Designing for speed. . . lets talk theory.

[blackhawk]

But a hornbow doesnt gain much advantage over other designs untill over around 60 pounds toomany.

The term "horn bow" covers a broad spectrum of bows of many designs sizes and drawlengths, which by default must perform differently from one an other, and cannot all be dumped into one category in regards of performance. At least I would think so? But I really don't know...

Ok...so how about ya make every type and test it,and then report back to us in 20+ years...lol 
l

[Badger]

  Horn bows actualy test out about the same as good wood bow. We tested a 50# horn bow with 6" reflex against a 50# red oak board bow with zero reflex and they both hit 170 fps for a virtual tie.  More modified wood bow designs can go much faster than this. Horn bows have a distinct advantage with the extra long draw lengths they can use and also have some advnatages shooting the extremely light arrows because they are short and carry little mass. Talking 10 grains per pound and normal draw lengths wood bows, horn bows, sinew backed bows will all end up about the same if built properly.
   Even modern glass bows are only a tad faster than all wood bows when designed properly. Glass has zero hysterisis or very close to it and wood has a measurable amount, I would say from 3% to about 15% depending on moisture and how well the bow was tillered out, but hysterisis is the deciding factor as any bow has to be designed aroundf the materials we use to build it. I don't believe the TBB is the best source for info on this as advances are constantly being made and the references in the bible are more toward basic primitive designs that are optimized.

[toomanyknots]

normal draw lengths wood bows, horn bows, sinew backed bows will all end up about the same if built properly.   

This always seems to be the culmination of these discussions. I just always thought and still do think that there is room for improvement with natural wooden bows. Take classical guitars for example, been around for a good little bit of time. Pre - 1850 or so, most of these guitars would be called today "parlor" guitars, and were quite a bit smaller and peanut shaped compared to todays guitars. And I guess they probably were nice little guitars to play. But than comes along Antonio Torres and he completely revolutionizes the acoustic guitar, perfecting it's design and creating an incredible instrument. So much so that without Torres we wouldn't have the acoustic guitar we have today. Now flash forward 150 years, and the design is considered long since perfected, and kept alive by german master luthier's like the hauser family and such. And then here comes along Matthias Dammann, with his blasphemous self. Now the top of a guitar vibrates and the thinner it is, the more it vibrates. The more sound is produced the more it vibrates, so a thin top is something to be desired more or less in an acoustic instrument. But thinness has to be balanced with stability, and there is alot of pressure from the strings on even a classical guitar with lesser tension nylon strings verses higher tension steel. That's where inner bracing comes in. Which there are alot of types for different types of sounds and guitars, but all bracing patterns must do one thing: keep the guitar from blowing up! This can be achieved pretty easily, but to achieve stability and allow the top to vibrate to produce sound is something that the masters like Torres achieved and "perfected" somehow. So Matthias Dammann figured a way out to sandwich the top with insanely thin pieces of wood and thin Nomex in the middle for stability. And thus the double top is born, and becomes an incredible improvement (although not favored by all) to the so called "perfected" design.  I just think there might be something to gain sometimes from innovation and experimentation... especially with the tools and knowledge we have today that our ancestors never had access to.

[PEARL DRUMS]

My bows with the most reflex are the fastest regardless of design or backings.

[Badger]

My bows with the most reflex are the fastest regardless of design or backings.

Pearl, interesting statement that could mean two things. It could mean that the more reflexed a bow is the faster it is or it could mean the better the bow held its shape from the start the faster it is. My experience tells me that to some extent the latter is true. I find you can peek out most designs with as little as 2" reflex.

[PEARL DRUMS]

2" is the most any of my bows hold Steve. So your latter comment is probably true. I have also noticed that WHOLE limb reflex is faster than limbs with reflexed tips only. Like some of my statics I have. They would have at least 1 1/2" of follow if I didnt have the tips turned so far ahead. Im a stickler for whole limb reflex and not just turned tips, overlays alone can add some reflex.

[rossfactor]

Pearl - Badger

Than a stave with significant "natural" reflex, that is tillered with no-set tillering would get at both ends of the spectrum.

I keep wondering if induced reflex has less value (for speed) than natural reflex.

Gabe

[rossfactor]

e.g. it would reduce hysteresis while maintaining the value of the reflex..

Gabe

[Badger]

Ross, I have two almost identical bows from the same log, sister staves. One I heated in a small amount of additional reflex, it was natural with about 2" I added 1 1/2", after tillering I have about 2 1/2" right after taking the string off. The other bow started out with about 2" and maintained all of it, loosing only about 1/4" while I shoot it. They both shoot the same speed or close enough I did not detect a difference on my chrono.

[toomanyknots]

2" is the most any of my bows hold Steve. So your latter comment is probably true. I have also noticed that WHOLE limb reflex is faster than limbs with reflexed tips only. Like some of my statics I have. They would have at least 1 1/2" of follow if I didnt have the tips turned so far ahead. Im a stickler for whole limb reflex and not just turned tips, overlays alone can add some reflex.

I would say that you have a recurve with 1 1/2" set then. Because that is really what you have. I don't know why you would count that as reflex, reflex is the entire limb. I have never measured set this way.

[PEARL DRUMS]

2" is the most any of my bows hold Steve. So your latter comment is probably true. I have also noticed that WHOLE limb reflex is faster than limbs with reflexed tips only. Like some of my statics I have. They would have at least 1 1/2" of follow if I didnt have the tips turned so far ahead. Im a stickler for whole limb reflex and not just turned tips, overlays alone can add some reflex.

I would say that you have a recurve with 1 1/2" set then. Because that is really what you have. I don't know why you would count that as reflex, reflex is the entire limb. I have never measured set this way.

There is no way to know how much set my bow has taken without knowing how much reflex I started with.

Bows that hold full limb reflex have higher early string tension than bows with mushy mid limbs and recurved tips.

[RyanY]

This topic is usually where I find most interest in bow making but its been far too long since I've been able to put a lot of thought into it to be able to contribute a good and coherent response. Hopefully getting back into it soon.

Recently I've been thinking about making a flight bow in a D/R design. My thoughts after a similar bow I made are that the design allows for a high string tension at brace and low string angle which will give some good energy storage. The design also allows for narrow/low mass outer limbs that I would probably feel less willing to produce in a recurve. This bow would also be short, probably 52", because it would only be drawing 23" but also because shorter limbs have less mass and a shorter bow uses a shorter string (less mass).

I think the idea that any well designed bow will shoot about the same comes from the idea of tiller shape matching front view profile to make sure that the mass is moving efficiently. I'm not so sure if this is something that could be measured but my guess is that making sure you do this makes all designs equally efficient.

[PEARL DRUMS]

I think the idea that any well designed bow will shoot about the same comes from the idea of tiller shape matching front view profile to make sure that the mass is moving efficiently. I'm not so sure if this is something that could be measured but my guess is that making sure you do this makes all designs equally efficient.

Right on Sparty. And if done properly the starting side profile and lack of set takes care of itself. 

[JW_Halverson]

All else fails, look into my patented bottle rocket fletching and a lit cigarette in the corner of your mouth.   

[toomanyknots]

2" is the most any of my bows hold Steve. So your latter comment is probably true. I have also noticed that WHOLE limb reflex is faster than limbs with reflexed tips only. Like some of my statics I have. They would have at least 1 1/2" of follow if I didnt have the tips turned so far ahead. Im a stickler for whole limb reflex and not just turned tips, overlays alone can add some reflex.

I would say that you have a recurve with 1 1/2" set then. Because that is really what you have. I don't know why you would count that as reflex, reflex is the entire limb. I have never measured set this way.

There is no way to know how much set my bow has taken without knowing how much reflex I started with.

Bows that hold full limb reflex have higher early string tension than bows with mushy mid limbs and recurved tips.

Yes, I guess I meant to say follow, but I am sure you know what I meant as I referred to the 1 1/2" follow you said the bow would have, and I do understand the terms set and follow. What I am saying is that adding overlays shouldn't be thought to add reflex like you stated. I can see adding recurve which is what I think you mean, but reflex just shouldn't be measured in that manner as it is inaccurate. If a limb is reflexed than it is reflexed. If a limb is recurved it does not automatically equal reflex.