Boo Yew RD

[sleek]

If you have the materials and the mind to do it you should build another one identical in profile. The ONLY difference should be that instead of 6 1/8" of reflex, only put in 5 1/2" inches. This bow should take 0 set and be even faster than the one you got now.

[Badger]

    That is amazing speed, would you like to have that bow shot at the flight shoots in september? We could shoot it in the 35# class. Great job!

[silent sniper]

Congrats DC for reaching your goal! 210 FPS at 10gpp is an absolutely incredible accomplishment!

[Tommy D]

If you have the materials and the mind to do it you should build another one identical in profile. The ONLY difference should be that instead of 6 1/8" of reflex, only put in 5 1/2" inches. This bow should take 0 set and be even faster than the one you got now.

Sleek - if he did the same as a trilam ... gluing in deflex before pulling in reflex what would you feel the outcome would be?

[Markus]

Very nice bow. I hope you don’t mind me asking if that speed test was done with the bow mounted in a shooting machine and with a mechanical releaser, and shot through two chronographs set up in a tandem configuration, to make sure straight arrow flight is measured. Thats how the pros is doing their testing. Shot from a shooting machine the arrow speed is higher than if fingershot.
If you had your bow tested that way and achieve 210 feet plus, it is faster than the fastest glass recurve tested until now. A Morrison Carbon with the extreme hooks. That is with 9 grains pr pound.
Anyway you sure have a smoker
https://www.thetradlab.com/morrison-max-6

[PatM]

Very nice bow. I hope you don’t mind me asking if that speed test was done with the bow mounted in a shooting machine and with a mechanical releaser, and shot through two chronographs set up in a tandem configuration, to make sure straight arrow flight is measured. Thats how the pros is doing their testing. Shot from a shooting machine the arrow speed is higher than if fingershot.
If you had your bow tested that way and achieve 210 feet plus, it is faster than the fastest glass recurve tested until now. A Morrison Carbon with the extreme hooks. That is with 9 grains pr pound.
Anyway you sure have a smoker
https://www.thetradlab.com/morrison-max-6

   That's the fastest glass recurve?

[Badger]

    I think you found the near perfect design for yew. I doubt you could have achieved that with any other wood. Yew has almost double the elasticity of other woods.

[DC]

Thank you very much for the comments, I really appreciate it.
Tuomo- I'll work on that today. You can't get the FD measurements from the graph?
Lonbow-I heat treated both sides of the belly thoroughly
Hilongbow- Thanks
Tommy- I don't hunt and I don't target shoot too much any more. My bows don't get a lot of use. Maybe I'll send it to Badger
Sleek- Thanks. I tried to do that with the one I'm working on now. I'm having difficulty getting equal and repeatable reflex in the bows. The reflex is kind of a crap shoot at the moment. I glue up one limb at a time because I use two piece backing and that doesn't give me the chance to compare the limbs. A better caul will sort that I think. That and better wood. I'm scrounging up scrap strips from all over the shop. I think this bow was the last set of decent wood I had. I've got enough Yew and Boo for 4 more I think.
Badger- I'm seriously considering that, thank you. I noticed a little change in the tiller after I did the FDC last night so I'll keep my eye on that for a bit. I only draw about 26" so I don't think I'm straining it that much shooting it. It was very muggy yesterday so maybe that affected it. I think it would like the Flats.
Markus- I do all my testing with the machine. I can't reliably draw 28". I do have two chronos. I bought the second one because I was doubting my results with earlier bows. I'm not sure if I have room to put them in tandem but I do like the idea. Remember that the 210 was a one off. It was backed up by a few 208's but it hasn't reached those speeds since. I think it was because the bow had been out in the sun for two days drying the tung oil. At least I hope it was. There is a very high chance the bow could start to go downhill. It's pretty stressed.

[DC]

    I think you found the near perfect design for yew. I doubt you could have achieved that with any other wood. Yew has almost double the elasticity of other woods.

If I could get some good sister billets and get some luck with the glue up It might be a little more reliable. I'm getting a little worried about it at the moment. I have the feeling that nice straight edge grain is the answer. The grain runs all over on this one.

[simk]

GREAT DC!!! 😀✌️😀 congrats from switzerland too and enjoy your cigar 👍whats next? 😀

[avcase]

There is one thing that is important when comparing 10ggp performance to glass bow tests in order to compare apples to apples. The glass bow tests use an AMO Standard to determine the reference point for the draw length. This reference point is 1.75” from the deepest part of the grip. So, if you are using the belly side of the bow handle as the reference point, then drawing the bow 26-1/4” from this reference point is the same as The 28” AMO Standard. Is that confusing enough?

Based on the FD curve, it looks as though the belly side of the bow handle is used as the reference point or measuring draw length. This makes the 28” draw point on the force-draw curve the equivalent to drawing the bow 29-3/4” according to the AMO Standard (Looks like 41 pounds on the force-draw curve).  Let me know if I am wrong. 

It looks like you may still be very close to a true 200fps at 10ggp at 26-1/4” from the deepest part of the grip using the AMO Standard. This is beyond exceptional!

Alan

[DC]

I measure from the back of the bow and the handle is 1 1/2". I've had a little indecision about how this should be set up. I sounds like nit picking but changing the draw length 1/4" could be quite noticeable. Since you use the same distance to measure the DW which affects arrow weight it can all add up. I try to use my FDC peg board when doing all these measurments but there is lots of room for indecision to creep in. The draw length on the shooting machine could be slightly different too, just to add another doubt.

[willie]

There is one thing that is important when comparing 10ggp performance to glass bow tests in order to compare apples to apples........

Alan,
If Don is fairly close to AMO standards, then one big difference between his bow and most glass bows tested is Dons 5.5" brace height.

What is your opinion about possible gains or losses a comparable glass bow would exhibit  at such a low brace?

[avcase]

There is one thing that is important when comparing 10ggp performance to glass bow tests in order to compare apples to apples........

Alan,
If Don is fairly close to AMO standards, then one big difference between his bow and most glass bows tested is Dons 5.5" brace height.

What is your opinion about possible gains or losses a comparable glass bow would exhibit  at such a low brace?

If I understand this right, the 5.5” brace height on the force-draw curve is measured from the back of the bow?  It is 4” from the belly side of the bow handle?

I would love to see this bow flight shot at the Salt Flats!  The force-draw curve is amazing!

Willie,
It depends on the bow design and the properties of the string. Usually bow efficiency drops at very low brace heights. Energy storage increases, but efficiency drops and often counteracts this. A string made of very high tensile stiffness material helps the bow tolerate a lower brace height.

Alan

[DC]

I played with the brace height and the best was right around 6" on two similar bows. I didn't get too anal about it cause it's a PITA to do. Between 5 and 6 inches I gained about 4fps. There may be an arrow mismatch going on here too. I'm using 500 carbons with whatever tip makes the weight I want.