Author Topic: Question about Foil Assembly  (Read 725 times)

JVM

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Question about Foil Assembly
« on: May 15, 2020, 05:44:06 AM »
So I sell Takuma Foils but there is no info on the assembly of the foil. I understand where everything goes but is there a specific torque these bolts should be set at? Also do the foil wings sit perfectly square to the mast or is it normal to have them offset a bit.

Thanks in advance from Nova Scotia!
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Wetstuff

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Re: Question about Foil Assembly
« Reply #1 on: May 15, 2020, 06:56:56 AM »
JV... You may want to PM Rob Pirie ..he used a Takuma recently  ...and made this really choice video.



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PonoBill

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Re: Question about Foil Assembly
« Reply #2 on: May 15, 2020, 08:13:33 AM »
Max torque for 6mm stainless screws is about 70 inch pounds. It's pretty hard to exceed that with a screwdriver. If the mast or other parts are aluminum you need to worry more about galling (the stainless screw actually pressure welding to the aluminum) than torque, so use a little tef-gel or any anti-seize lube that contains moly the first time you assemble the bits.

The foil wings should fit perfectly square.
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.

exiled

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Re: Question about Foil Assembly
« Reply #3 on: May 15, 2020, 05:00:52 PM »
Would switching to titanium screws help prevent galling in this case?

PonoBill

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Re: Question about Foil Assembly
« Reply #4 on: May 15, 2020, 08:00:22 PM »
OK I guess if you like spending the bucks, though it can be extra difficult to find bolts in the length and head type you'd like. And it wont solve the problem since titanium actually galls worse than stainless steel, and if you use it with aluminum the huge difference in elasticity can create problems with thread pulling. While the high modulus reduces the load on the first thread and distributes load better we used to sometimes run into total thread failure issues on the race bikes I worked on when Titanium bolts were used with aluminum female threads. The fancy, schmancy guys used special taps to get a slight mismatch in thread pitch. I was never sure what that was supposed to do but it caused all kinds of headaches working on the Honda and Yamaha endurance racers--you could put a titanium bolt into a case and it would be fine, but replace it with a steel bolt and it would jam noticeably when you torqued it, and wouldn't come out.

I love looking at titanum parts, and now that you can have complex titanium bits made with 3d printing I'm just salivating over the potential, but I probably won't be making unobtanium bits for foils.
« Last Edit: May 15, 2020, 08:02:07 PM 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.

JVM

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Re: Question about Foil Assembly
« Reply #5 on: May 16, 2020, 09:04:42 AM »
So looks like the fuselage doesn't sit properly on the mast. It's out by 32mm tip to tip on the front wing. Tried shimming but that's a PITA and doesn't seem to do enough and only closes the difference a bit
« Last Edit: May 16, 2020, 09:09:04 AM by JVM »
DEALER FOR--------------------------------
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ISURUS
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liv2surf

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Re: Question about Foil Assembly
« Reply #6 on: May 16, 2020, 10:09:18 AM »
OK I guess if you like spending the bucks, though it can be extra difficult to find bolts in the length and head type you'd like. And it wont solve the problem since titanium actually galls worse than stainless steel, and if you use it with aluminum the huge difference in elasticity can create problems with thread pulling. While the high modulus reduces the load on the first thread and distributes load better we used to sometimes run into total thread failure issues on the race bikes I worked on when Titanium bolts were used with aluminum female threads. The fancy, schmancy guys used special taps to get a slight mismatch in thread pitch. I was never sure what that was supposed to do but it caused all kinds of headaches working on the Honda and Yamaha endurance racers--you could put a titanium bolt into a case and it would be fine, but replace it with a steel bolt and it would jam noticeably when you torqued it, and wouldn't come out.

I love looking at titanum parts, and now that you can have complex titanium bits made with 3d printing I'm just salivating over the potential, but I probably won't be making unobtanium bits for foils.

My bigger problem with stainless bolts and aluminium masts is galvanic corrosion and seizing (not galling....AS FAR AS I CAN TELL... but maybe I don't know the difference). Despite the galling risk you mention above for this combination, I guess the risk of galvanic corrosion is lower. SO, at the end of the day (when I never maintain my gear correctly), is the risk for seizing in our foiling applications lower or not appreciably lower using titanium bolts into aluminium. Thanks.

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PonoBill

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Re: Question about Foil Assembly
« Reply #7 on: May 16, 2020, 01:23:25 PM »
Nope, Titanium will drive you nuts. I have half a $60 titanium axle around here someplace with a $20 nut welded to it. Some idiot tried to spin it off with an impact wrench. It yanked the wrench right out of my hand when it stuck.

Seizing happens as you tighten or loosen the bolt--it's friction welding, and it's exacerbated by how quickly you turn the bolt. The tough oxide coating that prevents corrosion is only molecules thick. scrape it off and the materials are happy to intertwine their atoms. You'll know exactly what it is the first time it happens to you. When I see folks using drills to tighten stainless bolts I always want to say something, but I shut up because nobody wants to hear it. The threads weld together and they won't come apart. You can do it a hundred times and it will work fine, and then one time it won't. The only choice is to drill out the bolt or if it's a bolt and nut, cut the bolt.

When I was installing the framework for the solar panels on my stupid motorhome project I used a cordless drill to run the zillions of stainless screws into their stainless nuts. Every time I got sloppy and ran the motor too fast I seized the screw into the nut and got to spend twenty minutes cutting them apart--and five minutes cursing my stupidity. Even when you know better you can do dumb shit.

A good anti-seize compound that stays on a long time (not water soluble, super high viscosity) will help with corrosion as well, but the best bet is to not leave the metals in contact as they dry out. A couple of wet/dry cycles in salt water makes for a powerful electrolyte. Electrolytic corrosion can spread very quickly from the tiniest pinhole in the corrosion shield.
« Last Edit: May 16, 2020, 01:32:17 PM 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.

SanoSlatchSup

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Re: Question about Foil Assembly
« Reply #8 on: May 16, 2020, 11:56:10 PM »
So looks like the fuselage doesn't sit properly on the mast. It's out by 32mm tip to tip on the front wing. Tried shimming but that's a PITA and doesn't seem to do enough and only closes the difference a bit
You might want to post a picture of what it is you're measuring, and trying to get level.

Because there's an "angle of attack" (wings/fuselage angle compared to the bottom of the board), and the "angle of incidence" (the angle of the wings as they relate to the fuselage).

So at least for myself...I'm not sure I'm understanding what angle it is you're trying to get "perfectly square" to the mast...unless you're talking about fuselage to mast, instead of the "wings". IOWs, I don't ride with my wings "perfectly square to the mast" either...
Me: 6'1"/185...6'0" Kings Foil Board...6'0" Chelu Foil Board...9'6" Bob Pearson "Laird Noserider"...9'6" Costa Azul Wide Body...14' Lahui Kai "Manta"...8'0" WaveStorm for when proning urges still hit, and 7'3" Chuck Glynn foil board backup.

JVM

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Re: Question about Foil Assembly
« Reply #9 on: May 17, 2020, 07:20:58 AM »
Meant to post a pic to show what I mean.
DEALER FOR--------------------------------
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ISURUS
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PonoBill

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Re: Question about Foil Assembly
« Reply #10 on: May 17, 2020, 08:15:56 AM »
Yeah, that's not good. Takuma needs to fix that.
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.

SanoSlatchSup

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Re: Question about Foil Assembly
« Reply #11 on: May 17, 2020, 05:00:44 PM »
Meant to post a pic to show what I mean.
Oh yeah, that's not at all the angle(s) I thought you were talking about initially.

But yeah, whether that's a problem with the a) wing to the mast, b) connection between adapter to mast, or c) bent mast itself...you definitely need to have Takuma take care of the problem if it was shipped to you like that.
Me: 6'1"/185...6'0" Kings Foil Board...6'0" Chelu Foil Board...9'6" Bob Pearson "Laird Noserider"...9'6" Costa Azul Wide Body...14' Lahui Kai "Manta"...8'0" WaveStorm for when proning urges still hit, and 7'3" Chuck Glynn foil board backup.