Author Topic: Something new?  (Read 5084 times)

LaPerouseBay

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Re: Something new?
« Reply #30 on: December 02, 2022, 07:21:32 AM »
« Last Edit: December 02, 2022, 07:24:04 AM by LaPerouseBay »
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LaPerouseBay

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Re: Something new?
« Reply #31 on: December 02, 2022, 08:56:28 AM »
That would be a blast to see, but you'd still need to instrument the heck out of the foils to get good data.

Or, one could skip all that and just jump in and start testing foils.  We did a run Wednesday in conditions that pool can easily match. 

That gang I tag along with (I'm in ski) is remarkably foil brain damaged.  They go when it's light whitecaps on the south shore.  No wingdings, just paddles.  No excessive pumping like those aliens on flat water.  Several rest stops, (because they had foil surfed Ka'a that morning).  The girls were on foils relative in size to the 899.  All on Barracudas, of course. The foils Randy and Chan will be using would tear that pool up.   
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PonoBill

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Re: Something new?
« Reply #32 on: December 02, 2022, 10:34:49 AM »
I would dearly love to be able to do that. Too old, weak, and fat I fear. I've tried--it seems hopeless. Maybe with a motor.
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: Something new?
« Reply #33 on: December 02, 2022, 11:30:22 AM »
I worked there in the 90s back when I was sailing high performance international canoes.  We were totally "canoe-brained" which was the equivalent to foil brain now.  My boss and I used to dream about sneaking into the huge wave pool to sail around, that wasn't going to happen though.

Years before I got there, in the 70's they built a half mile long towing tank with a gantry that could reach 100knots.  They were testing hydrofoils to try and accomplish ship designs for the "100knot navy" goal that someone or other had dreamed up.  That's idea didn't take I guess.  I helped with a few tests on that rig.  If you really really want to know exactly how a foil performs, that would be the way

LaPerouseBay

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Re: Something new?
« Reply #34 on: December 02, 2022, 02:06:59 PM »
I don't foil, but I've listened as the gang worked up from the original big blue gofoil.   

Nowadays, it seems to me that increasing the useable range of speeds is going to be the limiting factor in the Gorge.  Those waves are steep.  You are going to want to stay up on foil and move around from wave to wave.     

As all you foilers are aware, you want lift at low speed to get up.  Dave's barracuda was a game changer.  It opened the door to an entire group of foil surfers (and wing dingers) that had given up on downwind paddle foiling.  They are rocking maliko runs now.  The barracuda allowed them to learn the initial liftoff timing in lumpy seas.  Then they quickly move to a 'faster' wing. 

The south shore of Maui is basically a wave pool.  Zero fetch, steep wave faces, max 0.5Hz frequency (2 second period).  From shore, we often see ribbons of waves, a single, unbroken trough easily reaching out over a half mile.  Just a bit of a chevron across the wave, but one line all the way out - just like that pool.  This is ideal for learning to downwind.

So, next step is they start pushing the top speeds.  Not because it's more fun - because it's easier to link glides. 

Nobody like pumping on foil.  'Slower' foils may lift easy, but they blow up pretty fast - even on the south shore.  Extra lift requires them to avoid steeper wave faces. Once in the trough, they need to pump and paddle out of it.   With a 'faster' foil, they effortlessly glide thru those troughs, up to the next wave.  If they choose to zoom down the face, the foil won't blow up.  They also have the option to carve the wave face.  Tail wings are a big deal, as you all are very aware.  The 2 second (max) 'swell' period is the key here, the overall speed isn't very fast.

So, next step for them is how to negotiate the north shore and it's warp speeds. Swell periods from the East top out at 10 seconds, which is spooky fast for mere mortals.    Most alpha girls won't go when it's too big and windy.   They don't have the weight to hold the nose down.  When they cross the crest to fade out the back of a big one, the wind can knock them over.  Guys just float down the road, like a bus.  Weigh is a big advantage in big wind, big maliko, Oc-1, ski and foil.  It hastens the zoom down to a high top speed, momentum prolongs it.           

So, next up for foiling at a nuthouse like the Gorge is speed brakes.  That's what we do in boats.  I broke several paddles braking in my Oc-1.  Thankfully, ski wing are much stronger.     

Mechanical brakes.  Probably won't take much to open up a wide range of practical lift.  Fast forward to 6:46 if youtube doesn't.

https://youtu.be/O22eHzc8yl0?t=406

Gorge is crazy steep.  Almost too big for boats.  Almost.

https://youtu.be/Y_hm5zpSWJs

   
« Last Edit: December 02, 2022, 02:12:13 PM by LaPerouseBay »
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PonoBill

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Re: Something new?
« Reply #35 on: December 02, 2022, 07:06:46 PM »
Wow, for a non-foiler you certainly understand all the issues. The gear is in flux more than the casual user understands. Even fakers like me are on faster, more challenging equipment, which is, at the same time, easier to use when you get to the outer limits of the current envelope. The first time I saw an Axis 1000 I thought "no way I could ever get up on that." Now it's in the rearview mirror. Big and slow.

There's a good reason I live in Maui and the Gorge. Nonstop crazy fun. And yes, brakes would be good, as evidenced yesterday on the south side. Fairly light wind, but still, when I turned downwind to jibe my Axis 999 was humming like an organ. I could feel the vibrations in my feet.
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: Something new?
« Reply #36 on: December 02, 2022, 11:04:51 PM »
"Doubles the airplanes drag".  What a great visual.

https://youtu.be/O22eHzc8yl0?t=417

tarquin

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Re: Something new?
« Reply #37 on: December 02, 2022, 11:05:25 PM »
My dad always told me foiling would take over sailing one day. When I was a kid he gave me a model of a trimaran he made. He said what everyone is doing wrong is making the foils too big to get early lift. You want something that goes fast enough to be able to use smaller foils. Only a small difference in boat speed allows you to have much smaller foils.
 He also said once people figure out it works and actually spend money on CFD specifically for foils things will develop very quickly. The elusive 50 knot barrier will become the norm.
 Eventually they will need to figure out how to slow down to be able to tack and gybe.
 The AC boats and some other classes are talking about have some system of being able to slow down.
 He thought foils would eventually become totally computer controlled and you would be able to change the shape. Some sort of second skin that could be inflated and deflated. He also said air brakes, as said above may become a thing on sailboats one day.
 Anyhow I wonder if those paddle glove things would be enough to slow you down. Like a kid flying your hand out the window of a car.

tarquin

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Re: Something new?
« Reply #38 on: December 02, 2022, 11:08:16 PM »
He wanted to call me Peregrine, after the Peregrine Falcon that changes it's head into a wedge shape to reach crazy speeds.

tarquin

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Re: Something new?
« Reply #39 on: December 03, 2022, 04:21:38 AM »
Lots of studies have been done on Peregrine falcons and how they change shape to go crazy fast. 

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Re: Something new?
« Reply #40 on: December 05, 2022, 09:18:43 AM »
For conventional setups on an Axis Fuselage, this is a nice way to match up a rear wing with all of the Axis fuselage contours in that area.  Create a plane in software, bend it to the fuselage profile contours and then match it to the outline.   With that you can vertically pull the base points of the stabilizer.  Software will snap to the new plane and take care of all the smoothing based on your control loops.  Sweet.  This will be even easier when my scanner shows up.  Stoked for that.

« Last Edit: December 05, 2022, 11:46:42 PM by Admin »

PonoBill

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Re: Something new?
« Reply #41 on: December 05, 2022, 09:41:50 AM »
What scanner did you get. I've got the latest Revopoint at my shop. I've never used it but I expect that to change. I'd ask Tad to get it for you, but it would be hard for him to find it.
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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Re: Something new?
« Reply #42 on: December 05, 2022, 11:32:20 AM »
This guy I know had suggested the Revopoint Mini and it sounded like something I needed :).  Really, though, that thing looks incredible.  Thanks for the suggestion!

 


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