Supersonic car targets 1,000mph

Thorsten

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To me, this seems like "race walking" or a contest to see who can whisper the loudest. If you want to go really really fast, build an airplane.
That's not the point of these record hunts. Any spacecraft already was way faster than an airplane long ago. Nobody is fascinated by that.

The point is to keep going with some defined challenge although technical progress made that pretty stupid. The jackass comparison is pretty much spot on (and that's what keeps people engaged). To top the stupidity, there's still the 'fastest boat' record to catch - more than 80% of people who tried so far died in the attempt. Doesn't keep yet more from killing themselves.
 

Urwumpe

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Still - that is part of humanity.

The fastest sailing yacht Vestas Sailrocket 2 BTW reached 65 knots speed over 500 meters distance in 2012. Peaking at 68 Knots. At 25 knots winds. Thats already enough wind for letting smaller boats stay at home.

For getting such speeds, you need to foil. For foiling, you need to maintain a careful balance to stay on the foils. If you fail to foil and drop your bow into a wave, you can break your neck already at half the speed. You had seen such errors pretty often in the last Americas Cup, very spectacular - It even hit the same team that managed to stay o the foil for 100% of the race a few days before, the fuselage not even touching the water during turns - which is extremely difficult to achieve.
 

C3PO

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Huh?
Something does not add up here.
If you sail closer than 90° to the wind, your apparent wind is faster than the true wind speed.
 

Urwumpe

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Huh?
Something does not add up here.
No, that is absolutely normal for modern bermuda-rigged yachts.

First of all, there is an phenomena called apparent wind, which is the sum of the ships velocity vector with the wind vector. It does not apply that much to classic fully-rigged ships, which move in direction of the wind and thus have LESS apparent wind than the true wind.

Second, the modern sails act more like wing foils already and this especially apply to such extreme catamarans, which really have wings instead of sails. They have a much higher L/D than any classic sail could have. Such catamaras are actually fastest when they are moving slightly against the wind.
 

Artlav

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So you are telling me it's actually possible to sail faster than the wind?
Is there any explanation of how this works?
I can't picture the physics of it.
 

Urwumpe

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So you are telling me it's actually possible to sail faster than the wind?
Is there any explanation of how this works?
I can't picture the physics of it.
Yes - its not just possibly, its common, for example wind surfers do it.

This diagram shows the state at maximum speed for any yacht:



This is essentially what you want to achieve in a perfect race, of course, you need to optimize speed you can get at a wind vs velocity made good towards your destination.

See also here:

http://www.telegraph.co.uk/sport/ot...p-how-the-yachts-go-faster-than-the-wind.html

https://www.theguardian.com/sport/2...n-wind-vestas-sailrocket-sailing-weatherwatch

And yes, depending on the construction depending beta angle, a yacht can be up to six times faster than true wind.
 
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Fabri91

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That is something that I too haven't quite been able to picture. I think the key here is not to consider the sail as an object necessarily perpendicular to the wind, but more like a vertical wing, whose "lift" then can move the boat.
 

Urwumpe

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That is something that I too haven't quite been able to picture. I think the key here is not to consider the sail as an object necessarily perpendicular to the wind, but more like a vertical wing, whose "lift" then can move the boat.
Exactly. Just a wing that you can shape according to the wind speed. Low wind? Give it more curve, sail with a bigger angle of attack. High winds? Make the sail as flat as possible, have the sail at a low angle of attack.

This page goes pretty deep into sail-trimming, could be interesting there:

https://sites.google.com/site/catalaocml/home/sistemas-apoio-navegacao/velas
 

Thorsten

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The fastest sailing yacht Vestas Sailrocket 2 BTW reached 65 knots speed over 500 meters distance in 2012. Peaking at 68 Knots. At 25 knots winds. Thats already enough wind for letting smaller boats stay at home.
Sailing record I can understand. That's a combination of skill and design. Not madness.

Mounting a jet engine on a boat, waiting for the one day where the wind is so still that not even ripples are on the water and blazing away in the hope that there's *really* no wavelet that throws you out of the water however is something else entirely.
 

Urwumpe

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Sailing record I can understand. That's a combination of skill and design. Not madness.
Was about similar to your jet engine case. This yacht was simply made for reaching maximum speed in a wave protected bay at good winds - on a straight line course.

From what I can tell, it did not even have the ability to do rapid turns.
 

C3PO

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Modern bermuda rigs can go as close as 30° to the apparent wind. The trick is to balance the rig and the keel forces. Sailboats have large keels for a reason.

---------- Post added at 05:31 PM ---------- Previous post was at 05:25 PM ----------

Was about similar to your jet engine case. This yacht was simply made for reaching maximum speed in a wave protected bay at good winds - on a straight line course.

From what I can tell, it did not even have the ability to do rapid turns.
Wasn't there an "unofficial" record attempt using wings instead of sails? I'm not sure if it ever did a successful run. It was optimized for a specific wind angle, but totally unusable as a mode of transportation.
 

Urwumpe

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I just read that the record for land sailing (using a sail on a wheeled trolley) is at 126 mph.... :blink:

 

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That's not the point of these record hunts. Any spacecraft already was way faster than an airplane long ago. Nobody is fascinated by that.

The point is to keep going with some defined challenge although technical progress made that pretty stupid. The jackass comparison is pretty much spot on (and that's what keeps people engaged). To top the stupidity, there's still the 'fastest boat' record to catch - more than 80% of people who tried so far died in the attempt. Doesn't keep yet more from killing themselves.
Reminds me of something I heard once, about the number of dead frozen bodies you have to climb over to get the the peak of Everest these days...
 

Urwumpe

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Reminds me of something I heard once, about the number of dead frozen bodies you have to climb over to get the the peak of Everest these days...
Yeah - hardly surprising if you look WHO is climbing there. Money can buy you everything, but no good physique or mountain climbing experience.
 

MaverickSawyer

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Yeah - hardly surprising if you look WHO is climbing there. Money can buy you everything, but no good physique or mountain climbing experience.
As the Admiral in "Top Gun" said, "Your ego is writing checks your body can't cash."
 

Notebook

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Sailing record I can understand. That's a combination of skill and design. Not madness.

Mounting a jet engine on a boat, waiting for the one day where the wind is so still that not even ripples are on the water and blazing away in the hope that there's *really* no wavelet that throws you out of the water however is something else entirely.

Sadly, done before:

 

Thorsten

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Campbell is neither the first nor the last.

With an approximate fatality rate of 85% since 1940,[1][2] the record is one of the sporting world's most hazardous competitions. Two official attempts to beat the 1978 record have resulted in the death of the driver; but despite this there are several teams working to make further attempts.
Source: Wikipedia Water Speed Record
 

Notebook

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Hopefully among the last.
I mention him as he was probably the "heroic" type that was around when I was growing up. Endeavours are more calculated these days.

The lake surface on the first run look perfect, sadly not on the return.

M.
 
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