D/R selfbows?

[Kegan]

If a full length stave is naturally straight, with no deflex, is there any benefit to try for a D/R profile? Does it help performance any over a regular straight or slightly reflexed bow?

[JackCrafty]

I dunno.  As far as I understand, the higher tension in the string at brace is what gives the advantage on a reflexed design.

[Del the cat]

S'pose in theory a bit of deflex keeps the stability and the reflex at the tips improves the string angle and gives a bit more tension at brace.
I only do it if one limb is already that way inclined and I'll steam the other one to match. It's also handy to put in some deflex if you want a long draw from a short iffy stave and you're not sure if it will take the strain.
Matching the limbs up does make tilling easier and makes it more pleasing to the eye. The current Yew ELB I'm working on had an ugly deflex on one tip, I wanted to leave it au naturelle but I just couldn't stop myself bending it to match D'oh 
Del

[jwillis]

I think that a good strategy is to add a bit of reflex in the limbs and leave the handle straight when starting the tiller process. As the bow takes set during tillering and break in it will hopefully gain just the right amount of deflex into the handle but keep enough reflex near the tips to improve the string angle at full draw. If you look at the draw force curves of enough different profiles you'll discover that anything you do to the limb to reduce deflex and increase reflex allows the bow to store more energy during the draw. The challenge of course is getting the bow design to perform efficiently by transferring the additional stored energy to the arrow during the power stroke. Like Del said, It seems that deflexed handles help direct vibration away from the handle area. Jim

[Marc St Louis]

Exactly how would you introduce the deflex if it's straight?

[Kegan]

Exactly how would you introduce the deflex if it's straight?

Steam/heat the limbs and clamp it to a form of some sort.

...But I think I'm trying to do something that has no point. The "needle tip" style flatbows that I've made were plenty fast and had little shock. I'll just leave the D/R shape for when I come across a deflexed stave or a set of billets.

Thanks for the input everyone.

[Lukasz Nawalny]

I just make d/r selfbow , few days I show you pictures

[Marc St Louis]

It is a real pain steaming in deflex into a handle.  You can't do it to a full depth stave as the wood is just too thick so you have to reduce the thickness to about 1" thick, even then it's pretty hard to do.  Then you can run into other problems.  It's very easy to introduce a bit of twist as you make the bend and even a small amount will throw the outer limbs off.  I've done it a few times and most likely won't be doing it again.  Splicing is soooooo much easier

[Lukasz Nawalny]

I have build steaming machine , over 3000 watt , I can make deflex in handle little over 3 cm thickness . On photo I make core on assyrian hornbow , but d/r selfbow longbow I can make in similar way.You have right with twist , extrem hard problem , I fight with this  few days and I hope will be ok , we will see.