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Lightest xbows: comparison


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#1 jopsa

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Posted 06 June 2010 - 03:53 AM

Xbows total weight only under 7 lbs.

1) 4,2 lbs (245 fps) Barnett Panzer V
2) 5,1 lbs (315 fps) Middleton DTM315
3) 5,5 lbs (330 fps) Middleton DTM330
4) 5,5 lbs (260 fps) Horton Scout HD
5) 5,7 lbs (355 fps) Middleton DTM355
6) 5,7 lbs (260 fps) Barnett RC-150
7) 5,9 lbs (280 fps) Barnett WildCat C5
8) 6,0 lbs (375 fps) Middleton DTM375
9) 6,2 lbs (305 fps) Excalibur Ibex
10) 6,25 lbs (300 fps) TenPoint GT Flex
11) 6,3 lbs (330 fps) Excalibur Vortex
12) 6,3 lbs (305 fps) Excalibur Phoenix
13) 6,4 lbs (330 fps) Excalibur Exocet
14-15) 6,5 lbs (350 fps) Excalibur Exomax and Equinox
16) 6,5 lbs (260 fps) Horton Summit HD150

please:
1) complete
2) thoughts
3) congratulations for the best (chapeau bas again, Mister Derrick Middleton!)

Edited by jopsa, 06 June 2010 - 03:56 AM.


#2 Chuck Gravel

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Posted 06 June 2010 - 08:07 AM

while i was shopping i noticed that some of the lighter ones felt a lot heavier based on the fact that theyre is more weight on the front of the bow compared to others

#3 OLDFLYER

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Posted 06 June 2010 - 08:11 AM

jopsa

I would check the accuracy of your scale unless those figures were gotten from the mfg. If it was the latter, I would not totally trust those weights.

#4 Moon

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Posted 06 June 2010 - 11:10 AM

hung over your shoulder no matter the weight distribution. Can't get around that.:eek:

#5 ezmoover

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Posted 06 June 2010 - 12:17 PM

Comparing advertised speed figures without including the arrow weights that were used (and any optional string upgrades) is worthless.

#6 jopsa

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Posted 06 June 2010 - 05:48 PM

Comparing advertised speed figures without including the arrow weights that were used (and any optional string upgrades) is worthless.


Timidly and respectfully I notice that you are wrong. During hunting arrow weight does not matter. Each arrow used for each of those crossbows has too much kinetic energy to kill a big deer. Enough just about 30 ft / lbs (so has my traditional vertical recurve bow). The weakest crossbow has twice more. You need much more kinetic energy only if you are a terrorist and you want to pierce bullet-proof vest. :)
Arrow drop depends only of the speed and air resistance.

Arrow weight is significant only for the safety and stability of the bow. For example, the compound xbow need heavier arrow than recurve to safely obtain the same speed.
regards - Robert

#7 ezmoover

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Posted 06 June 2010 - 08:30 PM

Sorry Jopsa, but I believe that you are wrong.

The issue(s) are much broader than just something as simple as a difference in kinetic energy. (Although that is still a very valid issue.)

If bow "A" shoots a 350 grain arrow @ an advertised 330fps and bow "B" shoots a 450 grain arrow @ an advertised 330 fps, then (assuming all other attributes are equal) you always select bow "B".

Why? Another law of physics called momentum. (speed multiplied by mass)

Bow "B" not only offers significantly more scapula-bone busting kinetic energy, it also offers more momentum. More momentum preserves speed better over distance which means less arrow drop (over same distance) relative to bow "A". It will shoot flatter.

More momentum also means greater arrow stability over same environmental conditions (wind).

More momentum ultimately helps ensure better chances of a good, clean kill.

Finally, if this information (arrow weight) is withheld from the consumer, then he/she is unable to make an important, informed decision.

Advertised speeds without including the corresponding arrow weight is worthless.

#8 jopsa

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Posted 07 June 2010 - 03:13 AM

Sorry Jopsa, but I believe that you are wrong...


Sorry ezmoover, I don't think so...

If bow "A" shoots a 350 grain arrow @ an advertised 330fps and bow "B" shoots a 450 grain arrow @ an advertised 330 fps, then (assuming all other attributes are equal) you always select bow "B".
Why? Another law of physics called momentum. (speed multiplied by mass)
Bow "B" not only offers significantly more scapula-bone busting kinetic energy, it also offers more momentum..


Do you want kill a man? Or a deer? Deer scapula is over the killing zone...

More momentum preserves speed better over distance which means less arrow drop (over same distance) relative to bow "A". It will shoot flatter..


This is not true. The same speed, bow "B" -> more momentum = more kinetic energy = more mass = more gravitation force. If the size of the booth arrows are the same - drop is the same. But in practice, heavier arrow is roughly = more air resistance = greater arrow drop... bow "B"!!!!!


More momentum also means greater arrow stability over same environmental conditions (wind)..


You're right, but I knew about this, not upheld because it is not many important. Right, more momentum - less influence of wind. But in practice heavier arrow has more shaft surface - again influence of the wind grow... But you're right, when arrow is heavier, less susceptible to wind action. But just a little bit.

Advertised speeds without including the corresponding arrow weight is worthless.)


Big momentum and great kinetic energy is important for a tactical xbows. But if anybody want buy bow for hunting (the same speed) - arrow 350 grain you can advertised to 450 grain (if is possibility of safely using). Phisic laws - "A": a little less arrow drop, "B": a little better in windy condition. Kinetic energy and momentum enough...

regards- Robert

Edited by jopsa, 07 June 2010 - 08:49 AM.


#9 ezmoover

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Posted 07 June 2010 - 10:27 AM

Originally Posted by ezmoover
More momentum preserves speed better over distance which means less arrow drop (over same distance) relative to bow "A". It will shoot flatter..

Originally Posted by Jopsa
This is not true. The same speed, bow "B" -> more momentum = more kinetic energy = more mass = more gravitation force. If the size of the booth arrows are the same - drop is the same. But in practice, heavier arrow is roughly = more air resistance = greater arrow drop... bow "B"!!!!!

Yes it is true.

If both arrows travel at the same speed, then the heavier arrow will have less drop due to greater momentum. It's called inertia. Another law of physics...

#10 casper

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Posted 07 June 2010 - 11:00 AM

Please let it go,before this gets out of hand too. :D ezmoover your last statment was 100% correct.

Edited by casper, 07 June 2010 - 11:03 AM.


#11 casper

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Posted 07 June 2010 - 11:02 AM

Please let it go,before this gets out of hand too. :D ezmoover your last statment was 100% correct.

#12 jopsa

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Posted 07 June 2010 - 11:59 AM

If both arrows travel at the same speed, then the heavier arrow will have less drop due to greater momentum. It's called inertia. Another law of physics...


Sorry... Time for the laws of physics:

Momentum: p = mv
m: mass of the arrow, variable for each arrow.
V: velocity the same, therefore no effect on the result of the comparison

Drop force = gravity.
F= G x m x m1/r2
m: mass of the arrow, variable for each arrow.
Other parameters the same, therefore no effect on the result of the comparison.

Arrow "B" m= 450 grain, 100 grain more than arrow "A" (during moving "B" more momentum, but more gravity force too).
Profit from the growth momentum is fully liquidated by the increase of the gravity force.

regards- Robert

Edited by jopsa, 07 June 2010 - 01:54 PM.


#13 ezmoover

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Posted 07 June 2010 - 12:30 PM

Basis of physics from elementary school... If you still do not understand - I more simply can not explain. Ask a teacher at elementary school.
regards- Robert



This will be my last post to you.

I took three semesters of college physics during my undergrad years (prior to earning my masters in analytical chemistry).

You said:

"How do you thing the force of gravity does not depend on the mass"
and
"Profit from the growth momentum is fully liquidated by the increase of the gravity force."

The gravitational force on any physical body is the same! Gravity's rate of acceleration is constant and does not change based on a body's mass. We were all taught this in high school. I cannot use cold hard facts to discuss science with someone that is from the flat earth society.

#14 jopsa

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Posted 07 June 2010 - 01:27 PM

Gravity's rate of acceleration is constant and does not change based on a body's mass..


Unnecessarily confirm my words. I wrote: "F= G x m x m1/r2
m: mass of the arrow, variable for each arrow.
Other parameters the same, therefore no effect on the result of the comparison." Gravity's rate of acceleration (G) is ever the same, as I wrote...

The gravitational force on any physical body is the same!.


Are you sure? whether the formula is correct?
F= G x m x m1/r2
Is correct, is not it? F = gravitational force. G - ever the same. m1 - mass of the first body (Earth). r - the distance between the gravity center of arrow and gravity center of the Earth. m1 - arrow mass, which is different for arrows "A" and arrow "B". If "m1" has a variable value - must have a variable value "F" (gravitational force).

I cannot use cold hard facts


Sorry, you use errors, not cold hard facts.

with respect - Robert

Edited by jopsa, 07 June 2010 - 01:57 PM.


#15 ezmoover

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Posted 07 June 2010 - 02:22 PM

Are you sure? whether the formula is correct?
F= G x m x m1/r2
Is correct, is not it? F = gravitational force. G - ever the same. m1 - mass of the first body (Earth). r - the distance between the gravity center of arrow and gravity center of the Earth. m1 - arrow mass, which is different for arrows "A" and arrow "B". If "m1" has a variable value - must have a variable value "F" (gravitational force).



Sorry, you use errors, not cold hard facts.

with respect - Robert



Yes. I said would be my last post but realized I mis spoke. I wanted to make a point about rate of acceleration and went too fast. But I'm willing to admit that.

However, until you have an accurate understanding of momentum and inertia and how these laws affect projectiles, then there's no point to continue.

#16 jopsa

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Posted 07 June 2010 - 04:07 PM

However, until you have an accurate understanding of momentum and inertia and how these laws affect projectiles, then there's no point to continue.


Opinion "do not understand something" means nothing, if you can not logically explain and demonstrate. Please show:

1. Will gave the wrong formula?
2. Maybe the parameters in formulas are wrong?
3. Maybe you find logic errors?

Please: accurate data, with the formulas and calculations. If you can not enter data with logical explanation - do not disturb others choose the appropriate bow and arrow. If you can - we'll admit you're right, when you have the right.

regards - Robert

#17 Moon

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Posted 07 June 2010 - 05:05 PM

the weight of the arrow's point. It could be 100 grains up to 250 grains of the overall weight of the arrow and that affects rate of drop/ decay..............doesn't it?:)

#18 AndyC

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Posted 07 June 2010 - 05:15 PM

Always gives me a chuckle when ego's clash in these kinda arguments, and it turns into an all out p*ssing contest :)

#19 cur_dog

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Posted 07 June 2010 - 05:30 PM

please make it stop! lol. :)

#20 Moon

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Posted 07 June 2010 - 06:38 PM

:):p