"which tiller is better for what?"

[BowEd]

Ahhhh yes I can vouch for that with bows I made the first couple of years.Taking too much set mostly mid a little outer till I had to refine the wood removal there to hold up better or putting more reflex there to hold up better.Choosing to narrow and thicken there to reduce mass.
I wanted to say now something about limb tip profile[the last 8 to 10"] affecting brace and full draw look.Maybe this is a given here or moot.Narrower and thicker there will bend less to affect that.Flat,wide and thinner it bends more.When someone posts a bow that is streamilned as I've heard Badger say,you can see it's a more than probably a good sweet performer from the top profile seems like especially if it's shown at rest from full draw.
For the archer that wants performance speed is all that's important.For the hunter I would say arrow placement is all that's important.Why not do both heh???
As for consistency of arrow placement in the target your right that is a group effort type thing.The handle/string nocking point/arrow spine.The way a person holds the bow.Sweet shooting to me is no stack/no handshock.Even along the whole way of draw so my bow arm does not deviate from position I want it at.

[mikekeswick]

Wiilie - you haven't 'created' set because humans cannot create things....
Joking aside on the first bow with a circular tiller which is then made elliptical - no extra set because you have thinned the limb therefore it can take the extra bend. However your inner limbs aren't now doing their share of the work and the now overly worked outer limbs are thinner.....a thinner limb doesn't have the same return speed as a thicker limb. So by doing this to a pyramid bow you have lowered energy storage and made it less efficient. Not my idea of ideal!
Again you may not induce anymore set by making a parallel limbed bow have too much bend in the inner limbs but again the same principle above applies and this time you will also have handshock added into the mix. again not exactly ideal.
You may assume that you can make any front profile have any tiller and indeed you can if you really want but that is not correct for the materials we are working with.
It is not me that is making all this up you know and I don't for one minute suggest that these are my 'original' ideas it is backed by plain old facts and common sense! The theory for all this stuff has been worked out many years ago - read the book 'Archery the Technical Side'. It explains all this in detail and gives the equations to work it all out mathematically. If you want me to repeat what is already out there I could 'back up' what I have already said with numbers but.....I guess most people wouldn't be too interested in the proofs.
When you start talking about light flight arrows the same principles apply but most people don't shoot flight arrows and are therefore generally making bows to shoot 'normal' weight arrows. Clean arrow flight has little to do with tiller profile. Clean arrow flight has many variables not linked to the shape of the bows limbs.....

[willie]

Mike-

You may assume that you can make any front profile have any tiller and indeed you can if you really want but that is not correct

I agree entirely, if of course by "correct" you mean to say, getting the most efficiency or speed out of the arrow.

I started this thread with hopes to look into some of the less tangible qualities of arrow launching, a bow may have. Qualities that one may wish to have, even if giving up a few FPS.  I cannot help to think of a few bows in the past that were just a joy to shoot, even if they were not the fastest. Of course my "thought experiment" bows were not meant to be efficient, but were examples of what might be done, if one so desired

Thanks for your input,  your assertion  that "Clean arrow flight has little to do with tiller profile." is well received. Perhaps a thread on "what makes for clean arrow flight" would be a good thread for another day.

Just a question if I may ask,

.....a thinner limb doesn't have the same return speed as a thicker limb.

those of us who find performance defined as "FPS", don't have to be reminded that the fiberglass guys have us beat with their high modulus materials.  Do thinner limbs have anything to do with that performance gain?  Or am I taking your statement out of context?

willie

[Badger]

  I don't think thickness should receive any consideration. We have energy storage and efficiency. You make the bow as thin as it takes to accomplish whatever your design calls for without damaging the wood. A thicker limb will usually have more working limb which does not always contribute to high efficiency.

[sleek]

Regarding your question Willie, I am pretty certain I am referencing Badger here when I say that the problem with thin limbs is they tend to deform on release. Its not just a pretty lottle arch back as when you slowly let down. The limb actually starts to set up a wave pattern, though i could be describing wrong. Point is, thin limbs tend to distort, or do distort, on release making a negative impact on efficiency. But I believe that can be countered with shorter limbs, which allows then to resist distortion better. There may be a width to thickness to length formula to be made.

[willie]

Sleek

you describe the sort of limb motions that I wonder about sometimes. I appreciate your bring it to the discussion. Today as I was driving home from work, I thought about another observation made by Badger earlier. About "Most of the records set are set using simple designs."

Seems like some of the more radical designs focus on high early draw weight as a goal. High early draw weight certainty makes for a fat F/D curve, and theoretically would seem to offer the potential for better arrow performance.

I have to wonder if  high early weight makes it harder for the limbs to return to brace at the same time because of that distortion. Of course that assumes a well timed limb is supposed to return at the same time as the other, and nothing else causes the string to impart any unwanted forces to the arrow. Too much pent up energy at brace height might make for a bow that is harder to tune or keep in tune from shot to shot.

[PatM]

 The old flight records dispute your radical design being less optimum theory  Seems there would be less distortion in a radical design because more limb is eliminated from joining the wave.

   Don't get Steve started on timing and limb return. 

[Badger]

  PatM, I was only referring to arrow flight when I made that statement. I have bows that will shoot up to 300 fps but I can't seem to get the distance from them that I get from much slower bows.If tuned properly and properly matched to an arrow of course a faster bow will shoot further. Just using shorter arrows makes a huge distance difference but they are illegal in the primitive classes.

[bradsmith2010]

seems like the arrow is a fault with the 300 fps bow,,not the bow,, am I oversimplifying,,??

[Badger]

seems like the arrow is a fault with the 300 fps bow,,not the bow,, am I oversimplifying,,??

  Brad, really difficult to get good arrow flight from a 23" arrow below about 180 grains. Once in a while you get lucky but the slightest sideways motion or tailwagging coming out of the bow kills the arrow. It might straighten right out within 20 yard or less but all the power is already gone. If you can see you arrow you can almost be sure you didn't get a good shot off. Nocking point and release have to be right on. 

[sleek]

Wow, 300 fps is pretty quick. What design are you getting that from steve?

[Badger]

Wow, 300 fps is pretty quick. What design are you getting that from steve?

   Just a short recurve about 52" long but that is shooting very light arrows about 130 grains, not fast at all with a 500 grain arrow.