Bow design and development

[PatM]

It's called reflex....  It's just concentrated more in one spot.  There is definitely a bit of a blurred ,line between reflex and recurves when it's a scenario like that above.  Back in the day they called it a semi-recurve.

 A reflexed bow strung up really can still flip around if it's narrow.  Your statement of reasonable width limbs can be the difference maker.

 A reflexed narrow longbow is rather prone to reversing unless care is taken. 

[Halfbow]

Reflex isn't the word. We agree that bow C is reflexed right? But it has no concavity of the back at brace. Reflex can become convex at brace.

Edit: For a reflexed longbow to flip, the limbs (while constrained by the string) have to bend sideways to the same degree you want them to bend toward the belly. This isn't out of the question on something like an out of alignment elb where the string doesn't track over the handle. Because it's a bow that's not far off from being as thick as it is wide (so it can bend to the side about as easily as it can bend toward the belly), and it has small string angles. This is pretty far from how I picture bow C being. I think we agree here, but I don't want the effect of a limb that's considerably wider than it is thick to be minimized. On a longbow, I think the effect would be profound without the width being extreme.

Concavity of the back at brace opens up another mechanism by which a flip can happen. Twist. Twisting a long bow won't change it's effective profile much, but twisting a recurve (for example) will.

[DC]

Isn't that reflex?

[Halfbow]

DC you may have missed my previous post. ^

[DC]

I see what you're after now, I think. Don't think there is a name for it here's your opportunity to be famous.

[PatM]

Reflex isn't the word. We agree that bow C is reflexed right? But it has no concavity of the back at brace. Reflex can become convex at brace.

Edit: For a reflexed longbow to flip, the limbs (while constrained by the string) have to bend sideways to the same degree you want them to bend toward the belly. This isn't out of the question on something like an out of alignment elb where the string doesn't track over the handle. Because it's a bow that's not far off from being as thick as it is wide (so it can bend to the side about as easily as it can bend toward the belly), and it has small string angles. This is pretty far from how I picture bow C being. I think we agree here, but I don't want the effect of a limb that's considerably wider than it is thick to be minimized. On a longbow, I think the effect would be profound without the width being extreme.

Concavity of the back at brace opens up another mechanism by which a flip can happen. Twist. Twisting a long bow won't change it's effective profile much, but twisting a recurve (for example) will.

  It's still reflex, it's just not flattened and bent past straight until the draw progresses.   The bow is a deflex /reflex. No need to re-name the parts and profile depending on what the bow is currently doing.

 Let's not have it become silly like a string follow versus set semantics discussion.

[Badger]

What happens when you have very low string angles is that instead of a braced bow being pulled more toward the shooter the bow is being pulled straight in on itself just as if you were trying to push the top of it into the ground like a spear. Thats what makes them unstable.

[DC]

How did you know that was going to be my next question? I'm still unsure of the whole string angle thing although I do understand how using a long string for too long can affect tillerig. I think that's close to what's going on here.

[Halfbow]

DC, oh man. The pressure. Lol

Pat, to be clear I'm not discounting the word reflex. Reflex is a very useful word that does a good job of describing what it describes. Very necessary. It's also definitely related to the word I'm looking for. And I agree, sections of limb that remain concave on the back when braced are merely the sections of reflex which weren't pulled past straight. Absolutely.

However, because you can make different areas of a limb bend different amounts, the profile at brace can take on a quite different character from the unbraced profile. I could draw out another thought experiment showing how the same unbraced profile could bend to become very different bows at brace. Kind of the reverse of the A B C experiment I already drew. Unbraced, these bows would be exactly as reflexed as each other, and have that reflex in the exact same places. But bending from there, strong reflex can disappear. Or remain. Strong convexity can form where there was none before. Or not.

We don't need an extreme example like bow C to show that. Common bows show that. And because the geometry of the bow in use (between brace and full draw) is what matters most for its stability in use, and the profile's effect on f/d curves, and other such concerns, it seems useful to me to have a piece of vocabulary to make clear that you're talking about the shape of the bow while in use.

As it is now, the word "reflexed" doesn't work at all to describe the braced shape of certain reflexed bows, bow C being a good example. Or any reflexed longbow really. If I handed one to you as a mystery bow, strung, you'd never call it reflexed either. You wouldn't be able to tell it was reflexed. Even though it very much is. Without some fairly detailed science, you'd have to unstring it to know much about its reflex. This is true of all bows really. Braced geometry seems like a sufficiently distinct concept from "reflex" as people usually mean it. But to talk about it, I'm stuck with the super awkward "concavity/convexity of the back of the bow at brace". Can you think of a better way to convey the same info?

It seems to me that we could all talk about things in a clearer way if the terms reflex and deflex referred to the unbraced profile (as they usually do already) and we had different words that described a braced profile. Suddenly communication becomes easier.

As an anology, I think about our language for animals and food. We have the words cow, pig, and chicken, and then the words beef, pork, and poultry. Your view seems similar to someone arguing the we shouldn't have the words beef, pork, or poultry. Who needs em? But the specific words only serve to clarify, and take away nothing. When I say I got some pork at the store, you don't have to wonder if I have a new pet.

(Are you describing bow C as a deflex/reflex bow? I wouldn't agree with that.)

Badger, yes, exactly.

[willie]

Willie, that fixture looks great. I know you were mostly focused on arrows, but did you get any impressions about different setups for bows?

not yet, the range is not ready yet. I hope to use a consistent bow setup to evaluate arrows, then play with the bow variables to see what works for best cast.

[PatM]

I'm not having trouble with any of the accepted ;labels.   No need to complicate things with mystery bows and  not knowing unbraced shapes.

I did not mean that bow C was a D/R.  I meant the actual pictured bow.

[Stick Bender]

Thanks for posting the real world bows & thanks for illustrations Half bow , but this thread has covered a lot of different areas , but my question is how are we judging the designs ,FDC or arrow speed or other ? Ben , Ed made a good point about brace height on those more angular braced bows needing more brace height , that's been my exsperience also !

[Badger]

       I think if you are judging a bow you would have to look at speed, stability while shooting, at least some degree of longevity, obviously a flight bow doesn't need to shoot a thousand arrows but it does need to be able to shoot enough arrows to tune the bow to the arrows. Good speed won't happen if a bow takes too much set regardless of the finished profile. You can still get very decent speed but a rocket launcher is unlikely.

       I am in the camp that feels extreme designs don't work well with wood and are not worth the trouble. In my opinion Mark St Louis bows incorporate the design features that allow for about as extreme as you can safely go. He reflexes them right out of the handle and produces nice sweeping curves in the outer limbs that are not difficult to tiller out. He also gets them working right into the fades giving the bow more working limb to work with. If I were to try and find fault in Marks design I would suspect that some of them mainly a few years back might have started with too much reflex to maintain through tillering and shooting in.

[DC]

We haven't talked much about stability over the years. Is it just about accuracy or does it affect speed and longevity. I'm thinking lack of vibration affecting the last two. Maybe someone could give a short dissertation about stability, it's causes and effects.

[Badger]

  DC, when I talk about stability I usually am just referring to a bow that comes back to a normal brace after the shot. Too much limb behind the handle with too much working limb will be unstable. Hornbows have very little working limb and remain pretty stable. Extremely low string angles for a long part of the outer limb will be unstable especially if you have quite a bit of reflex.