Originally posted by pavan:
Then the next question, for a 5'9" (and shrinking) short draw shooter like myself with my little 26" left hand draw length, how much performance difference is there between the 62" bows that I have compared to a 68" R/D? What would happen to the shooting qualities of an R/D bow that was under-stressed at full draw because of its longer length? The Driad boys seem to think longer will always out shoot shorter. That does not seem to be the case with Hill style bows, although I have seen some exceptions to the rules with those, such as, an under drawn bow can have more hand shock.
This is a really good question bro.... i'd like to shed a bit of light on the subject if you don't mind....
I'm uncertain where you got your info from Dryad about longer bows always out shooting shorter bows. But i think you may have misinterpreted that info.... First of all there are advantages and disadvantages to longer and shorter length bows..... your example of a 62" vs a 68" bow is a good comparison..... But.... the draw weight and draw length of the bow is a huge factor in determining hand shock and smoothness between the two.
With a 68" long bow with a narrow profile and a deep core thickness. These bows have excellent potential for high performance and low hand shock if you can get enough tension on the string at brace height to stop the limbs clean. this is where the reflex in the limb before stringing the bow comes into play for lowqer poundage bows especially.
You can take a Hill style straight limb bow that strings up in a perfect "D" shape at 70 pounds At 28" and have a real nice stable limb that shoots excellent at a about 63@26" draw...... But once you drop the draw weight down to 50@28" you loose your pre load tension at brace and the string isn't tight enough to stop the mass weight of the limbs clean....
Rob gave a good example of the Sparrow Hawk bow advantage of narrowing up the limb and removing a huge amount of limb mass that needs to be stopped in order to transfer the energy to the shaft....
There are many other ways to make a longer bow or a shorter bow draw smooth with good limb stability, by manipulating the working portion of the limb. If you go too far towards the tips, you get a "Whip tip" bow going on that doesn't store enough energy throughout the whole limb.... if you go the other direction and the limb is bending hard at the fades, you are storing more energy, but you have too much mass weight of the outer limb moving forward and it requires a lot of draw weight & preload at brace to stop the limbs clean....
the perfect combo on "D" shape bow is having the energy stored evenly in the full length of the limb with the limbs mass weight balanced properly to the draw weight..... this is the part that often gets over looked. as we drop our draw weight down the over all width and depth thickness needs to be reduced proportionately to the draw weight to maintain equal performance.
The problem is... if you have a good design that has a 1.25" to 1/2" width profile at 60 lbs... you can not reduce the profile by a third going down to 40 pounds without loosing your stability.
So you end up with too much mass weight in the outer limb that can't be stopped clean.
The answer to this problem is going with a shorter bow that stores more energy with less mass weight in the limbs, or... using more reflex in the limb using less material to increase the preload.
Hopefully i didn't get too long winded on this for you guys... It's a favorite subject of mine.
Kirk
Topic: the "D" shape R/D longbow appreciation thread! (Read 47621 times)
