A good explanation of momentum

[Friend]

As previously submitted:

“In archery terms, this simple equation states that the force slowing the arrow down (mainly air resistance) is proportional to the mass of the arrow and how quickly it decelerates.” – I agree!!!

“Because the two arrows have the same frontal profile, the air resistance will be the same “ .  – I disagree!!!!!

As the arrow’s velocity increases, the air resistance increases exponentially.  The resistance of air as the medium is reliant on the square of the arrow’s velocity (assuming like arrows). In other words, if the arrow’s velocity doubles, the resistance increases by a factor of four.

Notes: Increasing momentum may definitely be an attribute by increasing wt., since momentum is a unidirectional force vector: however bottom line for me is over-all terminal performance.

Just some other related significant factors:

Shaft flex has proven to be a major factor in impeding penetration. The shorter the forward lever arm, the stiffer that section is and the less it flexes at release, paradox and impact.

Penetration enhanced arrow designs, weighing well over 100 grains less than tuned normal FOC arrows with same point configuration may have greater penetration – formally documented as well as discerned from own observations. Optimized arrow designs could permit up to 35 -40% reduction in arrow mass to achieve similar penetration.

It’s reasonably certain that there is progressing increasing rate of penetration as FOC continues to climb above 19%. The rate of penetration gain is progressively increasing as the FOC climbs. Still under substantiation and validation- When comparing virtually identical tuned arrows where one is 19% and the other is 32% Ultra-FOC, the penetration gain preliminary results indicate a 7.4% penetration increase for every 1% FOC increase.

Test for yourself, then decide for the results are easily discernable and you won’t have to take for granted what has been merely documented. If I couldn’t easily discern the difference, then I wouldn't bother with them nor recommend anyone to validate this for themselves. Instilling your own confidence is paramount.

[Keefer]

[USN_Sam1385]

Originally posted by ChrisM:
"which is how you get a 330 fps arrow that only penetrates about 6 inches and a 170 fps arrow that sticks in the tree past the animal.      

Classic

[**DONOTDELETE**]

i know you guys are all pushing the heavy shafts with lots of FOC.... but I'll give you a test to try that might be interesting....

The thing that isn't mentioned is that the deceleration of a heavy shaft with too much FOC is a LOT more than a lighter shaft with 12-15% FOC, especially using a true helical fletching. and the heavy arrow trajectory is poor by comparison.

before you do all these calculations again. set up your chronograph about a yard in front of your target.... then shoot those heavy shafts at 20-25 yards through it, and compare it to a bow shooting 330 FPS..... now take your velocity and do your calc's .....i believe you'll get seriously different numbers...

or simply shoot the two bows side by side into the same 3D target..... now do the same thing with a 3/4" piece of plywood..... i think you'll have to rethink some of this stuff once you've actually tested this stuff yourself. or better yet just quit thinking about it completely....

BTW....an arrow weighing 427 grains flying 297 FPS will blow clear through a Roosevelt elk breaking ribs at 50 yards.... who ever told you 330 fps is only getting 6" of penetration is full of horse feathers.

[snag]

I don't think heavy arrows just to be heavy is the goal. You can go too light and you can obviously go too heavy. Everything in moderation I say. I was merely looking at the reason for shooting an arrow that is 10+gpp with a trad bow vs the light weight arrows that the compound guys have been lead to believe is the only way to go.