Arrow Speed Formula?

[Neo]

Is there a way of finding out your arrow speed without using digital speed meters?

Is there a formula for recurve, i suppose there would be a lot of variables,

Limb IMCS and quality, string, arrow materials and spine.

but has anyone come across one.

just out of interest

[Schme1440]

I think there is one but as you say there are so many variables that it wont be accurate. However Im sure someone will post a very complicated formula which will give a good estimate.

[KevinH]

there was a formula suggested in an archery focus article some time back, but there are a lot of variables including bow efficiency and shape of draw force curve.

The article also suggested you can make a fair estimate by using the difference in sight marks between two distances, thereby removing the need to know all the bows characteristics. A couple of the sight tape software packages do this.

[joetapley]

There are a number of different ways of making a reasonable guess. My drift programme estimates arrow speed just using arrow weight, arrow length and draw weight - lots of assumptions but the result is in the right ballpark.

The simplest measurement approach is based on arrow drop over distance. With two measurements you can apply a rough correction for the effect of drag (commercially these are known as pin tape programmes).

For an nice example of this approach - gives you arrow speed and sightmarks see: http://www.cs.toronto.edu/~apostol/arrow/

[Kae]

ow, yet another thread that makes my head hurt, I know why I'm studying Biology now, lol.

I'd recommend Joe's site, if your interested in these painfully mental calculations to do with bow mechanics.

http://homepage.ntlworld.com/joetapley/

Kae.

[Neo]

Well Been a long time since A Level physics, drunk far too many beers since then to think of al the variables.

cheers guys.

[Ffish]

Speed = Distance / Time.

You know you're shooting (say) 80 yards, get someone with a stopwatch to time your arrow from the moment it leaves your bow, till the moment it hits the target. Then just do the maths!

You'll probably find it's *about* 130mph

[Mistake]

Originally Posted by Ffish

Speed = Distance / Time.

Woo for VUSAT

Thats what i was going to suggest as well as this should get you in the right area, although human start/stop delays as well as sound delay would have to be taken into account (assuming your using the sound of the arrow striking)

[archeryal]

The computer geeks among you may understand this (I'm not even close): I understand there is a program that you can set on your computer to detect the sound of the arrow leaving your bow (twang) and the sound of the arrow hitting the target (thunk), dividing the time between the sound by the distance, factoring in the time it takes for the sound to go from the target back to the line and subtracting it from the time to target. It will then calculate the arrow speed. It sounds like a cool system, but beyond my capabilities.
Any tekkies out there who have the details? I'm sure this is the system that Robin Hood used in Sherwood.

[Rhys]

Could probably do that in Matlab, but would take me a while lol