Rick, "5mph is 2.1m/s. So a force of 315N applied at a velocity of 2.1m/s is 662W - basic physics. AND 662W is 0.89HP."
I think I see one of your problems. You are assuming that the boat sailing at a 20˚ angle is going 5 mph. Why are you making that assumption? And then using the boats velocity to determine force? Drag maybe.
I was careful just to compare a single force being generated. The velocity of the boat has little (none) relationship to how fast the boat is being accelerated.
Force = Mass times Acceleration, not Velocity. In other words Force = Mass times the change in Velocity. So can you see why even with your 5 mph assumption, your math is wrong? 1 N = 1 kg x m/s^2
I am also concerned that my hp calculations of the wings lift are wrong^^ Obtaining the lift (force) is easy, 912 kg m/s^2 which is a kilogram-force meter second which multiplied by 9.8 m/s^2 gives Newton meters or Watts directly. So a 912 kilogram-force m/s^2 equals 8,900 watts or 12 hp.
I think I was wrong about the 911 n it should have been 8,900 newton meters. Now all the numbers make aproximate physical sense to me and my real world observations.
Back to the example, It appears that all of your power calculations are off by a factor of 9.8. Sorry about my contribution to your error.
Talador
Maybe that Statics class years ago wasn't such a blowoff class after all ^^
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Posted by: taladorwood@yahoo.com.au
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