How does tiller affect performance?

[PEARL DRUMS]

I'm a little slow. I can't wrap my head around an elliptical tiller with 10" stiff tips.

A bow has to have an amount of stiff tips to form an ellipse at draw and not be a round shape. The length of the stiff portion only changes the shape of the ellipse, but its still elliptical. Hope that makes sense.

[JonW]

So the ellipse is only reflected in the working portion and not the whole limb? Am I getting it?

[PEARL DRUMS]

Nope, the whole limb. The working portion is nearly round on most bows for around 16" or so, but as it stiffens at the tips it straightens and that stops it from being round and makes it ellipse in shape. Ellipse is basically half an oval.

[JonW]

Not to be argumentative but how can an ellipse have a straight section?

[PEARL DRUMS]

That's what makes it an ellipse, if it was all round it would be round, not ellipse. Think of it this way Jon, split a tear drop shape in half the long way and you have an ellipse shaped bow limb.

[Selfbowman]

I am sure now I'm dizzy.  Still looking though.  Arvin 

[BowEd]

Badger...I have a friend who makes his own FG bows[he's made self bows too] and has adopted the stiffer tips design I shoot.Don't exactly understand all of the reverse wedges etc. used to get the job done but he likes the bow better and it is faster.Not so much reflex though as you described on his.Maybe a couple inches at the very most.

  The r/d bows get squirely once you get past about 2" reflex. The limbs will rock back and forth at brace. The soulution for that is less working limb. Actually less working limb solves a whole plethora of problems but it brings a few of its own, mostly just too much strain.

Yes his bows like that we noticed had less working limb.On a 64"  R/D bow.Sort of like horn bows in a way.Not as short of bow but with FG limbs weighing less mass wise it is working for him.Glue ups on that had to be perfect for it to hold up.

[BowEd]

Great topic. and one I have spent some time ruminating over.  I like the idea Sleek put forward.  Good analogy.  As to whether getting the bend to run from outboard - inward...is that the ideal?  I ask the question because I am unsure.  That is to some degree is how I tiller most of mine, without giving it much thought during the process.  I have been threatening to build an Elmer Wilcox Duoflex for years now.  I have toyed with it on several staves and cant get the balance anywhere near right.  Stability issues yadda yadda, so I've yet to get close.  If you look at the FD curves on them as reported, they are pretty amazing for a wood bow.  They are built quite to the opposite.  Thick inner limbs bend first before the working recurves open up at the end of the draw.  I believe Marc built one if not more some years back.
I think it was actually Russ Willcox.
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SLIMBOB.....I think your right with Elmers's bows there.They have to be shorter limbs though to negate the mass weight of the working recurves.

[BowEd]

JonW....Anytime I make a what I'm calling a stiff levered bow eliptically tillered my working limbs are for the most part parallel width.The taper is in thickness along it.

[JonW]

Ed I guess that is what I'm saying. The "working" section is elliptically tillered not the whole limb. Maybe "stiff" tips and "non working" are where I'm getting hung up.

[BowEd]

Yes could be.The tips are just along for the ride so I try to get them as light as I dare.Reducing string angle in the process too.The more I make bows the farther I want to push the wood.So I've gotten out of characterish type bows looking for cleaner wood lately,but and a big BUT if I could find an osage stave around here that has the nice snake to it[like Pappys' bow] I would cherish that paticular bow making it in a within reason type build.
Tillering affecting performance.....Personally I think it can make a difference on how heavy of arrows a person wants to shoot too.Lighter arrows where the outside parts of limb work more and heavier arrows where the inside parts of the limb work more.

[Marc St Louis]

Marc, I dont understand?

If you don't have more working wood in the outer limbs then the bow will take a lot of set from being tillered like that and the extra mass won't help either especially shooting flight arrows

[LittleBen]

All I know is when I tillers tha bows good they shoots good thanks bye