simple physics question?
03-25-2016, 04:07 PM
#16
Rennlist Member
While acceleration differences are small, they cumulative down a long straight, and make a significant difference in track position. This is why drafting works. When I used to run 944 Spec at Road America the guy starting a straight on the bumper of the car in front of him, would very often motor on by, with the same HP. The only difference in acceleration was the aero advantage (fairly small), and yet it would mean 20+ feet of track position (1st place vs. 2nd place).
When we tested ram air on the 944's, we would see an inflection point around 80MPH on TM data, and about a 2MPH difference at the end of the straight at Road America. This was pretty repeatable, using the same car back to back. That was enough to change track position again (and enough to have to regulate in the rules).
So at track like Road America, I'll take the HP over the weight every time. at Autobahn, maybe not, especially over a longer race where tires can go away.
When we tested ram air on the 944's, we would see an inflection point around 80MPH on TM data, and about a 2MPH difference at the end of the straight at Road America. This was pretty repeatable, using the same car back to back. That was enough to change track position again (and enough to have to regulate in the rules).
So at track like Road America, I'll take the HP over the weight every time. at Autobahn, maybe not, especially over a longer race where tires can go away.
There you go, yes, the HP can make a difference on the long straight, but so can the weight as well.. and its usually more of a factor, because you have braking and corrnering to deal with and that might trumph your aero drag/hp ratio. its an easy thing to plug into a simulator. But, as you say, its hardly a rounding error. 3hp , over 15 seconds, like at road america, is what ? How many HP-seconds? right ---45hp -seconds! if some guy could appply 45hp for 1 second with a button on that straight, you would be pissed! it all adds up!
