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Author Topic: Getting ejected out the front door...  (Read 5271 times)

Dwight (DW)

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Re: Getting ejected out the front door...
« Reply #30 on: November 09, 2021, 06:42:50 AM »
Is what we are talking about good ole' fashion windsurfing

SPIN OUT

Those of us with a windsurfing background know Spin Out to be a function of going fast and loading up a fin on a choppy, or aerated, surface. 

We have been fighting it for decades.

Thatís my guess too. Pushing sideways instead of leaning the board over and maintaining all forces straight down the mast. Easy to make this mistake riding toe side.

Alysum

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Re: Getting ejected out the front door...
« Reply #31 on: November 09, 2021, 12:41:46 PM »
Is what we are talking about good ole' fashion windsurfing

SPIN OUT

Those of us with a windsurfing background know Spin Out to be a function of going fast and loading up a fin on a choppy, or aerated, surface. 

We have been fighting it for decades.
It happens to me a low speeds too. Many think it's because of the higher speeds we're getting with the new foils but it's not.
I once just water started and 2 secs later it ventilated at low speed.

Dwight (DW)

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Re: Getting ejected out the front door...
« Reply #32 on: November 09, 2021, 01:46:23 PM »
Windsurf fins spin out at low speed too. Donít push sideways and see if this helps.

Solent Foiler

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Re: Getting ejected out the front door...
« Reply #33 on: November 09, 2021, 01:52:46 PM »
Is what we are talking about good ole' fashion windsurfing

SPIN OUT


Sort of... It is ventilation, but instead of the fin releasing downwind, this is the mast releasing upwind with a roll to windward as a minimum, and taking air down to the stab with catastrophic loss of lift at its worst.
I'm 5'10", 65kg riding:
Gong Lethal 4'6 65L
Gong Catch 5'3 34L
Gong Hipe v2 4'11 70L
Axis ART 999
Gong Fluid L-S, XXL-S on 85cm mast
Duotone Slick 3m, 4m, 5m

Dwight (DW)

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Re: Getting ejected out the front door...
« Reply #34 on: November 09, 2021, 03:25:27 PM »
When I think about all the wingers with poor body form, I have to wonder if this is not the issue.

Bending at the waist. Getting themselves in such poor position the wing is pulling them one way and they are pushing back the opposite way with their feet.

Everyone should aspire to copy Johnny Heinekenís body form.


PonoBill

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Re: Getting ejected out the front door...
« Reply #35 on: November 09, 2021, 03:40:20 PM »
Is what we are talking about good ole' fashion windsurfing

SPIN OUT

Those of us with a windsurfing background know Spin Out to be a function of going fast and loading up a fin on a choppy, or aerated, surface. 

We have been fighting it for decades.
Yes and no. Spinout has numerous components, including ventilation. Ventilation means an airfoil that pierces the surface has enough differential pressure to pull air down the edge of the foil--in this case, the foil is the mast. When the air envelopes the stabilizer it's game over. A windsurfing fin generally has the bottom of the board to insulate it from the surface. If you bounce clear of the surface in chop the fin can ventilate and spin out. Most of the time though it's mostly the sideways vector of the wind and foot force that overcomes the fin's lift and it slips. Once it starts slipping and going sideways it's tough to regain control because there's no flow across the airfoil to generate lift. Likewise, landing from a jump covers the bottom of the board and the fin with air. Differential pressure from the residual forward speed keeps the air in place until there is enough flow across the fin. In that case there is virtually no lift from the fin and you have to straighten up long enough for the air to bleed off before the fin starts working. I spent a stupid amount of time measuring side thrust on fins, developing and throwing away fences and other devices to minimize ventilation. I settled on canard or slotted fins, which won't help at all with foils.
« Last Edit: November 09, 2021, 03:45:45 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.

jondrums

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Re: Getting ejected out the front door...
« Reply #36 on: November 09, 2021, 04:16:40 PM »
canard mast???  hmm, got me thinking about this
I thought I put all this behind me when I gave up windsurfing all those years ago

PonoBill

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Re: Getting ejected out the front door...
« Reply #37 on: November 09, 2021, 07:10:56 PM »
I suspect that cleaning up the aluminum masts will go a long way to fixing this. I'd start with sanding off the logo and filling the dip with bondo and sanding it all super smooth--I'd probably paint the whole thing to seal the bondo and finish with 600 grit. then polish and wax. That's the cheapest way to move the needle higher.

I don't have the problem often, so I'm not that motivated to solve 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.

Solent Foiler

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Re: Getting ejected out the front door...
« Reply #38 on: November 09, 2021, 10:39:37 PM »
When I think about all the wingers with poor body form, I have to wonder if this is not the issue.

Bending at the waist. Getting themselves in such poor position the wing is pulling them one way and they are pushing back the opposite way with their feet.

Everyone should aspire to copy Johnny Heinekenís body form.

There could well be individual circumstances that make it worse, but that wouldn't explain the brand specific nature of my issue. Complaints on the Axis FB page seem to come from fairly experienced riders too, who also say the Axis mast is way more sensitive to it..
I'm 5'10", 65kg riding:
Gong Lethal 4'6 65L
Gong Catch 5'3 34L
Gong Hipe v2 4'11 70L
Axis ART 999
Gong Fluid L-S, XXL-S on 85cm mast
Duotone Slick 3m, 4m, 5m

Solent Foiler

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Re: Getting ejected out the front door...
« Reply #39 on: November 10, 2021, 12:44:19 AM »
https://youtu.be/2tIQlDJ-XPY

This was submitted as an example of the issue by an experienced rider... Watch the wake of the foil closely and you'll see the sideways movement of the mast just before the incidents...
« Last Edit: November 10, 2021, 12:47:16 AM by Solent Foiler »
I'm 5'10", 65kg riding:
Gong Lethal 4'6 65L
Gong Catch 5'3 34L
Gong Hipe v2 4'11 70L
Axis ART 999
Gong Fluid L-S, XXL-S on 85cm mast
Duotone Slick 3m, 4m, 5m

Fishman

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Re: Getting ejected out the front door...
« Reply #40 on: November 10, 2021, 10:53:51 AM »
https://youtu.be/2tIQlDJ-XPY

This was submitted as an example of the issue by an experienced rider... Watch the wake of the foil closely and you'll see the sideways movement of the mast just before the incidents...
I don't know which mast you use (or it's profile) but I wonder if you have experienced this with the Gong V2 aluminium mast?

 The newer V2 has a greater teardrop profile and I was curious as to why they changed from the old more symmetrical shape like the V1 and Axis mast have. After reading this I thinking this could be the answer

I would think the more teardrop shape would be less likely to aerate/ventilate if that is really what's happening.

 
« Last Edit: November 10, 2021, 11:12:03 AM by Fishman »
SupSurfMachine 9'9" longboard
SupSurfMachine  8'2" funboard

PonoBill

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Re: Getting ejected out the front door...
« Reply #41 on: November 10, 2021, 01:10:32 PM »
There could well be individual circumstances that make it worse, but that wouldn't explain the brand specific nature of my issue. Complaints on the Axis FB page seem to come from fairly experienced riders too, who also say the Axis mast is way more sensitive to it..

Of course it is, who else makes a 19mm mast? There's a tradeoff between strength/rigidity and the downsides of a thicker, wider mast--drag, weight, and ventilation.

Looking at the yaw angle of the board and how far he was hiked out, I'm not surprised the mast ventilated.
« Last Edit: November 10, 2021, 01:12:54 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.

Solent Foiler

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Re: Getting ejected out the front door...
« Reply #42 on: November 10, 2021, 03:15:44 PM »
There could well be individual circumstances that make it worse, but that wouldn't explain the brand specific nature of my issue. Complaints on the Axis FB page seem to come from fairly experienced riders too, who also say the Axis mast is way more sensitive to it..

Of course it is, who else makes a 19mm mast? There's a tradeoff between strength/rigidity and the downsides of a thicker, wider mast--drag, weight, and ventilation.

Looking at the yaw angle of the board and how far he was hiked out, I'm not surprised the mast ventilated.

So you agree this is more of a design issue rather than a technique issue? DW was suggesting otherwise, which is what my comment was responding to.

I'm in the design issue camp, but with the caveat that individual circumstances can make it worse. Rider weight seems to be cropping up as one possibility (from FB comments), lighter riders being more susceptible, but there's no hard evidence yet...

Fishman - I do have a Gong V2 mast but only recently got it and only used it with my big foil. I will try it with my Fluid LS this weekend and see how it behaves... I normally use one of the older thinner Naish masts (similar to the Gong V1) which fits my modified Gong fuse with the LS, after my Gong carbon mast started cracking after jumping it. It's that carbon mast that's currently getting modified to fit the Axis fuse...
I'm 5'10", 65kg riding:
Gong Lethal 4'6 65L
Gong Catch 5'3 34L
Gong Hipe v2 4'11 70L
Axis ART 999
Gong Fluid L-S, XXL-S on 85cm mast
Duotone Slick 3m, 4m, 5m

PonoBill

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Re: Getting ejected out the front door...
« Reply #43 on: November 10, 2021, 05:13:44 PM »
I'm certain it's a design issue, an intractable one. There are things you can do to mitigate it, but it's a fundamental element of pushing an airfoil that pierces the surface through the water. Every mast will do this under the right conditions. Skinnier masts, like the raft of 15mm ones that most companies use for an aluminum mast, will push the initiating conditions further.

I'd rather have a rigid mast that works in most of the circumstances I use it for than a floppy one that eliminates a condition I rarely encounter. But that's me.
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.

JohnnyTsunami

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Re: Getting ejected out the front door...
« Reply #44 on: November 10, 2021, 07:24:36 PM »
Happens to me on my art 999 and 420 tail wing (tail sanded a lot on the trailing edge and half a winglet broke off) with the 86cm carbon mast.
Iím 77kg.

Iíll try and wing with more and less yaw. Iím mostly going upwind to the max so I can ride downwind.

As a beginner I would ride flat and try and yaw my way upwind. Now I ride more canted over. Front foot straps. I feel with a back foot strap it might change my yaw amount, but I prefer to ride without one unless Iím jumping.

Iíd love to know a solution.

 


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