what wood and design would you use to get the best performance and efficiency from an 80# selfbow? performance is paramount! recurve? reflex/deflex longbow? something else?
i want to shoot an animal that happens to be big and dangerous with a stone point.

I disagree, that performance is paramount, IF what you want is to shoot an animal.  You open up a big can of worms, like 86" bows, or bows w/ 7", 8" of reflex or recurve or bows braced 4".  While some of these bows can be very effective hunting bows, it's not the most common configuration.

That said, generally you want a more dense wood for a more heavy draw weight bow.  Simply because you can use less width and lenght to achieve the same stored energy.

Most (of the very good) selfbows vary very little in terms of performance, particularly when you rule out the radical designs.  So, since it doesn't really matter, lots of folks tend to prefer relatively short flatbow designs, and where the region calls for it, woods like osage, black locust, mulberry, yew which have sap which seems to help mitigate changes in, or the effects of changes in moisture content.  For selfbows moisture control is perhaps as important as any other aspect when one wants to maximize performance w/in a particular design.

To answer your question, osage would be the preferred choice for my needs.  In an extremely cold environment like Canada, depending upon the season, you might do fine with other wood choices.  Most any reasonable wood will make 80# @ 28" without too much extra design consideration, beyond a little extra limb width.

i'll be using this bow in northern australia. it'll be about 35-40 celcius and 70-90% humidity

that sounds like fun hunting conditions Clint. Them cane toads get big up there, can't blame you for building a canon.    Might work on Buffalo too.

I've never made an 80# bow but I've seen several that heavy and heavier.  They were either osage or yew.

If you use osage, go with a flatbow, 66-68" and 1-3/4" wide for half the limb.  Yew makes a nice English Longbow.

Quoteposted by ozy clint:
it'll be about 35-40 celcius and 70-90% humidity

I was about to ask for this, as for some reason, I had the impression this bow would be used on something - big and black and horny - I meant to say horned of course    

I doubt that Yew will hold up under that conditions. And I would go for 100# to start with anyways ...

It's hard to beat a good Osage bow for most applications! I would suggest that if you go that route you heat treat the belly to help keep up it's compression strength in muggy conditions. A tropical wood such as Ipe would be a another good choice for the hunting conditions you mentioned.

Hard to beat just a good ol' straight bow design IMO. You gotta hit what you're shooting at you know  :D  ! -ART B

I'd bet an 80 lb IPE bow would be just the ticket with a heavy arrow

yeah the cane toads are big and nasty. so are the buffs

CLINT IM BULDING TOM A 70 # HOLMGRAD OUT OF SAGE BARK HICKORY  AT THE MOMUNT I BELIVE THAT D WORK VERY WELL OF THEM BUFFS  AS IM GONNA FIND OUT ALSO AS ILL BE GOIN OVER THERE BU T BETWEEN YOU AND ME I SHOT A AMERICAN BUFFALO WITH A STONE POINT AND NOPE I WONT DO IT AGAIN I FINISHED HIM WITH A SNUFFER  AND UR BUFFS ARE 3 TIMES AS DANGOURS AS THESE  HAVE FUN  BROCK

Under these conditions only one wood will do - Osage. And at 80# recurving will probably be too much. I recommend a semi pyrimid osage longbow with some reflex put in with a little heat.  Use a light string like 12 strand TS-1. Hickiry will loose cast and set under the humid conditions.

Mike

I've made 3,80#,1,90#,2,100# bows.The one 100# blew apart on the tillering board.The one 90# bow got about 4"s of set after about a year.The 2,80#bows both made great bows.Both ended up with an 1" of set. And were very fastbows.All were made of o'sage unbacked.Twice I tryed 80# hichory bows again unbacked both got 4"of set after a year or so.Yew is surpose be good wood for heavy poundage.I once made a 75# yew which made it ok.I say O'sage is the way to go.If your going unbacked.

ok, say i wanted to drop down draw weight (i'd probably get better accuracy) to 70# but keep the performance and also keep it primitive. would a sinew backing on osage be the go?

A well made 70# osage selfbow should be able to shoot through anything if you do your part.  Sinew backing won't necessarily make it any more efficient.  You have to design the bow to your desired parameters.  Give us your draw length, draw weight and bow length and we can help with this.

A simple, well made osage self bow would be less effected by temp and moisture changes and can handle the weight you are looking for. Anything else you do to the bow will be a possible weak link in the chain.

draw length= 27 3/4" to 28"
draw weight= 70# to 80#
bow lenght= that's up to more knowledgable guys like you.