FPS to MPH

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Normous
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FPS to MPH

Post by Normous »

Ever wonder how fast your arrows travel in MPH, a fast way to convert FPS to MPH is to divide the FPS by 3 and mulitply the answer by 2. The result is within 3%.
Need an answer dead on? Multiply the FPS by 0.6818 to obtain MPH.

350 fps is 238.6 mph
340 fps is 231.8 mph
330 fps is 225 mph
320 fps is 218.2 mph
310 fps is 211.4 mph
300 fps is 204.5 mph
290 fps is 197.7 mph
280 fps is 190.9 mph
270 fps is 184 mph
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j.krug
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Re: FPS to MPH

Post by j.krug »

That's a great conversion Norm. I think I might try to use mph instead of fps. 225 mph just sounds way cooler and has more WOW :shock: factor to the people who have no idea what I'm talking about. :)
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roly
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Re: FPS to MPH

Post by roly »

That is interesting, MPH does sound cooler

So.... are your arrows going faster than your Shelby :roll:
strum
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Re: FPS to MPH

Post by strum »

very cool norm ..that means if we get restricter plates we can run itn the datona 500 :roll: :roll:
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sumner4991
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Re: FPS to MPH

Post by sumner4991 »

Another easy way to get the conversion is to google.

Just input, 350 fps = mph , the search will get you the answer of 238.64 MPH.
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strum
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Re: FPS to MPH

Post by strum »

sumner4991 wrote:Another easy way to get the conversion is to google.

Just input, 350 fps = mph , the search will get you the answer of 238.64 MPH.
Dang Sumner,,thats too easy. :lol:
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Re: FPS to MPH

Post by TB »

Dang that's fast!!! And the deer can still beat you. :D :D
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Re: FPS to MPH

Post by sumner4991 »

Strum . . .I think it was pydpiper that showed us that trick . . .you can convert just about anything by inputting the measure you have and follow it by the = and the measurement you do not have . . .grains to grams . . .miles to inches . . .just about any conversion.
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nchunterkw
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Re: FPS to MPH

Post by nchunterkw »

Not that I think you shoot at a moving deer...but this is interesting.
If your arrow is going 300fps and the deer is 20 yards away, it takes your arrow 0.2 seconds to reach the deer. (actually a bit longer since the arrow is slowing down the whole time). If a deer is walking at 3 MPH he will move 10.56 inches in 0.2sec! At 2MPH he moves 7.04 inches in 0.2 seconds.
That is way more lead than I ever thought you would need to take that shot. Also why I like the reticle on the Varizone.

I prefer the term "math-alete" in case you were wondering :)
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Shakibods
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Re: FPS to MPH

Post by Shakibods »

I never did the math before, so I never anticipated 10+ inches at the rate of speed. I definitely appreciated the information and it goes to show you the importance of getting them to stop before the shot. Now the question is, what is the rate of speed of a deer during a string jump? Speed of sound is 680 mph @ sea level or 997.3 fps. At 20 yards, the deer will hear the sound in approximately 0.06 seconds, so it has 0.14 seconds to react. So how fast is the deer's acceleration when it spooks? :D
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Re: FPS to MPH

Post by nchunterkw »

Sticking with our scenario, if a deer has 0.14 seconds to react after it hears the noise, and it drops straight down (which is what they do to spring load their muscles), it would be dropping at the rate of the acceleration of gravity (best case) which is 32.15 f/s/s. The equation to use is 1/2 at^2 where a is accelerastion and t is the time squared. Using that I get the distance the deer can drop in 0.14 seconds as 3.78 inches - which is pretty much in line with what high speed footage shows us.
Now at 30 yards....at 300fps it takes the arrow 0.3 seconds to reach the deer, and the sound 0.09 seconds, so he has 0.21 seconds to react. In that case he can drop 8.5 inches. Using the average speed for the arrow between 0 yards and 30 yards (291fps) to somewhat account for the arrow slowing down, I get that he can drop 9.25 inches. I'm not sure how far they drop to get ready to run.
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strum
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Re: FPS to MPH

Post by strum »

yall stop it your making my brain hurt.. :lol:
Heres my math..
deer is 30 yards away my arrow flies 340fps ..if i miss is most certainly because he (the deer) has a degree in calculus and worked out the math in his head in .000002 secs...then spring loaded his butt and jumped within .0000202536 milli secs of my arrow..and thats my story..Dang educated deer 8)
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Re: FPS to MPH

Post by flightattendant100 »

strum wrote:yall stop it your making my brain hurt.. :lol:
Heres my math..
deer is 30 yards away my arrow flies 340fps ..if i miss is most certainly because he (the deer) has a degree in calculus and worked out the math in his head in .000002 secs...then spring loaded his butt and jumped within .0000202536 milli secs of my arrow..and thats my story..Dang educated deer 8)
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nchunterkw
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Re: FPS to MPH

Post by nchunterkw »

I hear ya. God sefinately made deer smart, fast ............and delicious 8)
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and walk in it and find rest for your souls. - Jer 6:16

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Tennessee Tom
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Re: FPS to MPH

Post by Tennessee Tom »

strum wrote:yall stop it your making my brain hurt.. :lol:
Heres my math..
deer is 30 yards away my arrow flies 340fps ..if i miss is most certainly because he (the deer) has a degree in calculus and worked out the math in his head in .000002 secs...then spring loaded his butt and jumped within .0000202536 milli secs of my arrow..and thats my story..Dang educated deer 8)
And beside's all that the arrow or bolt SLOWS DOWN ,, the 250 is down quite a bit in less than a mile !!!!!!!!
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