Driving it TOO easy....

[JHZR2]

Yep... I believe the ceremony was thursday at Pax River.

Go Navy!!!

JMH

 

[JHZR2]

quote:

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Originally posted by Rodbuckler:


Also, you are calculating the magnitude at which HP and torque in ft.-lbs are equal. I am just saying that they are unequal because one is torque and one is power.

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No, I'm saying that HP is merely a function of torque. the multiplication by rpm and 1/5252 are simply scalars... and the multiplication by RPM makes it a nonlinear function of greater magnitude than previously, thus the reasons why the numbers and curves dont fall on each othr, and thus look 'unequal'.

I think that everyone can agree that in the most basic sense, torque is a function of RPM. Sure, RPM can be a function of fuel consumption, air flow, combustion characteristics, etc. But all of these can be wrapped up into an RPM figure in a way. So let's say that torque is a function of RPM.

Lets say that Torque is directly equal to RPM, thus Torque(RPM)=RPM... simply noted, f(x)=x

OK, so now, lets 'scale the function to calculate HP... we get:

y(x)=x^2/5252

or written out,

hp(rpm)=(torque(rpm)*rpm)/5252

And since torque(rpm) is arbitrarily = rpm, then simplifying we get:
hp(rpm)=rpm^2/5252

See below, the torque "curve" is linear... the HP courve is scaled by the variable RPM, so it is no onger linear... however, devide by the scalar x/5252, and you retrace the torque figure at all points. Thus hp is merely torque multiplied by a nonlinear scalar, and are in fact saying the same thing.

 

[Rodbuckler]

quote:

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Originally posted by JHZR2:
I'm saying that HP is merely a function of torque. the multiplication by rpm and 1/5252 are simply scalars

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I guess this is where we are in disagreement. The RPM term (angular velocity) is not a scalar. The units conversion factor is a physically meaningless constant.

Form for calculating power from the torque curve:

f(x)=f'(x)*x,
where x is angular velocity
f'(x) is torque as a function of angular velocity
f(x) is power as a function of angular velocity

Other interesting tidbits:
Power (P) from a sustained force or thrust (F) is:

P=FV, where V is the velocity of the object.

If the power source is external to the object, then the force does work on the object. If the power source is internal to the object (like a car engine), then the external force (reaction) does not do work on the object. For instance, the contact patch is stationary.

 

[Craig in Canada]

quote:

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Originally posted by LouDawg:
Ssssssooooooooo...back to my original question....should I drive it harder or not?

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Yes.