Limb length vs felt poundage and speed?

[Kyodai]

Hello brothers (and sisters as the case may be!)

I just realized that all of the bows I currently own are all 60 inchers. I love the length, but I'm getting ready to order up a custom 2-piece longbow, and I'm thinking about a 62" length.

Is a shorter limb faster? Does a longer limb reduce felt poundage? I think I understand the physics of it, but then again I'm not a bowyer  

I am very familiar with the feel of a 60" bow, but I'm interested in hearing other's thoughts on preferred length on a longbow and it's effects on how it shoots.

Thanks for readin

--Kyo

[Sharpend60]

You are right on both accounts,
but of course each bow is a different animal...

The shorter bow ultimately has the the potential to be faster... but that depends on the working limb length. Alot of bowyers user the same workin limb and stretch the riser to get a longer length, thus changing the force/draw curve.

A more accurate statement would be... Is a shorter, more highly stressed working limb faster?

Felt poundage comes down to string angle at the tip. The closer you get to 90* the heavier the draw feels... Thats precisely why statics recurves feel so sweet. They dont seem nearly as heavy as they should. They peak early on a F/D and stay relatively flat in their optimal range.

The amount a de-flex right off the riser also plays a large role in the shooting experience.
Look at the brace heights on short recurves or some thing like a Shrew.

I find I prefer a longer bow, I currently shoot a static tip 62" recurve, I notice my 58" staitc hits a wall just before fulldraw... My 62" long bow stacks like a mofo. It is a known screamer btw...

Speak with your bowyer for more details. Any maker worth his salt is gonna be able to give ya all the details. Including info on a force/draw graph. You can actually see, on paper where a bow is fastest per pound. Or where it *feels* the smoothest.

[jacobsladder]

Good post sharpened60...I agree

[Bjorn]

2-3 years ago my son and I went from 62" bows to 64". Same design, same poundage just longer limbs, we used our old risers. Surprising difference-the longer limbs 'felt' so much better, very smooth and easier to shoot well-would never go back. Can't quantify-just a more enjoyable shooting experience.

[Kyodai]

Thanks for the replies guys. I'll talk with the bowyer more as well! I only draw 27" so I might get the same effect Bjorne got by going to a 64, with me moving to a 62.  Dang these short arms of mine...

Much obliged Sharp and company.

[pdk25]

Never noticed much difference in felt poundage at anchor.  A given poundage is what it is.  I believe this phenomenon to be a myth.  Different styles have more preload, which is going to have an impact on how smooth the draw feels.  The subtleties of small variations in the force draw curve are lost on me unless you are into the bows stack.  I know, I am in the minority and a bit of a neanderthal, so be it.

[BWD]

I am no expert and should not be confused with one; however, in a non-scientific test, I used the same 15" ilf riser with short recurve limbs(56" bow), and long recurve limbs (60" bow) of the same brand and marked draw weight, same arrows, same string type and number of strands, and shot them in the backyard the better part of one afternoon. No chrono, but just watching the arrow fly, from different distances, I believe, at my 26 1/2" draw, the shorter limbs performed better for me.
I've owned bows from 54" to 66", and at my draw length and draw weight, mid 40s, finger pinch is not a factor, but might be with heavier draw weights and short bows. Longer bows are normally smoother drawing for me, but I can't say I shoot them any better. A lot just depends on the bow and the shooter.

[Pheonixarcher]

Interesting stuff! I'll be watching this one. Perhaps this topic would be better served on the bowyer's bench.

[Dan Bonner]

"Felt" weight is all about preload and string angle at full draw. The bow that tends to feel best for me has a ton of preload, meaning it adds a lot of draw weight in the first few inches of the draw cycle. This early weight equates to better performance also as the first few inches of draw is the last few inches of the power stroke at release. Simply put the bow with a lot of preload is pushing the arrow hard all the way to brace. This bow generally performs better assuming the bowyer keeps the limb weight low so the limb can stop vibrating quickly after returning to brace. This requires a light weight but rigid limb design.

As the string angle approaches 90 degrees at the tail end of the draw the number of pounds/inch of draw weight increases dramatically. This is when "stacking" occurs. Longer limbs will usually stack less at a given draw length. There are other ways to avoid stacking though. Stiffening the last several inches of the limb will mitigate this problem in most designs. This is what the ACS design does, it can also be achieved with tip wedges or a sharp bend in the outer limb in the case of a static recurve. These are all methods of fine tuning where in the limb the bending happens to maximize preload and string angle.

To me the ideal bow has lots of preload and a string angle at full draw well under 90 degrees. It needs light but rigid limbs that stop quickly at brace after the shot. Most bowyers can accomplish this in either a LB or RC  with a range of limb lengths depending on requested draw length by changing limb pocket angles and adjusting limb bending using the methods discussed earlier. The great thing is that the bow that "feels" the best will likely be faster and quieter than the bow that does not all else equal.

Bonner