McLaren F1 ... automatic brake cooling?

I believe it does have several electric fans for brake cooling via "forced air re-distribution" (I think that's what McLaren calls it). Perhaps it even has a fluid cooler?

 

The McLaren F1 under hard braking had a small wing on the back that would pop up to aid in rear downforce. When this wing popped up it would expose additional brake ducts that would direct air to the rear brakes. I'm pretty sure this is the automatic brake cooling Murray was referring to.

 

Stronger (cooler) rear would help in high speed braking stability.

 

LoL!

In seriousness, what happens is that you can with strong front brakes really rapidly decrease the rate of the front relative to the rear (recall fronts do most of the work).

When this happens the rear wants to 'over take" the front.

In strict linear braking this is not that bad, but even the slightest turn off of straight can result in the rear VERY rapidly overtaking of the front by the rear in what we call a spin.

If you like slight braking while you turn (or late braking as it sometimes necessitates the same if you miscalculate), it is nice to have the rears rather strong on your car. (I use gripper pads in the rear relative to the front)

 

The Mclaren F1 has an active rear spoiler, it's purpose being to move the CoP forward and feed air to the rear brakes. The Mclaren has very compliant suspension which results in a lot of body roll and much dive under braking. One of the results of brake dive is that as the body is tilted forward the Center of Pressure (CoP) of the airflow over the car is moved forward resulting in the front brakes having to do more work. The rear spoiler, when deployed, effectively moves the CoP rearward which allows the rear brakes to do more of the work.
There is a portion of this spoiler on each side that extends forward of the hinge, and as the rear spoiler lifts, this portion extends below the plane of the closed spoiler and down into the mouth of a duct on each side, which in turn feeds this additional air to the rear brakes.
Of course this air flows only under heavy braking, and for a short time after, until the spoiler closes.

Murray desperately wanted, and experimented with, composite bakes to lower the weight of the F1, but they just weren't ready for prime time when the car was designed.

 

I answered too quickly in the above post. I don't know what the forward tilting of the car under braking does to the CoP, I should have simply stated that as on any car, as the car brakes the load on the rear tires decreases and on the front tires it increases. The deployment of the spoiler moves the CoP rearward to offset this braking induced forward shifting of the load. And, in fact, the compliance in the suspension may not substantially affect this load shift under braking.
Anyway, I have had the chance to drive the F1 a couple of times, once for an extended period on the race track. The brakes are good, but I did I get the pedal to go a little soft after repeated laps that included hard braking from over 140 mph into a second gear corner. Maybe the brake fluid should have been changed, but I wouldn't consider the braking substantially better than a 360's. Now the acceleration, on the other hand...........

 

Omar, I do not believe this is quite right. Too much rear brake bias will cause a spin. Too much front bias merely causes the car to plough straight ahead.
Philip

 

Ask Will H about 512TR brakes and why you shouldn't upgrade just the front.