Long overhangs vs. Short Overhangs

Hey, sorry for starting another thread so soon, but I couldn't resist. So yea, what are the advantages/disadvantages of having long overhangs or short overhangs. Like what effect do they have on the car's handling, acceleration, braking, etc.?

Ever thought about buying a book on chassis/body design and theory? It will effect handling in that you will be turning from a more centered location rather than the front if you have a very long over hang, and the opposite is true if you have the wheels sticking out infront of the car past the body. Braking would not be effected except when it is used inconjuntion with handling.

i would be more concerned with wheel base than overhang. make the wheel base as long as you need it (longer is better to a certain point) and then make the body as short as you can past the wheel base. I mean make the overhang as small as possible to save weight but take as much room as you need for aero and mechanical stuff. Like everything else, it is a compomise.

lol yea, so is that why the cars like the McLaren F1, Zonda, Enzo, all have long front overhangs and short rear overhangs?

Hey, sorry for starting another thread so soon, but I couldn't resist. So yea, what are the advantages/disadvantages of having long overhangs or short overhangs. Like what effect do they have on the car's handling, acceleration, braking, etc.?

Overhangs mainly affect turning and aerodynamics. Acceleration and braking are generally not affected, unless the overhangs consist of chassis members, or heavy lead weights, instead of mostly hollow bodywork. Long overhangs can help reduce drag and/or increase downforce, depending on how the bodywork is designed. Usually, increasing downforce comes at the cost of increased drag, but there are solutions which don't have drag penalties.

Turning, is also another matter where overhangs matter. The closer that the mass is to the center of the car, the easier it can turn. In techincal terms, you want to reduce the cars's polar moment of inertia (a number which says how well it resists a turning force, or torque.) You can test this by moving your arms in and out while spinning around on your desk chair ;)

Cars are styled with a mix of aerodynamics, and aesthetics in mind. With mid-engined supercars such as the F1, Zonda, and Enzo, you'll see the overhangs styled in a way that makes the most aerodynamic sense for the type of layout that the cars have. Aesthetics do come into play, but aerodynamic performance is most important.

ah, I see. That makes sense

btw you know any good books on supercar/prototype design or engineering? :biggrin:

btw you know any good books on supercar/prototype design or engineering? :biggrin:That depends on whether you're just into technical reading for pleasure, or you want hard engineering information on the cars. You're probably not going to find a single comprehensive book that tells you how to design a supercar.

You might find a book like "Driving Ambition" which explains the story behind the F1, including some of the design concepts that went into it, but none of the hard engineering details behind it. There are, however, plenty of automotive books out there, which cover specific topics -- things like engines & turbocharging, or suspension design, which are written by engineers, for engineers.

There are less technical versions of the books above that are intended for mechanics and tuners. But again, nothing that tells you how to design a complete supercar. Companies aren't usually keen on revealing the reason for their design choices when they have competitors to outsell and outrace.

True. But if you want my opinion I think anyone could learn more and understand it better from people over here at AF than from any book :smokin: . I'm not saying that the books aren't good because the four pages of Driving Ambition that I read were really good too.

True. But if you want my opinion I think anyone could learn more and understand it better from people over here at AF than from any book If you're looking for general technical information, there's lots of people who can provide that.

If you want engineering though, books really do have internet forums beat.

point taken

one more question. What are the benefits of using an elongated nose like Group C cars, and F1 cars? Because I know the Enzo featured a elongated nose too.

i would have to say its purely for aero. To give a less steep angle to the front and to provide a place to mount a wing.

and also wouldn't it help in like wight distribution and you'd also be able to house a larger radiator

you generally dont want to add weight anywhere, ever, especially to the front of a car not to mention (and im just gonna talk about F1 cars) the carbon fiber used to make the nosecone doesnt weight that much. Also in F1 cars the radiators are to the sides slightly behind the driver.

also one more thing, if the whole purpose of an airdam or windsplitter is to prevent air from going under the car, how come some race cars have like a notch in the middle-lower front bumper section? Isn't that like inviting the air to go under the car?

here's an example- The F50 GT
http://www.a-h.ch/galerie/Ferrari%20F50%20GT%201998.jpg
You see how the lower front bumper has like a notch in the middle of the bumper at the bottom?( by notch I mean the front splitter goes slightly up towards the middle of the bumper) Wouldn't that allow air to go under the car?

another example-the new Audi R10
http://www.classicdriver.com/upload/images/_de/3273/img01.jpg
the middle of the front splitter goes up, again wouldn't that allow air to go under the car?

Airflow under a car isn't necessarily bad. Chin splitters aren't designed to prevent airflow under a car, but rather control how much, and in what manner the air flows underneath the car. If too much air flows underneath the front of the car, the nose can lift up. The reason that there's a "gap" in the middle of the chin splitters is partially to direct air away from the front tires, where there would be lots of drag and turbulence. You can't eliminate all of the air flowing underneath of a car, so the goal is to manage it as best as possible.

Of the air that does end up flowing under the car, it is often used to suck the rear end of the car to the ground. Many supercars and race cars use flat undertrays, or specifically sculpted underbodies which accelerate the air to create a lower pressure between the car and the road. The car acts as a forced narrowing in the airstream to create a venturi effect: the air flowing underneath of the car is allowed to expand once it passes the rear bumper, creating an area of low pressure. In the case of flat undertrays, the "rake angle" of the car is setup so that the nose is slightly lower than the tail, to achieve the same type of effect. This way the air tends to push the car down onto the road, rather than acting like a wedge tryint to pry the car off of the road.

o, so basically you want to control the amount of air that goes under a car, and make it work for you

o, so basically you want to control the amount of air that goes under a car, and make it work for you

You might also want to use the high pressure zone above the splitter to create some downforce by letting the pressure act on the area of the splitter.