Shooting high from a tree stand in spite of the Geometry

[scottflesher]

I've been wondering about the newer range finders and their use of ARC technology (compensates for upward and downward trajectory). I have an internal conflict that seem to go against what i've read about these devices. I'm somewhat of a math nerd, so bear with me while I set up the conflict i'm having.

Most folks know that if you shoot from a treestand, you'll almost always shoot high. Some say it's because the deer "string jumps" the arrow, or that the hunter doesn't bend at the waist thus changing his anchor point, but others say it's because of the geometry of the shot, which is where the ARC technology comes in. Most of these rangefinders say that you need to aim as if the target is shorter than the line of sight. WHY IS THIS?

Why I have a conflict with this statement is because of the pythagorean theorem. (Bear with me) This geometry theorem states that the hypotenuse (longest side of a right angled triangle) can be determined by squaring the two other sides of a triangle, adding them together to arrive at a figure and then taking the square root of that figure. C squared = A squared + B squared. I'll illistrate for ease of understandablity. Let's assume the terrain is perfectly flat.
Imagine your 30 feet in the air, we'll call that side B of the triangle. Imagine a deer is standing 30 yards from the base of the tree you are in, well call that side A of the triangle. Side B, 30 feet is 10 yards. 10 squared is 100. Side A is 30 yards, 30 squared is 900. So assuming the pythagorean theorem, A squared + B squared = C squared. So to find out the distance from your tree stand to the deer (position C), you would add 900 + 100 = C squared. 1000= C squared, equals 31.623.

I've added a link for a visual aid on a right angle. http://www.basic-mathematics.com/pythag ... lator.html

This tells us that if a deer is 30 yards from the base of your tree, you are 30 feet (10 yards) up the tree, the line from your stand, 30 feet up, to the deer is 31.6 yards. If the tendancy is to shoot high, wouldn't that indicate that the distance must be shorter? I know that 1.6 yards isn't a huge deal for most archers, particuarly at 30 yards, however you get the point I'm trying to make. I'm assuming that shooting high must have something to do with gravity being less on a downward shot compared to a perfectly horizontal shot.

Does anyone have an explaination to the above. I'd appreciate any comments, but I'm looking for something somewhat scientific.

[DanburyBowhunter]

the key may be arrow trajectory and gravity. You are essentially shooting down so gravity is no longer a Normal force (90 degrees to the arrow) No arrows flies flat.. they follow a ballistic arc. Its late so I'll leave the math to you!

[pgchambers]

http://www.loadammo.com/Topics/April04.htm

[Mastertangler]

Scottflesher
Being a math nerd myself, I struggled with this as well....but then something clicked.

The theorum would have the distance to your arrow hitting the ground, but the reality is that your arrow is actually hitting the body of the deer well short of that point. If the deers chest is 4' off the ground, you're taking roughly 2yds of distance off that "C squared" line. So instead of total distance being 31.6yds, it's probably more like 29yds.

Thus if you are dead zero at 30yds, your arrow is actually still a bit high and dropping at the 29yd mark, and thus you hit a bit high.

If you are taking a quality shot, the variance shouldn't be anything to worry about at such distances.

[fasteddie]

Your math theory doesn't matter at all . The distance you need to be concerned with is the distance from the base of the tree to the deer (horizontal distance) . So in your example , the distance to be considered is 30 yards . It's that simple !

[scottflesher]

eddie,
your comment is correct but i'm wondering how. To use a more extreme example based off your post that the math doesn't matter:

let's say you were 90 feet up a tree (extreme I know) and the deer was 5 yards from your tree. You'd shoot at him as if he was 5 yards away? Even though your 30 yards up a tree?

[jonny5buck]

eddie,
your comment is correct but i'm wondering how. To use a more extreme example based off your post that the math doesn't matter:

let's say you were 90 feet up a tree (extreme I know) and the deer was 5 yards from your tree. You'd shoot at him as if he was 5 yards away? Even though your 30 yards up a tree?

I got this one Eddie--

If your 90ft up a tree and a deer is 5yds from the base of the tree...you simply jump out of your stand and land on the deer...


I think he 's just stating the yardage from the tree is what it is...in extreme angles /height /aim low---or simply quit going that high in a tree.

This reminds me of Geometery in high school....i sat down...looked around and raised my hand...''i dont think i belong here''...i told the teacher....my last math class was like 3 apples plus 2 more apples is 5 apples--------

[scottflesher]

Johnny, I thought about the savage approach (jumping from the tree with my knife) when I was typing that comment.

I know that Eddie is correct, and i've always heard that the true distance is from the base of the tree rather than line of sight, and i'd never climb 90 feet up a tree, but my original post was simply asking how/why is this correct when you factor in the geomotry side of the shot. pgchambers gave us an excellent post that helps me a little.

The only area that confused me on pgchambers article was regarding the uphill trajectory. Thanks to all that posted.

[kellory]

Eddie is correct, because gravity is a constant, the same arrow will drop the same distance , no matter how high, or how steep,,IN THEORY However, the longer distance from you to your target does play a role. Your arrow will be slowing by wind resistance, slightly. and excellerating because of shooting down, there is some trade off. But for practical reasons, the only range you need to factor in is the distance from the base of the tree to the target. The other factors play a very small role. I use a string on a spool with loops tied at 10, 20, 30 and 40 yards. I painted gutter spikes hunter orange, and these are my range markers. Tie the string to a spike at the base of the tree, and spool out string to the knots and mark distances. Very easy way to mark your range. ..............................................................................................................................................................................................................................................on a side note, my cousin hunts very primative. climbs a tree with a long bow and cedar shafts. no stand. just sits on a branch. He had a large buck stop under him, and his razorhead touched his bow string as he was loading. TWANG!!!! The buck jumped but did not leave, and he could not find his spare bow string, so he stuck his bow in the branches, and dropped on the buck with the arrow and delivered it personally! Not something I will ever try, but he got his buck!

[Cut N Run]

That's one hard core cousin you've got there. I'd never consider jumping out of a tree with an arrow for what might happen if things went bad.

I'm probably the last guy to listen to about math (because I'm a career C math student) but I can tell you that if you have the distances from your stand down, you shouldn't have trouble hitting your mark. I always practice from a stand the closer it gets to deer season. I seldom hunt from the ground and really need to know where that arrow will hit when it counts.

Another thing that works for me it to visualize the deer as if it were split in half right down the middle from nose to tail and you are trying to put your shot between the heart and lungs. That way, if you miss a little high or low, you're still good. If you don't aim for a small enough point, you're more likely to make a poor shot. I usually hold for right above the bend of the foreleg.

Jim