Slashdot Mirror
The Bugatti Veyron
An anonymous reader writes "OK, most /.ers cannot afford the Veyron, but reading this article at HowStuffWorks is still fascinating. How do you fit 1,000 horsepower into a compact engine? How do you keep a passenger car on the road at 250+ MPH? The article links to a set of videos on the Veyron engine that are also very good. Are there any cars out there better than this?" There's also a story by Popular Science.
Cars are designed to use their engine at 10% of peak output most of the time.
Planes are designed to use their engine at 90% of peak most of the time.
Tire grip increases with weight, but it is a log curve- the more you increase weight, the smaller the increases in traction are. Since each increase in weight also increases the mass, the tires have to do more work to change the direction of the car. Thus, heavy cars tend to develop less and less traction than lighter cars.
Adding downforce increases the car's "weight" for purposes of calculating the grip of the tires on the road, but doesnt increase the mass of the car that they have to change the direction of.
This is why the "ideal" race car is a stick figure formula 1 type car with a giant engine and huge wings. The downforce keeps the car stuck on the road with the force of many times its weight, but since the car is so light it can change direction with mind boggling speed. This is why formula one cars can develop over 5gs of sideways acceleration. The powerful engine helps to generate speed which in turn increases downforce. The cars actually grip more the faster they go.
Eh, this is a bit of a peeve of mine. Hitler did NOT design the beetle. While Hitler was instrumental in getting the Volkswagen into production, he in fact did not create the beetle as those links would claim.
Ferdinand Porche had been designing automobiles for some 10 years when WWI ended, and as Germany's economy collapsed he realized the need for a family type car would be developing. For the next 15 years he pushed the idea, but at the time car makers were more interested in high-dollar luxury vehicles. It wasn't until 1934 he actually got a prototype built, an aircooled flat four-powered vehicle that almost anyone would recognize as a beetle. He had been working on the plans for several years prior.
In 1933/1934 Hitler came into power and started vocalizing his plans for the autobahn and the Volksauto. When Porche's employeer exited the automobile industry in that period, Porche basically panicked because he did not want his pet project to die. He did the letter writing campaign, and eventually Hitler heard about it. Through 1934 Porche and Hitler met, and found they both had similar views about building a "people's car". In the course of several meetings they settled on the specifications of what the car would be capable of.
From there Hitler funded Porche's prototyping and research.
There was a lot of simultaneous development going on here, Hitler had read much of Henry Ford's success, and was quite a car enthusiast. Hitler's idea of the volkswagen was his own, as much as it was Porche's own.
The design and engineering, however, is almost exclusively Porche's (though there are some allegations he stole some of the body design from another designer, I don't rightly remember who that would be though).
Later on, after WWII, the US saw the value of Volkswagen to rebuilding Germany's shattered economy, and put significant effort into rebuilding the destroyed factories and getting cars built again. In some ways, the US was as instrumental in VW's success as anyone else was.
Big powerfull engines only give you the potential to waste full, they do not cause the full usage.
Correct.
If you had 2 identical cars, but one has twice the HP they will both get the same mileage,
Incorrect. Fuel consumption is based on a few variables, horsepower is not one of them. It is possible that two engines with widely different horespower ratings will have the same mileage performance but that's a matter of coincidence not science. As an example consider the highly efficient 100HP/liter powerplants in the S2000, 911 and M3 compared to the 5.7 liter (and that's a key number) powerplants of American muscle cars of a generation ago (Mustang, Camaro, Corvette etc.).
In general, mileage is a combination of compression ratio, engine size, gearing, torque curve, aerodynamic and mechanical (especially tire) efficiency, valve train mechanics and a host of other factors. Horsepower is simply not one of them.
but people being people many would get worse mileage with the more HP version since they would use it more and accel. faster.
Again, generally true
But for a driver who knows what they are doing they would get the same either way.
Again no, the largest factor in mileage these days is engine capacity. To run an engine you need to maintain stoichiometric balance of the fuel to air ratio, typically between 12 and 14 parts fuel to air by mass. The larger the engine capacity the worse the fuel efficiency at equivalent rpm and compreson ratios. Some manufacturers experimented with shutting down fuel flow to cylinders at cruise in order to make the engine effectively smaller. Emission problems due to accumulation of oil in deactivated cylinders, poor engine life due to thermal stress and pumping losses made that a failed technology. The next big thing in fuel efficiency for conventional piston engines is the variable timing and lift technology now available in BMW's 4.5liter V8 and soon to come form other manufacturers. Fully variable timing and lift allow optimization of pumping losses across the rev range, as well as improved combustion efficiency for higher torque at equivalent RPM, at the price of potentially larger valve train mechanical losses. Total power may also be limited by a lower RPM limit compared to other engines in the same class, although Formula 1 powerplants, which use a different but related valve control system, can apporach 20,000 rpm.
Still to say this thing sucks fuel based on peak power is not correct.
True, but the turbocharged (= high compression ratio at high rpm) 8! liter capacity of the engine doesn't help.