Boo Yew RD

[PatM]

It's just about the 200fps 10 gpp at 28" draw barrier.

 DC ,  the good news is you're stronger than you thought.

[Marc St Louis]

Impressive.  On the plus side you can continue chasing that elusive 200fps barrier.  I think low to mid 190's is about as good as I was ever able to get

[Tommy D]

IMO it's virtually impossible to make an arrow too light... if it's strong enough to withstand being shot it will be heavy enough.
Or do you have to reach some arbitrary gpp for some competition regulations?


Del

His bow is a heavier draw weight than than he thought ... he is chasing speed at 10 grains arrow weight per pound of draw ... so he now has to shoot a 420 grain arrow not a 390 grain arrow... that’s my take!

[DC]

Bad news. My scale has three options pounds, kilograms and jin. A Jin is a Chinese weight that equals 1.1023 pounds. My scale somehow got on "Jin" which is close enough that I didn't notice. So once I put it on "pounds" the bow weighs 42#, not 39#. This means my arrow was too light. True speed is 191fps. I'm bummed. I'm not sure when the scale got changed. I'm hoping it was recently. I thought this was too good to be true.

Dunno what you mean by your "arrow is too light"... it weighs the same as it did before you re-weighed the bow!
IMO it's virtually impossible to make an arrow too light... if it's strong enough to withstand being shot it will be heavy enough.
Or do you have to reach some arbitrary gpp for some competition regulations?
Del

I check the DW and readjust the arrow weight every time I do anything to the bow to maintain  10 gpp. Just an arbitrary goal I set for myself. I suppose if I just changed my goal to 200fps@9gpp this would all be over.

[DC]

Impressive.  On the plus side you can continue chasing that elusive 200fps barrier.  I think low to mid 190's is about as good as I was ever able to get

Thanks Marc but since I've only been following your lead I don't know that I'll catch you. I'll be re testing the last ten or so bows this morning just to find out where I stand. I think it was just last week that I changed the batteries in my scale. It probably defaults to jin. I'll check that so I don't get caught again.
 Just a sec.
No, it defaults to Kg. I must have pushed the wrong button. Anyway this is the scale. It's a great scale but if you have one watch out the Jins don't get you. They're on the right hand side of the screen.

[Sagebrush]

Thanks DC!!!

[Selfbowman]

DC what does the force draw look like on that style bow? Arvin

[DC]

I tested the last 6 bows I've made. I put a positive stop at 28". From where I stand the parallax was showing my weight a little less. That compounded the Jin problem. Reality check today. 5 of the 6 were just under 190. 187 was the lowest. This one was 193, double checked everything. It's only 36#@28". maybe you can tell me something about the FDC. I'm not sure what to look for other than a convex curve.

[Selfbowman]

I will do a force draw on a couple of bows Of different Weights. My curiosity is how if  at all how they differ? Also can you math guys add up the total energy stored to predict better performance of one design over another. Using the whole force draw added together. Just asking. Arvin

[PatM]

The total stored energy hints at potential but does not guarantee that it will  all be delivered, nor the rate which it will be delivered at.

[DC]

Here's a 42# shoots 185fps. Definitely not as fat as the other one. This calls for a closer look.

[DC]

The total stored energy hints at potential but does not guarantee that it will  all be delivered, nor the rate which it will be delivered at.

Yeah I wish there was a release FDC. I guess, in a way, that's what the chrono is. I had one bow I was testing shot in the 190's and I realised that the arrow was too light, something like 10 grains so I changed tips to correct it and the speed dropped to 185 or something. Way more than I expected. I went back and forth a couple of times to check and the data was good. This bow reacted to a light arrow way more than normal. I have to go back and look at it again.

[Selfbowman]

Ok should it not loose the same pounds on release less the calculated arrow weight. And then I guess the weight of the arrow will affect the cast as the draw gets shorter. Where is the happy face pulling his hair out. Arvin

[Selfbowman]

Never mind my scratching. Maybe you can get a idea. These bows where all built on the same caul.

[Selfbowman]

It seems that the bows of different weights off the same caul has the same force draw only enlarged. Hummm