I can say it again.
This is the LAST time I will try to explain it ok?
Power = Torque * angular velocity (since we are talking a rotating movements)
Now we have the famous formula:
M1*v1 = M2*v2 (that’s in a perfect world where you don’t have any mechanical losses on the way but that doesn’t matter here.)
Now let’s take the car example again:
M1 = torque on the engine’s crank shaft
V1 = speed of engines crank shaft
M2= torque on the rear wheels (where you want it! This torque will cause the acceleration)
V2= speed of rear wheels.
Since we are interested in M2 we have:
M2 = M1 * v1/v2 now use eq.1…… M1*v1 is ….. P! Engine power. Engine hp!
Hence M2 = P / v2
So where did the engine torque go? We lost is somewhere in the transmission!
Now what happens as the speed increases? The wheels will turn faster right?
V2 will increase. In order to continue the acceleration we need to keep our M2. So what do we need? More P, more hp.
So the fundamentals of all this is: The ability to cut more chips from a log or drive faster with a car is directly dependent on the power, raw kW.
(prefer kW over hp since hp is not unambiguous, depends for example on where on earth you live because of different g-constants)
A 600hp with 500Nm of torque will pull a heavy truck up the hill just as fast as the 600hp 2500Nm truck diesel engine. Engine torque as specified in car magazines only tells you what the characteristics of the engine look like. What the power vs. rpm looks like. It has nothing to do with the ability to accelerate fast or reaching high top speed.
Disclaimer: I've rented alot of beer tonight, RiverRat and Lakeside will be very pleased to know that it was microbrew. I can't remember what label. They were in brown bottles, so that narrows it down!
Anyway, I've been working on returning it though there may still be some lingering effect. If I appear to be obnoxious, it's the beer. Be glad I don't drink whiskey much anymore.
opcorn:
This thread has gone, what... 13 pages? There've been lot's of opinions floating around Peter, your's included. I'm happy to see we've arrived at equations finally! I dig it!
Ok Pete, can I call you Pete?, Good! What happened to the torque? Someone stole it and doesn't want to give it back? Naw, it's there, always has been. From your last equation Pete:
Where M2=Torque at the rear wheels
P=Power in horseypower
and V2=Speed of the rear wheels
and we'll also use this from your post. Especially the part I highlighted (of course you emphasized it with exclamation points, like you wanted me to see it. Thanks, I will use it!).
M2 = M1 * v1/v2 now use eq.1…… M1*v1 is ….. P! Engine power. Engine hp!
Something I will tell you right off the bat Pete. When you're juggling equations, sometimes it's a good idea to factor your answer into simpler units. It gives you a different perspective. So let me give you a different perspective.
Wait, I have to return a beer.
Much better!
Now good ol fuzzle was kind enough to put up this picture for us.
Remember that picture? I have a feeling you never looked at it or didn't comprehend it.
Soooooooooooo, (those o's look so cool all lined up! How do they do that?) if we know Power=(torque/time) and we look at your equation
LOOK, there's a
P in your equation that you say is
P! Engine power. Engine hp!
Now this makes it
really easy!
We take your equation Pete, and we substitute (torque/time) for P or power or horseypower or whatever you're calling it this week... which yields:
M2 = (torque/time)/ v2
I think we found the long lost torque Pete!!! It's as real as real can be! Have a beer for yourself and good job!!!!
edit: Pete, I had to add this just because it was mentioned so long ago. The answer was there for you if you had read it.
Or horsepower = (torque/time)
So Peter, everywhere that you have mentioned horsepower, we can substitute the term (torque/time)
