Thursday, 10 July 2014

Deflex Reflex Bow

I'll explain some more.
This style of bow is essentially the shape of all modern target bows. It was the first "scientifically designed" bow designed and patented by Clarence N Hickman in 1935 as a bow of radical design. There had been plenty of recurved bows in the past, like all the Asiatic bows.
Hickman describes his bow as a deflexed recurve. Essentially it is a recurve but with the limbs mounted deflexed towards the archer. The maths and physics is beyond me, but the theory is that it gives a more even acceleration to the arrow rather than the huge kick up the backside that you get with a longbow.
The reason he set about designing it was to allow him to be competitive with a lighter draw weight as he had lost some fingers of one hand in a rocketry accident. (He's the guy who designed the Bazooka used in WWII amongst may and varied other achievements).
The limbs start at brace with the reflex showing (although you can see it's mostly pulled out of the right limb on my bow) as the bow is drawn the limbs uncoil to almost straight, angled towards the archer. This shows quite well in the video. The left limb needs to uncoil a bit more. You may be able to see I'm pulling it to 60# from a low brace, I'm not sure how hard I actually dare pull it, I do want to see it perform before it goes bang,
As I've been at pains to point out, this is all experimental for me and I'm doing some things which are "wrong" if I'm after maximum performance. E.G I've decrowned the stave at some points on the back and also removed wood from one edge of the back where the limb is twisted.
Some twist and misalignment has been removed with heat.
So, I can't really explain more, and there may well be people out there scoffing at my efforts, which is fine. The joy of making bows is the constant learning and trying new things.
video
The left limb seems to hinge near the grip, but this is just part of the rough and ready deflex I put into it with heat. If you watch, you will see the 'hinge' barely flexes.
The bow is pulling back fairly nicely and I'll heat treat the belly, whilst restoring the reflex in the right limb.
Hope fully it will draw smoothly and shoot fast... ok, maybe not as smooth and fast as a Bazooka!
There is a book about Hickman.
Clarence N Hickman, the father of scientific archery ISBN 0-9613582-0-3

He also made high speed cameras for use in rocketry development and was the first to film the answer to the archers paradox using the cameras.
I don't feel Hickman get the recognition he deserves. In fact I heard one rather pompous chap explaining how he'd applied for various scientific papers from America about the aerodynamics of rocket fins to help him fletch his clout arrows. When I said, you mean Hickman's work? He said words to the effect of  "I don't know, I'm not interested in other people's preconceived notions!"
He added that he had a library full of archery books, some of which were quite rare, but he didn't read them as he didn't want to pollute his own ideas!
He was happy enough to use Hickman's work but couldn't even acknowledge it.
For the record, I believe Hickman allowed free use of his ideas and designs and didn't use them for personal profit.

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