Archery calculator realistic? Compared to a chrono

[shoeshineman]

I'm using the archers advantage calculator and the numbers I put in seem to show a good spine, weight I'm looking for, grains/Lb, etc.

But, it shows I'm going to have 240-ish fps. I'd like to be higher, of course.


Has anyone compared their calculator to real world chrono values? Are the calculators realistic?

------I'm not asking anyone to critique my personal build, I'm asking "are the calculators realistic?"

Thanks!

 

[NEhunter]

The chrono at my local archery shop is reading my set up 20fps slower than archers advantage is showing. Ymmv.


Sent from my iPhone using Tapatalk

 

[nphunter]

They assume that your bow actually hits its IBO rating. A lot of them do not!

 

[RosinBag]

Actually, your spine will change every time you change your sight in marks. That is where your FPS rating comes from. If you make your marks farther apart your FPS will go down, if they are closer together, your FPS will go up.

It also changes drastically if you are using the inch method in your sight in verse picking your specific sight.

AA works best when you input all of your data, including your sight in marks. With all of the data, your speed should come out within a few FPS, which in reality probably close to reality since chronographs have an acceptable variance.

 

[Brendan]

I don't use Archers Advantage, I use pinwheel SFAX. But, similar to Doug, if I am meticulous about my measurements, I am very consistent within a couple FPS of my chrono.

 

[BDT60x]

Archers Advantage always seems to off a few feet a second but is generally close(within 5-10fps). There is several variables that play into it though. Is your poundage on you bow scale accurate. Generally speaking if you use 3 different bow scales you will get 3 different reading. The old style spring scales read way different than the newer digital scales. Also what is your exact arrow weight. Excessive glue of the fletch or insert is very common.

 

[RosinBag]

With AA, if you are not measuring all your data yourself and confirming them with the data you are inputting into the program, you may as well not even use it. Every data inputted should be exact as possible, every measurement, weight and sight in mark. That’s how you get your tapes and FPS to be accurate.

 

[Trial153]

I have two chronos, I find that AA is fairly accurate when you put in good numbers

 

[stonewall]

Slightly off topic. As I play around with numbers in AA, why does it keep changing the bows ibo speed? For example, my wife’s infinite edge has 310 ibo. As I change different arrow lengths, point weights, etc. it will randomly change ibo to other numbers (sometimes higher, sometimes lower). As a result it will, maybe incorrectly, say certain arrow setups are spinned too weak or too stiff

Why does the ibo randomly change? To confirm, ibo should be set on factory stated number right?

 

[RosinBag]

IBO will change with data input as well. IBO speed is a singular number. I know bow companies like to say their bows are a specific number but it is based off of one specific draw length usually. AA is calculating IBO based on your input data.

 

[Brendan]

I don't use AA, but you need to think about 3 numbers: The rated IBO speed of the bow, the actual IBO speed of the bow, and the actual speed of the bow. Here's an example - I shoot a Prime Logic CT5, IBO speed rated at 340 fps. Based on calculations, my calculated/actual IBO speed is around 335 fps. But, the actual speed of my bow is 280 fps with the arrow I'm shooting, the poundage and draw length I have it set at. Confused yet?

The calculated IBO speed changes because bows are more/less efficient depending on arrow weight used. Rated IBO is usually done to the manufacturers advantage, no weight on the string, etc. Some are better than others, but they like to fudge the numbers...