03-09-2015, 03:48 PM
(03-09-2015, 12:00 PM)JustJohn_imp Wrote: So what are the "Frictional losses" called? And "weeks" without end? How about years? Whats that called? Balls? Its not hard for me to grasp...but your theory of it is. I totally appreciate your insite and time to post. However you will not convince me. Nor will simple physics lessons. NOT for motorcycle engines per se...but put a few locomotives or ships out there and tell me about torque and HP.
Frictional losses are called frictional losses. If we are measuring horsepower at the crank of an engine that power is what is generated post all engine frictional losses so it is irrelevant to an engines rated horsepower although it would probably have bearing upon fuel consumption. Modern ships can reach any port on earth in less than three weeks. I am assuming that most ships are used to transport goods so they do need to stop to offload cargo. Military diesel powered ships on patrol do stay out for months if necessary but most of them go to port every month or so as well where they are shut down to be serviced. I am not aware of any diesel powered ships, locomotives, or even stationary engines used to pump water on farms that run for years without being shut down for maintenance. But that isn't really relevant here either. You are giving examples of specific applications where low RPM and long term operation is beneficial and you are clearly a fan of such engines. That's great. But extrapolating from those specific applications that turning force in an engine is a measure of that engines power regardless of how many times per minute that turning force is applied is incorrect. What I have described here is not a "theory of mine". These are not original thoughts that I am cooking up. They are established facts you can verify with some study in engineering or elementary science. That the earth is round is not a theory no matter how many people don't believe it. And writing that a pound of feathers will push down upon a scale with exactly the same amount of force as a pound of lead is not a theory, it just is.
One horsepower equals 33,000 foot-pounds of work per minute—that is, the power necessary to lift a total mass of 33,000 pounds one foot in one minute. This value was adopted by the Scottish engineer James Watt in the late 18th century, after experiments with strong dray horses. The electrical equivalent of one horsepower is 746 watts in the International System of Units (SI), and the heat equivalent is 2,545 BTU (British Thermal Units) per hour. This measure of power is not a theory of mine, it's been an established and accepted fact for over 200 years.
You are arguing that the force of an individual hammer blow is a measure of how much work a carpenter can do and you wish to ignore how many hammer blows per minute he strikes. Then you argue that because nobody uses high RPM motors in ships, low RPM motors that produce lots of torque at low RPM must be better. Your final sentence would be the equivalent of me proclaiming, "Show me a winning funny car with a huge Volvo inline 6 diesel and then talk to me about torque and HP". That big Volvo diesel would get owned in every race.
If you want an example of a very heavy vehicle that has been successfully powered by a high RPM, low torque motor in hard use for decades then I'll give you one. It's the M-1 Abrams battle tank. It weighs 68 tons, the heaviest main battle tank in use today yet it is the fastest (capable of 60 mph ungoverned) as well as the fastest accelerating tank that has ever seen service. It has a very high RPM, low torque turbine engine with 1500 HP and about 2700 FT/LBS of torque. A 1500 HP diesel would have over 6000 FT/LBS of torque (over twice as much torque as the turbine). During development diesel engines were considered and tried but the low torque turbine smoked them in performance tests. The battle tanks of almost all other countries are high torque diesel powered and they are no match for the M-1.
A major benefit of that low torque turbine is that it is much lighter. A 1500 HP diesel engine weighs about 5000 lbs, that 1500 HP turbine weighs 2500 lbs. So why aren't turbines used in more heavy trucks and ships? Because they are expensive, require more maintenance, have slightly higher fuel consumption, and don't last quite as long. Again, these factors are unrelated to engine power.
All I can do is present established facts and inarguable long accepted units of measurement and if they run contrary to someones belief system, I can't help. All the best.
Chip