Bowyer mind teaser

[mmgrode]

For all you bowyers out there, here's something I've been thinking about:

Lets say you had a bow with a straight end lower limb and a recurved upper, both the same length(before bending the recurve).  How much positive or negative tiller should a bow like this have?  How about the other way around(longbow on top, recurve on bottom)?  What do you guys think about shooting dynamics, etc of such a bow?  Lets see if we can get our brains going on this one.  Looking forward to your ideas.  Matt

[Pat B]

With wood bows, especially from staves, the bow at brace doesn't necessarily tell you much. The only way to tell a well tillered bow is at full draw and especially when being pulled by the ultimate shooter. When making wood bows I don't measure positive or negative tiller at brace...as a matter of fact, I never measure positive or negative tiller at all. I use brace and especially a short 4" first bracing to tell how well the string tracks along the bows length and if there are any particularly stronger or weaker spots along each limb. Other than that I eyeball my full draw tiller on the tiller tree but also with a picture of me at full draw with the bow. I do use the block wall behind my tiller tree as a reference but thats about all.
  On a bow with one straight limb and one that is reflexed or recurved I generally try to make both limbs equal with a bit of heat to start with but short of that, the stronger limb should go on the bottom.
  If a wood bow is properly tillered it doesn't matter what the braced or unbraced profile are. On a properly tillered bow both limbs take equal  amounts of stress and pass that on to the arrow on release. It doesn't matter if one limb is recurved and one straight, or one limb is osage and one in yew, both limbs will impart equal tension at full draw and recover equally on release if proper tiller is achieved.    
   Pat

[Dano]

I'm with Pat, I've built some character bows that might as well be recurved and straight, once tillered properly they shoot just fine, a little ugly tho.