Fastest Bow Design?

I say reflex loses you draw weight... of course I mean draw LENGTH.

[jamesdavid]

Good to hear and see you talk Del. I've spent a lot of time on Primitive Archer in the past and remember looking at your bows. It's always interesting to me to have the British perspective, being that you guys are basically cousins in culture and in archery. When I started making bows, my tips were horribly wide...then I went to OJAM, saw Timo's bows, and realized that those suckers only need to be about 1/4"! My bow making was changed forever. I'm currently working on an English longbow, because I just gotta have one. Never made one before...it's elm, with the white sapwood and reddish-brown heartwood....a poor man's yew I suppose. I'm literally neck deep in osage out hear on the great plains, but yew is nowhere to be found.

[treelore]

Large deflex with large reflex looks good but it needs much higher brace height to reach the initial tension of a simple straight bow and eventually that eats up the power stroke unless draw length is increased. Lots of these features and styles are getting crossed over from different construction types and often they don't mix well. I'm a believer in sweet spot and appropriateness considering the properties of the material.

[mrredeef]

Try sinew, it allows the bowlimb to achieve a much more extreme bend without snapping or taking set.
That's how they were able to pull off an extreme recurve like with eurasian and native american bows.

[johnbarron]

These are some nice points Derek! As for the fastest self bow design, a few design features come to my mind:
1. Working limb should be as short, wide at the base, and thin as possible. Shortness leads to faster potential cast. However, a shorter limb must bend on a tighter radius of curvature so the tip displacement is the same at full draw. So thinner. But shorter and thinner means wider in order to store the required amount of strain energy at full draw.
2. A very long rigid riser/middle section. This spaces the string nocks farther apart and enables the use of a longer string. A longer string has a larger apex angle throughout the draw, increasing the archer's mechanical advantage in flexing the limbs and also increasing the speed multiplying effect the string has on the arrow from the limb tips. I wouldn't rule out strings over 100 inches in length. If you can get the angle between the arrow and the string to never dip below 70 degrees at any point in the draw, then the speed multiplication will be at least 3:1, even at full draw, resulting in a very efficient bow. Yes, the string will be heavier, but with modern high-strength bowstring materials, string mass is far from being the limiting factor in speed.
3. A radically-recurved limb that is nearly a complete circular arc in side profile at brace, with a central channel in which the string rests along a large portion of the overall length of the limb. This permits the use of a very high string tension at brace without adding much initial bending stress to the limb since the load is applied nearly parallel to the limb. The result is a very steep draw force curve initially, enabling more energy storage for the final draw weight.
4. A limb that tapers linearly in width from the base to the tip and is of uniform thickness. The pyramid taper is a well-proven efficient limb taper. The trick, as you noted in the video, is to approach a zero-width tip as closely as is feasible. Ensuring that the string nock groove is smoothly contoured and well-shaped to accommodate a heavily-padded string loop with as much bearing surface area as possible will enable very narrow limb tips to be used with a greater degree of protection against shear splitting of the wood.
5. The bowstring deserves some attention in any discussion about the fastest possible bow. Obviously, a low strand count of a high strength-to-weight bowstring material will be the ideal choice, with as many strands added under the end serving wrap as needed to get the desired amount of loop padding, and as few under the center serving as possible to fit the smallest-groove nocks available. BCY Mercury is likely the fastest bowstring material available.

[briananuvattanachai]

Thanks for the video, I kind of understand better now.

[stefanhansen]

Interesting ideas here. How fast, in FPS, is your fastest bow? Thanks!

[notshared]

I have been reading about the Korean Gakgung bows - centuries old composite bows of buffalo horn, bamboo, mulberry/locust, sinew, and birch mark. They have so much recurve that they are shaped like the letter O when unstrung. It's crazy. Have you ever gotten your hands on one? I'd very much enjoy a review from a Western bowyer. One with a chronograph.

[roman_sudneko]

Thank you for your inspiration. Could you elaborate more on heat treatment. Never heard of it. I only heat for bending. Thanks again.

[draven]

I shoot only osage bows and I do the reflex deflex 72" 85# draw @28"

[ianjohnson]

What heat treating do you do to increase draw weight?

[gushlergushler]

Did you ever experience any problems storing yew warbows standing? I usually lay mine down just to be sure but I was wondering if storing it standing over a longer time could cause problems.

[ThiccboiSalmon]

Great video as always Del! At some point could you talk about limb twist in self bows, your explainations are to the point with a good flare of humour.

[jkhippie]

If you reflex deflex a bow that is composite it will probably survive right ? I mean that's what king Tutankhamun was running.

[larryreese]

First, I gotta say those are awfully nice looking bows. But basically, with the reflex deflex design you're just ending up with the same bow you'd have with a straight stave bow. I figure a bows performance has to do with the amount of energy a bow can store and how well it can import that stored energy to the arrow. I'd figure a highly reflexed recurved bow would potentially store more energy. Light limb tips would do a better job delivering that energy. So, all things considered, I'd think design is everything.

[jimathybindlenim]

Why is it called an English long bow when it was invented in Wales?

[appalachianarcher]

That draw talk wasn’t very accurate for the US.