 Zaphod
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Posted: 12/27/2011 10:27:05 PM
[Last Edit: 12/27/2011 10:27:52 PM by Zaphod]
THE IMAGE ABOVE IS A PAID ADVERTISEMENT OK, now that we got the obvious out of the way, could someone please explain WHY? I understand that the lack of an arrow to absorb the energy can destroy the bow, but what I don't understand is why. Once the string returns to the brace height, what "feedback" is present that can shatter limbs, bend cams, snap strings, etc.? Can someone clue this newbie in on the physics of all this? Thanks. |
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EdwardAvila 
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Posted: 12/27/2011 11:07:49 PM
Welcome to the club!
The key is all that potential energy having nowhere to go... The bows limbs have nowhere to deliver the stored energy and it can cause a back lash and very viollent vibrations and stress throughout the entire bow. The cams, wheels and their parts take the brunt of it, so it can "explode", derail cables, crack limbs, or other damage. The problem is some damage may not be visible. At the same time, many bows have been dry-fired with no perceptible damage, and some manufacturers conduct dry-fire testing in their development. Search YouTube for some dry-fire accidents, and avoid repeating. |
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Zaphod
Jus zis guy, you know?
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Posted: 12/28/2011 10:29:41 AM
[Last Edit: 12/28/2011 10:36:56 AM by Zaphod]
I haven't looked at YouTube, but will. Thanks.
I guess I just haven't wrapped my mind around the whole backlash thing. Does the bow really transfer THAT much energy to the arrow as the string flies forward, that if the arrow isn't there, the bow destroys itself? Wow. 
ETA: I just watched one video about derailments. Holy crap, I have a lot to learn! Thank God I didn't twist or do anything like that when I've drawn mine. |
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EdwardAvila
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Posted: 12/28/2011 10:49:27 AM
Originally Posted By Zaphod:
I haven't looked at YouTube, but will. Thanks. I guess I just haven't wrapped my mind around the whole backlash thing. Does the bow really transfer THAT much energy to the arrow as the string flies forward, that if the arrow isn't there, the bow destroys itself? Wow.
ETA: I just watched one video about derailments. Holy crap, I have a lot to learn! Thank God I didn't twist or do anything like that when I've drawn mine. Yeah- it's not good! Some comparisons have been made with throwing a punch as hard as you can with nothing to absorb the energy, or "throwing an object" like a baseball without having something in your hand, or even kicking a ball. All that energy has to be absorbed by the arm or leg much like the bow would do if there was no load to transfer it to. Limbs can "hyperextend" and cause damage; if the cables derail, it can exaggerate this effect. |
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Zaphod
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Posted: 12/28/2011 11:02:52 AM
Is it also a bad idea (as suggested by some of the comments on the videos I've watched) to use your fingers to draw?
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EdwardAvila
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Posted: 12/28/2011 1:23:28 PM
Originally Posted By Zaphod:
Is it also a bad idea (as suggested by some of the comments on the videos I've watched) to use your fingers to draw? There are a few reasons why a finger draw is a "bad idea". Number one, today's short ATA bows were not designed for a finger draw; the string angles are much sharper than in long bows of the past. Secondly, a finger draw can introduce twist in the string which can rotate a peep sight, rotate an arrow right off the rest, and what you probably saw is that it can contribute to pulling the string off the cam. Start shooting with a release and a loop on your string, and you'll notice better results. This is why it is important to go to a competent shop to get your bow set up specifically for you, as they will set your peep, adjust your draw length, install a loop, and help you get set up with what you need before you develop bad habits. If your bow came from a local shop, they will typically do this for free, otherwise it is typically an under $50 service and that will pay off much more than any other investment. |
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Zaphod
Jus zis guy, you know?
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Joined: Mar 2001 USA
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Posted: 12/28/2011 8:40:37 PM
Thanks again, Ed.
I will be taking the bow in tomorrow. I do know that they need to adjust the existing draw length (29") to 30". The bow came with the drawstring and the peep sight, along with a fiber optic front sight. Like I said, the guy the wife bought it from buys a new bow every year, and takes this seriously, so this thing is tricked out and well cared for. Looking forward to first shots this weekend.  |
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EdwardAvila
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Posted: 12/28/2011 8:59:47 PM
Sweet- sounds like you got a good setup then, so it should shoot well for you.
The rest is spending some alone time with it, so the two of you can get familiar with each other.
Keep us posted! |
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Posted: 1/7/2012 8:04:49 PM
Originally Posted By Zaphod:
DON'T DO IT!!! OK, now that we got the obvious out of the way, could someone please explain WHY? I understand that the lack of an arrow to absorb the energy can destroy the bow, but what I don't understand is why. Once the string returns to the brace height, what "feedback" is present that can shatter limbs, bend cams, snap strings, etc.? Can someone clue this newbie in on the physics of all this? Thanks. Dry firing a compound bow is like diving off the high board at the pool –– without any water to catch you. The water catches the diver and slowly transfers the energy he has built up with his weight and gravity. The arrow does the same thing by slowing down the mechanisms involved and absorbing the energy stored in the bow. If the arrow is not there, everything happens much faster, and the forces are returned to the place they came from. If the bow was made to handle that, it wouldn't matter –– but that bow would probably weigh much more, and have a lot more crap hanging off it. |
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Posted: 1/8/2012 7:32:34 AM
that transfer of energy is called Kinetic energy it has to go somewhere normally 75-80 % goes to the arrow the rest through the bow no arrow with the draw force curve all energy goes through the bow and sound like a rifle going off Boom bam ching aling 
Originally Posted By EdwardAvila:
Welcome to the club! The key is all that potential energy having nowhere to go... The bows limbs have nowhere to deliver the stored energy and it can cause a back lash and very viollent vibrations and stress throughout the entire bow. The cams, wheels and their parts take the brunt of it, so it can "explode", derail cables, crack limbs, or other damage. The problem is some damage may not be visible. At the same time, many bows have been dry-fired with no perceptible damage, and some manufacturers conduct dry-fire testing in their development. Search YouTube for some dry-fire accidents, and avoid repeating. |
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HighStrung1
Chronic Road Rager
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Joined: May 2003 FL, USA
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Posted: 1/9/2012 8:56:44 AM
[Last Edit: 1/9/2012 8:59:29 AM by HighStrung1]
What bow did you get? Some bows have draw length specific cams which might require you or the archery shop to order the appropriate cam. Others are adjustable my loosening two allen bolts and rotating a module or swapping in the correct module?
Have you shot a compound before before? ETA: spelling |
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loonybin
non compos mentis
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Posted: 1/17/2012 10:31:43 PM
[Last Edit: 1/17/2012 10:34:23 PM by loonybin]
Originally Posted By EdwardAvila: In general, shooting a compound with fingers is a bad idea as Ed stated. However, there are some compound bows –– competition bows, specifically –– that are designed to be shot with either fingers or a release. Maitland USA is one company. Rob Maitland's new 2012 competition bow, the Session, is designed this way, and in fact, he designed it with finger shooters in mind. It also has an axle-to-axle length of 40". Shooting fingers out of my Maitland Retribution with a 33" axle-to-axle would be a bad idea.Originally Posted By Zaphod: Is it also a bad idea (as suggested by some of the comments on the videos I've watched) to use your fingers to draw? There are a few reasons why a finger draw is a "bad idea". Number one, today's short ATA bows were not designed for a finger draw; the string angles are much sharper than in long bows of the past. Secondly, a finger draw can introduce twist in the string which can rotate a peep sight, rotate an arrow right off the rest, and what you probably saw is that it can contribute to pulling the string off the cam. Start shooting with a release and a loop on your string, and you'll notice better results. This is why it is important to go to a competent shop to get your bow set up specifically for you, as they will set your peep, adjust your draw length, install a loop, and help you get set up with what you need before you develop bad habits. If your bow came from a local shop, they will typically do this for free, otherwise it is typically an under $50 service and that will pay off much more than any other investment. Originally Posted By EdwardAvila:
Don't be surprised if your wife gets jealous and starts calling your bow your "mistress." My 6.8SPC AR used to be my mistress, but now it's just my girlfriend because I picked up my new mistress in June (just check out the picture thread).The rest is spending some alone time with it, so the two of you can get familiar with each other. Keep us posted! Oh, and just like pics of the wife/gf are mandatory, so are pics of your bow. if you haven't posted pics yet, you better!  |
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