Author Topic: High gear/low gear  (Read 6680 times)

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Offline PatM

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Re: High gear/low gear
« Reply #15 on: March 26, 2019, 01:15:41 pm »
I think it was Dan Perry.

Offline Woodely

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Re: High gear/low gear
« Reply #16 on: March 26, 2019, 01:55:55 pm »
Dc, gearing is why i was saying you want the fades to bend only in the last 3 inches of draw on your bow you just made. Last to bend is first to straighten on release. The inner part of the bow is all torque, and the outter limbs is all horsepower. It takes torque to get a car off the line, it takes HP to get it there quick. So ideally,  on release, you want the limbs to lool like they are doing the wave, starting at the fades and moving toward the tips.  The inner third gets the arrow moving, mid limb is mid range, and outter is top end red line.

 I think that is right,  because I have videoed myself shooting my bows and played them back, paused them on release.  I notice that the tips are vibrating slightly a few inches before returning to brace height.  It does appear that the tips are the last to stop bending.
Nice to have a camera because I can rest it on the edge of a 2x4, cant do that with a smart phone.  Good way to analyze your form and bow glitches.
"Doing bad work is an exercise in futility, but honestly making mistakes is trying your best."

Offline willie

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Re: High gear/low gear
« Reply #17 on: March 26, 2019, 07:00:49 pm »
Quote
tell me about the hardware.

string stretch seems to be a big part of the discussion at PP

Offline DC

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Re: High gear/low gear
« Reply #18 on: March 27, 2019, 08:00:10 am »
It seemed like anytime Alan showed a graph with something cool on it he would then introduce string stretch and it would mess everything up. It seems to be the great leveller.
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Offline Badger

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Re: High gear/low gear
« Reply #19 on: March 27, 2019, 12:29:53 pm »
   I never cared for the term gearing but I can see where it could apply some. For the most part efficiency is more important when shooting light arrows and high energy storage gets a slight nod when shooting heavier arrows. Practically speaking in most cases the fastest bow with any arrow will usually stay the fastest regardless of arrow weight. When you start getting extremely light or extremely heavy with the arrows this is where you really start to see a difference. Bows that bend more in the inner limbs near the fades will tend to store more energy but also tend to be less efficient because of increased opportunity for limb vibration. I am of the belief that if a bow is tillered so that the bend increases from the fades to the other it will mitigate most of the vibration. I also believe in as short of working limb as you can get away with and still not take set. When you measure the FDC and calculate stored energy and then find the efficiency based on arrow speed I think that cancels out the entire conversation on gearing. Bows with low string angles at brace will generaly store more energy than a bow with higher string angles and the same amount of reflex.

Offline Woodely

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Re: High gear/low gear
« Reply #20 on: March 27, 2019, 01:13:29 pm »
Quote
tell me about the hardware.

string stretch seems to be a big part of the discussion at PP

Your post quotes quote who is quote.  What hardware.
"Doing bad work is an exercise in futility, but honestly making mistakes is trying your best."

Offline willie

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Re: High gear/low gear
« Reply #21 on: March 27, 2019, 07:17:22 pm »
woodlely,

 "tell me about the hardware"  was DC's request in the opening post. I was just dragging the string factor into the discussion. Some of us visit infrequently, so I apologize if the discussion seems disjointed.

Badger,

from the other discussion at PP, one of Dans goals was to put more energy (aka. acceleration) into the arrow earlier after the release, presumably so that it would not have to have so much delivered to the arrow at once at the end of the powerstroke. Wouldnt this make sense if one were trying to avoid undue flexing of the lighter flight arrows right at release? mabye even having an advantage that would outweigh having  a setup that has the best efficiencys?

Offline Badger

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Re: High gear/low gear
« Reply #22 on: March 27, 2019, 07:52:48 pm »
woodlely,

 "tell me about the hardware"  was DC's request in the opening post. I was just dragging the string factor into the discussion. Some of us visit infrequently, so I apologize if the discussion seems disjointed.

Badger,

from the other discussion at PP, one of Dans goals was to put more energy (aka. acceleration) into the arrow earlier after the release, presumably so that it would not have to have so much delivered to the arrow at once at the end of the powerstroke. Wouldnt this make sense if one were trying to avoid undue flexing of the lighter flight arrows right at release? mabye even having an advantage that would outweigh having  a setup that has the best efficiencys?

  Light tips and low string angles do exactly that. The arrow however light needs as much control over the tips as it can get. You can best accomplish this by having as much of the limb as possible already have completed its task, hence the elliptical tiller. I think most of the flex is right at the beginning anyway but don't hold me to that.

Offline willie

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Re: High gear/low gear
« Reply #23 on: March 28, 2019, 08:03:32 am »
Steve

I have always been a bit unclear about the string angle terminology. To clarify, when one generally reads about 'string angle', are most talking about the angle between the string and the tip?    and at full draw or at brace?

Offline DC

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Re: High gear/low gear
« Reply #24 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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Offline sleek

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Re: High gear/low gear
« Reply #25 on: March 28, 2019, 09:54:53 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?

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.

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Offline sleek

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Re: High gear/low gear
« Reply #26 on: March 28, 2019, 10:12:05 am »
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.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline sleek

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Re: High gear/low gear
« Reply #27 on: March 28, 2019, 10:29:21 am »
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.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline DC

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Re: High gear/low gear
« Reply #28 on: March 28, 2019, 10:45:23 am »
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.
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Offline DC

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Re: High gear/low gear
« Reply #29 on: March 28, 2019, 10:48:31 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. 
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.
« Last Edit: March 28, 2019, 10:52:57 am by DC »
Vancouver Island
If you don't have any questions you must not be paying attention.