Let's talk about arrow length!

[SPIKER]

Last night I decided to cut down some of my new CX Maxima 250s. Now that I'm shooting 28" DL, with a ripcord rest, I figured that I could cut down to at least 26 1/2".

But before I did, I called BT to make sure...good thing too, because I learned a few things that I didn't know.

Such as the fact that a shorter arrow is more unstable than a longer one, hence the demise of the overdraw. My biggest concern being a weak spine issue because 63-65# seems to be the transitional point of many manufacturers spine charts...Maximas included (@ 28", so that's why I wanted to cut down).

So BT tells me to be at least a half inch in front of the berger button to the front of the riser. Also, that if I wanted to go shorter I might have to sacrifice a few shafts to find out the proper length.

Well, I took his advice, and made up three at 27". I have a half dz. Carbon Force radial x weave Predators @ 27 1/4"that fly real good that I would use to compare......

The end results from today....The Predators out flew the Maximas....hands down...grouped tighter, and tracked better all day......d amn it........$129 compared to $90.

OK, I believe that at this point I have sacrificed three shafts...but now...do I cut down another three @ 27 1/4? Maybe the Predators fly better because of a different spine, and not the length?

There's only one way to find out...BT, maybe we can do some kind of test with different length arrows to show how much flight can be affected.

[royden]

Spiker - arrow length does make a big difference ... and yes a 1/2" in front of berger hole is probably a good length. But if you have a saw and patience you can experiment with arrow length.

Here's what I did. Started with 3 arrows too long. How much too long is your choice - I did full length. Fletch 2 and leave one bare shaft. shoot 1 BH, 1 FP and 1 bare shaft and compare their impact points. Cut the shafts 1/4 - 1/2" and compare the difference. When you reach the point that the grouping begins to get larger after you shortened you went to far. You are changing the FOC and the spine of the arrow. It was an interesting experiment for me - the full length broadhead out of a tuned bow shot 8" high and left. As I shortened the arrows the fp group tightened and the BH moved down and right. Finally I was a 1/2" in front and stopped there. At that point I shot a bareshaft with a slick trick on it and impacted within a few inches of fp at 20 yards Don't try that at home

[BT]

I told you to start long and end short

This is pretty much common knowledge that has been proven out over the years among the pro staff's out there.
I'll forgo sacrificing arrows to prove a moot point

As I was saying before....bringing the arrow past the center point of the riser increases the amount of torque that is reflected in the arrows flight.
Ideally the arrow shaft itself (not the point ) should end at the forward part of the berger hole because this is the center axis of the riser and will receive the least amount of torque effect.

Look at it from the position of balance where the center of any point of mass is the balance point.
The same holds true for anything that can be put into motion.
The center point controls balance but at the same time puts the mass of itself into a lack of balance.

When the riser is held it is in an in control/out of control point of balance and therefore the center is the only area which can maintain that balance.
Putting the arrow behind or past that point of balance brings the torque into play unto itself as it now becomes part of that awkward mass.

Thats why the air rest is such a great idea although it is a crude devise that needs far more refinement before it can enact the benefits that is addresses.

[royden]

wew BT - I kinda like the short version (long/short)

After mulling over your post I can see a thread of logic - I just think it makes more sense in your head than I can get in mine. So, I'll take the short version and run with what works.

hmmm... I kinda like the long version too - It got the rusty brain cells churning again. Wouldn't it make sense for the center pt of the arrow to be at the center pt of the bow following your in control/out of control logic?

[BT]

Like a teeter toter .... the arrow will work off the center axis of the riser to absorb(if you will) the torque of that center point.

The further forward or rearward of that center point the arrow sits,the more amplification that is induced by the process of riser torque.

[royden]

So what your saying is the berger button being in the center of the bow design has the least amount of movement or is the most stable. Having the tip of the arrow here (especially with a drop away keeps the tip of the arrow the most stable when shot. More forward and the arrow teeter tootering amplifies hand/shot torque.?



teeter tooter - that's a good word pic for a rusty brain.

[jamaltwy]

yes no more than 3/4 in front of berger hole... too long of an arrow affect the F.O.C which is the balance of the arrow it should be 7%-12% if you go to the gold tip site it will show you with a program what is optimal...... measure 2-3 times cut once better too long then too short!!!!


here is the link: www.goldtip.com/byoa/index.asp?rnd=1180121088481

hope this helps

[SPIKER]

Ok ...I get it...I get it...but in my defense, I knew that 27 1/4" was good, as well as 28".

I needed to see if 27" (which by the way brings me about 1/4 " in front of the berger), would make a difference...no way to tell unless I did it...so there it is.....I've been schooled!

[jamaltwy]

hey spiker

are those maxima a little lite ( underspined) just thinking 350 would suit your setup better!!

just went to carbon express site and according to your profile and the info you have given 350 would suit you much better go to the site and plug in your specs and your adj poundage is plus 10 lbs or 75 lbs .. that puts you in the 350 catagory sorry for snopping but i see to many guys underspining their setups just trying to help!!

[SPIKER]

Not at 27 1/4"... my Predators are smoking with this bow at that length.....just have to hope that the Maximas follow suit ...or guess what, I just wasted 129 bucks!!!