Author Options:

British Land Speed Recod Was a Breeze, Thrashes US Record. Answered

On the morning of March 26th, on the dry Lake Ivanpah, The Ecotricity Greenbird driven by British engineer, Richard Jenkins smashed the world land speed record for wind powered vehicles. The Greenbird clocked 126.1 mph (202.9 km/h) , eclipsing the old, American held, record of 116 mph , set by Bob Schumacher in the Iron Duck in March 1999 at the same location.

The fully-composite craft (the only metal is in some of the bearings) used a solid wing to reach speeds up to five times that of the actual wind.

The wing also provides unwanted lift, so it uses the same downthrust technology as F1 cars - at speed, the 600kg car presses down on the salt-flats with a force of almost 10,000N.

Greenbird website.


They should drive it upside down just to show off. 10,000N could easily support the downward force of the car (600*9.8).

(It's not 10,000N extra, it's total - I just couldn't bring myself to type that it pressed down with 1000kg force)

"had an effective weight of 1000kg"?

Exactly - mixing up mass and weight like that really grates on my over-enhanced pedantry nerves.

Wait hang on that was wrong as well wasn't it >_<

"had an effective weight equivalent to that of a car with a mass of 1000kg" is going to confuse a lot of people, though. You can always use the engineering cop-out solution of the "kilogramforce" unit, a force of 9.81N?

Not single one of my professors has ever mentioned ""kilogramforce" unit, a force of 9.81N", and I'm sure they'd nail me to a wall if I tried to pull that.

It's not the sort of thing you'd hear professors mention- I usually see it associated with torque, as in "450 kgf m", and it might be one of those archaic things like the slug and the dyne. I thought the name was just an engineering abbreviation for "the force equivalent to the weight of one kilogram". After all, "pounds per square inch" is closer to being a measure of density than pressure*, but it is implicit in that unit that "pounds force" are meant, ie 4.45 Newtons. If your professors would nail you to a wall for saying "pounds per square inch" rather than "poundals per square inch" then I'll accept that it's a duff unit. :)

Anyway, using the wrong units and bad dimensional analysis gets me annoyed just as much, but when someone asks how much your baby weighed at birth you don't say "35.6 Newtons". As much as I rage about people saying amps when they mean amp-hours or whatever, I will forgive mass/weight interchange because as long as you don't go into space they always have a linear relationship.

*Well ok, density if thickness is assumed, thickness if density is assumed, otherwise "mass per unit area"

So you are saying you all can go fast, but you confuse mass and weight? ;-)

Fair point, I should read the article :-)

I wonder if they would enter the energy-saving contest?

Oh yeah, well.... America invented spaghetti!