what is it?

Doug Lord

Super Anarchist
11,483
21
Cocoa Beach, FL
Question I have is , I read or heard the the high speed Americas cup boats were really hard on the foils , after every day the foils had to be pulled out and repaired / tidied up due to the abrasive reaction due to cavitation (air bubbles) at high speed . How the hell are you going to maintain the foils on a boat like that . If you were to cross an ocean ect , by the time you got half way you would have no foils left?
Generally, you don't have cavitation until speed is well over 40 knots. The G4 probably won't go that fast......

 
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fastyacht

Super Anarchist
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Upwind flat water. Ho hum. And even then, the GC32 bottomed out a few times. That's not good.

 
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Doug Lord

Super Anarchist
11,483
21
Cocoa Beach, FL
Upwind flat water. Ho hum. And even then, the GC32 bottomed out a few times. That's not good.
You don't know what you're talking about. She dropped off the foils because, probably, it was fairly light air-all foilers do that from time to time. There was no sudden stop as the previous "expert" said was a characteristic of these kind of foils. "Bottoming out" is when a foiler is in short,steep seas and can't platform or contour the waves. It's experienced by the foiler staying on foils but having waves strike the bottom(and is slow)-hence "bottoming out". Having a foiler is no substitute for basic seamanship-every foiler has conditions that aren't ideal and/or that require not flying. Even in those conditions the foils help with the motion and with pitch stability.

GC 32 did 36 knots in these conditions:

GC32record2014.jpg

 
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fastyacht

Super Anarchist
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Doug, you are so totally missing the point. And you obviously don't understand the wavegoing issue at all. This is flat water. Very different situation.

There wasn't light air when she bellyflopped. Nope. Try again.

Yes, they "work" but no, they are not the end all be all to this. Why do you think Hydroptère has a servo system?

 

floater

Super Duper Anarchist
5,164
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quivira regnum
Luna Rosa AC 45's on UptiP foils:
LR Franken45's likely have active control on the rudder.
AC62's will have active rudder trim as well.

Does the GunBoat? I guess it's a rather bold experiment - but they are smart people building these boats.

 
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Doug Lord

Super Anarchist
11,483
21
Cocoa Beach, FL
Luna Rosa AC 45's on UptiP foils:
LR Franken45's likely have active control on the rudder.
AC62's will have active rudder trim as well.

Does the GunBoat? I guess it's a rather bold experiment - but they are smart people building these boats.
When you say active , do you mean electronic or manual control via electronic/hydraulic control of the rudder AOI? Do have a link for either one or the other?

As far as I know the GC32 and FP have manual adjustment of the rudder AOI.

 

floater

Super Duper Anarchist
5,164
887
quivira regnum
Luna Rosa AC 45's on UptiP foils:
LR Franken45's likely have active control on the rudder.
AC62's will have active rudder trim as well.

Does the GunBoat? I guess it's a rather bold experiment - but they are smart people building these boats.
When you say active , do you mean electronic or manual control via electronic/hydraulic control of the rudder AOI? Do have a link for either one or the other?

As far as I know the GC32 and FP have manual adjustment of the rudder AOI.
Trim'able while racing - but manual. Something the AC72's did not allow but the AC62's will.
But yeah, not fully automatic like a wand or Herbie as some would like.

Believe the LR Franken45 rudder trim is powered and adjusted via handheld remote - something not allowed for the AC62 or the new flying AC45s. An image was posted of Draper holding this device.

PS: Latest AC rumor is that encoded foil trim sequences may be allowed - as long as they are "baked" into the servo control chips and initiated manually. For example, consider a jibe - click the 'initiate jibe' button and the following happens:

- windward board drops

- leeward board rake trims to reduce lift

- rudders trim to keep platform flat through turn...

Perhaps this is active enough?

 

Doug Lord

Super Anarchist
11,483
21
Cocoa Beach, FL
It's interesting that rudder foil control seems to be a big deal in some boats. In Dr. Sams Rave the standard boat didn't have rudder foil flap control as standard but it was available. In my Rave sailing it was never needed. Dr. Sams Osprey does have rudder flap control. My F3 RC foiler didn't require rudder flap adjustment and the new Fire Arrow test model doesn't require rudder foil AOI adjustment-so far.

 




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