Primitive Archer

you are right Badger - I messed that up - the short bow does store less energy but is more efficient.
But why does it store less energy? String angle?
And why is it more efficient? Limb mass, limbtravel and inertia?
And why does the d/r in Tuomos experiment store more energy than the straight limbed bow? string angle?
Now: In practice we often see that short bows are faster — especially with light arrows — than the longer ones: is that  maybe because limb mass and limb inertia (efficiency) matters more than stored energy?
If that is the case,  when trying to make a fast bow, one should maybe focus more on efficiency than energy storage? How to optimize these contradictory facors?
Given that more stored energy usually means heavier and slower limbs, how do we find the sweet spot where arrow speed is maximized?
It must be where increasing stored energy starts to cost you too much efficiency by increasing  limb mass and inertia.
Now where is that?

Interesting idea thinning the outside of those turns. Makes sense.  I’ll have to keep that in mind when I take on some of the snakey staves I have collected. Sharp looking bow!
Mike

Nice work, Brian. Form and function. 

Nice BJ , looks like you are pretty good with leather to me. Pappy

yes, Tuomo, I had around 50 or so different bows from different bowmakers on the shooting machine....maybe post that in a seperate thread, its sure interesting.

How do you optimize the front profile
The longbow is self stabilizing when strung - you can make it as narrow as you like without getting into stability issiues. A recurve needs a certain width at its base. At the same spot the longbow can be made much narrower resulting in a different top profile and mass difference. Your experiment does not take in acount relevant specific characeristics of the design. Namely the lighter limbs of a longbow, and the extra mass of recurves. If we compare the experiment with reality we also must say, that you put recurves mainly on shorter bows - 68" is a bit long to make a recurve.

But this is all about fps. If we only talk about stored energy and sideprofile and leave the fps aside, this a very good experiment.

Shorter bows automatically store more energy - this we know - and also that reflex is another key factor. Now we have same length and same reflex. So the small differences we see come from the sideprofile (and tiller).

Maybe Tuomo could upload the force-draw-curves? Visualizing the stored energy? Maybe we see a nice hump in the curve of the d/r?

And Tuomo: Do these bows all have same length of string? Any Differences?

Gettin' curious again 

Do you still have the shooting machine set up? Im very interested in your experiments, please do post it, here or on another thread.