Arrow trajectory question
 

According to the arrow trajectory calculator link below, my arrow drops 51 inches at 40 yards. How is this so when at 40 yards, my arrow actually only drops 14 inches below where I aim? I understand there's a slight upward travel for the first 15 yards of so but that plus 14 doesn't add up to 51 lost verticle inches!

My set-up is a Vectrix at 26" draw length, 311 grain arrow, with 30 grains on the string, all of which trips the chrono at 250 fps. My arrows are CX maxima 250 3-d selects cut at 26" tipped with 85 grains. Is there something I'm not understanding or is this program just waaay off?

http://home.att.net/~sajackson/ballistics.html

RE: Arrow trajectory question
 

That is total drop if the arrow is shot level to the ground.


Your arrow isn't shot level to the ground so you have that to compensate for,plus,you have a pin that is above your arrow.This gives you sight paralax that needs to be compnesated for as well.

RE: Arrow trajectory question
 

That's why arrow drop numbers are completely bogus. They don't tell you anything you need to know in the first place, and a lot of folks come away completely confused after looking at them. Shooting perfectly level with the ground, off a cliff? C'mon! Who does that often enough they'd need to have it calculated? :D Just ignore the arrow drop stuff.

Trajectory is what we need to look at. Jackson still has a link to Andrew Middleton's graphing trajectory calculator on his site, but the link is busted. I haven't been able to find it anywhere else on the net, and I've desperately hunted for it. Excellent tool. It works real well for making sight tapes for single pin sights.

I'm eventually going to have to break down and buy one of the super spiffy archery programs so I can have everything I need right here, and not have to worry about sites shutting down. [&:]

RE: Arrow trajectory question
 

This is what my trajectory looks like at 40 yards.

RE: Arrow trajectory question
 

I hate those trajectory charts. By using equal increments for inches on one axis and yards on the other, it makes you look like you're shooting 50 lb logs. However, they are useful for visualizing arrow flight (with a little imagination).

RE: Arrow trajectory question
 

Yeah, SA, it does look like a camel back. But it sure smacks down that stuff about 'flat trajectory,' doesn't it.:D

I like having a trajectory chart like this for each sight pin I have set.

RE: Arrow trajectory question
 

Yes it does. I just love it when I hear someone say they use the same pin from 10-30 yards, "holding right where I want it to hit". I can only imagine what they are doing wrong to make that happen.

RE: Arrow trajectory question
 

They usually aren't that good of a shot.

RE: Arrow trajectory question
 

OOOOoo!! He said it out loud, right in front of God and everybody! [:-]

[8D][8D]

RE: Arrow trajectory question
 

yep:D