Hoon
Autocross Champion
- Location
- Rhode Island
Really? So you're saying horsepower is not merely a calculated derivative from torque?
On a dynojet, horsepower is measured and torque is calculated.
Still not sure where you're going with this.
Really? So you're saying horsepower is not merely a calculated derivative from torque?
On a dynojet, horsepower is measured and torque is calculated.
Still not sure where you're going with this.
On a dynojet, horsepower is measured and torque is calculated.
Still not sure where you're going with this.
I think his dementia has kicked in.
Really? So you're saying horsepower is not merely a calculated derivative from torque?
The winner! HP cannot be directly measured, only torque can. HP is calculated from torque. I did like the pulling against a horse answers.
relief (absorption) of shock loads and inertia.I'd ask why Navy ships use a hydraulic motor powered by an electric motor to drive the winches that transfer goods from one ship to another instead of just an electric motor with a gearbox, but I don't think anyone else spent time on ships.
relief (absorption) of shock loads and inertia.
ex-squid
I was waiting for someone to throw the incorrect internet answer out...
You can measure HP, it's not black magic, it's a rate of work. You can calculate it from torque OR you can measure it directly by recording actual energy output from a generator (watts) while the car spins it or calculate it from drum speed (without knowing the torque).
HP is derived from torque if you use a dynometer:
How Does The Dyno Work?
Although due to the miracles of technology it only takes milliseconds for the computer to calculate your horsepower and torque it is not as simple as it may look. It is all just basic laws of physics applied with one another to calculate the measurements. This is a very basic explanation of what goes on inside the computer when you are making a dyno pull, there are a few more details but these are the main points. Lets get started...
First The Computer Must Calculate The Force Force = Mass x Acceleration
"The force required to accelerate an object is proportional to the mass of the object and the acceleration given it."
NEWTON'S SECOND LAW OF MOTION
The torque is the rotational Force the computer is calculating here. The first variable, Mass, is the rotational mass of the two 2700 lb. drums. This is programmed in the computer by Dynojet and due to fact that it is a inertia-type dyno it is a standard variable that can not be changed. The second variable is the acceleration, this is simply how fast you turn over the drums. Just multiply the two together and you have the Force.
Second The Computer Has To Calculate The Work Work = Force x Distance
It is very easy to now find the Work. The computer simply takes the force is has just calculated and multiplies it be the distance you have gone. The distance is nothing more than the circumference of the drum multiplied by how many times it has rotated.
Third The Computer Can Calculate The Power
Power = Work / Time
Now the computer takes that Work and divides it by the time taken and you then have your Power or Horsepower as we call it.