Weather Talk For BC no matter what you ride

Windfoiling Jericho

Windsurfing shop talk

by grantmac » Tue May 14, 2019 10:23 pm

You can oversimplify the airfoil shape by saying it acts like a loose leech it doesn't really work that way.

Rather they took an airfoil developed specifically for foiling (looks like one used for the AC72 cats) which has a very stable center of lift. The original H2 has more lift per cm2 but the undercambered shape is notorious for changing center of lift with speed. This is that building of front foot pressure and eventual instability as speed increases.

Washout just softens the stall and reduces the chance of tip stalling which should help lock it in during carves/gybes.
grantmac
 
Posts: 278
Joined: Tue Mar 21, 2017 11:53 pm

by morrison » Wed May 15, 2019 7:18 am

Airfoil?

"A foil is a solid object with a shape such that when placed in a moving fluid at a suitable angle of attack the lift (force generated perpendicular to the fluid flow) is substantially larger than the drag (force generated parallel to the fluid flow). If the fluid is a gas, the foil is called an airfoil or aerofoil, and if the fluid is water the foil is called a hydrofoil."
morrison
 
Posts: 196
Joined: Wed Apr 29, 2015 11:24 am
Location: Squamish

by grantmac » Wed May 15, 2019 9:43 am

My background is aeronautical, old habits die hard.

Also from a physics standpoint air and water aren't very different depending on the speeds, which gets us into Reynold's numbers etc.

Most foil profiles are based on one of the NACA series.
grantmac
 
Posts: 278
Joined: Tue Mar 21, 2017 11:53 pm

by morrison » Wed May 15, 2019 1:14 pm

grantmac wrote:My background is aeronautical, old habits die hard.

Also from a physics standpoint air and water aren't very different depending on the speeds, which gets us into Reynold's numbers etc.

Most foil profiles are based on one of the NACA series.


Yes, agreed. I was just trying to be humorous. My aeronautical background was limited to leasure.
XZdroppingballast.jpeg
XZdroppingballast.jpeg (564.22 KiB) Viewed 2434 times
morrison
 
Posts: 196
Joined: Wed Apr 29, 2015 11:24 am
Location: Squamish

by grantmac » Wed May 15, 2019 1:21 pm

Leasure here too, although a long time since I did ant soaring.

But I built a few RC sailplanes including tailless designs, which use a reflex airfoil for exactly the same reason that Slingshot does.

Hydrofoils experience a very wide range of Reynold's numbers while being basically a weight-shift craft. A combination that demands a lot of stability.
grantmac
 
Posts: 278
Joined: Tue Mar 21, 2017 11:53 pm

by morrison » Wed May 15, 2019 1:34 pm

"Hydrofoils experience a very wide range of Reynold's numbers while being basically a weight-shift craft. A combination that demands a lot of stability."
CofG above center of lift. Like trying to fly a Hang Glider from on top the wing.
morrison
 
Posts: 196
Joined: Wed Apr 29, 2015 11:24 am
Location: Squamish

by windsnow40 » Thu May 30, 2019 8:24 am

here is my FrankenFoil courtesy of Dave M (Murray Fin Works) here in Nanaimo. Yet to get out on it.
Attachments
frank.jpg
frank.jpg (83.96 KiB) Viewed 2094 times
windsnow40
 
Posts: 20
Joined: Wed Jun 28, 2017 1:45 pm

by john m » Thu May 30, 2019 9:45 am

Did you move the mast track and change Tuttle box?
john m
 
Posts: 43
Joined: Fri Nov 15, 2013 8:51 pm

by adam2 » Thu May 30, 2019 10:33 am

windsnow40 wrote:here is my FrankenFoil courtesy of Dave M (Murray Fin Works) here in Nanaimo. Yet to get out on it.


That is rad! Let us know how it goes.
adam2
 
Posts: 175
Joined: Thu Nov 20, 2014 3:01 pm

by telus022420 » Thu May 30, 2019 11:19 am

I think you could call it Frank..n board a Pocket Roberts. Similar to RRD

http://www.robertoriccidesigns.com/equipment/windsurf/pocket-rocket/
telus022420
 
Posts: 137
Joined: Thu Jan 16, 2014 11:02 am

PreviousNext

Return to Windsurfing