Limb profiles

[Woodely]

Just wondering if some of you have built bows using the profile "A" in the picture or stick mostly with "B" .   Is profile "A" more common to ELB bows built during the English longbow era years ago.  Some of you still build with that profile,  is there any advantage to having a rounded profile (egg shape) or the normally flat style design like "B".

[IrishJay]

I'm far from an expert, as I've only built a few shootable bows so far, but one was in the ELB style. It's profile was actually more of a hybrid between A and B. The back was like B and the belly was like A. Mine was 71" ntn 50lb at 31", shoots well. 

[DC]

Because I usually make sapling bows(except for recently) mine are halfway. Flat belly and crowned back. Theoretically the crowned back concentrates the stress down the centre of the limb but I've never had a problem with that. I think I remember hearing that warbows were rounded so the chrysals formed down the centre of the belly and weren't a big a problem as if they were all the way across. That theory has some holes in it from my opinion.
My recent bows have been flat mostly because it's convenient but I do think it spreads the tnsion and compression out better.

[txdm]

The recent March 2019 issue of Primitive Archer magaazine has a great article on this subject.

[Woodely]

Because I usually make sapling bows(except for recently) mine are halfway. Flat belly and crowned back. Theoretically the crowned back concentrates the stress down the centre of the limb but I've never had a problem with that. I think I remember hearing that warbows were rounded so the chrysals formed down the centre of the belly and weren't a big a problem as if they were all the way across. That theory has some holes in it from my opinion.
My recent bows have been flat mostly because it's convenient but I do think it spreads the tnsion and compression out better.

Thx for that insight, "Theoretically the crowned back concentrates the stress down the centre"  thats usally what I attempt to do.

[DC]

 "concentrates the stress down the centre of the limb" was not meant to be a good thing. Putting too much stress in one spot is never a good thing, but maybe pulling some of the stress away from the edges might not be a bad thing. This is the back I'm talking about here.

[Woodely]

This is the back I'm talking about here.

Yep I know what ya saying.

[Pat B]

A lot depends of the wood you use. Some bow woods like osage can handle a more lentricular shape where other woods handle a more rectangular profile better.
 In general, for a more durable bow you want the entire working portion of the limb to share the stresses and "B" would give you that security. The only problem with that is it hinders experimentation.