Compound bow - set up question
 

I'm trying to figure something out in my head.

When we set our nocking point up......we do so with a square or a laser level (or some people simply do it by sight.....which is just fine).

So.....Scenario is a 20yd shot.

Now......we talked the other day about the arrow going above the line, when it leaves the bow.....and Matt/PA mentioned it did this at about 8yds (I think)......then re-intersecting the line at the 20yd mark.

WHAT makes the arrow go above the line? I know the archer's paradox on traditional gear is to clear the riser. Why does an arrow shot from a compound react the way it does (going above the line)?

RE: Compound bow - set up question
 

It’s not that the arrows pointed up as it sits on the bow (nock & rest) your bow is pointed up. At least that is the way I envision it. If you drew an ATA line, it would not be perpendicular to the ground. Now all this is minute and might not even be detected just looking at it.

RE: Compound bow - set up question
 

Umm, gravity? Seriously, even with the speed of today's compounds we need to compensate for arrow drop so you have to aim slightly upward so the arrow will drop into where you are aiming.

Bowtech may be taking the ARCH out of archery, but it's not gone.

RE: Compound bow - set up question
 

Notice the arrow path. It will cross the line of sight initially close, then will once again cross further out due to trajectory. There really isn't a trad/compound line in the dirt drawn on this concept.

I probably got the question wrong though.:D

RE: Compound bow - set up question
 

That's what I'm getting at Bry. And Rybo may have eluded to "why". Are we shooting "up" towards the target.......even though our arrow IS "level" (in relation to our bow)? If we drew lines from our peep.....through our 20yd pin......to the target.....that would be a straight line.

The line from our nocking point.......to the "spot" at 20yds would be another straight line.

Would the line still be straight if we added a third point (on the nocking point line) to include the arrow tip?

RE: Compound bow - set up question
 

Jeff, I believe the arrow tip would be above the nock-target line.

RE: Compound bow - set up question
 

No,

The arrow tip is above the nock-to-spot line as rybo said.

Gravity is the reason the arrow must travel up and break the sight line before falling back down into the"spot". If it did not first travel up (in an arc path) there is no way it would ever be able to hit the spot we aim at...

...I think

RE: Compound bow - set up question
 

There it is.

The arrow is shot up to compensate for gravity. If you shot with your arrow perfectly level to ground, your arrow immediately begins to drop thusly, we shoot up so our arrow archs and intersects our intended target. Think about it, the farther we need to shoot, the higher we RAISE our bow.

Same goes for bullets out of a gun. People think the bullet rises out of the barrel but this is not the case. When a bullet leaves the barrel, gravity pulls on it and it immediately begins to drop. The reason people think it rises because the barrel is actually pointed up in contrast to the scope/line of sight to again, compensate for the drop thusly a bullet also has an arch.

RE: Compound bow - set up question
 

No, it couldn't be. Take a look at the very rudimentary illustration below.



All points are going to the same point on the target, but since the tip of the arrow and the nock are not on the same plane because the arrow is notcompletely perpendicular to the ground they cannot be on the same line.

RE: Compound bow - set up question
 

If you drew a perpendicular line from the center line of an imaginary circle directly to a theoretical sharp corner would the difference be greater than or equal to the foc of a binary equation?


This is one of those questions I just can seem to find a logical answer to.Any help would be much appreciated.
If it make a difference to your answer. You are on the down wind side of a white oak tree seventeen and one half feet from the ground in a summit viper using non mechanical broad headsthis is on aThursday evening after a Monday new moon hunting public land.

RE: Compound bow - set up question
 

No, the illustration that Bry presents is accurate, rudimentary but accurate. What it doesn't show is nock travel would create a line compensating for the arch the arrow must travel to drop into the target. If you followed the arrow path in flight with a line, nock travel would would rise because the bow/arrow is angled up, not nock to rest but because human influence.

RE: Compound bow - set up question
 

Yesalong with air resistance.

RE: Compound bow - set up question
 

I'll address these questions individually as soon as I finish the equation Binary/FOC with a square root of KE minus FPS squared. I almost have it worked out.

RE: Compound bow - set up question
 

True dat. :)

RE: Compound bow - set up question
 

Of course it would. You can always draw a straight line between 2 points.

My question is.....we're compensating for the line of the arrow (it would seem, to me) by the line through the peep, 20yd pin and target (at 20yds) pointing in a downward line.

So.....would THAT (alone) compensate for the arrow NOT having to be in a straight line to the target? I'm simply asking.

RE: Compound bow - set up question
 

Hey look its my Nova! I feel so special.

RE: Compound bow - set up question
 

If you held your arrow perfectly level and released it, it would never rise, only drop. (assuming your nock point is level and your bow has perfectly horizontal nock travel).

When you are aiming at targets at a distance, of course you have to aim higher to compensate for gravity. In that case, the arrow does initially rise. But thats only because you are pointing it slightly skyward.

RE: Compound bow - set up question
 

Air resistance has no effect on the FLIGHT PATH of the arrow...only the speed. Imagine a world with air, but no gravity. Your arrow would slow down, but never fall.

RE: Compound bow - set up question
 

Then why do bowhunters use flu-flus when pheasant hunting? How can you say that air resistance has no effect of the flight path of an arrow? If that was true, you should be able to use Flu Flu fletch and Blazers at 80 yards and they would have the same flight path.

RE: Compound bow - set up question
 

Using Matt/PA's example......of the arrow line and the sight line meeting at 8yds (+/-....it really makes no difference where these lines meet....as long as we agree they DO "meet" at a relatively short distance.....prior to 20yds)........It would seem, to me, that the lines intersect at 8yds (naturally;)).

My question, again.....is...is the line thorugh the nocking point....the arrow tip....and the target at 20yds a straight, levelline.....and "compensation" made by the arrow drop beyond the 8yd intersection point?

Again....it would seem, to me, that the line from the eye.....through the peep.......through the 20 yd pin.....to the spot at 20yds.....HAS to be "straight".

RE: Compound bow - set up question
 

OK let's imagine that scenerio. Why would it slow down if there was no gravity? Maybe because of air resistance? If it starts to slow down, would it continue to slow down to the point of stopping?

RE: Compound bow - set up question
 

I'm understanding more what your asking. If you draw a straight line from your nocking point to the 20 yard target, your broadhead/arrow point will not be in that straight line. The tip of the arrow will be above it. Matt's example is the the arrow intersecting the line of sight.

Yes, that is fact. That is line of sight.

RE: Compound bow - set up question
 

To SLOW the arrow down.

Because it doesn't. Air does not cause the arrow to fall to the ground. Gravity does.

That would be true in a world with air but no gravity. Just as I said in my earlier post. A slower arrow "feels" the effect of gravity in a shorter distance, but it is still ONLY gravity that causes the arrow to drop.

RE: Compound bow - set up question
 

atlas I mean Badger girl is correct.

Air resistance has effect on arrow speed, not path. Air resistance slowing the arrow down allows gravity to pull it faster to earth. An object in motion equation comes into play.

RE: Compound bow - set up question
 

Yes, it would continue to slow down to the point of stopping. But it would never fall. The Flight Path of the arrow would be a straight line. With no gravity, there is no force to change the flight of the arrow from its original "straight" trajectory. Newton's Laws.

RE: Compound bow - set up question
 

I also agree. I understand where Badger is coming from and her point in the strictess sense. I think in practice both are at work on an arrow to make up the arrows trajectory though.

Good work Badger!;)

RE: Compound bow - set up question
 

They need to teach physics in bowhunter ed

RE: Compound bow - set up question
 

OK. So.....taking this a bit further......the the arrow is NOT "level" if you were standing on perfectly level ground......to the ground????

In other words.....if we drew a line from your nocking point through your arrow tip......would this line be perpendicular to the ground (again....assuming we were standing on perfectly level ground)?

RE: Compound bow - set up question
 

Thinking about that last question.......I suppose it would be level on "some" shots (according to what distance you were holding on).....and I also assume that distance would vary with each setup.

Make sense?

RE: Compound bow - set up question
 

Badger Girl, you seem to be schooled in physics. Care to comment on how many archer use KE in the strictestlaws of Physics? :D------I'm just kidding, please don't...............:D

RE: Compound bow - set up question
 

I think it would be relevant to the raising or falling of the barometric pressure.And the direct perpendicularly arc free straight line to the equator.:eek:

RE: Compound bow - set up question
 

Okay, Badger girl is technically correct if we are talking about a word with no gravity and only air resistance.

But since I do most of my bowhunting on EARTH, where we have both gravity AND air resistance, then I'm sticking with my assertion that both air resistance AND gravity affect the flight path of the arrow.

RE: Compound bow - set up question
 

I'm thinking about this more and more.

Question...

"IF" we use a square with levelers (with bubbles)for plumb and level......HOW can the arrow not be parralel to level ground (on ahorizontal plane) AND the string not be "Plumb" to said ground (level ground)?

Does it have something to do with the arrow at full draw NOT being "level"? (v. the bow not being drawn)

RE: Compound bow - set up question
 

During the equinox you would be exactly right.;)

RE: Compound bow - set up question
 

Of course one must take meridian arc into this equation.:eek:

RE: Compound bow - set up question
 

how could you still hunt earth, its got horrible LOCATION compared to mars.




;):D

RE: Compound bow - set up question
 

I think you're thinking about this slightly backwards. The image posted here of the EYEtoPEEPtoSIGHTtoTARGET line is very deceiving.

The line of sight is quite simply, from your EYE to the TARGET. The peep and pin is aligned on that line to ensure your arrow intersects the line at the target. Thats why we have to sight in our bows for different yardages, because the arrow flys in a parabolic curve.

Consider how you anchor your bow. What you do is fix the relationship between your eye, and the nock/string intersection. (not exactly if you use a kisser button, but to close to notice a difference). You then rotate your bow up or down about that fixated point, that changes the angle of the arrow in relation to the line of sight.

I hope this helps...

RE: Compound bow - set up question
 

Jeff, if your at full draw and aiming at a 20 yard target your arrow will not be level to earth, it will be point high/nock low. Your arrow does not leave the bow level when shooting at targets down range, remember the arch,

So if you draw a straight line from your nocking point, down your arrow that straight line would go straight over the target not intersect with it. (when at full draw).

RE: Compound bow - set up question
 

Then how do you explain setting one up with a level and a square? If it's perpendicular/plumb to the string......it's Perpendicular/plumb to the ground. Ifyou're using a bubble level to set your arrow......what's it "level" to?

Also......This has nothing to do with the original question......but wouldn't the location of the target at 20 yds determine whther or not your arrow was "level" with the 20yd spot? Or....are you saying that ther eis nowhere you could put your target and have your arrow be "level"?

RE: Compound bow - set up question
 

The arrows elevation on the bow at rest is set in readings that are 90 degrees to the string. The string however would not be perpendicular to the ground if you were shooting at a target 20 yards out shoulder high. The arrow would also not be parellel to the ground.