Bow design and development

[Stick Bender]

Nice looking bow Steve , I can only speak to bows I have made myself but there is always pro's & con's to every design but the D/R  bow has a lot to offer in a mild shooting fast hunting bow , but Don what is it you where after info wise in comparing natural to glass ? I think Brad said it best there 2 different beast ?

[PatM]

Leonwood, there is absolutely no doubt that reflex/deflex bows are excellent, both in performance and in shooting characteristics. They are likely legitimately the best design for many people. But when you say they're really fast, I'm curious what you're comparing them to. It's a claim I hear a lot, but I expect many people's impressions come after comparing them to longbows, and not highly reflexed bows. Have you tried a highly reflexed bow? (Not an attack, just curious. I haven't tried any extreme examples myself.)

If you read that article I linked about the Turkish bows (http://www.atarn.org/islamic/Performance/Performance_of_Turkish_bows.htm) I think you'll be impressed by the performance. All three of those bows pictured are made of natural materials and are toying with 200fps at 10 grains per pound.

 Are they that close to 200 at 10 grains per pound?

[Del the cat]

I think there is some confusion/mixing up of design and materials in this thread.
Horn sinew composites are the shape they are because it suits the materials.
Modern D/R shaped bows (F/G Carbon etc) (spits on floor) are basically down to Clarence N Hickman's work in the 50's
D/R designs in wood/boo are toned down versions of the above tailored to suit the materials, and yes they'll give better F/D curves but only when the design and draw weight matches the material.
Del

[leonwood]

Leonwood, there is absolutely no doubt that reflex/deflex bows are excellent, both in performance and in shooting characteristics. They are likely legitimately the best design for many people. But when you say they're really fast, I'm curious what you're comparing them to. It's a claim I hear a lot, but I expect many people's impressions come after comparing them to longbows, and not highly reflexed bows. Have you tried a highly reflexed bow? (Not an attack, just curious. I haven't tried any extreme examples myself.)

If you read that article I linked about the Turkish bows (http://www.atarn.org/islamic/Performance/Performance_of_Turkish_bows.htm) I think you'll be impressed by the performance. All three of those bows pictured are made of natural materials and are toying with 200fps at 10 grains per pound.

First of all, I am in no way suggesting that highly reflexed bows are not good at all! I sure have made several highly reflexed bows and they where definitely the fastest bows I ever made. However I found that they break down in speed over a year or so and lack the extreme smoothness of highly deflexed bows. This is especially true for longbows. (My recurves usually shoot smoother due to string angle etc)
Now most of my rd bows shoot 175+ and some even in the 180ties. The highly reflexed recurves I made shoot 192 and one even 195 but they did drop down to 185 after a few 100 shots. My first few reflex/deflex bows still have the exact same poundage as the had when I made them and had thousands of shots over the last two years.

Now over here we al shoot either target or 3D courses so accuracy is favourable above extreem speed, the reflex/deflex gives me really good accuracy, no handshock, and if done correctly also more then enough speed. Another important aspect of the deflex is that because of the lower strain at brace, the bow still shoots the same after long hours of brace time, this really helps for 3D competitions which can take all day.

[Stick Bender]

Lol Del he mentioned the FG in the original post thats the reason I mentioned it , Im glad he didnt say carbon , you would need a spit tune 

[DC]

but Don what is it you where after info wise in comparing natural to glass ? I think Brad said it best there 2 different beast ?

I wasn't really comparing the material, it's the design(RD) that most bows seem to be now. I was hoping that there might be so info available from the manufacturers development that might explain why it works so nice. Unfortunately I'm a "Why" person and while a lot of people will accept some pretty vague explanations as to why things work I can't do that. Things like "It's the string angle" leave me wanting more. I want to know why the string angle does what it does. I just grabbed string angle as an example, it may or may not have much to do with this. There must be a reason why they chose the deflex angle they did. Possibly they did it by trial and error and even they don't know the real reason.
   I have a theory that has to do with the lever length of a limb. The actual lever length of a straight bow gets shorter as the limb bends. Reflex and recurves minimise or reverse this so the actual lever length can get longer as the limb bends(or straightens) as you draw it. I've made models that show this and it's not a lot but the difference is there. Sorry, I'm rambling

PS Modified to separate my theory from the rest of my rambling

[Halfbow]

Badger, wow that sounds like quite a bow you made there. Props on making one like that which failed gradually rather than explosively. What was it made of? As I'm sure you're aware, your design theories there have a lot in common with the Turkish bows I talked about. Tiny working areas and long rigid levers.

Are they that close to 200 at 10 grains per pound?

Yes, according to that article. They got quite scientific with it, you can read all about their methodology. With lighter arrows they got as fast as 357fps, and have several reasons to think in better conditions the bows could have shot faster. Computationally this means (given good arrows) they're creeping up on the historical Turkish flight record of 930 yards.

First of all, I am in no way suggesting that highly reflexed bows are not good at all! I sure have made several highly reflexed bows and they where definitely the fastest bows I ever made. However I found that they break down in speed over a year or so and lack the extreme smoothness of highly deflexed bows. This is especially true for longbows. (My recurves usually shoot smoother due to string angle etc)
Now most of my rd bows shoot 175+ and some even in the 180ties. The highly reflexed recurves I made shoot 192 and one even 195 but they did drop down to 185 after a few 100 shots. My first few reflex/deflex bows still have the exact same poundage as the had when I made them and had thousands of shots over the last two years.

Now over here we al shoot either target or 3D courses so accuracy is favourable above extreem speed, the reflex/deflex gives me really good accuracy, no handshock, and if done correctly also more then enough speed. Another important aspect of the deflex is that because of the lower strain at brace, the bow still shoots the same after long hours of brace time, this really helps for 3D competitions which can take all day.

Sounds like we are in complete agreement then.

I think there is some confusion/mixing up of design and materials in this thread.
Horn sinew composites are the shape they are because it suits the materials.

I would look at this a little bit differently. Of course design will differ for different materials. Just as materials can be quite different from each other, ideal designs for materials can be quite different from others. If you start with a certain material as an unchangeable given, and set out to arrange that material in to the best arrow shooting device you can, you will eventually arrive at your favorite design for that material. And if you start out with different materials, you will arrive at different favorite designs.

I don't think this is what people were up to when they developed the Asiatic composites. Material wasn't an unchangeable given. They weren't suffering from a lack of wood (or bamboo) and were forced to figure out how to make do with mostly sinew and horn. Their unchangeable givens were concepts. Concepts like, all other things being equal, light limbs shoot faster. Short limbs are lighter. Reflex reduces stack and increases speed. Etc. Then they went out and figured out which materials would allow them to take those concepts to whatever extreme they could make possible. And it resulted in the hardest shooting bows the world had ever seen. With these bows (and horses) they overran pretty much anyone who stood against them, from the ancient Romans to the medieval Europeans, and made the largest continuous land empire in history.

So with the original question being, "why so many modern reflex/deflex bows?", I'm adding to that, saying that I'd be curious to see more modern companies taking these proven concepts to whatever extreme they can with whatever modern materials they can.

I'm all about traditional bow making, and that comes from my interest in history. But I'm also curious... what could a modern materials bow reflexed like this do?


I'd love to see.

[bradsmith2010]

I think the bow bow badger posted is good example,, if that bow were fiberglass it would not break down and woould be shooting the same,with the wood bows,, the breaking down of the wood adds an extra challenge to the design,,,the fiberglass will hold up to many more design ideas,, so a great design on a fibergass bow,, might break down a wood bow quickly,, so makes it hard to apply the fiberglass ideas,,,, some things are universal,,but the fiberglass and wood are just too far apart in what can be done with each,,  I think as a starting point,, a great design for a wood bow,, will work nicely for a fiberglass bow,, but not the other way around,,
Halfbow,, nice post, I would like to see that too,, 

also do you think that the Turkish flight record is due to better archers or design,,???

[Bayou Ben]

Some good points being made here.  I'll start by saying I have no desire to ever work with FG, but when the FG guys talk design on the other site I listen.  Some of those guys are very meticulous on recording FDC's, as well as other things like string tension at brace. 

One trend that I noticed in FG bows are forward handle r/d designs.  Many individuals are building them, and some of the performance numbers are pretty good, high  190's and 200's w/ 10gpp, all while being forgiving, stable, and accurate.   So if FG doesn't take set and break down like wood, why would a mild r/d forward handle FG bow perform better than most other FG designs?  I don't know the answer to that, but it makes me consider that string angle has a lot more to do with efficiency than we realize. 

It seems that a forward handle design would have more benefit for an all wood bow than it would for FG.  I'm currently working on a bow that is applying and testing this concept.  My thought is that the forward handle will allow more draw while giving better string angle and less stack farther out in the draw.  We'll see how it goes....

Ritchie (Stick Bender) refers to this bow as angular.  I'm not sure about the terminology.

 

[bradsmith2010]

its over my head now ,, but I listening,, 

[Stick Bender]

When I saw your design Ben I instantly recognized it & it's some thing I thought about doing with maple/osage/sinew,  I'm glad some body is trying it in wood ,I say angular meaning the braced profile of these bows similar to Egyptian  composite bows , I'm not really a technical bowyer but after building a few of these & testing them I came to intuitive ideas about them ,I think maintaining the string angle threw out the draw is a huge plus ,but also the high limb return speed is huge ,I discovered that by accident when I made a 64 in version expecting it to shoot heavy arrows fast when the opposite happened it shot lighter arrows better, I look at this design as the lower limbs doing the majority of the work with the mids assisting and helping to maintain the angle coupled to the rigid tips ,the power lam in my bows extend about 3 in. Beyond the fades  , I'm curious about your power lam length in your bow , Im very interested in your bow please post about it when your done I think another hidden feature with these bows is because of the curvatures of the limbs they end up with more working limb in a shorter foot print ,I think it would make a great bow in wood might take some trial and error but that's half the fun !

[Halfbow]

Wow I tried a very similar looking bow once.



(The back is up in the pic)

I planned to eventually add siyahs. Unfortunately mine was a failure before it even got to bend, just because of a stupid mistake on my part. Hope you have better luck with yours! Seems to me that the design could make a great bow.

But I'm not sure I follow how a handle that bulges out on the back of the bow would improve string angle much. I just liked the idea because it seemed like it would fit the hand better than a similar shape bulging out the belly.

There must be a reason why they chose the deflex angle they did. Possibly they did it by trial and error and even they don't know the real reason. I have a theory that this has to do with the lever length of a limb. The actual lever length of a straight bow gets shorter as the limb bends. Reflex and recurves minimise or reverse this so the actual lever length can get longer as the limb bends(or straightens) as you draw it.

I'm not sure if this is what you meant, but you've got me thinking. If you take a bow with strongly recurved tips, hold it vertically, and draw it, then as the main part of the limbs bends to become more horizontal,  the recurved tips are doing the opposite, becoming more vertical.  This keeps the nocks far away from the handle on the vertical plane, giving you more leverage. The two parts of the limb trade off the job throughout the draw. That's cool. I've never thought of it that way before. However, that would be just as true for a reflexed recurve as it would be for a deflexed recurve.

also do you think that the Turkish flight record is due to better archers or design,,???

Better design. Unless archers back then were better than a quick drawing instant release shooting machine.

[PatM]

  But  "simpler" modern designs greatly exceeded the Turkish records.

 The Turkish data from Adam K doesn't really show a 200 fps 10gr/p trend.

[Bayou Ben]

Half bow, my thought behind forward handle and string angle is as you draw the bow back your string angle increases.  If you put let’s say an inch of handle up front as opposed to the belly and you pull your bow back to 28” then you would have the same angle as pulling a traditional belly handle bow 27”.  Not that big of a difference it seems, but it’s definitely something.  And in that same example, a wooden bow has the benefit of less stress, as equivalent to only pulling a belly handle bow 27”.  Those 2 coupled together should result in a less stressed belly with more energy storage.   
A FG bow doesn’t benefit from less stress since it has no memory, so it leads me to believe the string angle on those last few inches are more than insignificant.  Plus on most FG bows with big risers, they are putting closer to 1.5” up front. 
We’ll see though.   These are just unproven thoughts in my head at this point. 

[DC]

However, that would be just as true for a reflexed recurve as it would be for a deflexed recurve.

Yes it would. I didn't mean to tie that in with the deflex stuff. I little punctuation may have sorted that out

PS I went back and sort of straightened it out