10 grains per pound is not correct

[lonbow]

Thank you very much for bringing up this topic, sleek! Itīs a very interesting one.

For chosing the right arrow weight, you have to ask yourself what you are using them for. Is it for hunting, target archery or flight archery? What distances are you shooting at? Do you want to have the quickest arrow flight possible or not? Your equipment (bow and arrow) must be adapted and tuned to each purpose. So I think that only comparing quite simular bows using the same draw weight and draw lengh will give you meaningful results which you can compare to each other.

Let me show you this hypothetical example for clarity:

Letīs say we have two different historical examples of composite warbows with the same draw weight (letīs say 130 lbs).

1: ottoman bow, 42" lenght, 130 lbs @ 27", mass: 14 ounces
2: manchu bow,  70" lenght, 130 lbs @ 32", mass: 32 ounces

Both bows are tested with a very light 450 gn arrow (3,46 ggp) a typical arrow weight for ottoman war bows.
The ottoman bow will easiliy outperform the manchu bow, because of the very low mass of the bow.

After that, both bows are tested with a heavy 1500 gn arrow (11,54 ggp), which was a typical arrow weight for manchu war bows.
The manchu bow will easily outperform the ottoman bow, because it stores a lot more energy due to its length, longer draw length, strong reflex and its long sharp angled syhas.

Testing different bows only with one arrow weight could lead to false conclutions about their performance. Itīs like comparing apples to pears. In order to see the real potential of a bow design, you have to test it with an arrow weight matching the bow design. Bearing that in mind, you can say that both the ottoman and manchu bow were excellent designs for their own arrow weight and purpose.

But of cause you can much better compare two bows of the same design with similar parameters.

Greetings, lonbow

[Del the cat]

Nice post Lonbow
Del

[Dances with squirrels]

Ah yes, "Matching bows to arrows." Dean Torges wrote an article about it. It's on his website.

"I guess if my goal were to be to build a bow that shoots a 10 gpp arrow the fastest, id build a bow to that purpose, and take draw lenth into account. If thats the only goal. No complaints there.

If the goal is to put all bows in a level playing field, where midgets can run against giants in a fair equal foot race, the field needs to be adjusted accordingly. Then its a fair compareisin in all bows to eachother, and not to a specific purpose or task."

I agree, Sleek.

I don't care about that race, or any formula that would attempt to integrate and level those fields. I DO I have specific purposes for my bows, but have found the numbers I need to build them on a tape measure.

[Yellarwoodfellar]

Me too squirrels. My bows are made to hunt with so balance and noise are my only real worries. If I were to make lng distance bows I would worry more about speed. To me if it shoots where I'm looking in twenty yards What does it really matter that my arrow weighs 10gpp if 5 gpp does as well in that range. In fact lighter arrows would be faster to the animal which should make more accurate shots. Sound right?

[Badger]

Me too squirrels. My bows are made to hunt with so balance and noise are my only real worries. If I were to make lng distance bows I would worry more about speed. To me if it shoots where I'm looking in twenty yards What does it really matter that my arrow weighs 10gpp if 5 gpp does as well in that range. In fact lighter arrows would be faster to the animal which should make more accurate shots. Sound right?

    A broadhead flight shoot is not about distance flight bows, it is about hunting bows shooting hunting weight arrows. It is just verifying the cast

[Yellarwoodfellar]

I think of the collagen in a bow as only being able to stretch eversoslightly before it loses tension (takes set) so naturally a bow only drawn to 24 inches would have more snap than a bow drawn to 28. But due to the shorter draw there is only so much overall energy available to the arrow. The longer bow could drive the same weight arrow better because of the longer stroke but I has lost efficiency because it has stretched more than the fibers should. Am I getting this right badger?

[PatM]

The fibers compress rather than stretch and they are not collagen.

[Badger]

I think of the collagen in a bow as only being able to stretch eversoslightly before it loses tension (takes set) so naturally a bow only drawn to 24 inches would have more snap than a bow drawn to 28. But due to the shorter draw there is only so much overall energy available to the arrow. The longer bow could drive the same weight arrow better because of the longer stroke but I has lost efficiency because it has stretched more than the fibers should. Am I getting this right badger?

   Pretty close, it is mainly in compression where the efficiency is lost

[Selfbowman]

Maybe we need a bigger playing field! See ya at the flats.

[willie]

This conversation with Sleek in Badgers thread seems better off moved here.

     . I personally don't feel there is a good way to even the playing field by using a set formula to adjust weight. Lots of variables that doesn't allow for.

There can be a difference between a formula of "what is supposed to be", and a formula derived from actual shooting stats.

  Different styles of bows will have different types of fdc's. I doubt a perfect formula for this really exists.

I think we agree a perfect formula does not exist. A process derived from actual stats would not be a formula in the classical sense. "Formula" was a poor choice of words, I am suggesting  something more like a correction factor.   A perfect formula would be an attempt to predict how a bow should shoot, correction factors would be more about how a variety of  bows styles and construction, arrows lengths, arrow weights, drawlengths etc. have shot in the past,  the factors being developed as  records are kept. A way to equalize various concerns about how "level" the field is going forward. Moving the goalposts, as some might say, could be a way to shoot with a broader range of arrows without having to develop and define lots of rules and create numerous classes.

You seem to want to make a flight bow compare with a hunting bow ( as an exaple you didnt give).

Sleek, I am thinking of a way to broaden the arrow weight and drawlength specs, but stiil stay well  with in the realm of Steves proposed hunting broad head round.
Something that might include 90% of what guys hunt with. A rough example might be 26" to 30" draws and 8gpp to 12gpp. It would let a guy shoot what he has developed as his best hunting set up. It would be a shame if you could not compete with the arrow you like to shoot with your bow/drawlength.

[joachimM]

I too have the impression that short draw bows can be made to shoot a bit faster, that is, with Woodbear's formula that allows for lighter arrows at shorter draws.

There is obviously a trade-off between length of the power stroke and energy returns. 
At 24" draw there is less energy storage than at 28", nobody argues about this. But also less hysteresis. For hunting purposes (or warfare for that matter) penetration damage is crucial. A longer draw will store more energy, and allow a heavy arrow to penetrate further. At the expense of taking a bit more set. The extra 4" draw doesn't pay off as much as the previous 4", but enough to tip the balance in favour of more power and energy storage (and efficiency).

For flight shooting, a short draw with lighter arrows (which incidentally also oscillate at higher frequencies, and therefore stop wobbling faster) is more advantageous than a long draw. Raw energy storage is less of an issue, with light arrows efficiency (the energy put into the cast divided by the energy stored in the draw) hardly matters. Raw speed is what matters (next to arrow-bow and release tuning).

But don't go comparing (as the last questions to Badger) a bow made to shoot 28" but only drawn at 24" to a same design bow shot at 28".
I think Badger's point is that a 24" draw bow isn't necessarily slower than an 28" bow. And because care is taken (in his case) to hysteresis and set, his bows stay fresh more easily when limited to 24" ,than when drawn to 28".

As for the short bows: they have less inertia, so a little excess mass at the extremities is less of an issue than in long bows. Making a long bow (67" or more) and shoot it at 24" and being very fast requires utmost attention to mass reduction in the lower limbs.