Primitive Archer

This has been a very educational thread.  Thank you.  It seems like there's going to be even more information added before it is complete.  I'm not an engineer that understands all of these science/physics concepts, but I have made, owned, and shot a lot of bows and base my opinions on that.  The fastest selfbow I ever owned/shot was made by Marc St. Louis.  It was highly reflexed and also had static recurve tips.  The bow shot a 10gpp arrow 199 fps.  It has always been a quest for the best all-around combination of speed and shooting characteristics.  Most of the speed bows didn't shoot my hunting weight arrows well or were not pleasant to shoot many arrows from a day.  When I settled on the DR design it was just because it shot as fast as nearly all of them, plus it was very pleasant to shoot.  I also agree that the design benefits from having the tapers correct.  There is a fence 200 yards from my shop door, and it serves as a testing site when a bow is being made.  It seems like the best ones will always send a 10gpp arrow over that fence...which is OK because it's my hay field on the other side of the fence.    Thank you for the sharing of so much knowledge.   

That's gorgeous! I love the profile and the snakeyness!

It seems that they are bending mainly near handle area...... If not, it indicates that there is unnecessary material (and thus mass)
I dont think so: The mass towards the outers is mainly needed for stability. If you want your outers stiff by purpose for some reasones then you keep them stiff of course and save mass by making them narrow.

And to me strain mainly is a function of bending radius vs thickness. And if that is correct you can actually see strain in the tiller. Look at Karpovitz idealized schemes.....or others....the bend and the strain are concentrated towards the handle. This is also why a d/r will do better than a straight limb....because you can move your bend closer towards the handle without overstraining weaker materials like wood.

Why it is better to have the bend closer to the grip still is an enigma to me - I just know it will make your bow faster as long as you keep your outers narrow and as light as possible. We of course also have that string angle thing.....the closer your bend is to the handle, the better your string angle at fd...but tbh, I never really understood the effects of string angle....I have discussed that topic with more than one physiscian but never got a reasonable answer - please enlight me 

I'm also adding a picture of my fastest bows, which are a horn/sinew composites. And one of a horn bamboo longbow which is very similar to your model 3 (although very slim compared to your model. If my bows were evenly strained the wouldn't usually all fail in that same spot 

and btw Arvin: I think its true that the shorter bows outperform the longer ones with light arrows (due to shorter limb travel and higher dryfire speeds). On the opposite I dont think the longer bows have a advantage with heavier arrows at the same drawlength....that is a myth imho. These short reflexed bows can handle 10gpp  very well.

Guys I’m getting in over my head as usual but if the outer  reflex is working reflex I think we might be getting a bit of whip affect. Giving you more energy in longer bows and heavier arrows. The shorter bows with lighter arrows with more strain on the inner limbs will give you more stored energy. This is just a guess like I said it’s over my head  at this point. Think about the unwinding of the Turkish bows and they shoot lighter arrows farther. Not so good with heavier arrows.

To best use the stored energy it needs the optimized tiller. Looking at actual flightbows I seldom see even strain in the limbs.

The question is that how do you optimize the tiller? What is the parameter which is altered? More bending towards the tips, or handle? Something else?

About flightbows (or any other bow), you cannot see the strains, it cannot be judged just according to the bending. It is impossible to know. For example, classic Turkish flight bow. It seems that they are bending mainly near handle area (sal) but they are stressed more along the limbs (up to kasan area) than it seems to be. If not, it indicates that there is unnecessary material (and thus mass).