Statistics: Posted by Robert Biegler — Wed Nov 06, 2024 9:45 pm
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This diagram is clearly for a single skin mainsail on a rotating mast but it might give us a clue.
At the bottom of the diagram you see the edge of the boundary layer to scale. The wrinkles you see on video of AC75 sails seem to be mainly in the aft third of the sail, towards the leech, and fairly close to the foot of the sail. In this region the boundary layer on the leeward side of the sail is quite thick (say at least a few inches) so the wrinkles would not penetrate through that boundary layer and I would not think they would matter too much. On the windward side of the sail the boundary layer towards the leech is much thinner so I would guess that the wrinkles in that area will increase drag. The boundary layer is very thin around the mast on the leeward side and any roughness that penetrates the boundary layer there may promote separation so I guess it is particularly important to keep the surface smooth in that area and in the case of the AC75 mainsail to minimise any step where the leeward mainsail skin is joined to the Dee section mast.
Statistics: Posted by John Perry — Mon Sep 23, 2024 5:44 pm
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Although you often see wrinkles on sails, mainly radiating from the tack or clew, surely this can’t be good for airflow, power or drag.
What does anyone think?
Statistics: Posted by Chr1sgould — Tue Sep 03, 2024 3:31 pm
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Stored in a coach house since last used (flown) over 20 years ago.
Joddy Chapman
South Brent, Devon.
Statistics: Posted by ejcchapman — Mon Jul 08, 2024 5:18 pm
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Statistics: Posted by AYRSwebadmin — Fri Feb 02, 2024 9:46 am
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The next project will be to try and sort out WIG flying/sailing and for that, I need a Happa and anyone else who fancies having a go.
Have a look at another thread on here, showing a boat that combines hydrofoils for support and leeway resistance with a wing (probably) in ground effect for stabilisation: viewtopic.php?f=19&t=3860Also have a look at the Swedish Speed Sailing Challenge: https://www.trampofoil.com/speedsailing/index.html From what little I can see, I think they use something similar to Paul Ashford's anchor dog, but they have not shown pictures. They do say their design tracks the water surface well enough that it experiences accelerations up to 20g. If they are willing to share details, that should give you a good design.
Statistics: Posted by Robert Biegler — Mon Dec 04, 2023 5:54 pm
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Statistics: Posted by Heimfried — Sun Oct 01, 2023 5:21 pm
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Statistics: Posted by Heimfried — Sun Sep 24, 2023 7:08 pm
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