| |  Re: Salt water vs. Freshwater.
[Re: Cheshirecatman]
#146311
06/20/08 02:25 PM 06/20/08 02:25 PM |
Joined: Jun 2001
Posts: 12,310
South Carolina Jake 
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South Carolina | Slight tangent...
I've talked to several surfers that say they can feel differences in the weight of the water due to temp? Cold water being denser of course. Has anyone felt that difference on a boat. You'd really have to be tuned in. Don't forget to calculate temperature in your equation.
Slight tangent of the tangent...
Has anyone ever noticed that 20kts in colder wind feels like more than 20 kts of warmer wind? Case in point 20 kts in Santa Cruz or SF bay feels like it has more power than So Cal.
Densities...Cool. They could have a point. I wasn't going to post this but..... http://www.lsbu.ac.uk/water/explan5.html#STCheshirecatman Yeah, but look at the realism in the data: ![[Linked Image]](http://www.lsbu.ac.uk/water/images/surface.gif) They're saying in a realistic water temperature difference between 70F (21C) and .072 and .075 Nm^2 which is about 1.04427171 × 10^-5 psi....that's .0000104 psi. That's not much difference. (or wait, what is Nm-1?)
Jake Kohl
| | | Re: Salt water vs. Freshwater.
[Re: blockp]
#146312
06/20/08 02:28 PM 06/20/08 02:28 PM |
Joined: Jun 2001
Posts: 12,310
South Carolina Jake
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South Carolina | Where's Timbo when you need him. I'm sure he can tell us about trying to get a plane off the deck on a hot humid day.
I don't know the details of it, but I know it doesn't work as well as on a nice crisp winters day. Heard too many stories from my pilot friends about trying to get fully loaded cesna's, etc off the runway on hot days.
Is it because on the cold day, the motor has more power, or because the wings have more lift? Get a flight out of Jidda, Saudi Arabia. You have to leave late at night because the air is too hot and thin during the day for the plane to take off reliably. Been there - got the t-shirt.
Jake Kohl
| | | Re: Salt water vs. Freshwater.
[Re: blockp]
#146315
06/20/08 03:08 PM 06/20/08 03:08 PM |
Joined: Jun 2004
Posts: 502
Port Noarlunga, SA, Australia Darryn
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Port Noarlunga, SA, Australia | Where's Timbo when you need him. I'm sure he can tell us about trying to get a plane off the deck on a hot humid day.
I don't know the details of it, but I know it doesn't work as well as on a nice crisp winters day. Heard too many stories from my pilot friends about trying to get fully loaded cesna's, etc off the runway on hot days.
Is it because on the cold day, the motor has more power, or because the wings have more lift? One of my jobs is fixing those aircraft "motors". They definitely produce less power as air temp increases. Engines are temp limited, if the air going in is hotter less fuel can be added before max temp is reached, less fuel equals less power. Density can be compensated for by more compression, fly at 38000 feet where its cold gas turbines produce plenty of power and use less fuel. Darryn Mozzie 1782
Last edited by Darryn; 06/20/08 03:10 PM.
| | | Re: Salt water vs. Freshwater.
[Re: Will_R]
#146316
06/21/08 06:14 AM 06/21/08 06:14 AM |
Joined: Jun 2001
Posts: 12,310
South Carolina Jake
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Carpal Tunnel
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South Carolina | Are you kidding or serious?? Nm-1 = N/m Yeah, never seen that nomenclature...why not show it as n/m?
Jake Kohl
| | | Re: Salt water vs. Freshwater.
[Re: Karl_Brogger]
#146317
06/21/08 04:02 PM 06/21/08 04:02 PM |
Anonymous
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| Anonymous
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| I have heard from an experienced sailor that he almost never pitchpoles his H16 in salt water and does it all the time in fresh water. I have not sailed a H16 on salt water, so I cant comment. | | |
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