Mechanical vs Fixed

I have an older Hoyt. I believe its a Mystic Rebel. I think the last time I got it clocked it was only 275fps.

 

275fps out of a hunting rig is nothing to sneeze at.

 

Speed means nothing in terms of a hunting rig really.. Kinetic Energy and Momentum are more important. What is the finished weight of your hunting arrow?

 

Normally I agree with this but with rearward deploying mechanicals, I think having more speed is advantages.

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Without speed you can't have KE, without knowing your fps you can't hand calculate your KE. So how does speed not matter for hunting?

 

I believe you have taken that out of context. The heavier the arrow, the higher the ke and momentum will be from one bow regardless of the speed. Decrease arrow weight to get more speed and ke and moment go down.

From that context, the speed really isn't relevant

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That is completely incorrect unfortunately. Wish it was then I could shoot a 500 grain arrow and get away with it. You cand just increase grain weight, there is a fine line between peak KE and too heavy. For every archers set up this fine line will be different, draw length speed and arrow weight all effect KE. Using the KE formula FPS x FPS x WEIGHT / 450,240= FT LBS KE here's some math based on a theoretical set up with a 400 gr arrow. 280 x 280 x 400 / 450,240 = 69.65 FT LBS KE. Now lets say that same set but faster 300 x 300 x 400 / 450,240 = 79.95 FT LBS KE. Now for those that say just go heavier we need to be realistic in understanding that with the same bow and draw length a bow will shoot slower. So now a theoretical set up with a 500 gr arrow. 200 x 200 x 500 / 450,240 = 44.42 FT LBS KE. Now lets say by some miracle you can shoot a 500 gr arrow faster than that. 280 x 280 x 500 / 450,240 = 87.06 FT LBS KE.
So I say again how is it that speed doesn't really matter to a hunting set up?

 

Btw I am a gun tech by trade so I understand ballistic tables and how to produce KE. These ballistic rules still apply to archery just on a slower scale that's all.

 

Guns and bows are different. With bows you have efficiency to deal with and a heavy arrow is more efficient than a lighter one. This means you use more of the potential energy from the bow with a heavy arrow.


This has been argued over and over again and I assure you, the physics and facts state a heavy arrow out of a bow will yield more ke and momentum than the light one.


This is fact, tested and proven

Oh, and I know how the math works. Been playing with arrow ballistics for years.:D
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See what I'm saying kid............Democrats and Republicans

 

The numbers work like this for my setup when I'm at 56#

366 grain arrow @ 261 fps= 55.3 ft/lb ke or .4241 lb/ft sec momentum
415 grain arrow @247 fps= 56.2 ft/lb ke or .4551 lb/ft sec momentum

 

I've lost a lot of confidence in both but republican align more with my views.

 

I tested a 280 grain hyperspeed and its ke was 54.8 and momentum was .3692 at 297 fps.

 

Well we can agree to disagree then lol
My set shoots about 290 fps with a 385 gr arrow producing 71.91 FT LBS KE so ill keep my set up. I'm pulling 72 LBS peak weight on my Captain

 

Do the testing,you will see what the large majority of the archery world already knows. You could even buy an arrow ballistics program and run a few numbers.

 

I never said you needed to shoot heavier or lighter arrows. Your setup is more than adequate for any animal in North America.

Just stated you(anyone) will have more ke and momentum with a heavy arrow. Something to think about if you plan on shooting cape buffalo.

 

Could you run numbers for my set up? I'd be curious to see what my numbers are .

 

Here's an online calculator if you know your arrow weight and velocity.


http://archerycalculator.com/archery-kinetic-energy-and-momentum-calculator/


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Im at 61# 26.5DL

500 grain arrow @ 206 fps= 47.067 ft/lb ke or .4569 lb/ft sec momentum

Im not sure how good or bad of a number that is for momentum but thats what it came out to.

 

I know this wont be taken well by some but try shooting a lighter arrow, something closer to ibo weight and I bet your KE will increase. In fact I'd be willing to put money on it. A 500 gr arrow is REALLY REALLY heavy for a 61# draw weight.