There is still plenty of theoretical stuff being tossed around on this thread. We all still hear of the fantastic capabilities of horn but it's rarely like that in real life.
Horn is never actually compressed 8x farther than wood and chrysaling of horn is frequently reported.
I don't think it's incorrect to say that wood "resists" compression more than horn. It may collapse sooner but that doesn't mean it's not resisting more than something that just gives, even if it does bounce back.
Nothing quite makes a person lose credibility about these style of bows more than the mention of Sitka spruce siyah's.
Compression is a description of the force that is acting on a material.
Sure horn will chrysal once it has been pushed beyond it's ability to be compressed - right after it has reduced in length by around 8%.
It has the ability to store more energy than wood because of it's cell structure.
The point I was making is that horn will bend a whole lot further than wood can and it has the capability to store more energy during this bending than any wood can.
This is directly related to the original question because he was asking if it's possible to make a hornbow without the horn essentially - the simple answer is no.
The longer answer is that you can make a wood bow that will, to the untrained eye, look SIMILAR to a hornbow. However it is impossible to make a dimensionally correct hornbow out of wood and still have it being drawn more than 12 inches because the materials have vastly different limits.
My advice would be to forget the hornbow (unless you want to make one) and just make either a wood only recurve or a sinew backed recurve.