Lever tips/stiff tips.

[Hunter Van Winkle]

As we know, leverage is force multiplied over distance. The length of the lever multiplies any force input. That's what the Atlatl is, is a lever that multiplies the force that you input with your arm into the dart.

So, have there been any studies or any data comparisons showering the effectiveness of stiff tips (4-5") or lever tips?

Also, are there any special tillering adjustments that must be made when making a lever tipped bow?

[Cloudfeather]

I'm not sure of the exact science behind it. But, I believe, the lever action is what makes a molly such an effective bow. I compare it to your arm. If you try to swing your whole arm, it takes a lot more force than if you bend at the elbow and just swing half of your arm. I might be totally off with that analogy, but it makes sense to me. lol 

[tattoo dave]

Ya, not sure of any scientific studies, but I'm sure somebody here can point ya in the right direction. Those molle bows are super cool, and shoot like a rocket. That's all I need to know.

Tattoo Dave

[PatM]

You can read Dan Perry's thoughts in the chapter on flight shooting in volume 4 of TTB.
 The papers by Kooi also discuss recurves and retro tips as well as the optimum  angle for efficiency rather than just energy storage.
 A Mollie is a great design and as you dial back rthe angles of the stiff tips you will find that perfect blend.
 When Dan Perry made that stiff tipped flight bow a few years ago everyone speculated on duplicating it with a little bit of reflex and setback to the levers. Few if any attempted it. though.

[Weylin]

I'm trying to wrap my head around this concept of levers too. I'm building a molle right now and my father asked me why it was advantageous to have non-bending levers as opposed to limbs that bent out to the tips such as a pyramid bow. I know some of the reasons but I realized I couldn't make a very cogent or complete argument in favor of the stiff levers. Is the advantage purely due to the slightly lower mass that the tips afford? but even if that's the case wouldn't it be better to reduce them to the point that they work, even a little bit?

[Gus]

Cool Thread.

The way I read it is:
Since the bending limb is shorter it takes it less time for it to return to it's braced position once the string/arrow is released.
The end of the bending limb at the lever fade, has a shorter path to travel in order to get back to brace.
As apposed to the end of the bending limb of a long bow, which is further out toward the limb tip.
The end of the working limb of a long bow has to cover more linear distance to return to brace.

At least this is my understanding as of 12:00 pm today...

-gus

[SLIMBOB]

This is Tim Bakers explanation.

"The principles involved are simple. Straight outer limbs store more energy, and extremely narrow, low-mass outer limbs transfer more of the bow's stored energy to the arrow. That's all there is to it. This larger energy transfer happens for two reasons: a stiff and low outer limb reduces energy-robbing limb vibration, and light outer limbs allow quicker acceleration of the arrow during early and mid portions of the return. This increases efficiency, I believe, because less of the bow's energy is then asked to rush to the arrow during that last train wreck moment of string impact."

[PEARL DRUMS]

Dont forget wind resistance and tip mass weight. 

[k-hat]

Good point Chris.  Wind resistance is small but if you think about it the resistance on the tips of a molly will be about 1/2 that for a flatbow.  Lots of little things that add a few feet per second.  Think i may be trying one of these soon.