Forum Index |  Albums |  Classified Ads |  Catamarans For Sale |  Calendar |  Submit Events
Announcements
New Discussions
Adding a Jib to a Mossie
by Gary Fleming. 12/07/17 11:29 PM
F101 finally in production
by Jake. 12/05/17 06:49 PM
Tradewinds Regatta?
by samc99us. 12/05/17 04:30 PM
Easy way to really learn the Racing Rules
by Mike Fahle. 11/28/17 07:30 AM
Dynema trap lines diameter?
by mmadge. 11/25/17 08:10 AM
foiling chasing UFO
by northsea junkie. 11/23/17 03:12 AM
New Mystere 4.3 in Central Florida
by Mike Fahle. 11/22/17 04:46 PM
36th America's Cup
by waterbug_wpb. 11/21/17 12:10 PM
Fatality During Clipper Race
by Redtwin. 11/20/17 07:56 AM
--Advertisement--
Previous Thread
Next Thread
Print Thread
Rate This Thread
Hop To
Page 2 of 3 1 2 3
#286795 - 05/12/17 01:15 PM Re: What's up with the America's Cup [Re: Timbo]  
Joined: Sep 2006
Posts: 586
Dazz Offline
addict
Dazz  Offline
addict

Joined: Sep 2006
Posts: 586
Hobart, Tasmania, Oz.
50 footers and not nearly as fast, they are way faster that the 72's around the course.

seems that the rig and hulls are not as important as the foils

Originally Posted by Timbo
These cats are what, 45 feet long?

And they are making nearly the same speeds as the 72' cats from 3 years ago!

Wow.

It used to be that a longer waterline made for a faster boat, but once they get up on the foils I guess it comes down to weight and sail area for determining max speed. Foil mechanics and control are becoming more important than waterline length.


C2 AUS 222 by Goodall design
"Darph Bobo"
-- Have You Seen This? --
#286796 - 05/12/17 04:52 PM Re: What's up with the America's Cup [Re: mbounds]  
Joined: Jun 2001
Posts: 12,278
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,278
South Carolina
Originally Posted by mbounds
The bow down attitude is the result of restrictions in the angle of the rudder foils and the different speeds upwind vs. downwind.

Upwind, the boats are relatively level; the boats are moving 25-30 kts. A higher angle of attack is required on the rudder foils to lift and stabilize the back of the boat.

Downwind, the speed increases to 35-40 kts; a lower angle of attack on the rudder foils is required to achieve the same lift, so the boats assume a bow-down attitude.


I do realize that's what Oracle said about their bow down...but it also stands to reason that they would want to rake their rigs more vertically when sailing downwind and rake them back upwind...all I'm sayin. There is no advantage for everyone to spill their techniques - trust nothing any team says at this stage wink


Jake Kohl
#286800 - 05/13/17 07:56 AM Re: What's up with the America's Cup [Re: Jake]  
Joined: May 2004
Posts: 1,379
Ventucky Red Offline
veteran
Ventucky Red  Offline
veteran

Joined: May 2004
Posts: 1,379

#286823 - 05/16/17 03:30 PM Re: What's up with the America's Cup [Re: Timbo]  
Joined: Jun 2001
Posts: 411
Mike Fahle Offline
addict
Mike Fahle  Offline
addict

Joined: Jun 2001
Posts: 411
Toledo, Ohio (western end of ...
The smaller bicycle racers do the best in the mountains only because they have less weight to lift all of those meters. Their power goes into overcoming wind and rode drag AS WELL AS lifting their own weight up the mountain. The best sprinters are usually bigger guys with more raw power but they fade badly in the mountains due to the extra weight that has to be carried up the mountain. So good sailboat bike riders (that's gonna take some getting used to) use ALL of their power only to pump hydraulic fluid so the focus is on only who can produce the most power; any lifting is provided by the boat, making them more like the sprinters - bigger and stronger. Oracle is looking at converting the tactician station into a bike so that he can keep his head up, produce more power, and be well stationed to talk to the helm.

#286824 - 05/18/17 08:56 AM Re: What's up with the America's Cup [Re: Mike Fahle]  
Joined: Jun 2001
Posts: 12,278
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,278
South Carolina
This whole bike thing has a tinge of "absurdity" to it.


Jake Kohl
#286826 - 05/18/17 09:55 AM Re: What's up with the America's Cup [Re: Jake]  
Joined: Jun 2001
Posts: 885
David Parker Offline
old hand
David Parker  Offline
old hand

Joined: Jun 2001
Posts: 885
Dunedin Causeway, FL
Cap'n Don says it's a hoax.
Cap'n Bob says it's a fad.

But NZ has a long memory of yelling "Hydro, hydro...!" back in San Francisco when pressure went down. I bet it was high on their "never again" list.

[Linked Image]

Listen in at about 1:48
NZ f-up

I love watching these old videos of SF. Would someone post once again how to embed a video, please.

#286828 - 05/18/17 11:13 AM Re: What's up with the America's Cup [Re: Jake]  
Joined: Dec 2001
Posts: 5,573
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,573
Naples, FL
Originally Posted by Jake
This whole bike thing has a tinge of "absurdity" to it.


Legs have more power than arms (well, except for kenny), so I would have thought a recumbant type setup with proper gearing could do the trick.. I hadn't thought about in-line bicycle style pedaling. But I guess you could stand up and crank (can't do that in recumbant format)


Jay

#286829 - 05/18/17 11:50 AM Re: What's up with the America's Cup [Re: David Parker]  
Joined: Mar 2017
Posts: 94
Mn3Again Offline
journeyman
Mn3Again  Offline
journeyman

Joined: Mar 2017
Posts: 94
fl
Originally Posted by David Parker
Cap'n Don says it's a hoax.
Cap'n Bob says it's a fad.

But NZ has a long memory of yelling "Hydro, hydro...!" back in San Francisco when pressure went down. I bet it was high on their "never again" list.

[Linked Image]

Listen in at about 1:48
NZ f-up

I love watching these old videos of SF. Would someone post once again how to embed a video, please.


Dave, I don't see it anymore = perhaps when Damon made the upgrade (march) the feature to embed a video has disappeared and all you can do is post it as a link


Mn3
#286830 - 05/18/17 12:06 PM Re: What's up with the America's Cup [Re: Mn3Again]  
Joined: Dec 2002
Posts: 238
Damon Linkous Offline
Damon Linkous  Offline


enthusiast

Joined: Dec 2002
Posts: 238
Memphis, Tennessee
I think it is supposed to work with only the share url

Let's try


https://youtu.be/toYyzaAE-SA

That doesn't seem to work, let's try the video page url

https://m.youtube.com/watch?v=toYyzaAE-SA

#286831 - 05/18/17 12:07 PM Re: What's up with the America's Cup [Re: Damon Linkous]  
Joined: Dec 2002
Posts: 238
Damon Linkous Offline
Damon Linkous  Offline


enthusiast

Joined: Dec 2002
Posts: 238
Memphis, Tennessee

#286832 - 05/18/17 06:41 PM Re: What's up with the America's Cup [Re: Jake]  
Joined: Jun 2001
Posts: 411
Mike Fahle Offline
addict
Mike Fahle  Offline
addict

Joined: Jun 2001
Posts: 411
Toledo, Ohio (western end of ...
Jake, The crew was substantially reduced to help lower the cost of entry for an AC team (that old head count issue that all organizations deal with) and later on it developed that there were times when the power needs were beyond what the crew could create in the moment even though they have made massive efforts on developing the physical output of the crew. That is why there has been so much hydraulic system and equipment design and development for this AC. They need to apply the hydraulic power as efficiently as possible and even then be able to accumulate power around the course so that they have enough to meet "peak demands", like the leeward mark when the foils are changing and adjusting and there are big trims on the wing and jib. The partner companies have been finding applications for this work on systems they can use in their native industries, especially airliners. So in that engineering sense it is not absurd but on a conceptual level it definitely is!

I will be there to watch the end of the quarterfinal series and I am really hoping to get closer looks at the boats and equipment; not likely except for maybe the odd boat out at that time, probably France. The teams that are out at the end of that series will probably not be in the mood to let gawkers in but I will look if I can. I have read that New Zealand is developing 30% more power than the grinding teams so maybe they will not need the accumulators that the other teams have had to develop. That would save weight and complexity... it would be interesting to know these technical details but I am not sure if we ever will.

#286833 - 05/19/17 06:21 AM Re: What's up with the America's Cup [Re: Mike Fahle]  
Joined: Jun 2001
Posts: 12,278
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,278
South Carolina
Mike,

I didn't mean in the sense of technology or whether or not it made sense - I just meant in the sense of sailing. I'm very familiar with the systems in use on those boats. I'm all for multihulls, wings, foils, etc. at the bleeding edge of the sport but you take someone not familiar with the America's cup and show them the New Zealand boat, everyone jumps to the conclusion that they are peddling props on the bottom of the boat. It takes a lot of explaining through furrowed brows that the bicycles (another mode of human transportation) were mounted to a sailboat (typically considered relatively slow) to build up hydraulic pressure so the two or three guys at the back of the boat can push buttons and control the sails and foils and make it go. To someone not fully invested in sailing as a sport, it sure as hell seems like a lot of complication to go 40 miles an hour....hence the tinge of absurdity.

Last edited by Jake; 05/19/17 06:23 AM.

Jake Kohl
#286834 - 05/19/17 07:46 AM Re: What's up with the America's Cup [Re: Jake]  
Joined: Dec 2001
Posts: 5,573
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,573
Naples, FL
Jake, I'm sure they said that back in the days of the galley boats...

Lots of dudes sitting at oars while a guy in the back pounds a drum and pushes buttons (or rudder) smile

But you engineers could help me understand the most efficient way to store hydraulic power. Since liquids are essentially non-compressible, are they building up pneumatic pressure to apply the hydraulics later? If not what is the mechanism used to "build" up the power to be used "during peak demand"?


Jay

#286835 - 05/19/17 11:04 AM Re: What's up with the America's Cup [Re: waterbug_wpb]  
Joined: Mar 2017
Posts: 94
Mn3Again Offline
journeyman
Mn3Again  Offline
journeyman

Joined: Mar 2017
Posts: 94
fl
Originally Posted by waterbug_wpb

But you engineers could help me understand the most efficient way to store hydraulic power.


I'm no engineer but i did stay near a Holiday Inn last night...

i think they use this type of machine to build and store the hydro power
[Linked Image]


Mn3
#286836 - 05/19/17 02:17 PM Re: What's up with the America's Cup [Re: Mn3Again]  
Joined: Dec 2001
Posts: 5,573
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,573
Naples, FL
oh, that's easy smile


Jay

#286838 - 05/20/17 10:00 AM Re: What's up with the America's Cup [Re: waterbug_wpb]  
Joined: Jan 2005
Posts: 6,021
Timbo Offline
Carpal Tunnel
Timbo  Offline
Carpal Tunnel

Joined: Jan 2005
Posts: 6,021
Sebring, Florida.
I know on most big jets there are hydraulic accumulators that do have a nitrogen precharge of around 1000 psi. This accumulator system is usually only on the brakes. The problem is, once you pump the breaks a couple times, the precharge is gone, so you need hydraulic pumps (either electric or mechanical off the gearbox) to recharge the system.

There are period of very high demand for hydraulic pressure on an airliner, which are when the gear is retracted right after takeoff and at flap extension/gear door retraction after extension on configuring for landing. The 767 and 777, in addition to electric and mechanical hydraulic pumps, have an air driven demand pump, which use bleed air off the engines and only kicks on during periods of high demand, or if one/both of the electric/mechanical pumps fail.


Blade F16
#777
#286842 - 05/22/17 07:03 AM Re: What's up with the America's Cup [Re: Timbo]  
Joined: Dec 2001
Posts: 5,573
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,573
Naples, FL
so you don't have to pump the brakes? smile


Jay

#286844 - 05/22/17 10:52 AM Re: What's up with the America's Cup [Re: waterbug_wpb]  
Joined: Jun 2001
Posts: 12,278
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,278
South Carolina
So does anybody have any idea if/when/where we will be able to watch any of the America's Cup racing here in the USA?


Jake Kohl
#286846 - 05/22/17 03:52 PM Re: What's up with the America's Cup [Re: Jake]  
Joined: Jun 2001
Posts: 12,278
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,278
South Carolina


Jake Kohl
#286848 - 05/22/17 04:05 PM Re: What's up with the America's Cup [Re: Jake]  
Joined: Jun 2001
Posts: 885
David Parker Offline
old hand
David Parker  Offline
old hand

Joined: Jun 2001
Posts: 885
Dunedin Causeway, FL
You can always go to the America's Cup website for the latest.

NBCSN Viewiing schedule

What does the SDD mean in the footnote?

(Edit: I see it now...*SDD (same day delay))

Last edited by David Parker; 05/23/17 08:34 AM.
Page 2 of 3 1 2 3

Moderated by  Damon Linkous 

Search

Who's Online Now
0 registered members (), 17 guests, and 286 spiders.
Key: Admin, Global Mod, Mod
Newest Members
pussycatcatman, Shotsailor, PointDume, Winsto, hotrudderedbum
7723 Registered Users
Top Posters(30 Days)
Jake 6
Timbo 3
P.M. 2
Forum Statistics
Forums27
Topics22,268
Posts266,189
Members7,724
Most Online554
May 12th, 2017
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.012s Queries: 16 (0.003s) Memory: 0.9227 MB (Peak: 1.1766 MB) Zlib enabled. Server Time: 2017-12-12 08:23:30 UTC