Arrow Ballistics Chat

[RickBarbee]

Arrow Ballistics Chart

Created using the Kinetic Energy and Momentum Calculator from
ARCHERY REPORT for the data, and Microsoft Excel for the Chart.



(1)
All of the data was created in the calculator, and based on a high efficiency 60# Recurve Bow.

(2)
Bow efficiency was calculated with 600gr / 10gpp arrow weight being the center point of the chart.
Center point indicated by the Vertical Solid Black Line at center of the chart.

(3)
Minimum arrow weight 400gr / 6.6gpp for the low weight, and 800gr / 13.34 for the high.

(4)
Calculator says - 140fps for the lowest arrow speed, and 220fps for the highest arrow speed.

(5)
The Arrow Kinetic Energy does not start to drop off until between the 9.5 & 10 gpp area,
and then only slightly to the end.

(6)
The Arrow Momentum has some slight change, but it is so fractional, that it basically remains flat lined.
This is due to the drastic reduction in arrow speed as the arrow weight is increased.

(7)
The efficiency of the bow, whether increasing/decreasing, will change the numbers from high/low,
but the incremental changes in the chart stay the same, and the sweet spot stays in the same arrow gpp window.


The Vertical Black Dotted Line is the point at 9.5 gpp. This is the area I have always found to produce the best
penetration, and overall (combined) performance on my hunting rigs, and the chart shows me exactly why that is.

My conclusion of this is - There are only two ways to increase output/delivered energy of your rig.
(1)
By increasing bow draw weight, and/or bow efficiency.
(2)
By increasing arrow weight, but this option forces you to increase the bow draw weight/bow efficiency
proportionally the same, or it's all a wash at best, or you lose energy at worse.

I'm just throwing this out there as food for thought.
You can draw your own conclusions.

Rick

[RickBarbee]

I have a couple of guys using my data to make a better looking chart.
Can't wait to see the results.

Rick

[RickBarbee]

That was my first time to use Excel, and to create a spread sheet.

Getting all the data together, and creating the sheet wasn't a big deal, but I just could not figure out how to make it look all fancy.

Rick

[Draco]

Don't we do this for the simplicity of it? That's too complicated Rick.

[RickBarbee]

Dan Worden image from my data.
Looks much better than mine.



Rick

[RickBarbee]

Here's Matt's Chart.

Another real nice one.

Rick

[TP3]

How am I supposed to memorize all of that before season opens?

[RickBarbee]

How am I supposed to memorize all of that before season opens?

The only thing you have to memorize is - according the the very accurate data of the ballistics calculator, the very best arrow weight is between 9 & 10 grains per pound of bow draw weight.

Rick

[DRT]

Whew. I was wondering how I missed all that in physics class. Honestly I wish I were tough enough to shoot more weight but 50lbs is about all I'm going to be able to master I think. I may never shoot a Cape Buff with it but a few whitetail and pigs will do fine for me.

[flywise]

I appreciate the effort that has gone into all charts and data unfortunately my brain only understands
nock
Draw
Release

[Dry Bones]

^ LOL Perfect.
Some are more numerical minded and read things like charts and graphs and store them easily. Others read it in linear evaluations.
I like the graph, and in the case of my new bow I know I would get even better performance if I was to back off the arrow weight a little, but then I would need to get a new set of arrows in weaker spine so that my reduction in tip weight would still shoot as desired.
Rick, I really like data like this, but answer a question for me. I have an arrow that weighs 465 grains and one that weighs 525 grains. They both are shot from a 43# bow, the same 20 yard mark using the same gap. The lighter arrow hits approximately an inch above the heavier one. Which one is carrying more proposed kinetic energy? (I did this yesterday several times to get a solid feel for the different arrows)
Obvious statement- 525 grains from 43# bow = 12.2 GPP
465 grain arrow from 43# bow = 10.8 GPP

[DRT]

Which one penetrates the target better?

[Dry Bones]

DRT, that's the odd part. I have no real feel if either give me consistently more. Obviously heavily shot targets have some hollow or weaker locations, and I have not been able to get a solid measure on which one gets in more. I feel like it may be the heavier arrow, but ...?
From my 51# longbow the heavier arrow does get more penetration, but it's 51# which is what that arrow was tuned for. Not certain about the recurve yet.

[DRT]

I know I'm shooting into a new Rinehart target and I'm getting about 3 inches of penetration at 20 yards.

Sent from my SM-J710MN using Tapatalk

[SwampRabbit]

A better way to represent the data would have been to use normalized percentages so you get a better idea for the gains/losses. The first graph I saw I chuckled because it minimalized the momentum because the scale of the Y-axis was so thrown off. The second graph is better, but it is still meaningless unless you understand the impact of what a 25% increase in momentum means... at that momentum. BTW, what was your X-axis in the new chart... it is hard to tell what units 0-160 would reperesent?

Your conclusion is only partially correct. The best way to get more energy out is to increase the draw weight (because you are putting more energy in.) However, you can find the spot where you maximize the energy out (KE of the arrow.) Clearly to maximize energy out, you would use a (eyeballing) 8gpp arrow as that is where the maximum KE occurs. But... that is if you care about energy... and not momentum.