Spitfire Problems
10-06-2003, 02:34 PM
#11
Join Date: Feb 2003
Location: New York NY USA
Posts: 35
RE: Spitfire Problems
AtlasMan,
I appreciate your comments about Kinetic energy opening mechanicals. As a relatively new bowhunter, I migrated to mechanicals for the same reasons as everybody else.
How can I quickly and simply calculate what Kinetic energy I am creating?
What is the minimum necessary for efficient use of a normal mechanical?
Are there some mechanicals (ie 1.25 " blades vs 1.5 " blades) that require less KE?
Is the shot distance important (ie up to 20 yards there is enough KE while at 35 yards there is not enough KE)?
I appreciate your help on helping me figure this out before I run into problems.
Chrisvst
I appreciate your comments about Kinetic energy opening mechanicals. As a relatively new bowhunter, I migrated to mechanicals for the same reasons as everybody else.
How can I quickly and simply calculate what Kinetic energy I am creating?
What is the minimum necessary for efficient use of a normal mechanical?
Are there some mechanicals (ie 1.25 " blades vs 1.5 " blades) that require less KE?
Is the shot distance important (ie up to 20 yards there is enough KE while at 35 yards there is not enough KE)?
I appreciate your help on helping me figure this out before I run into problems.
Chrisvst
10-06-2003, 05:46 PM
#15
Join Date: Feb 2003
Location: NY
Posts: 4,668
RE: Spitfire Problems
www.bowjackson.com
If I remember correctly you want to have 55lbs KE minimum to shoot mechanical heads effectively. Even then you should stick with the smaller cutting diameters of 1 1/8" for example.
I may be off on my figure there so anyone feel free to chime in.
Shooting bigger heads like 1 1/2" or 2" cutting diameters requires even more. If you are marginal then just play it safe and shoot a fixed head. There has to be one out there that will fly right for you. I myself bought 3 sets of heads this year. Magnus 100 grain Stingers 2 blade.......SteelForce 100 grain 4 blade serated.....and Muzzy 100 grain 3 blade(These were sent to me free by Muzzy because I had trouble with the 90 grain 4 bladers last year)
I myself believe if you are under 60 lbs KE you are asking for trouble with penetration of a mechanical head.......I was in the mid 50' s last year and the buck I shot with a WASP JAK-HAMMER.....the head stopped at the opposite side hide. Between the ribs through the lungs and right through the middle of the heart (see pic below
).........I would hate to think what would have happened if I clipped a rib. With no exit hole I was left with a VERY difficult blood trail and it took me and 3 hunting buddies an hour to find a deer that was dead 10 seconds after I shot him.......scarey.
I don' t know about you guys but after last year I want to see BLOOD!!! I' m talking blood that flows.......not drips. Now I realize that you have to make a good shot to see that kind of blood but I feel like I made that shot last year and didn' t get the red brick road I was looking for.
The WASP JAK-HAMMER did what I wanted it to do. It flew straight and killed the deer I shot at very quickly. Great head and I recommend it highly to anybody with enough power to get a passthrough with it.
I myself have placed priority #1 on penetration this year.........straight flight is a must......but that is true of ANY head. My goal is a passthrough if I make a good shot. It is hard enough getting a deer inside 20 yards of your stand and then making the right moves and perfect shot placement.......the last thing I ever want to do again is feel the fear I felt when I thought I might not be able to find the buck I KNEW I had killed.
I DID my research and picked as small a head as I could find and made a perfect shot and I still almost lost that deer due to a lack of blood to follow. I wish mechanical heads were REQUIRED to list KE minimums on the packages.
They make some really great heads today but I can' t even count how many times I have heard someone say a mechanical didn' t work for them and 99.9% of the time it is because their setup was not powerful enough to utilize that head.
Of course it doesn' t help that they fly so well because that is lure enough to get people to buy them. Combined with some pro shops and sporting goods stores that will sell them to anyone and in fact recommend them to people because they fly so well causes many failures IMO.
If I remember correctly you want to have 55lbs KE minimum to shoot mechanical heads effectively. Even then you should stick with the smaller cutting diameters of 1 1/8" for example.
I may be off on my figure there so anyone feel free to chime in.
Shooting bigger heads like 1 1/2" or 2" cutting diameters requires even more. If you are marginal then just play it safe and shoot a fixed head. There has to be one out there that will fly right for you. I myself bought 3 sets of heads this year. Magnus 100 grain Stingers 2 blade.......SteelForce 100 grain 4 blade serated.....and Muzzy 100 grain 3 blade(These were sent to me free by Muzzy because I had trouble with the 90 grain 4 bladers last year)
I myself believe if you are under 60 lbs KE you are asking for trouble with penetration of a mechanical head.......I was in the mid 50' s last year and the buck I shot with a WASP JAK-HAMMER.....the head stopped at the opposite side hide. Between the ribs through the lungs and right through the middle of the heart (see pic below
).........I would hate to think what would have happened if I clipped a rib. With no exit hole I was left with a VERY difficult blood trail and it took me and 3 hunting buddies an hour to find a deer that was dead 10 seconds after I shot him.......scarey.I don' t know about you guys but after last year I want to see BLOOD!!! I' m talking blood that flows.......not drips. Now I realize that you have to make a good shot to see that kind of blood but I feel like I made that shot last year and didn' t get the red brick road I was looking for.
The WASP JAK-HAMMER did what I wanted it to do. It flew straight and killed the deer I shot at very quickly. Great head and I recommend it highly to anybody with enough power to get a passthrough with it.
I myself have placed priority #1 on penetration this year.........straight flight is a must......but that is true of ANY head. My goal is a passthrough if I make a good shot. It is hard enough getting a deer inside 20 yards of your stand and then making the right moves and perfect shot placement.......the last thing I ever want to do again is feel the fear I felt when I thought I might not be able to find the buck I KNEW I had killed.
I DID my research and picked as small a head as I could find and made a perfect shot and I still almost lost that deer due to a lack of blood to follow. I wish mechanical heads were REQUIRED to list KE minimums on the packages.
They make some really great heads today but I can' t even count how many times I have heard someone say a mechanical didn' t work for them and 99.9% of the time it is because their setup was not powerful enough to utilize that head.
Of course it doesn' t help that they fly so well because that is lure enough to get people to buy them. Combined with some pro shops and sporting goods stores that will sell them to anyone and in fact recommend them to people because they fly so well causes many failures IMO.
10-06-2003, 05:52 PM
#16
Nontypical Buck
Join Date: Feb 2003
Location: Wisconsin
Posts: 3,903
RE: Spitfire Problems
I emailed NAP about the kinetic energy minimums required for their spitfires and shockwaves awhile back. I believe I received a well thought out and honest reply from their tech. Here' s the reply
We publish a minimum specification for all of our mechanicals of 50 FT/LBS.
Depending on your set up and arrow weight you may be able to use a much
lower KE than this. However that is a personal choice.
Few people realize that broadhead penetration has very little to do with
broadheads. Rather, penetration has almost everything to do with arrow
flight. A well tuned 50 pound bow with arrows that fly without wobble
penetrates better than an 80 pound bow with aberrant arrow flight. Probably
the greatest disadvantage of mechanicals in general is that as a group they
tend to be much more critical of arrow spine than replaceable or fixed
bladed broadheads. For instance, because there is a loss of energy of about
1 to 3 ft/lbs. when a Spitfire contacts a target, and because this energy
loss is directly opposite the direction of travel, an improperly spined
arrow will have an additive effect. Generally an improperly spined arrow
fails to penetrate well regardless of broadhead style because the energy is
partially lost in some direction other than straight forward when the arrow
strikes an animal. A standard broadhead in this scenario would most likely
penetrate and stick in the animal with enough of the shaft inside to lodge
it until the animal does something that causes the shaft to break or
possibly get pulled out during escape. Spitfires along with most other
mechanicals will almost instantly back out because of the additive effect of
the spine related energy loss, reverse energy of opening the blades and the
fact the blades can close easily preventing any anchoring effect. Arrow
flight is especially important on high angle shots. If the arrow is
wobbling back and forth or up and down, then when it hits the target/animal
the energy continues to the side rather than straight forward. On a
mechanical this would have the effect of pivoting the broadhead and reducing
penetration. Keep in mind that if your arrow flight is good then increased
angle has NO effect.
Another thing to consider is momentum. Momentum is often disregarded in
archery because people tend to concentrate on kinetic energy. Let me
explain the difference. Kinetic energy is the impact energy of the
projectile. It is a very good way to determine how efficient your bow
transfers stored energy in the limbs to dynamic energy in the arrow. For
the most part kinetic energy in the 50 ft/lbs. to 60 ft/lbs. range is ample
for taking animals in the deer to elk range. Kinetic energy in the 60
ft/lbs. to 70 ft/lbs. will effectively take any animal in North America.
For example, Chuck Adams took his 1400 pound Kodiak Grizzly Bear with about
65 ft/lbs. of kinetic energy. I believe he used an arrow in the 630 grain
range that traveled about 220 fps. While there are several arrow/speed
combinations that would produce 65 ft/lbs. of kinetic energy, Chuck opted
for a heavier slower arrow because of the momentum. Momentum is the ability
of the projectile to continue in motion. Momentum is a linear function of
mass. The idea is the greater the mass the more resistance is required to
slow or stop the object. Think of it this way if someone were to pitch a
baseball and a bowling ball to a batter, and both balls had the identical
amount of kinetic energy even though one is traveling very fast and the
other is traveling very slow. The batter would be able to hit the baseball
and move it in the opposite direction very easily while the bowling ball
would most likely break the bat. The bowling ball has tremendously greater
momentum and therefore is much more difficult to stop or slow down.
Hope this helps.
Cary J. Pickands
Technical Support Specialist
New Archery Products, Corp.
7500 Industrial Drive
Forest Park, IL 60130
800-323-1279
We publish a minimum specification for all of our mechanicals of 50 FT/LBS.
Depending on your set up and arrow weight you may be able to use a much
lower KE than this. However that is a personal choice.
Few people realize that broadhead penetration has very little to do with
broadheads. Rather, penetration has almost everything to do with arrow
flight. A well tuned 50 pound bow with arrows that fly without wobble
penetrates better than an 80 pound bow with aberrant arrow flight. Probably
the greatest disadvantage of mechanicals in general is that as a group they
tend to be much more critical of arrow spine than replaceable or fixed
bladed broadheads. For instance, because there is a loss of energy of about
1 to 3 ft/lbs. when a Spitfire contacts a target, and because this energy
loss is directly opposite the direction of travel, an improperly spined
arrow will have an additive effect. Generally an improperly spined arrow
fails to penetrate well regardless of broadhead style because the energy is
partially lost in some direction other than straight forward when the arrow
strikes an animal. A standard broadhead in this scenario would most likely
penetrate and stick in the animal with enough of the shaft inside to lodge
it until the animal does something that causes the shaft to break or
possibly get pulled out during escape. Spitfires along with most other
mechanicals will almost instantly back out because of the additive effect of
the spine related energy loss, reverse energy of opening the blades and the
fact the blades can close easily preventing any anchoring effect. Arrow
flight is especially important on high angle shots. If the arrow is
wobbling back and forth or up and down, then when it hits the target/animal
the energy continues to the side rather than straight forward. On a
mechanical this would have the effect of pivoting the broadhead and reducing
penetration. Keep in mind that if your arrow flight is good then increased
angle has NO effect.
Another thing to consider is momentum. Momentum is often disregarded in
archery because people tend to concentrate on kinetic energy. Let me
explain the difference. Kinetic energy is the impact energy of the
projectile. It is a very good way to determine how efficient your bow
transfers stored energy in the limbs to dynamic energy in the arrow. For
the most part kinetic energy in the 50 ft/lbs. to 60 ft/lbs. range is ample
for taking animals in the deer to elk range. Kinetic energy in the 60
ft/lbs. to 70 ft/lbs. will effectively take any animal in North America.
For example, Chuck Adams took his 1400 pound Kodiak Grizzly Bear with about
65 ft/lbs. of kinetic energy. I believe he used an arrow in the 630 grain
range that traveled about 220 fps. While there are several arrow/speed
combinations that would produce 65 ft/lbs. of kinetic energy, Chuck opted
for a heavier slower arrow because of the momentum. Momentum is the ability
of the projectile to continue in motion. Momentum is a linear function of
mass. The idea is the greater the mass the more resistance is required to
slow or stop the object. Think of it this way if someone were to pitch a
baseball and a bowling ball to a batter, and both balls had the identical
amount of kinetic energy even though one is traveling very fast and the
other is traveling very slow. The batter would be able to hit the baseball
and move it in the opposite direction very easily while the bowling ball
would most likely break the bat. The bowling ball has tremendously greater
momentum and therefore is much more difficult to stop or slow down.
Hope this helps.
Cary J. Pickands
Technical Support Specialist
New Archery Products, Corp.
7500 Industrial Drive
Forest Park, IL 60130
800-323-1279
10-07-2003, 04:12 AM
#18
Join Date: Sep 2003
Location: Plum Boro, PA
Posts: 1,423
RE: Spitfire Problems
Few people realize that broadhead penetration has very little to do with
broadheads. Rather, penetration has almost everything to do with arrow
flight. A well tuned 50 pound bow with arrows that fly without wobble
penetrates better than an 80 pound bow with aberrant arrow flight.
broadheads. Rather, penetration has almost everything to do with arrow
flight. A well tuned 50 pound bow with arrows that fly without wobble
penetrates better than an 80 pound bow with aberrant arrow flight.
Probably
the greatest disadvantage of mechanicals in general is that as a group they
tend to be much more critical of arrow spine than replaceable or fixed
bladed broadheads.
the greatest disadvantage of mechanicals in general is that as a group they
tend to be much more critical of arrow spine than replaceable or fixed
bladed broadheads.
Here is another big boo boo in my opinion. How many guys are shooting underspined arrows? Based upon what I read here on the BBS pertaining to different peoples setups, a lot of us are shooting underspined arrows. So in addition to the out of tune bow we are adding to the problem with an underspined shaft. No wonder all the posts here pertaining to mech' s.
Momentum is a linear function of
mass. The idea is the greater the mass the more resistance is required to
slow or stop the object. Think of it this way if someone were to pitch a
baseball and a bowling ball to a batter, and both balls had the identical
amount of kinetic energy even though one is traveling very fast and the
other is traveling very slow. The batter would be able to hit the baseball
and move it in the opposite direction very easily while the bowling ball
would most likely break the bat. The bowling ball has tremendously greater
momentum and therefore is much more difficult to stop or slow down.
mass. The idea is the greater the mass the more resistance is required to
slow or stop the object. Think of it this way if someone were to pitch a
baseball and a bowling ball to a batter, and both balls had the identical
amount of kinetic energy even though one is traveling very fast and the
other is traveling very slow. The batter would be able to hit the baseball
and move it in the opposite direction very easily while the bowling ball
would most likely break the bat. The bowling ball has tremendously greater
momentum and therefore is much more difficult to stop or slow down.
With all that being said, what it comes down to is knowing our equipment. If you don' t know how to tune your bow...Learn. If you don' t know how to select the proper shaft size...Learn. And by all means, don' t get so caught up with arrow speed that you will sacrifice penetration. If the arrow chart lists two or three shaft sizes for you setup, don' t automatically go with the lightest because it shoots the fastest. A heavy shaft is not a bad shaft. Do not take shortcuts.
10-07-2003, 07:01 AM
#19
Join Date: Feb 2003
Location: Sinking Spring PA USA
Posts: 210
RE: Spitfire Problems
Wow someone hung this bait and allowed the faithful fixed blade crowd the chance to climb on their soap boxes yet again. So I might as well offer my $.02 worth.
It is all about the set-up and preparation.
Knowing your equipment and yourself go a long ways - what you can and can' t do.
Weekend warriors and a few " seasoned veterans" don' t practice enough, maintain their equipment and don' t really make the time or desire to know more about it. Ok I could start to rant further and go into it but it comes down to simple truth or knowing your equipment and ability before entering the field.
It is all about the set-up and preparation.
Knowing your equipment and yourself go a long ways - what you can and can' t do.
Weekend warriors and a few " seasoned veterans" don' t practice enough, maintain their equipment and don' t really make the time or desire to know more about it. Ok I could start to rant further and go into it but it comes down to simple truth or knowing your equipment and ability before entering the field.
10-07-2003, 07:20 AM
#20
Nontypical Buck
Join Date: Feb 2003
Location: VA
Posts: 1,921
RE: Spitfire Problems
I too am interested in finding out my KE. I shoot a Hoyt HavocTec, 29" draw length, set on 62 lbs. My arrow setup is as follows: 400 gr. Behman ICS Hunters (cut, but I am not sure how much), with 100 gr. NAP Spitfires. Anyone know what my approx. arrow speed and KE are?