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High gear/low gear

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sleek:

--- Quote from: DC on March 28, 2019, 08:48:00 am ---I've always thought(with nothing other than my gut and looking at FDC's) that a traditional bow gave the big push at the beginning of the power stroke and a compound sorta saved it for the middle/end. I thought this was why compounds were faster and it all made sense in my beady little brain. One of Alans graphs showed that it's the opposite. Trad bows save it for the end. So much for my brain. So, the idea is that we want a huge push at the beginning of the power stroke? Now does time enter into this at all? If we have a high gear bow the limbs are going to have to work a lot harder to get the arrow moving. This is going to slow the power stroke(like trying to start your car it 3rd gear) Does this matter? Do we care how long it takes for the arrow to clear the bow as long as it's going like a bat out of hades when it does?

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There js so much science into this that as soon as i try to place my point of view, i find myself with more questions than answers.

Im gonna say that when it comes to your 3rd gear scenario, the gearing isnt so important as tje power behind it, and the weight its pushing. The power to weigjt ratio. A motorcycle can start in 3rd gear and take off faster than a car in 1st. A bow that feels like its in 3rd gear would do better with a lighter arrow,  and still empart as much energy into the arrow in form of a higher FPS than a 1st gear bow. Lets call 3rd gear biws flight bows that shoot ligjt arrows, and first gear bows, those are most effecient at 10gpp.

sleek:
Tjings to consider are, where in the bow is what % of energy stored vs how effecient is its release from there.
How does an arrows level of kenetic energy affect the release of a bows potential energy based on tiller shape at diffent points on release.
Is a bows energy release best all at once, or gradual?

The handle has all the energy of a bow focused like a lense on it, and the tips have none. The flow of energy across the bow is like a wave, with the crest in the center, and trough at the nocks. The arrow needs to harness the energy flow best as it can, be it for penetration power with weight, or high speed with low weight. The gearing can be looked at as different parts of the wave and hiw they affect the arrow.

sleek:
The arrow has 0 kenetic energy at full draw and the bow has 100% potential.  As the arrows kenetic increases, the bows potential decreases, forcefully dropping the bows power to the arrows weight ratio. Using that logic, the first part of the bow that moves upon release should be built in a way that has high torque, is good to get weight moving, the last part of the bow to move should be built in such a way that low energy is most effecient at moving an arrow whose weight is being affected by its speed. 

How does speed affect an arrpws weight? It makes the arrow feel heavier to the bow, as the bow struggles to keep up, its power no longer having the advantage over the arrows mass. Tjis part im still working in in my head because tje arrow mau actually be lighter to the bow as it is moving away and no longer resting its weight in the bow tips as hard. Still thinking.

DC:
It's interesting to talk about this stuff but I'm sure most of it is speculation(I know I'm speculating) and everyone has a different idea. Computer simulations seem to help although I'm with Del here, a little suspicious. Simulations are only as good as the input. A good example is when Alan ran simulations with a stiff string and then with a little stretch. A world of difference. One little input missing and the whole thing goes down the tube. Are we missing anything? This is why conversations like this are important. We may be having a nice little talk and something may come up with something that Alan missed. I'm picking on Alan because he's the only one I know of that's doing this stuff. Sorry Alan. Myself, I think it's all about acceleration and acceleration is all about weight. Even though I did some tip reduction tests that didn't show great gains, if any, I still think that the answer is in light arrow, light string and light limbs. I can't see that how or where the energy is stored has much to to with it. Just get that energy to the nocking point and physics will do the rest. Maybe getting it there is the key. Maybe that's what everyone else is talking about. I'm rambling.

DC:

--- Quote from: sleek on March 28, 2019, 10:29:21 am ---Using that logic, the first part of the bow that moves upon release should be built in a way that has high torque, is good to get weight moving, the last part of the bow to move should be built in such a way that low energy is most effecient at moving an arrow whose weight is being affected by its speed. 

--- End quote ---
We're going to have to disagree on that. I can't see how one part of the bow will start moving before another. That said, I can still see that the energy may be delivered to tha arrow at a varying rate depending on whether the leverage of the limbs(gearing) changes as the limb travels home.

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