I think it was just a number that allowed him to make a fortune by the improvement in efficiency of steam engines as I remember.
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I think it was just a number that allowed him to make a fortune by the improvement in efficiency of steam engines as I remember....and Watt was performing marketing. Horses are about 50% more powerful than that.
But the formula already has you plugging HP in as a known source, so why are you calculating it again?550 foot-pounds was how much work James Watt originally calculated one standard issue horse could accomplish in one point zero measured seconds.
Doesn't anybody teach history of technology anymore?
Cheers,
Wes
He asked what the significance of 550 foot-pounds was. I wasn't calculating anything, just answering his question.But the formula already has you plugging HP in as a known source, so why are you calculating it again?
...and that's another question....WHY are you commenting on this at all?He asked what the significance of 550 foot-pounds was. I wasn't calculating anything, just answering his question.
Sorry to resurrect this part of the thread, but I'm curious....why are you multiplying HP by 550? What does 550 represent?Efficiency is defined as useful work out divided by energy in. For a propeller, that would be airspeed (in feet per second) times thrust (in pounds) divided by (horsepower multiplied by 550) or, equivalently, airspeed (in meters per second) times thrust (in newtons) divided by power (in watts).
...and now that that got all mucked up, I'll ask again....ATTENTION: SWAMPYANKEE...
Sorry to resurrect this part of the thread, but I'm curious....why are you multiplying HP by 550? What does 550 represent?
Thanks in advance.
Elvis
Sorry to resurrect this part of the thread, but I'm curious....why are you multiplying HP by 550? What does 550 represent?
Well, excuse me for living! You asked a question, I offered an answer. I didn't realize I was intruding on a private conversation on this public forum. Excuse me all to hell. I'll don my dunce cap and go sit in the corner....and that's another question....WHY are you commenting on this at all?
It had nothing to do with you at all.
Thank you for taking the time to explain that.One horsepower is 550 ft-lbf (a unit of energy) per second. Power is energy per unit time. Confusingly, torque is also measured in ft-lbf (I know; some people use lbf-ft), but the two are fundamentally different quantities, like speed and hair color.
sustained 360 horizontal turn
Ki-43-I - 12.5-13 sec
A6M2 - 13-14 sec
A6M3 - 14-15 sec
A7M2 - 14-15 sec
A6M5 - 15-16 sec
Ki-61-I - 16 sec
Ki-84 - 17 sec
Ki-100 - 17 sec
N1K2-J - 17 sec
BF-109E - 17 sec
P-39N - 17-18 sec
Yak-9 - 18 sec
Yak-3 - 18 sec
Ki-44-II - 18 sec
J2M3 - 18 sec
P-40F - 18 sec
Yak-9U - 18-19 sec
BF-109F-4 - 19 sec
BF-109G-10 - 19 sec
La-7 - 19 sec
F4U-4 - 20 sec
La-9 - 20-21 sec
F4U-1 - 21 sec
F6F-5 - 21-22 sec
P-51D (67Hg) - 22 sec
P-38J - 22 sec
FW-190A-5 - 23 sec
Ki-94-II - 23 sec
P-47N - 26 sec
Which stall speed? At which altitude? An aircraft can stall out on full power while pulling many "G". Thats where these "spanwise lift distribution" discussions are important. A plane that is completely benign coming in to land obviously at 1 G can stall with no warning at all its power on limit.We should also try and find the stall speeds whenever possible as that will give the speed at which it becomes possible to pull a given g-load. That said, some airplanes are more sluggish than others and will take longer to pile on the g-load, so, it's just a start...
Any plane that needs to pile on the G load to do its job, such as fighters, fighter-bombers, attack planes, etc, while it may be sluggish in roll, isn't likely to be sluggish in pitch, as that's the working parameter in all combat maneuvering. A plane that reacts slowly in pitch is dogmeat, so elevator response and stick force gradient (the thing that will most likely impede pitch response) are critical design parameters.That said, some airplanes are more sluggish than others and will take longer to pile on the g-load, so, it's just a start...
What do you mean by "its power on limit"? "on limited power"? Or "power on its limits"? In other words, "reduced throttle" or "full throttle"? In either case a plane with no wing twist, so the entire wing stalls at once, can hardly be called benign. And if it has wing twist so the wing stalls progressively, root to tip, it's pretty hard to stall it without causing warning buffeting, especially at approach speeds and configurations.A plane that is completely benign coming in to land obviously at 1 G can stall with no warning at all its power on limit.