Wednesday 1st April 2009

Brit Breaks Wind Speed Record

Wind-powered Greenbird reaches 126mph

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Fast, emission free and very green

Another landmark moment for British engineering was reached last week as Richard Jenkins broke the world land speed record for a wind-powered vehicle by clocking 126.1mph.

The Greenbird is made almost entirely from carbon fibre, and is the fifth wind-powered vehicle Jenkins has built to chase the record. The new land speed record was set on a dry lake bed in the Nevada desert, where it smashed the previous record of 116mph set by American Bob Schumacher and his Iron Duck vehicle in 1999.

Weighing just 600kg, the Greenbird is the culmination of over 10 years work and is described by its creator as a 'very high performance sailboat'. The unusual shape of the craft creates a large amount of lift, so to compensate for this the designers built Formula One style wings to help keep the Greenbird on the floor. As a result of the specially designed wings over one tonne of downforce is produced while travelling at high speeds.

Now Jenkins has set his sights on conquering another surface, and is concentrating his efforts on beating the land speed record on ice.

[Fetchez la vache]

I was suprised this didn't show up last week! An amazing achievement.
Not every day that a Brit breaks a world speed record.

[DrGP]

Amazing - now why is this not the lead story on the news? Positives instead of 'minister buys porn' stories.

[johnnyv6]

thats because the business mantra of todays media across the board is "bad news sells", i blame the media for half of the ills in society today, balanced journalism i'm afraid is long dead and we buy into it which only encourages them to seek out more sensationalist crap for a cheap headline

[UncappedTag]

Awesome, imagine the sentation of speed in that thing so close to the ground

[patmahe]

Ok I thought this was an April fools joke especially when I saw the bit about Bob Schumacher in the Iron duck! but I looked that up and its true.

But why does it need so much downforce? Surely it would be best to be just about skimming the surface, less resistance = more speed I would have thought?

[herewego]

patmahe said:

Ok I thought this was an April fools joke especially when I saw the bit about Bob Schumacher in the Iron duck! but I looked that up and its true.

But why does it need so much downforce? Surely it would be best to be just about skimming the surface, less resistance = more speed I would have thought?

You need a safety factor. Suppose it hit a bump which kicked the front up, he'd be joining Donald Campbell.

[Nickellarse]

patmahe said:

Ok I thought this was an April fools joke especially when I saw the bit about Bob Schumacher in the Iron duck! but I looked that up and its true.

But why does it need so much downforce? Surely it would be best to be just about skimming the surface, less resistance = more speed I would have thought?

Imagine all that foward momentum suddenly being turned into lift. Campbell found that out the hard way.

Super achievement I bet there were a few celebrations.

Edited by Nickellarse on Wednesday 1st April 12:16

[patmahe]

herewego said:

patmahe said:

Ok I thought this was an April fools joke especially when I saw the bit about Bob Schumacher in the Iron duck! but I looked that up and its true.

But why does it need so much downforce? Surely it would be best to be just about skimming the surface, less resistance = more speed I would have thought?

You need a safety factor. Suppose it hit a bump which kicked the front up, he'd be joining Donald Campbell.

OK just thought 1 tonne was excessive but I guess they've done their homework, well done them an incredible achievement in a terrific machine.

[sc00byd00byd00]

Call me a pessimist............... BUT...........

Surely for a WIND powered car to go 126.1mph, the WIND would actually need to be going at that speed too (or even more)

What did he do, set of an atomic blast behind him to get the required acceleration & speed ?

I may be wrong or completely off track, but how would you get a WIND POWERED vehicle to go faster that the wind speed thats propelling it ????????

Edited by sc00byd00byd00 on Wednesday 1st April 12:35

[Crusoe]

sc00byd00byd00 said:

Call me a pesamist............... BUT...........

Surely for a WIND powered car to go 126.1mph, the WIND would actually need to be going at that speed too (or even more)

What did he do, set of an atomic blast behind him to get the required acceleration & speed ?

I may be wrong or completely off track, but how would you get a WIND POWERED vehicle to go faster that the wind speed thats propelling it ????????

Increase the area (of sail) and you increase the force and given that the mass stays they same you get acceleration as f=ma.

Sure the calculation would be similar for wind powered objects as for buildings below.

Wind Loading can be calculated in accordance with ANSI/ASCE 7-88 & ANSI A58.1-82 as follows:

Design Wind Force, F = qz * Gh * Cf * Af , lb.

Where ,

qz = Velocity pressure = 0.00256 kz (I V)2, lb/ft2.

kz = Velocity pressure exposure coefficient. Evaluated at height z above grade & exposure categories.

I = Importance factor. Depend on the classification of buildings and other structures for wind, snow, and earthquake loads. Categories I, II, III, and IV related to the nature of occupancy.

V = Basic wind speed, mph.

Gh = Gust response. The gust response factor is employed to account for the fluctuating nature of wind and its interaction with buildings and other structures, i.e. accounts for the additional loading effects due to wind turbulence over the fastest-mile wind speed.

Cf = Force coefficient

Af = Area of structures or components and cladding thereof projected on plane normal to wind direction,ft2

[z06tim]

Make it very light and have a large sail area! Wind is a pressure loading. Pressure is force/area. Make the area bigger and the force propelling the vehicle is bigger.

Crusoe - you beat me to it and with quite a bit more detail too!!!

Edited by z06tim on Wednesday 1st April 12:39

[911motorsport]

Crusoe said:

sc00byd00byd00 said:

Call me a pesamist............... BUT...........

Surely for a WIND powered car to go 126.1mph, the WIND would actually need to be going at that speed too (or even more)

What did he do, set of an atomic blast behind him to get the required acceleration & speed ?

I may be wrong or completely off track, but how would you get a WIND POWERED vehicle to go faster that the wind speed thats propelling it ????????

Increase the area (of sail) and you increase the force and given that the mass stays they same you get acceleration as f=ma.

Sure the calculation would be similar for wind powered objects as for buildings below.

Wind Loading can be calculated in accordance with ANSI/ASCE 7-88 & ANSI A58.1-82 as follows:

Design Wind Force, F = qz * Gh * Cf * Af , lb.

Where ,

qz = Velocity pressure = 0.00256 kz (I V)2, lb/ft2.

kz = Velocity pressure exposure coefficient. Evaluated at height z above grade & exposure categories.

I = Importance factor. Depend on the classification of buildings and other structures for wind, snow, and earthquake loads. Categories I, II, III, and IV related to the nature of occupancy.

V = Basic wind speed, mph.

Gh = Gust response. The gust response factor is employed to account for the fluctuating nature of wind and its interaction with buildings and other structures, i.e. accounts for the additional loading effects due to wind turbulence over the fastest-mile wind speed.

Cf = Force coefficient

Af = Area of structures or components and cladding thereof projected on plane normal to wind direction,ft2

Bloody hell

[Toltec]

It does seem counter intuitive that you can go faster than the wind supplying the motive force, but then if the drag is less than the applied force...

Being able to sail into the wind, albeit not directly into, does not make sense either until you find out how it works.

Brilliant achievement by Richard and his team.

[herewego]

Try this:
http://www.physclips.unsw.edu.au/jw/sailing.html

[mechsympathy]

Crusoe said:

Sure the calculation would be similar for wind powered objects as for buildings below.

AFAIK the sail acts as a wing, which is why boats/windsurfs etc travel faster across the wind than down wind. The sail effectively generates lift which pulls the boat forwards. Which is why this thing looks like a wing on its end.

[blueg33]

mechsympathy said:

Crusoe said:

Sure the calculation would be similar for wind powered objects as for buildings below.

AFAIK the sail acts as a wing, which is why boats/windsurfs etc travel faster across the wind than down wind. The sail effectively generates lift which pulls the boat forwards. Which is why this thing looks like a wing on its end.

Correct, this effect is called apparent wind, in effect the faster the wing moves through the air the more apparent wind it creates. I sail high performance windsurfers and it is not unusual to be able to sail a baord at 40 knots in 30 knots of wind. The only downside is that as you go faster the wind becomes more and more head on.

[stinkysteve]

incredible achievement.

To go faster than the wind, bear in mind you have something called 'apparent wind' when moving.

If you're doing 124mph then you have a 124mph head wind to play with.

Add to that the 'real' side wind and you have something called apparent wind.

These two combine and give you a wind of over 124 mph that's not a direct headwind which you can put to use into creating forward momentum if your sails/wings have the correct angle of attack.

[Xenocide]

Surely you could set a faster time with quicker wind? Doesn't that make breaking this record potentially easier as time goes on?

[Ed.]

Xenocide said:

Surely you could set a faster time with quicker wind? Doesn't that make breaking this record potentially easier as time goes on?

If you're good at predicting microbursts you mean?

[dandarez]

Ok great achievement.
What good does it do? Great life and living if you can get it.
Where do they get the funding from?
Can't see many of us wanting a sailboat any time soon.
I THOUGHT this was Pistonheads?

As for 'bad' news like Blue Labour spending 'our' money on their expenses, yeah, sorry, but I for one like that sort of thing to be exposed.

Back to land speed records, sailboats don't interest me one iota.
Cars? This one does, as it's private and using no one else's cash, but naturally it gets no publicity.

It's a 1967 BRITISH Ginetta G4 that's aiming to beat the current 'class' in the land speed record. The record is 121.779 mph. The G4 has been recorded at 124 mph fitted with a MAE 997cc so it has superb chance. Will it get publicity if it does get the record?

Nah, but if it was a sailboat it might.
Teaser taster here on YouTube

http://www.youtube.com/watch?v=XxYyN6vkYiY