Primitive Archer
Main Discussion Area => Bows => Topic started by: Yooper Bowyer on January 22, 2021, 07:43:52 pm
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I saw a guy on youtube measure the speed of a supersonic baseball using a highspeed camera and two posts in the ground. Could a smartphone do the same thing for arrows? I think so, because a 150 fps arrow travels 30 ft in .2 seconds. This means a camera with at least 5 frames per second would be enough.
My idea is to place two stakes in the ground 30" apart and film an arrow shot straight over them. All you have to do is note the time it takes it to travel between the two and do a little math.
This is harder than using a chrony, but a lot less expensive than the good ones, and probably more accurate than the cheap ones.
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There r apps that use the sound of the shot to measure speed that r probably easier.
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if the timing between frames is precise and repeatable, it could be accurate. you might try a number of shots at full draw, and a number at a lesser draw to see if the slower arrows are distinguishable from the shot to shot variance at full draw
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Saxton Pope used a stopwatch.
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I used the Chrono Connect Mobile Lite app. This shows pretty plausible results.
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I use the audio timer on phyphox, its a bit awkward but gives a plausible reading, you just need a good solid stand to hold the phone
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Audio recording software will be more precise. Free programs out there will be down to the millisecond. Make sure to allow time for the report to travel to your microphone at the speed of sound.
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How do the audio measurements work?
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Shoot a measured distance, the timer starts at "twang" and stops at "thump", gives you time and distance
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Shoot 9-10 grains per pound of draw. If the arrow goes220yds it’s a good bow.
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Shoot 9-10 grains per pound of draw. If the arrow goes220yds it’s a good bow.
Either buy a chrony or do this ^ :)
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Shoot 9-10 grains per pound of draw. If the arrow goes220yds it’s a good bow.
This only works if you use a good arrow
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If the fletchings are 2” or shorter and it’s spiked close it will get it down,
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If you want the best available this is what you go with. Can set Doppler up for 5 preset distances. This will give you data of what your arrow is doing along its path and deceleration. Work up to 100yds. As it is a radar they are regulated as to how much power output you can have as a civilian application in uUSA. They running about $600 with shipping.
https://mylabradar.com/
Shawn~
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Shoot 9-10 grains per pound of draw. If the arrow goes220yds it’s a good bow.
This only works if you use a good arrow
Assume a good arrow is available.
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Best not use one I fletched >:D
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I just tried the sound Method of measuring FPS... worked great. Look up a video on YouTube and you’ll see it’s very accurate. People who have crony already tried the sound method and got nearly the same FPS, just 1 FPS different.
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Primitive chrono - shot arrow, hit game before it jumped out of way - plenty fast arrow! (lol) (lol) >:D >:D. Couldn't resist! Good info in this thread! Still have to learn how to use my chronograph!
Hawkdancer
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How do the audio measurements work?
most audio would normally be with a microphone, but I have been collecting old guitar pickups and stuff to experiment with
would something like this work? one on the target face, on on the bow?
https://www.amazon.com/s?k=uxcell+10+Pcs+Piezo+Discs+15mm&i=industrial&ref=nb_sb_noss
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Primitive eyeball tell you all ya need to know.
Still like to have that LabRadar.
HH~
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I have always considered using a radar gun. I have one from my baseball-playing days.
There would need to be 2 considerations...well, 3, actually. The 1st would be just simply acquiring one...because at around $79.99 or so which was what my radar gun cost at the time they are not all that less expensive than a chronograph. 2, one would need a second person to actually attempt to gun the arrow’s flight (and they would need to be well-versed enough with using a radar gun to capture an accurate reading). And 3rd, the recorded results would then need to be converted from miles per hour to feet per second.
All in all, I would think that there are other fairly accurate alternatives to a chronograph...and they all might actually provide reasonably accurate results. And from what I have seen with a lot of people’s chronograph speed declarations, FPS numbers gathered by other means would be scrutinized equally as much as those from a supposed chronograph!! :D