Are all limbs the same shape?

[kinkychinky]

A newbie question.

Are limbs from the same brand/model the same shape (degree of recurve) or do they vary according to their rated draw weight?

If they are the same shape, why do online retailers allow you to specify draw weight for limbs?

I suppose the real question is, do the manufacturers of the limbs make just the one limb that caters for a large range of draw weight (eg 24lb - 48lb) or a single limb for each draw weight (+/- a few lbs)

Hope the question is understandable.

[joetapley]

I think the way limb manufacturers vary the draw weight of their limbs is by varying the thickness of the spacing between the two main working surface sections. The thicker the spacing the higher the limb poundage. This will presumably make a marginal shape difference between limbs of different poundage. Really need a limb manufacturer to give a precise answer.

[jeduffey]

I understand that varying the thickness of the laminations, in any application, allows for changing the draw weight. Thicker carbon fiber, or fiberglass, or maple laminations give a stronger draw weight, ect.

What about the actual shape of the recurve itself? I have seen pictures of bows from many different decades and it is obvious that designers and engineers continuously chase improvements. Some of that chase leads to changes in the very nature of the reCURVE itself. I'm focusing here on the curve. I'm interested in making recurve form to make my own bow. So, now I'm pondering the shape of the curve. Is a the conchoid series of curves a reliable design source? Is the conchoid of Nicomedes particularly good? Are other parabolic or hyperbolic shapes more efficient or less likely to produce hand shock?

Who else has struggled with this concept? Thanks for the help.

[JohnK]

Target recurve limbs vary quite widely. See the photos in this thread on the Sagi for some comparisons:

http://sagittarius.student.utwente.n...pic.php?t=2196

[HELLCAT]

I will try remember where , although I have seen a spec for limbs which have two distinct edges in the arc ...

[Shirt]

Greenhorn Ellipse.

www.greenhorn.be, I think.

[HELLCAT]

You were right

http://www.onlinearcheryequipment.co...&productid=243

[morphymick]

Crikey, I never knew the beer down my local was that strong.

Mick

[Meddler]

Originally Posted by HELLCAT

You were right

http://www.onlinearcheryequipment.co...&productid=243

Well, when I were a lad (circa 1971), the bowyers at Kings of Kelso (aka Border Archery) had the same sort of concept on their limbs. It was alleged that the cast from these bows was phenomenal.

I still have my Kings of Kelso "King of Diamonds" (ah, my first ever one piece recurve bow). It has the double bend on the limbs but more towards the recurve than towards the limb riser.

The story has it that George Birnie (?I think) (bowyer at Kings) drew round a recurve from another bow and the limb moved which left this shape on the paper. He made the form up for the recurve using that design and the rest is history.

Whatever the reality is, it looks like some ideas are being recycled...

[jeduffey]

You know, my favorite word in the English language is "and". I like putting this concept and that one and the other one all together to see if goes ballistic or fails miserably.

So, thanks for all the info. You guys put more good answers on the table faster than any archery site over here.