Akunob

'Smooth', the most overused word by instructors...LOL, I like Rob's preference for the word 'fluid'. Great article!!

multi21

Peter, what about low hp cars on the theory of diagonal lines. For example, with a low hp car, one would use less braking power on approach to a corner and use the tires and lateral load to slow it down with the goal of keeping the cornering speeds as high as you can because you can't "power" out of a corner. In the video you see in this piece with the reporter, it appears he takes the chicanes as a "dot to dot" type of approach to the diagonal lines exercise.

ProCoach

Hah! More after the holidays but the key is to utilize the maximum amount of the tire, a maximum amount of the time. Rob makes a BIG deal out of not necessarily "taking a set" with the steering wheel, but instead being "more active" with steering input, at the appropriate time.

The bold in your statement is what's important. Instead of less braking power initially and through a lion's share of the deceleration phase, it IS the focus on lessening braking "power" ON THE APPROACH to the ENTRY of the corner, KNOWING that the steering and lateral tire loading WILL perform the final deceleration adjustment needed to hit your marks. This is why Ross Bentley and others talk incessantly about "EoB," or "End of Braking" points.

The key is dwell. The amount of time at a particular control input, speed or state. It IS possible, even in a low hp car, to carry one or two mph too much down to the point where you want to begin reacceleration, and have that excess speed interfere mightily with the application of power. But then again, in a low hp car, if you brake TOO LONG or TOO SOON (and most people do both), you're dead in the water... And can't make it back.

In analyzing spec series cars with more hp, like IMSA GT3 Cup, this is often the SAME reason why the drivers in front are quicker than the less quick drivers... So this is one of the reasons why Rob uses a Vauxhall road car to demonstrate and practice with 12 of the current 20 F1 drivers he's worked with. The laws of physics don't know the difference...

Merry Christmas, everyone!

multi21

Good stuff!! -- Can't wait for class to resume after the holidays! Merry Christmas

AdamBrouillard

A car with less acceleration ability will need an earlier, faster apex so you would use less total braking force than if the car had more power, but the ideal spiral shaped entry technique is still the same. You just optimize for an earlier apex. You can search for "racing line quick reference" for a diagram showing the difference in lines between cars of lower and higher acceleration potential.

ProCoach

Agree with all except in bold. The fundamental skill execution of braking can be broken down to FIVE different phases.

Modifying only the last TWO would allow a low hp car to effect "an earlier, faster apex." The first three phases would be unchanged, especially in a competition environment.

So no, not "total braking force," only the last part of it.

This actually fits with executing your "ideal spiral shaped entry technique" very well.

AdamBrouillard

A car with less acceleration potential will have a faster, earlier apex so for example let's take 2 cars that are equal except for horsepower and have them tackle a corner. For simplicity in explanation we'll have them approach the corner at a given speed of 100 mph. If the higher horsepower car had an ideal apex speed of 55 mph the lower horsepower car would have one that is somewhat higher. Let's say 60 mph. Going from 100 mph to 60 mph requires less total braking force than going from 100 mph to 55 mph. These two lines are going to differ in other ways as well, but the total amount of braking required is going to be less in the lower powered car.

MSR Racer

AdamBrouillard

I think he is advocating not getting bogged down in trying to match what a lap sim tells you is the theoretical optimum. I doubt he would advocate avoiding a basic understanding of the physics that make you faster.

ProCoach

Yep...

morsini

Does the car know it has less HP?

AdamBrouillard

Not sure what you mean.

Gary R.

Where is Mr. Kilbort when you need him?

seanseidman

I believe he means that all cars are momentum cars regardless of hp

Slakker

I think the assumption being made is that the lower hp car is also lighter and capable of carrying more speed through the corner.