Sharp hooks ( a how to and lots of argument as to their merits )

[PatM]

I don't think I'll ever make another static again. Too much conversation about charts and plastic. Starting to sound a lot like work to me

There is a LOT more discussion about performance of other bows relative to a discussion of static angles.
 Four books in fact. You probably have them.

[joachimM]

But people WERE making black and white statements and I just asked if that fact had been physically proven.
   
  I am aware of the discrepancy between stored versus delivered energy and I always bring that up when people claim that a f/d curve tells the story of how a bow performs.
 The point of sharp recurves is purely for increased performance even  when  the relative inefficiency is considered.
  That's why they are reduced to absolute minimal dimensions in an effort to harness at least SOME of the increased stored energy.

But then my question is: what defines "performance"? See my latest results. I removed the deflex you commented upon in the sharply recurved bow, and shot it. Despite higher peak draw weight and a lot more stored energy, it still didn't outshoot the other bow with a straightish FD-curve. When I then also drew the other bow further (to strain it evenly to the same peak draw weight, thus with a 1" longer power stroke), it clearly outshot the sharp recurve, again.

So my suggestion now: you come up with a design of two bows to compare. You define the rules a priori, how they should look (clear drawings please), how to test them and what defines better or worse performance. If possible, I make the bows (PVC models) and test them. This way there's no more "well that's not what I meant" or "you're doing it wrong".

Deal?

[scp]

joachimM, I'm sure most people here appreciate what you are doing, a lot. Many people are simply making suggestions to make your experiment more relevant to them. You don't have to grant their wishes.

But I sure, as PatM, would like to see what happens if you "un-bend" the sharp hook a little. You already have everything set up. Kindly just heat the tips of the sharp hook bow and make the angle slightly less, say 75 degrees, and test its speed, for us, please.

[PatM]

I am just talking about the same bow with a slightly altered curve.  If you want to call that an entirely different bow I guess you can.
 But if you want to be realistic with the recurve at least make the effort to either reduce the weight of the tips or make them a sensible size relative to what's moving them. It's about finding a way to get SOME of that increased energy out of the bow and into the arrow.
  Do you think that is impossible?
 

   

[joachimM]

The big problem with PVC is that you cannot tiller it by removing material. Sideways you rely on the rigidity of the sides. if you remove that, you have floppy tips. If you cut out a V in the center and then push the rest together with heat, you still need glue  (and mass) to hold it together.

What I can do, however, is add wooden static recurves to the ends (just shove it in) of different angles/sizes. It's a lot more work than just taking a heat gun and adding a bend, though, but that way it's possible to reduce mass at the tips as needed. 
But tell me how sharp (degrees) and how long the recurves need to be (percentage of bow length). "Slightly altered curve" is rather susceptible to interpretation differences.

Also if testing different designs, it's often easiest to exaggerate so as to have enough statistical power to find differences with a limited number of observations. Hence my maybe exaggerated differences. I don't think that for a proof of principle this is bad.

[PatM]

I know the potential drawbacks of using it as a working model.
 Wooden tips are probably a more sensible  but labor intensive solution.

[Danzn Bar]

After 9 pages ....common since seams to be much more economical .....  
DBar

[PatM]

You  also don't get into debates. lol.

[Danzn Bar]

You  also don't get into debates. lol.

Maybe just smarter than the average "bar" .....
DBar

[PatM]

 Maybe. Or maybe not.

[Danzn Bar]

Your right ....I don't have any PVC...........

[PatM]

Neither do I.

[joachimM]

But I sure, as PatM, would like to see what happens if you "un-bend" the sharp hook a little. You already have everything set up. Kindly just heat the tips of the sharp hook bow and make the angle slightly less, say 75 degrees, and test its speed, for us, please.

Will do.

[Pappy]

All I can say is THANKS for keeping it nice guys. That says a lot for this bunch. But ha sharp hooks are cool looking so that should stand for something.
 Pappy

[H Rhodes]

wow...  The original post was something about how to get sharp hooks - steam or boiling/ straps or not....   Here's my contribution.  It depends on if I can chase a belly ring or not.  If I can reduce the belly to one ring in the area I am bending, then steam alone and going strapless works good for me.   If the stave has issues, drying checks/knots/pins, or I can't reduce the belly to one ring, then boiling and straps are my choice.   
     Some of the posts in this topic reminded me of a line from my favorite movie, Lonesome Dove.  Woodrow Call said "I swear Gus, you'd argue with a possum".