, 11:56:20 PM »
I've returned from my Surf Safari/Airstream Bambi demo so it's back to work. I laid up carbon on the bottom of one wing this afternoon. I added aluminum extensions to the trailing edge to support the carbon beyond the trailing edge. I wrapped the carbon on and taped it into place, lapping over the leading edge and laying flat on the extensions (which I waxed so they would release). Next step will be trimming the lap on the leading edge and grinding a precise margin into the trailing edge. Then I'll lay on the top carbon and bag the margins together to seal like the edge of a paddle. I think this will work well. If this thing works out, the next set I build will be in a mold, which is certainly the best way to make a part like this. might do them hollow.

I also welded up the rest of my mega battery build for my electric fatbike. Now I just need to solder in the BMS connections and see how it charges. It's a 12S13P battery made from 2500ma 18650 batteries. Cheap Chinese ones, but I wanted to try the thing before I do something expensive.
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.

 


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