Deep Cored R/D Longbows

Tradcat · October 15, 2015, 08:15:00 AM

I know that Hill Style bows have this type limb profile....just curious which bowyers offer a R/D model with deep cored limbs ?
Thanks

Bullfrog 1 · October 15, 2015, 08:32:00 AM

Dwyer original. Bill

Brianlocal3 · October 15, 2015, 08:51:00 AM

JD Berrys D/R bows are like that

Jerry Gille · October 15, 2015, 10:51:00 AM

My great northern critter gitter is like that.

Zradix · October 15, 2015, 11:05:00 AM

Toelke whip.
Maybe these pics will help you see the deep core used.
Narrow limbs sorta require deeper cores...

ChuckC · October 15, 2015, 11:29:00 AM

I am gonna throw out a question.

If you are talking serious R/D, I am gonna guess a truly deep core is gonna lose out to a more flat bow limb because of the amount of flex (pre-flex and drawn flex) in the limb, causing that much more compression of that much thicker material.

I wonder if as you go to more and more R/D design that a flatter limb should also go with that as part of the design change ?
ChuckC

Alexander Traditional · October 15, 2015, 11:34:00 AM

QuoteOriginally posted by ChuckC:
I am gonna throw out a question.

If you are talking serious R/D, I am gonna guess a truly deep core is gonna lose out to a more flat bow limb because of the amount of flex (pre-flex and drawn flex) in the limb, causing that much more compression of that much thicker material.

I wonder if as you go to more and more R/D design that a flatter limb should also go with that as part of the design change ?
ChuckC

That's a good point and got me to thinking. All the bows that I have that have the thick limbs are of less reflex deflex,and the ones that have a lot are not. All the ones that I have that are thick take on the D shape when strung also.

Zradix · October 15, 2015, 11:42:00 AM

Well Chuck..I think you are on the right path..
As a very general rule..
Deeper cored bows have lighter mass limbs.
all else being equal (which it hardly ever is) a lighter limb makes a faster bow with less feedback.

If you double the width of a limb you double the mass and double the draw weight.

If you double the thickness you double the mass and increase the draw weight appx 8 fold I believe.

So....a 50# deep cored limb can have a lot lighter mass limb than a wide/thin cored limb.

now....shallow cored limbs can bend more ie curve more during the draw than a deep cored limb.

which is why working recurve tips are generally wide and thin.

....and why "serious" r/d bows generally have wider limbs than "less serious" r/d bows....they gotta be able to make more of a curve.

The optimum balance between deeper core or wider limb is determined by the design of the bow and the materials used.

.....need to make sure those limbs don't want to twist or bend sideways...lol

Hope this helps a bit.

Tradcat · October 15, 2015, 12:25:00 PM

Thanks guys....

Green · October 15, 2015, 01:32:00 PM

The JD Berry Argos is a deep cored D/R bow. What an awesome shooter!

katman · October 15, 2015, 04:14:00 PM

And his Taipan,

**DONOTDELETE** · October 15, 2015, 06:18:00 PM

QuoteOriginally posted by Zradix:
Well Chuck..I think you are on the right path..
As a very general rule..
Deeper cored bows have lighter mass limbs.
all else being equal (which it hardly ever is) a lighter limb makes a faster bow with less feedback.

If you double the width of a limb you double the mass and double the draw weight.

If you double the thickness you double the mass and increase the draw weight appx 8 fold I believe.

So....a 50# deep cored limb can have a lot lighter mass limb than a wide/thin cored limb.

now....shallow cored limbs can bend more ie curve more during the draw than a deep cored limb.

which is why working recurve tips are generally wide and thin.

....and why "serious" r/d bows generally have wider limbs than "less serious" r/d bows....they gotta be able to make more of a curve.

The optimum balance between deeper core or wider limb is determined by the design of the bow and the materials used.

.....need to make sure those limbs don't want to twist or bend sideways...lol

Hope this helps a bit.

Great explaination John!

The only thing i might add is that deep core long bow limbs can take on different characteristics depending on material used in the core and how many laminations used in the limb...... Of course a heavier draw weight bow is going to be thicker than a light weight bow, the thickness can be minupulated by the core to glass ratio....

Typically thinner glass deeper core for light weight bows are much better performance......

For radical r/d long bows its a real balancing act to maintain good lateral stability using narrow deep core limbs.... Dan Toelke knows the value of using more thin laminations in his long bows....

Just for fun John take a look at the edge of your whip at the tips.... i'll bet he's got 4-5 lams not counting glass.... Dan builds a nice bow...

Zradix · October 15, 2015, 07:38:00 PM

wish I could Kirk...all I have is pictures anymore..lol
I do seem to recall that there were more than just a couple layers there though.

....those glue lines (especially when pre-stressed) can make a big difference.

October 15, 2015, 08:01:00 PM

I wonder where the Stotler design falls. It bends into a D and is very wide and flat in middle of the limb. They seem to get the job done very nicely as well.

damascusdave · October 15, 2015, 08:52:00 PM

I just got a Black Widow PL longbow and would have to say that it is at least somewhat of a deeper core bow...the limbs construction of these bows is also quite interesting...maybe a Widow longbow expert could chime in here and tell us a bit more about how they are made

DDave

ChuckC · October 15, 2015, 09:18:00 PM

If I recall, the Stotler design looks very much like a recurve, without the curves. It has a very large riser, albeit the handle is made more longbow like. Isn't that more of a flatbow ?
ChuckC

Sixby · October 16, 2015, 03:02:00 AM

Don't have to be super deep when using carbon back and carbon near the belly. You can build a narrow limb that is both light in weight and stable. Some bowyers are finding that they can build narrow limbs that are stable on recurves and even on static recurves. My static recurve tips are so narrow its scarey looking but they shoot well and light tips make for high speeds and low vibration. I personally love narrow deep core limbs.

God bless, Steve

tzolk · October 16, 2015, 11:35:00 PM

Here is a Toelke Whip (r/D) on the left and the Super D on the right. Both have 9 lams which includes the glass.

Sixby · October 17, 2015, 02:17:00 AM

Doing it right. God bless, Steve

Tradcat · October 17, 2015, 09:42:00 AM

Those Toelke bow limb profiles look powerful and awesome