This flight shoot is being held under GNAS rules so I checked their definition of an ELB. It's pretty much the usual, but they do allow bamboo and have a minimum length of 66" for a 27"+ draw.
I've set to making a Boo backed Yew bow, using Yew heartwood (heat treated) from the same batch as the last bow I made which had the suspect sapwood.
Flight shooting is a bit odd, because you'll be hard pressed to actually shoot 50# at 28" because the draw length is measured as the arrow length from the bottom of the nock groove to the tip and also to the belly of the bow. This is so that the bow can't be over drawn to pull extra draw weight.
To explain, if you measured in the normal way to the back of the bow as 50# at 28", and the bow had a 2" deep grip, once you'd drawn the tip of the arrow level with the back of the bow, you could continue to draw it another, say, 1.5" gaining about 4# extra as well as the extra 1.5".
There are problems with this arrangement, one being safety... if an arrow jams up against the belly of the bow it will explode when loosed. Also measuring the draw weight at full draw (using draw length to the belly) will possibly over stress the bow. This is overcome by measuring draw weight at 1" and 2" less than the stated draw length and doing the arithmetic to work out the draw weight at the full stated draw.
This arrangement of draw weight/length measurement puts a premium on the skill and nerve of the archer. Effectively the 50# bow will probably only get shot at 48# as I'm not going to risk having an arrow explode into my left hand!Anyhow, what seems like a simple task becomes more complicated, so the game plan is to build the bow to about 50# at 26" (conventionally measured) initially. Do some test shooting, brace height tuning with various arrows and then work out (guess) the optimum arrow and draw length which will keep me under 50#.
I've just made the string and taken a few scrapes off the middle of the lower (left) limb and it's now at 50# @26" but of course in flight terms that's 50# @ 25.5"The 2 pics show how tiller has progressed. Note on each pic the two ellipses are the same size, they are moved about so that the vertical axis of the ellipse lines up with where the limb starts at the fade.
The pictures have been rotated slightly to have the bow horizontal, 'cos that's the way MS Paint draws ellipses (with a horizontal and vertical axis).
In the second pic, the horn nocks have been fitted and the tips slimmed. You can see that the extra work has resulted in 2" more draw at the same 50#.
I went shooting up at Now Strike Archery on Sunday and tested it with some 24" flight arrows, the first two were 232yards and landed a foot apart. I opened the nock on the 3rd arrow which had been too tight and tried again with 3 arrows. I was more confident this time and got 230, 239 and 270 yards, it goes to show that getting that elusive clean loose can make a big difference. I was happy enough with that performance and I'll get it on the tiller again and see how it looks now it's been shot.
I was also hoping to see the Yew backed Yew tested, but the guy I made if for had cricked his neck so couldn't use it. My test pilot JT shot it and said it was good and smooth.
One of the other guys had a warbow which he'd bought on line, and wasn't very happy with, he asked me to put it on the tiller and have a look... he thought the upper limb was stiff.
Here's my take on it:- https://youtu.be/IoJdKEh6u1o
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