18 replies to this topic

[BoDiddly]

When a deer jumps the string it is really dropping down so that it can flex its muscles and push against the ground to move.
Therefore, the deer is freefalling due to gravity until it either hits the ground or pushes off in some direction.
There are three conditions that the deer can be in whenthe shot is fired.
1. The deer is looking at the shooter and is on high alert and sees the bow and arrow move and reacts within about 1/10 of a second.
2.  The deer is not looking at the shooter, is on high alert, and moves when it hears the bow fire.
3.  The deer is not looking at the shooter and is relaxed and does not react to the bow firing.

Let's examine the first two cases more closely.
The following table shows how far the deer would drop in inches before the arrow arrived if it had a 1/10 second response time after either seeing the arrow move or hearing the bow fire.

Range   Visual+Response  Sound + Response
    5 3.9 inches 3.14 inches
    10    6.6 4.7
    15    10    6.5
    20     14 8.6
    25     19   11
30     24   14
    35     31   17
40     38    20
    45 45    24
50     54    28


Notice that at 50 yards, the deer will hit the ground or have already pushed off by the time the arrow arrives.
If you are lucky, he has pushed himself back up into the path of the arrow.
Even at 30 yards, if the deer is looking at you, he could move out of the arrow path.

So, what we have learned from this is,
1.  Deer can move more than a foot before the arrow gets to 30 yards.
2.  If the deer is looking at you, don't shoot unless he is really close.
3.  If the deer is relaxed and not looking at you, you might pull off a longer range shot.

Happy Hunting and Good Luck.  We all need it.

Edited by BoDiddly, 01 February 2012 - 01:31 PM.

[Highlander]

At what speed arrow are you basing these figures on?

[BoDiddly]

sorry about that, the arrow speed was 350 FPS.  Here are the results for 400 FPS.
Range Yds  Visual+Resp  Sound+ Resp
    5 3.6   2.9
    10    5.9   4
    15    8.7   5.4
20   12    6.9
25   16    8.7
    30    20    11
    35    25    13
40 31 15
45 37     18
    50   43 20

At the longer ranges, you have to assume that the sound is weak enough not to disturb the animal or you would not have a chance.

[Highlander]

If an arrow is fired from a crossbow at a deer 30 yards (90 feet) away at 400 fps, then it would take 0.225 seconds to reach the deer (not including drag on the arrow for a round figure). The speed of sound is 1,129 fps which would mean it would take 0.079 seconds to reach the deer.

This gives the deer 0.225 - 0.079 = 0.146 seconds to react to the sound of the shot not including arrow drag.

The rate of drop due to gravity is 32.2 fps.

For a deer to drop 11" (0.92') (figure provided in your chart)  it would take only 0.029 seconds which I have not calculated until your post here.

This gives the deer reaction time as about 0.117 seconds which agrees with figures I have seen for between 0.1 and 0.2 seconds.

Amazing.

I guess they were able to calculate reaction time of deer from time elasped photography due to new technology. I assume the deer reaction time may not be the same for the same deer every time and there is an average for different deer as has been found in human studies. So the deer reaction time may vary for many reasons. The deer reaction time many double in many cases, so the deer drop may range from 5.5" - 11" in the above example.

Edited by HighlandHunter, 02 February 2012 - 03:19 PM.

[Corky]

Sooooo... Where do we aim?

Corky

[XBOWED]

SNICKER   YEAH IT'S ALL FRENCH TO ME TOO!! Glad I haven't been running all those numbers through my head before everyshot..I'd probably never take the shot..Come on guy's just shoot the deer...

[Jack Pine]

XBOWED, on 10 February 2012 - 07:34 PM, said:

SNICKER   YEAH IT'S ALL FRENCH TO ME TOO!! Glad I haven't been running all those numbers through my head before everyshot..I'd probably never take the shot..Come on guy's just shoot the deer...

Right on Ed, a noob would get the impression that deer have wings and need to be shot on the fly!

Jack ><>

[Aimo]

XBOWED, on 10 February 2012 - 07:34 PM, said:

SNICKER   YEAH IT'S ALL FRENCH TO ME TOO!! Glad I haven't been running all those numbers through my head before everyshot..I'd probably never take the shot..Come on guy's just shoot the deer...

LOL..you don't need to remember..just have your calculator handy ..i usualy leave one calculator in my tree stand...LOL

[Aimo]

XBOWED, on 10 February 2012 - 07:34 PM, said:

SNICKER   YEAH IT'S ALL FRENCH TO ME TOO!! Glad I haven't been running all those numbers through my head before everyshot..I'd probably never take the shot..Come on guy's just shoot the deer...

ohhhhh...sorry...forget to add the time to pull the trigger...so add another half secound..LOL

[Aimo]

Corky, on 04 February 2012 - 08:18 PM, said:

Sooooo... Where do we aim?

Corky

It sounds like we have to aim on the ground

[loneranger]

all I know is deer can react,,Real Fast ! I mean,,Really Fast!!

[XBOWED]

Yes they do !! By the way I was just kidding with the snicker snicker..statement Deer are very good at jumping the string...
    Best bet is to aim a little low because they drop down to jump away........Believe it !!!  

[Highlander]

Personally I don't hold a lot of faith in the figures provided above. Everything is based on deer reaction time which I have not been able to find any scientific studies on. The above example was computed using around a 0.117 second deer reaction time and where did they get this figure? It is fun to look at figures like this, but that is all it is.  

An eye opener for me was the fact that a deer can drop due to gravity 11" in about 0.029 seconds seconds. This is under ideal conditions though and may not be realistic. It takes time for deer to relax all the muscles involved and this adds to the total drop time. So these figures are off and can be off significantly when you get down to the nitty gritty. The actual time it takes a deer drop may be twice as long as this figure for example. You have to be careful when you play with statistics and don't take all the factors into consideration.

I just wanted to point all this out, so they don't take my computations to heart & are mislead by my previous statements. LOL

FWIW, I'm sure if you really get down to the factors involved there are many more that have not been discussed which will add more to the total time it takes a deer to jump the string. They are fast though.

Edited by HighlandHunter, 14 February 2012 - 08:38 AM.

[Jack Pine]

Over-concern or over-discussion of this issue is just unnecessary if [1] the deer doesn't know you're there [2] the deer isn't staring at you [3] they aren't on high alert due to over pressure [4] you wait for the right shot or let a bad/marginal shot pass. A little patience goes a long way toward preventing this. Although it is still a possibility, dwelling on it doesn't accomplish anything.  Good hunting practice can overcome it.

Bo, sorry brother but I have to respectfully disagree with #2,

"2. If the deer is looking at you, don't shoot unless he is really close."  

Don't shoot until the situation changes is better.



Jack ><>

Edited by Jack Pine, 14 February 2012 - 09:04 AM.

[SPECIALIZED]

^{I have often wondered if all deer are equal in athletic ability, are some deer faster than others,? do all deer have the same reaction time?,Sort of like all  male humans  in the same top shape,can they all run as fast or jump the same?, surely some deer are faster or slower than others.Lol}

[hanglide4life]

There's some great vids on YouTube if you searching slow motion or high speed camera and deer hunting string jumping or ducking or various  other keywords. Some are quite impressive.

[loneranger]

That is another great topic,{ Should you stop a moving deer?} I had two opportunities this fall. First deer was moving at moderate pace, but very close, so I just shot, made good hit, quick kill. Second deer was 26 yrds, twilight dawn, moving. With my dim eyesight at that time of morn, and the distance, I made quick decision to stop him with a blat. He stopped,,looked my way,I quickly took aim and shot, again good placement, and quick kill. I know every situation is different, every deer different and on it goes, but I always have tension in the stand as to which I am going to do,,Stop them or Not?

[Jack Pine]

loneranger, on 15 February 2012 - 07:35 AM, said:

That is another great topic,{ Should you stop a moving deer?} I had two opportunities this fall. First deer was moving at moderate pace, but very close, so I just shot, made good hit, quick kill. Second deer was 26 yrds, twilight dawn, moving. With my dim eyesight at that time of morn, and the distance, I made quick decision to stop him with a blat. He stopped,,looked my way,I quickly took aim and shot, again good placement, and quick kill. I know every situation is different, every deer different and on it goes, but I always have tension in the stand as to which I am going to do,,Stop them or Not?

I hear ya Loneranger, if you bleat, they stop but they look right at you to see where it came from, which is exactly what you don't want.
Last fall, well into the deer season, I bought a Flextone electronic caller to try to offset that problem, but I never got a chance to try it.  I wanted to set the caller up beyond where the deer would be coming out so that if they came out moving, I could hit the remote and they would turn in the opposite direction to see where the bleat came from.  I'm looking forward to being able to use it at the beginning of next season because it also has grunts, rattling, bleats, and other deer sounds on it, so I hope to score earlier next season.

Jack ><>

[loneranger]

That is an interesting idea,,using a caller to distract deer or call them in. How much one of those set ya back?$$---Wonder if anyone else has used one, here?