Would You Sacrifice Speed for a Slight Bump in Kinetic Energy?

[BTLowry]

Yes, in that poundage and DW range typically til you get over 600 gr shafts.

Is there some formula that you can plug known values into and come up with a rough arrow speed calculation?

Seems like you might have something figured out if you are questioning numbers generated by chrono

Would love to have a general idea of how fast an arrow is moving without having to buy a chrono

 

[Mighty Mouse]

Is there some formula that you can plug known values into and come up with a rough arrow speed calculation?

Seems like you might have something figured out if you are questioning numbers generated by chrono

Would love to have a general idea of how fast an arrow is moving without having to buy a chrono

If you have one arrow weight and speed data point, you can estimate speed at any other weight with a high degree of accuracy using the following method:

1. Calculate kinetic energy at known weight and speed: KE in ft-lbs = Arrow Weight in gr × (Arrow Speed in fps)² ÷ 450,380
2. Use KE calculated in step 1 to calculate speed at any other weight:
   Arrow Speed in fps = SQRT(450,380 × KE in ft-lbs ÷ Arrow Weight in gr)

If you don't have an arrow weight and speed data point to work from, the calculator on ABF's website will estimate speed based on bow specs. It tends to overestimate a bit IME, but it's the best free calculator I've found.

 

[KyleR1985]

Generally the heavier your arrows get, the more efficient they’ll be at absorbing energy from the bow.

If you’re taller than 5’7, and your bow is newer than about 2005, your bow and pretty much any arrow you choose is going to be sufficient to kill any big game reliably.

The difference in those two arrows from an “energy transfer” standpoint isn’t material.

The difference in speed could be, depending on your shooter and what he’s shooting and at what distances.

I take the extra speed if the bow is tuned, the arrows are square, and he’s shooting very sharp heads. I take the extra weight is his arrows are hitting animals sideways. But really, splitting hairs.


As far as stainless half outs go - I’ve killed the last 20-25 animals (whitetail hog elk mule deer - mostly whitetail) with rip tko 300 with 100gr SS half out and 125gr cut in contact head. I’ve made two holes every time. I’ve had zero insert failures. Probably a half dozen wound/misses in there where I encountered a leg bone and or rocks. Same no insert failures.

I have broken quite a few arrows though. Comes with the territory when shooting 530gr arrows 290fps. No bent inserts or broken arrows around the inserts. Most commonly they’re sheared by animals running I assume, but some I’ve heard/watched break.

 

[Billy Goat]

Is there some formula that you can plug known values into and come up with a rough arrow speed calculation?

Seems like you might have something figured out if you are questioning numbers generated by chrono

Would love to have a general idea of how fast an arrow is moving without having to buy a chrono

Yes and no.

Basically, there's nothing magic, weight costs speed and it's pretty linear. Increase force and speed increases.

1 fps per 3 grains, 2 fps per #.

Get on the outskirts and of stuff and it can change, but 27-30" DL and 55-75# those will put you pretty close.


Ibo numbers don't mean much, you need to have a good chrono number, and you can estimate from there. Archers Advantage gers my FPS within 1 or 2 fps if my inputs are correct with a good click sight.

 

[BTLowry]

Thank you MM and BG

 

[5MilesBack]

A very good video that most will ignore. People don't want the truth, they want the shortcut magic.

Man, that guy sweats as much as I do, and I live in a very low humidity place.

 

[KyleR1985]

A very good video that most will ignore. People don't want the truth, they want the shortcut magic.

Probably right most of the time.

But it’s 2024. The ability to tune a compound bow and the arrows you shoot is available to anyone with basic mechanic aptitude, and a couple thousand dollars. You can remove 99% of the noise with the equipment in very short order. It isn’t rocket science. It’s very simple. There was a lot of voodoo in the 30 years it took him to get to where he is. Now, the internet has flattened it.


Why anyone wouldn’t take a dozen hours to remove ALL variability besides themselves and the shooting environment is lost on me.

And getting the machine tip top does two major things for most people: you learn what little things introduce noise; you eliminate every single excuse but your performance.


so I agree with his premise 100% that the most important thing is taking the time to be an effective shooter (shoot a lot). I just disagree with the implications that has on bow tuning and arrow building.

It’s a low cost way to remove all noise but what the shooter and the environment introduce.


If I wanted to handicap myself and second guess myself I’d shoot trad.

 

[flyboy214]

If you want a fairly simple calculator to get you in the ball park try this one.

If you start with a known chrono speed and weight of arrow is stays pretty close to accurate. Errors occur when trying for super heavy or super light arrow velocities.

ArcheryCalc – Backcountry Bowhunting

backcountrybowhunting.com

The numbers are fun to play with but your time is likely better spent shooting than agonizing over arrow builds.