Author Topic: why a molly?  (Read 8430 times)

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Offline Lee Lobbestael

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why a molly?
« on: May 15, 2014, 11:15:58 pm »
Can somebody please fill me in on why you would decide on a molly design? What are the benefits of it? I have never made one but they seem to be popular on here lately. I try to get the entire limb (minus a few inches at the tips) working. It seems to me that this minimizes the stress at any given point and reduces set as well as prolonging the life of your bow. With the molly design it seems to me like you are purposely concentrating the stress on the inner limbs. Can someone explain what I'm missing here?

Offline huisme

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Re: why a molly?
« Reply #1 on: May 15, 2014, 11:29:57 pm »
Well for starters, the inner limb doesn't bend a whole lot more on a molle than on a full working limb bow. Think of putting a long stick on the tip of your finger: you only have to bend your finger a tiny bit to move the tip of the stick ten inches. Now make that stick very stiff but light and compare using it to propel something stuck on its end to propelling something stuck on the end of your finger.

The advantages are still up for debate, but all my fastest bows per draw weight have been mollegabets. The idea behind mass efficiency is that if you make a narrow, thick lever it can be lighter than a wide, thin working limb, and therefore reach higher speeds in the same distance. String angles are also less severe, and those light levers translate to low/no hand shock.
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Black locust. Black locust everywhere.
Mollegabets all day long.
Might as well make them short, save some wood to keep warm.

Offline Lee Lobbestael

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Re: why a molly?
« Reply #2 on: May 15, 2014, 11:43:27 pm »
Hey thank you that makes alot of sense! I should try one one of these days but I just love the look of a good tiller on a flat bow.

Offline PatM

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Re: why a molly?
« Reply #3 on: May 15, 2014, 11:49:59 pm »
Maximally stressing a piece of material is better use of it from an efficiency standpoint.  Stressing the whole limb to a lesser degree is not.
 A Mollie is the first step towards a static recurve which is a more efficient bow than a straight bow.

Offline huisme

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Re: why a molly?
« Reply #4 on: May 16, 2014, 02:24:49 am »
Maximally stressing a piece of material is better use of it from an efficiency standpoint.  Stressing the whole limb to a lesser degree is not.
 A Mollie is the first step towards a static recurve which is a more efficient bow than a straight bow.

I was able to keep a string on some recurved molle tips, but it was only because they were too thick and they pretty much defeated the whole purpose of the mollegabet. Know of any properly recurved mollies?
50#@26"
Black locust. Black locust everywhere.
Mollegabets all day long.
Might as well make them short, save some wood to keep warm.

Offline Del the cat

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Re: why a molly?
« Reply #5 on: May 16, 2014, 04:21:35 am »
A good thread, ripe for discussion I've not made one yet for much the same reasons.
Reduced mass in the outer third is easilly acheived without going to a full Molly... and yes we do see a few with Mollys from newbies with ends that could hold up a Cathedral roof (AROOGAH AROOGAH exageration alert ;D )
DO we find Mollys in flight records? Anyone got fps figures for like for like wood, draw length/weight of Molly vs other styles.
Prob a silly Q as I'd guess that any optimally made bow in almost any style would give similar performance.
Del
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blackhawk

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Re: why a molly?
« Reply #6 on: May 16, 2014, 08:44:30 am »
I'm sure some are waiting for me to chime in on this with my experience on making countless lever bows..BUT not sure if I wanna engage on this one as I see several quotes from a few different folks that can easily be debated and dispelled ...and it might get quite lengthy in my explanations to do so..sorry just don't wanna go there right now...I've made enough now to know the pros and cons of them,and what's fact and fiction  :-X


How about you make a few dozen of different kinds,styles,woods and make up your own conclusion  :-X

Offline Buckeye Guy

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Re: why a molly?
« Reply #7 on: May 16, 2014, 08:59:20 am »
Man I thought we were gona get to read the book ! :( :( :( >:D
Guy Dasher
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To God be the glory !

Offline Del the cat

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Re: why a molly?
« Reply #8 on: May 16, 2014, 09:00:05 am »
I'm sure some are waiting for me to chime in on this with my experience on making countless lever bows..BUT not sure if I wanna engage on this one as I see several quotes from a few different folks that can easily be debated and dispelled ...and it might get quite lengthy in my explanations to do so..sorry just don't wanna go there right now...I've made enough now to know the pros and cons of them,and what's fact and fiction  :-X


How about you make a few dozen of different kinds,styles,woods and make up your own conclusion  :-X
You big tease... I've met girls like that >:D ;) :o
Del
Health warning, these posts may contain traces of nut.

Offline lostarrow

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Re: why a molly?
« Reply #9 on: May 16, 2014, 09:34:24 am »
I'm sure some are waiting for me to chime in on this with my experience on making countless lever bows..BUT not sure if I wanna engage on this one as I see several quotes from a few different folks that can easily be debated and dispelled ...and it might get quite lengthy in my explanations to do so..sorry just don't wanna go there right now...I've made enough now to know the pros and cons of them,and what's fact and fiction  :-X


How about you make a few dozen of different kinds,styles,woods and make up your own conclusion  :-X

 You're more than welcome to express your conclusion. I would hope this wouldn't tun in to another pissing match. If it does , ....... Don't fall into the trap. The primary purpose of this board is information sharing ,I believe.I value your input and I'm sure I'm not alone.
  I think the real task of testing these theories ,is that most of us don't tend to build  comparable bows and keep them around. I'm in the ugly predicament right now of not having a real nice hunting bow for myself.   :o
   

Offline Marc St Louis

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Re: why a molly?
« Reply #10 on: May 16, 2014, 10:25:59 am »
I made one about 20 years ago when I first heard of them, they were called Holmegaards back then.  The one I made did not have the extraordinarily long levers of some of the ones I see people making these days.  I certainly was not impressed with the bow, to the point where I never made another. They are unique looking though and if I was to ever make another I certainly wouldn't make it with those long levers.

As an aside, there was a study done many years ago and the person, I believe it was O.L. Adcock, found that performance was maximized when the last 6" to 8" of the limbs were non-bending.  I would think that this would apply to Mollies as well.
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Offline PatM

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Re: why a molly?
« Reply #11 on: May 16, 2014, 11:10:23 am »
Blackhawk has shown many "recurved mollies" that presumably work very well . I guess the argument might be that they don't perform better than other styles.
 The best way to think of a recurved mollie is as a bow with siyahs.
 The best way to make one is to splice in the tips with the wood turned on edge to maximize the bending stiffness per mass.

The studies Kooi did showed that a lever tipped bow with a lower angle of 35 degrees is the most efficient bow.
 That's a recurved Mollie.
 The beautiful bulletwood laminated skeleton tipped bow made by David Brunetta a few years ago essentially fits this criteria and holds a flight record.
 I think where many people fail to explore the potential is by making the bow too light in draw weight relative to the mass of the outer limbs.
 There is a tipping point there which is similar to that seen in hornbows.

Offline Badger

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Re: why a molly?
« Reply #12 on: May 16, 2014, 11:39:37 am »
         In one of the above posts they were talking about stresses being more in a molly at certain places. truth is all bows with any design should have about the same amount of stresses. The streses are controlled by strategicaly ballancing the width and thickness of the bow with the amount it is bending. We know we get this right when we are not taking set in our limbs. I feel like mollys are a good design and will probably have a place in flight shooting with light arrows even if they haven't so much yet. The logic behind the molly bow is seen in almost all flight bows, narrow stiff outer limbs.
         Just talking self bows the recurves and the r/d bows with reflexed limbs will usually edge out the molly in speed if they are made properly. A lot of us employ the molly technology into our r/d bows by making hte outerlimbs stiff and narrow even if it is not as exagersted as we see in a lot of pure molly bows, same physics are still apllying. From what I have tested which is probably hundreds of bows over the years a regular straight american long bow with no string follow and properly made will usually hit about 172 fps, a real well made molly maybe 175 fps, an idealized r/d bow about178 fps and recurves up to about 182 fps. The great majority of all these bows are lower than these numbers. This is talking 10 grains per pound and 28" draw.

blackhawk

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Re: why a molly?
« Reply #13 on: May 16, 2014, 11:58:21 am »
Thanks for picking up "some" of the slack Steve  8) and when you start curving the levers it can easily be classified as a recurve and be in the same class as them ...also giving them a r/d shape seems to enhance them as well... I'll post some links of my better ones n such here in a few minutes..gotta eat first

Offline Buckeye Guy

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Re: why a molly?
« Reply #14 on: May 16, 2014, 12:48:21 pm »
the book is coming !!
Guy Dasher
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To God be the glory !