Archers Paradox

[snowplow]

Hey guys, first post here. I shoot an old unnamed long bow without a shelf. So the way I was taught was if I was looking at the bow in my hand to cant the bow so the top limb was to the right. This is because if straight up the arrow shoots to the left due to riser interference. I know the english longbowmen shot straight up and relied on the spine of the arrow to bend around the riser. Yet I like my method better as I think it is more comfortable, compact, and shootable in general. So my question is how does archers paradox effect the way I shoot. It seems to me that I would not be picking an arrow with a traditional spine setting in which it would bend around the bow, rather looking for a stiff spined arrow. I am relatively new to this, so feel free to correct anything I say. Am I on the right track here? Suggestions?

Thanks DC

[JimB]

If the arrow shoots to the left,it is too stiff.The less a sight window is cut toward center,the weaker spine you need,not stiffer.In your case,you will need a lot weaker than many bows.The only way to find the correct arrows is to shoot some different ones and tune them to the bow.

This is some really good information on tuning:
 http://www.acsbows.com/bowtuning.html

[moebow]

Jim has got it but I'll add...

The arrow is going to bend around the bow regardless of the cant of the bow.  All you are doing by canting is moving the "left" of a stiff arrow into "vertical" which for many is an easier adjustment to fix.

If you find that the angle (cant) of your bow affects your perceived accuracy, you need to adjust the spine of the arrows (and maybe your shot execution).

Arne

[pghrich]

hello, archers paradox exist no matter how much you cant the bow, canting the bow may make it easier to point the arrow in the direction you want it to go and keep it from falling off the shelf but the arrow must still bend around the riser. you still must find the proper spine arrow for your setup . hope this helps, rich pyle

[snowplow]

Thanks fellas, so you made me think of a few more questions.

They all revolve around asking what benefit would I have by buying a new set of lighter spined arrows?

It seems to me that stiffer spined arrows would transmit more kinetic energy due to less being lost in bending.

Also it sounds like all things being equal that would have me raise my aim. Which I dont see as a good thing. Right now I aim under the target just about always. Which is really nice as that with a canted bow allows me to see my target really well.

Lets say you got used to shooting stiff spined arrows. Wouldn't that be a lot easier to find shafts to shoot? I am assuming that most carbons are stiffer than wood.

Just some random thoughts. I wont lie, Im not excited to find proper spine. It sounds like its an expensive trial and error deal. Thanks for the advice!

[snowplow]

PS my bow is 52 lbs and I shoot Arrow Dynamics Traditional Lites. Which I thought at the time I bought them (years ago) it was said they were the right spine. I have shot for lots of years but have only dabbled with my long bow here and there. Now I finally put down the gizmo bow and am taking my long bow seriously.

[snowplow]

I just looked again (at 3 rivers). What am I missing? Are these arrows not the right spine?!

[**DONOTDELETE**]

Shooting arrows that are spined to stiff are not going to fly well, and using different cant angles will effect your windage .... by getting the right spine you will find you can shoot from vertical to a 90 degree cant with no effect on arrow fight.

btw... a stiffer spine arrow doesn't have higher KE than a lighter spine. The arrow deflection at the time of release doesn't change the speed or arrow weight. The only thing that effects the KE is arrow speed and  weight.

[Mike89]

Don't worry about energy lost in bending the arrow- there will be more lost during any fishtailing that a too-stiff arrow will experience.  Having the correct spine allows a more efficient transfer of energy from bow to arrow

[JimB]

Some good advice there.An arrow not properly tuned to the bow will squander a lot of your bow's energy and if you read that tuning information,you will also learn that if the arrow is not tuned to the bow,your broadhead arrows will not impact in the same place as your practice arrows.Tuning takes some time and diligence but it is worth every bit of effort it takes.Hunting with untuned arrows is akin to hunting with a rifle that is not sighted in.

[BAK]

Bottom line is you can make all the mistakes you want as long as you make them exactly the same every time you shoot.  

[pghrich]

hello, depending on your draw length you must determine your bows actual poundage, i assume your bow is 52#@28", if you draw less than 28" your poundage is less than 52 if you draw more than 28" your poundage is more than 52,  longbows with not cut to center arrow shelf you should probaly go with a little less spine, also you can adjust your point weight and arrow length, 3rivers sells a test kit of different spine arrows, you can always go that route, hope this helps a little, rich pyle

[**DONOTDELETE**]

Originally posted by Mike89:
Don't worry about energy lost in bending the arrow- there will be more lost during any fishtailing that a too-stiff arrow will experience.  Having the correct spine allows a more efficient transfer of energy from bow to arrow

I'm sorry.... but i have to point out this is a bogus statement regarding arrow spine effecting energy transfer from bow to the arrow....

It's true that the fishtailing of an arrow will slow the arrow down a lot quicker, resulting in lost KE at impact. But... The arrow spine has nothing to do with energy transfer from the bow to the shaft. Energy transfer is determined completely by the design of the bows limb, working limb location, brace height, and tension on the string at brace called pre load.

It's also true that a well tuned arrow will deliver higher Kinetic Energy  results at impact. This is very noticeable at longer ranges too.

[moebow]

pghrich.

FYI the word is SPINE NOT SP-L-INE !!

Arne

[pghrich]

Thanks Arne, never was good at spelling.

[bamboo]

Originally posted by Kirkll:


 But... The arrow spine has nothing to do with energy transfer from the bow to the shaft. Energy transfer is determined completely by the design of the bows limb,..... [/QB]

so you say-- if I shot a arrow spined for #25 out of a #100 pound bow you are saying spine would have the same energy transfer [to arrow] as a properly spined arrow?

IMO for it [arrow spine] to have "nothing" to do with energy transfer --I would have to be a 100% efficient spring --which I was taught is impossible[high school physics]

be sure -I don't want an argument--I want to understand!

I'll try to answer this one.

Lets use your spring example.  When you compress a spring and let it go, it will expand and then contract again.  This movement will get less and less until the spring is stationary.  That's because it's losing energy through heat loss and friction.  If, however, it was a 100% efficient spring, it would continue expanding and contracting forever, since it's not losing any energy.

Now, say you apply 2 lb to the spring to compress it, that is the energy you're transferring to it.  If you have a less efficient spring, it will come to rest quicker.  If you have a more efficient spring, it will take longer to come to a rest.  But the 2 lb and thus your energy transfer remains the same regardless of how well the spring uses the energy.

Same with a bow.  For argument sake, if you draw 100 lb that is how much energy you will transfer to the arrow.  The arrow only determines how well the energy is used.  So if you have a weak or stiff spined arrow, there will be more losses due to friction, etc. because the arrow isn't flying as well.  But the 100 lb is the same, regardless of the arrow!  That is also why a heavier arrow will fly slower than a lighter arrow.  It's the same force applied to two different weights, so it would be impossible for them to have the same velocity.

I hope this makes sense and doesn't confuse you even more.    

[creekwood]

Originally posted by Kirkll:
 

Originally posted by Mike89:
Don't worry about energy lost in bending the arrow- there will be more lost during any fishtailing that a too-stiff arrow will experience.  Having the correct spine allows a more efficient transfer of energy from bow to arrow

I'm sorry.... but i have to point out this is a bogus statement regarding arrow spine effecting energy transfer from bow to the arrow....

It's true that the fishtailing of an arrow will slow the arrow down a lot quicker, resulting in lost KE at impact. But... The arrow spine has nothing to do with energy transfer from the bow to the shaft. Energy transfer is determined completely by the design of the bows limb, working limb location, brace height, and tension on the string at brace called pre load.

It's also true that a well tuned arrow will deliver higher Kinetic Energy  results at impact. This is very noticeable at longer ranges too. [/b]

Perhaps what Mike89 really meant to say is that a correctly spined arrow will lessen "transferred bow to arrow energy" loss during flight which will make the delivery of the arrow more efficient. The more quickly an arrow recovers from it's paradox, the more energy the same arrow will impart down range.  

[bamboo]

" But the 2 lb and thus your energy transfer remains the same regardless of how well the spring uses the energy."
  so the spine has bearing on how much energy is delivered?

 " The arrow only determines how well the energy is used."

---so I'm reading this as: too weak an arrow wastes the energy transferred to it by the bow
while trying to stabilize through air friction and internal hysteresis --

---and too stiff an arrow would lose energy in a similar process with air friction [poor flight/longer recovery ] wasting the bulk of it

---leaving the arrow with the proper spine too deliver the least wasted energy down range---

For the second part - you're exactly right.  A weak or stiff arrow wastes more energy than a correctly spined arrow.

For the first part - no the spine has no bearing on how much energy is delivered.  I can elaborate somewhat on the spring example.  Imagine you have two springs of identical length, but one is stiffer and one is softer.  If you stand them upright and place a 2 lb weight on top of each one, the stiffer spring will compress less than the softer spring.  Remember, the springs are in effect pushing back on the weight (for every action there is an equal and opposite reaction).  So while they behave differently to the weight, because the weight is the same the energy transfer is the same.

It's the same with arrow shafts.  A weak spined arrow will behave differently to a stiff spined arrow from the same bow.  But the bow is effectively the 2 lb weight - it's the same for both arrows.  So for this same weight the weak spined arrow will flex more than the stiff spined arrow, but because the weight is the same the energy transfer is the same.

Because the arrows behave differently to the same force, what happens after the arrows leave the bow will be different and make it seem like the energy transfer was affected by the spine.  I think this is where some of the confusion comes in.

Apologies if I'm explaining too much, I'm just trying to be clear.