Peak Horsepower

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Hi again all,

If you want to see a demonstration of torque, check out this video.

That is a 150 Hp Case steam engine that was built new in 2018. It came to the Western Minnesota Steam Threshers Reunion the next year. Not only was I there, I was the person running the Prony Brake (dyno). That is my voice you hear calling out numbers. We got 4990 Ft-lb of torque at about 170 Hp.

Later,
Jerry C
Here is the one I was thinking of in my example, I miss remembered the numbers a little.
 
The torque is what it is all about. It is why we can beat the sports bikes out to about 60km/hr ..... when they fly past me out of sheer embarrassment. In the city, I rule the roads with my Rocket3. My ZX14R doesn't wake up until 6000 RPM and makes me crxx my pants from 8-11K
 
One more comparison....When you shut off a hose, the pressure builds behind the nozzle to say, 50lbs, and the pump shuts off. When you squeeze the nozzle, all 50lbs is there and the stream shoots out 10ft then drops to 8 feet as the pressure drops. Pump kicks in and tries to keep the pressure up, but is in equilibrium with the new system state (the leak). So, torque is that initial, available pressure and horsepower is the ability of the pump to maintain the pressure when it starts to "flow". Our Rockets have the initial water pressure set at 100lbs!, and can keep this up in a flat curve as compared to others with it's massive pump. It is only the large mass required to accommodate the initial pressure that is holding us back.
 
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OK, my point was shifting at PEAK TORQUE 4K RPMS will NOT give fastest run. I don't get it.
as stated in the article i linked to , you can not make that statement unless you know the gearing and profile for each gear. The article explains it for a car and includes the data why for that car shifting at redline is the best way of getting the best out of the combination engine/gears.

without that information the statement "shifting at PEAK TORQUE 4K RPMS will NOT give fastest run" can not be answered as being correct or not, and it also depends on what your definition of fastest run is.
 
Hi VSteel,

Thanks for finding that video!
That is the big Rumley. My friend Bill McCrery (spelling) was running the Brake that night. The Rumley will put out 3600 ft-lb of torque any day of the week.

Later,
Jerry Christiansen
 
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The context needs to be the rear wheel. Torque is the rotational force on the rear wheel. It is what jolts you when that force is applied. Horsepower is just the transformation of that torque to speed. If torque was not limited by the loss of mechanical efficiency of the engine and remained constant, the speed of the rear wheel (speed of the bike) would increase to an aerodynamic or physical limit (the bike would fall apart). The rate of increase of speed is limited by the amount of torque and the weight of the bike. The transmission is just a modulator to distribute the power to the rear wheel according to the limits of the engine - a Boss Hoss has only 2 forward gears and electric locomotives have no gear changes.
 
Hi VSteel,

Thanks for finding that video!
That is the big Rumley. My friend Bill McCrery (spelling) was running the Brake that night. The Rumley will put out 3600 ft-lb of torque any day of the week.

Later,
Jerry Christiansen
Those are some good flat belts you are using, and I am impressed how much you can get out of the steam engines, belts jumping is always a headache. I have seen the belts snap but from my personal experience they don't tend to really go too much of anywhere so as long as you are not right up on them you are pretty safe.

I always loved going to the Steam and gas threshing bee in Sturgis every year. I need to see if they have any good ones around here and start going again. I love that old iron.
 
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