Long bow vs. recurves

[Kopper1013]

Hey guys I recently posted a question about static tip vs. non static tip recurves and through the responses bornofmud brought about about recurves being hard to make "stable"

My question: What makes a long bow more stable/user friendly than a recurve?

One would think, with the wider limbs and more overall mass a recurve would be more stable, at least that's what I always believed.

Also What design characteristics help to make a recurve more stable?

[Sam Harper]

It's kind of hard to explain in words. But stability has to do with the limb tips being able to stay aligned without twisting when you draw and shoot the bow.  Recurves are less stable than longbows because if they're slightly misaligned at all, the string will pull to one side, causing the tip the twist out of alignment.  And this can be an issue even if the tips are prefectly aligned when at brace because some people torque the handle a little when they pull the string back.

Longbows don't have that problem because the tips aren't pointing in the opposite direction of where they are being pulled.  Longbow tips don't twist out of alignment nearly as easy, and that makes them more stable.

The reason recurve limbs are usually wider than longbow limbs is because wider limbs make the tips more stable by adding wood to either side of the potential twist.

[bornofmud]

I think Sam covered it there.  As far as design characteristics, the more wood you have bending away from the direction you're pulling (basically, the more recurve you have)the more unstable it will be.  If you want really long aggressive hooks, you'll want a wider limb to keep it stable.  1.75 is the 'standard' for recurves, but they are also pretty common at 2" wide.  The amount of deflex also will have an effect.  The more deflex, the more stable (usually, excessive deflex would destablize it i'd imagine), but you lose predraw (which can throw off your draw-force curve).

[bornofmud]

Also, they're not necessarily 'hard' to make stable, just harder than a longbow.  In terms of stability, the list would go:

hill style  (1.25"-1.5")
r/d longbow  (1.5")
recurve  (1.75")
static recurve  (1.75"-2")

The more you design a profile that is inherently less stable, the more you have to alter other aspects to keep it from getting too out of hand.  That above list is also in order of thinnest widths to widest (which i just added).

Bow length, riser length, riser to limb ratio, and how far the bow is being drawn all effect stability as well, can be a bit tricky getting everything to line up how you're intending on the first (or even fourth) try.

[KenH]

"Hard to make stable" is like incest -- it's all relative.        These two bows weren't hard to make stable.  Glue and stack and when you start to taper, make dang sure it's equal on both sides from the centerline.  It also takes a dead square and flat form.  Both bows are 1.5" wide with some tapering towards the tips.

The top bow is 44" tip to tip; the bottom one is 48" t-t-t.  

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