Crunching Numbers

[Daveinthebush]

I did some number crunching to show the differences between poundage, energy and trajectory. My bow is a BowTech Pro 40 set at 70 pounds with a 441 grain arrow.  The results may answer some questions for some of you. Numbers were crunched using The Archery Program Ver. 5.5.60 and rounded off.

Poundage  AW(gr's)     KE (fp)     Vel. (fps)  Sighted for 10, drop at 30

70.............441.............78.5.............283.............- 6.5"   
60.............441.............68.6.............264.............- 8
50.............441.............59................245.............-11

70.............551.............80................259.............- 9
60.............551.............71................243.............-11
50.............551.............61................225.............-14

70.............661.............83................241.............-11.5
60.............661.............73................227.............-14
50.............661.............63................211.............-17

What is interesting to note is that by increasing my arrow weight by 200 grains, I only gain 4.5 foot pounds of energy.  And, loose 5" of trajectory.

[Naphtali]

Daveinthebush:

Although you created this table to illustrate of draw weight, kinetic energy, and trajectory, can you work up numbers to incorporate pertaining to penetration? I leave what to penetrate to your judgment.

Since there will be no hydrostatic effect exacerbated by kinetic energy, would it be accurate to think of an arrow as a long-range knife?

You show that kinetic energy does not change significantly when arrow weight increases.

What happens to penetration? I suspect that momentum is more closely correlated to penetration than is kinetic energy. And I suspect that the biggest obstacle for an arrow to overcome is to penetrate lethally because breaking pelvises, hips, and shoulders is probably asking too much of an arrow.

[Daveinthebush]

I just took the information from my bow and punched the numbers in my archery program.

Penetration has too many variables: sharpness, type of blade, angle of entry, bone, hide thickness......

[ahunter55]

I have been bowhunting a long time & when I was a tourny shooter (pretty good in my day) I wanted all the speed I could get in my target bow.  I always went  with a heavy shaft/arrow in bowhunting.
I shoot a 2216 Easton, 29" long & a 125 grain 3 blade Rocky Mountain head.  I haven't weighed the arrows (I don't do those things after 49 years in the sport) but do know (2004)I got complete penetration on a 900# Buffalo at 41 yards, a 145# hog at 20 yards, a Big Fallow Buck at 25 yards-turned when I shot-entered mid rib cage & exited through the far hip & onto the ground & a 175# Iowa Doe at 25 yards from my 60# Darton Compound.

[Naphtali]

Daveinthebush:

Somewhere in my folded up pieces of paper is an article published several years ago in, I think, BOWHUNTER magazine. It was a penetration test of arrow points -- I think titanium crusher points had recently come onto the market?? -- that tested in soft medium like wet phone books or ballistic gelatin, and metal 55-gallon drums filled with water.

All I remember is that "sharp to the edge" two-bladed points were superior to any other shape. And heavier arrows out penetrated lighter ones.

I remember almost nothing of test details, though.

I remember thinking that it would/should be difficult to make the knife point sharp enough to cut yet sturdy enough not to bend or break.

[Daveinthebush]

[/url]http://www.american-hunter.com/broadheads/broadhead_test.htm[url]

Well the url is above and yo might have to copy and paste it. I have a Mac in my offoce and it is not worth the powder to blow it up.

Try this site!

[Naphtali]

A Mac?? What is this -- a Macintosh computer??

Does this somehow tie into this evolving thread?? If yes, please lead me.

[Daveinthebush]

When at work I have to use a Macintosh which won't do Italic, URL, smilies or most anything.  

So henceforth, I can't answer in the same manner as if at home at my PC.

[cam69conv]

<---- has extra powder...loans Dave a few grains...Call it an accident and collect th insurance