arrow shaft length

[Peter Thornton]

When one reads about arrow lenghts the general consensus is that the arrow shaft, excluding pile, should extend past the rest by 1" or in some cases 1 1/4". I appreciate the fact that the shorter the arrow then the stiffer it will be but can the extended lengh after the rest be as short as 1/4" to 1/2" or longer, say to 2". or is it a question purely of stiffness.
What is the percentage increase in stiffness per 1/4" in lenght over the standard 28".

[vertek]

Depends on the arrow i think.

[teknohippy]

The amount of extra length on an arrow beyond the rest needs to be greater when you are starting out, as your draw length increases it would be dangerous to have an arrow getting closer and closer to the rest.

I've seen 2 1/2" or more recommended to beginners and around 3/4" if your draw length is settled.

[NoIdea]

If you are using a clicker, will that make the statements above null & void. You shoot when the clicker goes off so will always have a set length.

[Duss]

Using a formula indicated to me by Joe Tapley, I can estimate the RELATIVE DYNAMIC stiffness increase with the shortening of an arrow shaft, all other conditions being kept the same (pile weight being the most important).

It is simply and approximately proportional to the ratio of the shaft lengths CUBED.

For example if you start with a shaft that is 30" long and cut it to 29" the stiffness will have increased by ((30*30*30)/(29*29*29)) == 10,7%

I have actually checked it with my own arrows. Do not forget that the STATIC spine will always be the same, since it always is the same arrow, but its behaviour (DYNAMIC spine) will change due to length.

[Kae]

Originally Posted by Peter Thornton

When one reads about arrow lenghts the general consensus is that the arrow shaft, excluding pile, should extend past the rest by 1" or in some cases 1 1/4". I appreciate the fact that the shorter the arrow then the stiffer it will be but can the extended lengh after the rest be as short as 1/4" to 1/2" or longer, say to 2". or is it a question purely of stiffness.
What is the percentage increase in stiffness per 1/4" in lenght over the standard 28".

It depends on how well you shoot.
My arrows are 1" longer than my draw length to the button, as I have a very consistent draw length, I'm not growing, and there is no chance I'll shoot myself in the hand.
Your asking a question that leads to a tin of worms. The length of the arrow when your just beginning should be a lot longer than your draw length (4"+), as your draw is likely to lengthen, even if you are fully grown.
When your experienced enough to have a set draw length, your arrow should be long enough so that the pile never gets pulled onto the arrow rest, the arrow is the correct spine at that length, and that you can use a clicker with that length if you wish. So there is no set length, although 1 - 1 1/4 inches is a good area to work in.

I'll let other deal with the maths question,

Kae.

[Flying Whale]

I believe there are reasons not to get the arrow too short, however consistent your draw length. If you bring the front nodal point back too far you may affect the arrow flight. This is covered in Simon Needham's book, but I have not really looked in to it. I think he recommends about 1.25 to 1.5 inches beyond the button, but I am quite happy to be corrected on that.