WHY are short bows slower?

[bow-toxo]

      Flight bows are very short bows, they tend to store good energy for their length but really capitalize on being more efficient.                                                                                                               ,

So if longer bows store more energy and shoot faster, why are flight bows shorter ?

[RyanY]

Flight bows shoot light short arrows. Shooting a shorter arrow means that the bow doesn't have to worry about stacking and can store sufficient amount of energy. They are also more efficient than longbows shooting lighter arrows because the limbs have less mass and they have a shorter string. Short bows thus have a faster dry fire speed at a shorter draw length than longbows do because less wood is moving. I think that's why. 

[Eric Garza]

Well say you built the bow to draw to 28". The FD curve would be shallow to a certain point and raise suddenly in the last few inches of draw to reach the full draw weight (this is what we know as stacking). This curve would be below a straight line curve produced from a longer bow thus storing less energy.

So an "S" shaped FD curve, starting above the line and moving below it before rising back up to it?  I've made several short bows and have plotted FD curves for pretty much all of them, and have never seen an FD curve turn out like the one you're suggesting.

[RyanY]

The curve wouldn't be S shaped but just a curve below the straight line. I haven't plotted enough FD curves to witness this but I'm referring to the FD curves as seen in TBB volume 1 which shows exactly what we're talking about with regards to stored energy and bow length. What it shows is that a longbow shows an even increase in draw weight through out its draw length. The short bow shows a low increase in draw weight earlier in the draw and then increase in draw weight later in the draw.