Author Topic: Learning foil pumping  (Read 6232 times)

Hdip

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Re: Learning foil pumping
« Reply #15 on: May 18, 2021, 09:46:40 AM »
I thought it was the same as "cowperson" for cowboy. Because "dewolfe" is a good joke for dewilde.

Why would you use a foil at all on your towboogie? Just a mast seems to be the norm for the foilzone guys around here who came up with the idea.

PonoBill

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Re: Learning foil pumping
« Reply #16 on: May 18, 2021, 10:55:22 AM »
Yeah, I yanked the foil off my eFoil to have it tow me around. I don't plan to have the TowBot rise on a mast like an efoil, it will be surface piercing on both sides, like the late, unlamented GeezerFoil. there are a few good reasons to add a foil, one is to control pitch. All of the small tow craft I've seen (mostly on video) have a problem with accelerating because they tend to pitch up from the towline drag. When they do, they generally torque steer and yaw. That can be solved to some degree by positioning the towline low, but that isn't ideal for the person being towed. With a foil I can control pitch during acceleration. If I'm going to do that I might as well make it fly--either a little or a lot.
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.

jondrums

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Re: Learning foil pumping
« Reply #17 on: May 18, 2021, 10:59:14 AM »
Pono, it seems to me that the issue of your towbot pitching due to towline force could give a lot of trouble if you're puttin it on a foil.  The towline would want to be down super low (maybe even underwater) in order for your pull variation not to result in pitching moment.  The pitching moment will almost certainly make the foil breach or porpoise.

PonoBill

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Re: Learning foil pumping
« Reply #18 on: May 18, 2021, 06:13:34 PM »
Actually, the idea is to use a foil to control pitch. Without a foil I've had to rig the towline in a Y, with one leg connected to the bottom of the mast, and the other leading through the PVC pipe that lets me steer the eFoil. A foil can be angled down to press the nose down, and once everything is moving at a reasonable clip, rotate to a neutral AOA to decrease displacement, or even lift the hull out of the water. All supposition, I can theorize all day, but I'm going to build this thing this summer. We'll see what it needs.
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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