Question please..

[akila]

Hello all, i have a question, and i hope i will manage to explain as clear as possibile what i have on my mind..im curiouse, if anione, had ever tested, how much poundage, the End's of a bow really take...i think that I'v read at a certain point, that the actualy poundage, that the end of a bow needs to stand is much smaller then the entire force of that specific bow..let's say that we have a 40lbs bow..the poundage at the end of the bow, where the overlays are, is the same or smaller?..i think its smaller, but I'm curiouse id there is a formula to calculate this.

[Pat B]

The total draw weight should be divided in half for the amount effort each limb will have to handle, I think. Also the stresses at the fades is higher because of the leverage of the limbs. These are more common since explanations than scientific explanations.

[wizardgoat]

Someone posted it a while back and I think it's in one of TBBs. Most stress out of the fades, a little less mid limb, and the least stress on the tips. On a properly tillered bow

[Del the cat]

At the actual overlay all the poundage is simply tying to crush the overlay, there is no leverage.
A simple test is to lightly clamp a bit of arrow shaft in a vice (wrapa bit of leather round it to stop it getting crushed)
Loop an old string over the shaft right next to where it is gripped and pull as hard as you can... you won't break it.
Now try with 6" of shaft sticking out of the vice and the string near the end, it will easily break.
Del

[huisme]

No thanks Del

[bradsmith2010]

what Pat said,, I actually tried to break some tips with a scale attached to the string,, tip in a vise..I narrowed them extremely thin and it was very difficult to break one,, really helped my confidence to narrow a tip to reduce the mass,,

[akila]

Thanks all of you for your replays..I'm also doing my tips really narrow now, even for 55-60 lbs bows..i just taught that maybe there is some kind  of formula to calculate this moore precise..what is the poundage that the last 6" needs to deal with ...but there they are so many variables , and its probably quite dificult to find a formula for this

[missilemaster]

Also be aware that the bowstring is under the most tension at brace, not at full draw. This is the reason that D/R bow typically perform better than straight standing bows. It all has to do with how close the string is to the end of the limb at brace.

[mikekeswick]

Not really - r/d bows are fast because the reflexed outer limbs keep string angle low and therefore store more energy through the draw than say a standard straight limbed bow. Similar to a recurve but without the potential excess outer limb weight. Of course better string tension at brace helps with early energy storage too.

[George Tsoukalas]

If a bow  were a lever  then for a 40# bow each end would experience a 20# force depending upon where the fulcrum is. But the bow is a spring so I don't think the tips experience half the poundage for a force...much less would be my guesss. Jawge

[Slackbunny]

Also be aware that the bowstring is under the most tension at brace, not at full draw. This is the reason that D/R bow typically perform better than straight standing bows. It all has to do with how close the string is to the end of the limb at brace.

Unless I'm over-looking something I'm pretty sure that's not right.

At brace the string is only dealing with the tension that the limbs are exerting on it. When you pull on the string, you are adding tension to the system.  This will necessarily increase the tension on the string.

D/R often perform better than straight bows, but its got nothing to do with the string tension.

[JoJoDapyro]

Also be aware that the bowstring is under the most tension at brace, not at full draw. This is the reason that D/R bow typically perform better than straight standing bows. It all has to do with how close the string is to the end of the limb at brace.

Unless I'm over-looking something I'm pretty sure that's not right.

At brace the string is only dealing with the tension that the limbs are exerting on it. When you pull on the string, you are adding tension to the system.  This will necessarily increase the tension on the string.

D/R often perform better than straight bows, but its got nothing to do with the string tension.

 You seemed to answer your own question. At brace the string is holding the braced weight of the bow, and at full draw the string is holding the drawn weight of the bow, the entire limb is working to distribute the weight, not just the tips.

[bradsmith2010]

wow that sounds very confusing to me

[Slackbunny]

Also be aware that the bowstring is under the most tension at brace, not at full draw. This is the reason that D/R bow typically perform better than straight standing bows. It all has to do with how close the string is to the end of the limb at brace.

Unless I'm over-looking something I'm pretty sure that's not right.

At brace the string is only dealing with the tension that the limbs are exerting on it. When you pull on the string, you are adding tension to the system.  This will necessarily increase the tension on the string.

D/R often perform better than straight bows, but its got nothing to do with the string tension.

 You seemed to answer your own question. At brace the string is holding the braced weight of the bow, and at full draw the string is holding the drawn weight of the bow, the entire limb is working to distribute the weight, not just the tips.

Yeah, that's why I'm wondering why he thought that the maximum string tension takes place at brace and not at full draw.

[DC]

Break out the popcorn.

I know I've read somewhere in TBB that Misslemaster is right, that string tension is higher at brace. I looked and can't find it yet. I decided to try it. I made up a string with a fishing scale in it and braced my 35# bow. It was a real PITA to brace. At low brace the scale reads 56# and as I draw it the weight drops off and by half draw or so is down to 35# and stays there til full draw. I'm convinced. I took some pictures but all I got was pictures of the scale so they don't prove anything. My photographer is out so anything more convincing is out. If you don't believe it, try it yourself, it took 15 min.