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Will the deer be able to get out of the way or even enough to result in a wound.

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Discussion Starter #1
Before you just say "yes" or quote some famous hunter who says "yes" Read what I have deduced


Keep in mind this is just a friendly debate and I just felt like crunching some numbers for myself and see what everyone else says after thinking about it.

The situation is Deer at 20 yards and is not aware of you nor looking at you. (I am saying this because I think if it saw you shoot it might be able to get out of the way, but I am just dealing with sound) Your hunting rig is spitting arrows at exactly 300 fps. (just a good speed to go off of :) ) The bow may be quiet on the shot or not, at 20 yards it will probably hear it regardless.

Will the deer be able to duck your arrow?

I think it will be very close, but I am not certain. The question is. How far can a deer move in about 26 milli seconds? Because that is about the time it will have.

The numbers...
Speed of sound = 761 mph (1116 ft/sec)
Speed of arrow = 204.5 mph (300 ft/sec)
Distance = 20 yards (60ft)
Probable reaction time of deer = .12 sec

Alright sure the sound # is at sea level and 59 degrees etc. , but is is close enough for our purposes unless you are hunting up in the mountains. The reaction time comes from the reaction time of your average world class athelete. This should be close enough to a deers reaction time due to the speed of their nervous system being the same as ours. (speed of neurons ranges from 75m/sec to 120m/sec depending on if you are discussing alpha, beta, or gamma nuerons, but on average the speed of our nervous system is about 100m/sec as well as a deer and nearly every other mammal)

The times...

It will take sound about .054 sec to reach the deer.
It will take the arrow about .2 sec to reach the deer. (yes I know the arrow will slow down, but at 20 yards that is minimal because my arrow is almost the exact same speed at 10 yards as 3 feet as far as my chrono can tell)

That leaves .146 sec of time for the deer to do its thing. If its reaction time is around .12 sec than that leaves .026 sec or 26 milli seconds of movement time. How far can it move in that amount of time? Not much.

What does everyone think?
Remember this is just a discussion, I am not suggesting that anyone not care about how loud their bow is or anything like that. I am just crunching numbers.:wink: :tongue:
 

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mmmmm.......beer!
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There are a lot of variables to take into account.

Where the person was aiming (Middle of lungs or heart)
Size of deer (depth of body from top of back to bottom of chest)
Was the deer on alert or totally relaxed

That's just a few. This could be interesting. :darkbeer:
 

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I do not believe a deer can move fast enough to cause a miss outside of the vitals assuming:

1) perfectly centered vital hit at 20 yards
2) animal not on high alert
3) 300 fps

At 35 yards I think it's possible.
 

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Techy,

Voted yes, because I think that it may be possible...so it could happen. I think the probability of it happening based only on the hypothesis in unlikely IMO.
 

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Discussion Starter #6
Rolo said:
Techy,

Voted yes, because I think that it may be possible...so it could happen. I think the probability of it happening based only on the hypothesis in unlikely IMO.
I feel the same way.:)

I voted "not sure"

It is interesting to discuss though.:darkbeer:
 

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I have a couple problems with the assumptions presented above.

I would say that a deer's reaction time is better than a world class athelete because they are able to reach a higher top end speed than a human, so they have more fast twich muscle for movement.

I would also assume than no person's hunting set-up will shoot at a true 300 fps with accessories, broadheads, and their hunting arrows. I would say mid 280's is a more likely senario.

Last year at 16 yards I had a deer jump the string at 240 fps bow enough to dodge the shot, so I would think it is very likely that at 20 yards with a 280 fps bow the deer would still be able to jump the string enough to dodge the arrow if on alert.
 

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I also voted yes but I must admit hat I hadn't read your post before I voted. If the deer is not on "high alert" I think it's highly unlikely that it would duck enough to miss the vital area on a well aimed shot.
 

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Discussion Starter #9
RangerAngler said:
I have a couple problems with the assumptions presented above.

1. I would say that a deer's reaction time is better than a world class athelete because they are able to reach a higher top end speed than a human, so they have more fast twich muscle for movement.

2. I would also assume than no person's hunting set-up will shoot at a true 300 fps with accessories, broadheads, and their hunting arrows. I would say mid 280's is a more likely senario.
1. An animals top running speed does not have a lot to do with their reaction time.

2. My hunting setup shoots 300 fps:wink:
 

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She's baaaaack!!!!
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I have used the same kind of numbers many times explaining this to people.
The best world class sprinters reaction time is .12 seconds (http://condellpark.com/kd/reactiontime.htm), I wonder if deer might be quicker.

I think a relaxed mature deer may at times move a few inches.
I really don't know how quickly a deer is capable of reacting to a sound.
But I've been quite impressed a time or two!
Other times they'll hear something and not move anything but their heads.

I wouldn't be surprised if a mature relaxed deer could or would move it's vitals six inches.
If the deer moves 3 inches it could make a less than perfect initial shot location terrible. If the deer pitches forward 3 inches and your arrow is initially launched such that it would hit 3 inches back, the deer will now be hit 6 inches back from the desired impact point. Of course if I execute a shot that should hit 3 inches low and the deer drops 3 inches the arrow is going to impact "perfect".
 

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I voted yes also before reading, if you have a quite bow, deer is not on alert, and you aim dead center, he probably won't jump string at 20yards with a 300 fps arrow coming at him, very unlikely I would say.
 

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Smilin' Bob
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a deer "ducking" can't duck any faster than the gravitational constant (32ft/s2) until its able to grab something and "pull" itself down.

I'd give the deer a little better reaction time...much like blinking when something flies towards your eye, some reactions are more instinctive and wired differently. They take far less time.

I come up with about .43 feet of "ducking" for them.
 

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Yes

From what I remember reading, anything under 18 yards the deer won't likely jump the string, unless it's already on high alert.
 

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Wow...you have put alot of time, effort, and mental concentration into this, why don't you just shoot a deer and see?
 

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Smilin' Bob
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Where's Medved when we need some technical expertise?:wink:
 

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I don't believe other than a yearling I hit bad last year that I've ever had a deer jump string on my. With that being said, I also am pretty well silenced or "muted," to an extent that there is little noise when I release my arrow. I know that on 2 occasions when I've misjudged distance, I've had a mature buck and a mature doe, just stand there, and then look behind them where the arrow went, without flinching. Can a deer jump string on a noisy bow with a slower speed, absolutely, I've seen it on video many times, but 300fps is pretty fast, that would give the deer exactly 0.2 seconds to react, and alert deer maybe, a browsing non-suspecting deer, I don't think so. And the ones I've shot at were of the latter type.
 

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The question is if the deer is relaxed and NOT on high alert. I would say not likely he would duck it, especially where i hunt (public archery only land) I have never even seen a deer duck an arrow.
 

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don't think so

Assuming all your numbers for correct and say you are taking a ground level shot shooting for the boiler room (lets say 1 foot (12 inches) below the top of the back). That is .026 seconds to move 1'.

The last number to take into account is the effect of gravity on the animals drop, since we are talking about ducking the arrow not jumping it. If you use a constant acceleration of a free falling object on earth of 32 ft/second squared. That means in the first second of freefall the deer would travel 32 feet toward earth.

So to simplify first our first crack at this; if we assume constant velocity in that first second rather than constant acceleration, the deer would move hypothetically .026 x32 = .83ft or about 10". So with an instantaneous constant velocity of 32ft/sec the arrow would hit 2" below the back line or right about in the spinal column.

Now if we assume constant acceleration, we have to apply the true forumla of 32ft/sec "squared" so that would look like 32 X.026 squared or 32ft/.000676 = .021 feet or about a quarter inch (1/4").

Remember all that movement would be happing in 2.6 one hundredths of a second. That is not alot to move and assuming no lag time in the reaction of the animal, this would barely register as the animal flinching to the eye of the shooter.

Good post, was fun to dust off some of that old shool math.
 

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Comparing wild animal reaction times to human beings is something you do around the campfire or on the internet to kill time. I'm not trying to rain on your parade, I'm sure we will learn much and everyone will have a good time.

However, there is no reason to believe that a live animal won't move before your arrow reaches it. They may even start to move during your release before the arrow actually starts forward for no reason apparent to you. A squirrel or rabbit could startle the targeted animal and off they go. :llama:

Deer are genetically predisposed to outrun preditors and are built to twist or duck or leap to avoid being eaten alive. They will paw and kick in certain situations but they are primarilly wired to run. Their ears are huge and always searching for danger in two different directions even while feeding. They will focus both ears toward anything suspicious if needed.

There have been far to many archery stories, and a few videos, for anyone to think that they can't duck an arrow. I hope they don't duck yours.

:cocktail:
 

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I voted yes, but your math is above me. I do have a video of a squirrel ducking an arrow at about 15 yards. Slow motion, he dodges it. Of course that is only about 2 inches of movement.
 
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