Perry Reflex Question

[DC]

Since the wood around the glue line in a PR bow is under stress when the bow is unbraced I was wondering if it should be held in a little reflex when unbraced? If it isn't wouldn't it take set(of sorts) just like a bow that is left strung?

[Dances with squirrels]

I haven't noticed any degree of set due to that. Mine are hung vertically by the string.

[Eric Krewson]

There is actually no such thing as a "Perry Reflex", it is a catchy phrase that really took hold when Dan Perry glued his flight bows in a reflex. People had been reflexing bows bows for thousands of years, a reflexed bow is reflexed bow and nothing else. 

[Mac43560]

But perry reflex stays more reflexed that heating steaming etc?  If the laminates are held with epoxy it too will hold reflex as opposed to weaker glues.

[Badger]

  A Perry reflex will outshoot a selfbow that is reflexed

[ErictheViking]

Go to the archive(read only) section and there is a link to Dan Perry telling exactly what he does and why it's NOT just a reflexed bow. You have to put a full thickness belly wood into reflex and add a backer. The full thickness belly wood put much higher strains than just thin laminations. He explains it in very exact detail. And he is very humble about the technique being named after him. So a reflexed bow glued up with thin or near finished thickness is JUST a reflexed bow. A bow glued up with a full thickness belly wood is "Perry reflexed".

[crooketarrow]

   VERY GOOD VIKING.

[Mac43560]

Thanks for mentioning that Viking.  I just read all the archived post.  I definitely haven't seen ppl do that specifically.   Flipping the bow and gluing it in reflex each time,  adding one lam at a time. It's way more stored energy in the limbs for tension and compression.

[Badger]

  The limbs won't start to store any energy until you start bending them. What the Perry reflex does is create more tension in the wood so you have a lower mass limb. They also seem to be lower in hysteresis. On the average a laminated bow will outshoot a self bow by about 10 fps with the same design. However, I have noticed that self bows that maintained their original profiles without loosing anything to set narrow this gap quite a bit.

[PatM]

  Interesting that the original description of Perry reflex in TBB contradicts Dan's later description. 
 However to say that reflex is just reflex is ignorant.

[Eric Krewson]

Now Pat, Dan himself said in an interview he didn't like the the "Perry Reflex" term.   

[PatM]

  So? That's because he recognized the technique was used historically but that doesn't mean "reflex is reflex".

[Eric Krewson]

Yep, however you do it, heat, glued in, prestressed or whatever, what do you end up with, just reflex. You may  achieve different results perhaps depending on which procedure you use, but in the end you just have reflex.

[scp]

Is pre-stressed concrete just concrete? "Glued-in reflex" would change not just the shape of the wood used but also the characteristic of the wood itself. It's not the same wood in different shape. Its back is pre-compressed and its belly is pre-tensioned, as well. This must have been proven experimentally by someone already.

[Badger]

   I think the evidence clearly points to one thing leading to the success of the Perry reflex. When the reflex is bent in it rleieves some of the tension and relieves some of the compression stresses with out lowering the strength. This would mean the bow would be inclined to take less set. The rare reflexed self bow I make that shoots right with the Perry reflexed bows all have one thing in common. They took almost no set. No set mean lower hysterisis.