Mid-engine, Rear- engines superior for aero?

[dcb]

Originally Posted by Unheard

Personally like oversteer for the tight bend british roads i drive on.

someone needs to introduce you to the handbrake

Obviously any oversteer or understeer arent really economy techniques. If you want economy, go slow through the corners and stay off the brakes, but it is good to know how to control your vehicle in any case.

http://www.youtube.com/watch?v=UyG0mWtcp6Y

[miket]

I would think understear or overestear could be economical if they stop you from having to either use the brakes and slow way down in the turns or drive the whole time at a less than optimal speed.

What kind of steer do they call it when you lose control and do a 360? When i was a freshman i was driving to college half asleep in my dads car i borrowed. The road had some damp leaves on it. I had the heat on defrost the windows. I started drifting that boat of a car to the edge then realized it and overcorrected the other way and lost control and went into a full spin. I hit the last few guardrail posts and then slide sideways through a bank of mud stoping suprising quickly. Luckily I went after the drop off and before the pole. maybe 10 or 15ft either way. I didnt have a scratch on me. The whole side of the car was dented and scratched, the front bumper was in pieces and the wheel fell off when pulling it onto the flatbed. I was borrowing the car because mine was in the shop getting a minor dent fixed that day. That 98 monte carlo LS was a front wheel drive and handled poorly. I remember my fathers teeny tacoma truck would fishtail when he would drive it in the snow and i remember the truck going into a 360 once or twice in the middle of the road. Other people seemed to like to hit that truck when it was parked in parking lots lol.

[some_other_dave]

Miket: You would be wrong. Oversteer and understeer are ways to scrub off speed; the brake is a much more controllable way to do that. Which also doesn't risk you stuffing the nose of the car into a wall (understeer), or sliding the tail of the car into the wall (oversteer).

Oversteer can be a way to get the car to change directions really quickly, but you lose quite a bit of speed when you use it that way. On pavement, it is pretty much always better to not get one end or the other of the car sliding. (Note: Gravel/dirt/snow can be different; the rally guys always seem to be sideways and it works for them!)

It can be beneficial for MPG to take a turn at a fast speed, because that means you don't have to slow for it so you don't have to regain that speed after you have slowed down. But sliding the car means losing speed, so you do have to use fuel to regain it.


BTW, the 360 you did is called many things, from a "360" to a "spin" to a "loop"; and the "starts to go one way then spins the other way when I tried to fix it" is called a "tank-slapper". They can be exciting, but are usually not so good for the car. If nothing else, you wind up having to do some cleaning of the upholstery. ("First you say it, then you do it!" )

-soD

[miket]

Google seems to think tank slapper is a term for something that happens on motorcycles.

[euromodder]

Originally Posted by miket

I would think understear or overestear could be economical if they stop you from having to either use the brakes and slow way down in the turns or drive the whole time at a less than optimal speed.

How could it be more economical ?

Understeers means you run off the road or into the oncoming lane unless it's corrected - typically by slowing down anyway.
Oversteer slows you down because of the extra drag caused by sliding sideways - that is, if it doesn't get you off the road to start with.

If you experience either, you've carried too much speed into the corner and could have slowed down well before the corner - say by coasting - or you could have started with a lower speed to begin with.
That'd have been economical.

[dcb]

I seem to think tank slapper is a term for something that happens on motorcycles.

[some_other_dave]

Some of us car folk have stolen that term pretty shamelessly from the MC crowd. Generally the same thing, over-corrections of increasing magnitude--usually with no good ending.

N.B.--working a car hard enough to spin at 70+ MPH can result in multiple 360s, in both directions!!

-soD

[aerohead]

If you are to streamline a car the location of the center of gravity is especially important in relation to the center of 9aerodynamic) pressure.
At high speed,and exposed to a side gust,a car should weathervane towards the gust direction,canceling out the yawing moment.
Typically,for streamlining,a front engine with front wheel drive is the most stable.
A rear fin can be a palliative to compensate for an improper CG/CP bias.

[some_other_dave]

You can also affect the self-steering by using suspension geometry. IIRC, in the front you want leading arms to give you the "steer into the wind" effect, while in the rear you want trailing arms for the same effect. The notion is that between the compliance in suspension bushings, flexing of parts, and so on, the arm will pivot roughly where it is attached to the chassis of the car when a side-force is placed on the car.

-soD