With all this EFOC and UFOC and all the other FOCs we all buy into, what does this do to the trajectory? Aren't we shooting very nose heavy projectiles ? If our nose is down at or near impact what happens to lethal penetration ? Would we be better served with the same weight projectile for penetration purposes but with the weight closer to normal FOC? Just some random thoughts. Thanks guys
:bigsmyl:
Given the same bow and tuned arrows, trajectory depends solely on arrow weight. EFOC arrows are no more nose down than any other arrow. The feathers trail behind: nose up as the arrow arcs up, nose down as the arrow arcs down.
It is just a total weight thing, however, it is quite often possible to get a quicker recovering wood arrow with a lighter point, lighter spine and more feather surface. which can help to get an arrow through the sticks at times. Personally, I go for a heavier point, so I can use a stiffer and heavier wood shaft and then slow it all down with a lot of feather. completely wrong, but I on a rather long shot this year, I snapped a rib going in, a rib going out and the arrow broke in half skipping off a sampling ten feet beyond the deer. That was with a 50 pound longbow and 26" draw, pushing a heavy for its spine cedar with an older file sharpened single bevel Hill that had seen its better days. I was shocked how such a narrow broad head could cause so much bleeding and bring a deer down so fast. Just some random thoughts from me, I believe that I over think things at times.
I am just going to keep hunting with what I am using
DDave
Indeed... too much thinking pisses off the Gods of Trad me thinks...
Don't ask me how I come to that conclusion... :rolleyes: :knothead:
Build a good arrow, practice with it till you know YOUR effective range for "good enough to kill" and then go forth and hunt!
I LIKE higher FOC cause I shoot lower draw weight as I got older and Uncle Arty came to visit and stayed...took a room in both shoulders...
I believe in the science that it enhances penetration, so with lower draw, I like the confidence it gives me...
No substitute for practice and then go and kill something...
Technically speaking - Trajectory depends on speed not weight. A 500 gn arrow or a 5000 gn arrow, each going 200 fps, would have identical flight paths. Good luck getting a 5000 gn arrow up to 200 fps.
I guess I do have too much time on my hands now that my arrows are flying well. You guys that reload will recognize the disease, trying to put five shots in one hole at amazing distances has kept me up in my room many winter nights. I was thinking that with the weight being proportioned more over the entire arrow that the arrow itself would stay flatter in flight. It would still be affected by gravity the same because of the same weight and duper but it's overall disposition would be more parallel to level.
See you can tell I reload. I also golf.
Ok!!! So you Golf... A 9 Iron is heavier the a 5 Iron... Heavier head = Longer Ball... I think :dunno:
(Me don'ts do Golf... Or Reload...)
My 9 150 yds My 5 190. Launch angle and spin rate.
I'm talking about two arrows weighing the same. One arrow with substantially more FOC than the other. If would seem that the less FOX arrow would have a better flight path for penetration. Not a flatter trajectory but a flatter posture upon impact
More weight up front increases the FOC, which in turn gives the fletching a longer lever arm, increases leverage which gives them more control, that's in my opinion ONE of the things that keeps them from tipping over. I hear over and over, guys and a few gal's say that increasing the tip weight caused their arrows to fly tip down, in reality they just increased their arrow weight which caused more of a rainbow trajectory. Longer lever arm helping the feathers stabilize flight is in my opinion the biggest single advantage to higher FOC numbers!
Well Chief that helps me understand it a little.
Gravity affects all things equally. The point is no more affected than the nock.
Correct but I still picture the heavier FOC arrow falling more point first. The leverage explanation helped some.
Picture a rock with a string tied on it, and a small ball of cotton tied on the end of the string. That's about as EFOC as you can get. When you throw the rock, the string and cotton ball just follow along behind the rock, with the string at a tangent to the arc of the rock, i.e. as the rock is rising, the string and cotton ball are angled up, and as the rock falls, the string and cotton ball are angled down. Clearly, a lot can happen to move the flight path of the string and cotton ball off tangent, but the relative weight of the rock and cotton ball isn't one of them.
To avoid flight problems when shooting a real arrow, it is necessary that it be tuned to the bow, which means that as you increase point weight, you have to also increase arrow spine. If these things aren't done, you can get all sorts of squirrelly flight characteristics, including some that might appear to be nose down (or as we prefer to say in arrow tuning, nock high).
That's right but when the rock is coming nose down and hits something like an animal isn't it going to track or want to track down steeper where as if the shaft was more level ( less FOC) the arc would be more gradual the change in course after impact would be less.
Two things of major importance that affect penetration are arrow weight and arrow flight.
The first factor is arrow weight. More weight = more penetration. As to your question, Dr. Ashby did studies a few years ago where he concluded that weight forward resulted in greater penetration than a more even distribution of weight. It is interesting to speculate on the physics of arrow flight, but he did exhaustive tests, and until we have better evidence, most bowhunters rely on his results.
The second question has to do with arrow flight. If an arrow hits an animal and the nock isn't directly in the line of force, if the arrow is porpoising or fishtailing, for example, the shaft will deflect away from the line of force, dissipating energy away from penetration. Optimal arrow flight and penetration are achieved when the arrows are properly tuned to the bow and archer. If an arrow is properly tuned so that a bare shaft flies true, then weight distribution for that particular arrow is irrelevant: tuned is tuned. I think some people have problems with EFOC because they try to get heavy heads to fly straight with weak shafts, but that is no different from anyone who tries to get mismatched equipment to work as they wish it would.
As far as the angle of attack that an arrow hits an animal, if one arrow hits an animal at a 45 degree angle, and another arrow hits an animal at a 90 degree angle, penetration will be unaffected by those angles as long as the arrows are properly tuned and the direction of force is the same as the angle of attack.
What people do worry about, validly in my opinion, is the tradeoff between using a heavy arrow and a lighter arrow, since the trajectory of any heavy arrow, EFOC or not, will be more curved than a lighter arrow shot from the same bow. This makes it easier to miss or wound an animal. Other people would say that the flatter trajectory of a lighter arrow makes it more likely that longer shots will be taken, leading to just as many missed or wounded animals. We're not likely to settle that argument here.
The shape of the broadhead can also play a part if the angle of the hit is more severe. It is also a large variable and difficult to predict, depending on what it hits no matter how good the arrow is flying and on the angle of the blade at impact. i like the statement that I got from a fellow with a very nice takedown recurve and very long efoc arrows, 'I don't get pass through, so you don't either.' He was referring to my shorter draw and tapered wood shafts with Grizzly and single bevel Hill heads. My answer was simply, 'sorry, but I usually do.' After some back and forth debate and theorizing, a couple of shots from my ladder stand reveled his problem. He had a two inch shorter draw when shooting from a tree stand than he had standing and stretching out his draw from the ground. His arrows flew terrible with the shorter draw. one can put al the fundamentals into a setup, but if the execution varies in a real hunting situation, the outcome can be completely different.
At standard hunting distances being 15-20 yards, trajectory isn't a huge factor when your target is wide open.... where flat trajectory really makes a difference is shooting through small windows through branches, or at longer distances....
Arrow speed determines trajectory, but down range when the arrow starts running out of gas, the heavy EFOC arrows with tiny fletching will nose dive at a steeper angle than a more balanced FOC shaft with a helical fletch..... That is simple aerodynamics....btw ...it IS rocket science...
The efoc and penetration thing has been debated for years and proven that more weight up front does penetrate better.
So Kirk, do you think that a heavy efoc has a low speed point where the attitude of the flight angle is nose down or is it that the flight line has a steeper parabolic curve, but the fletching is still behind the head weight?
Well i'm no aerodynamics engineer bro, and i don't really know how to explain it....But it sounds like you got it right.
Watching arrows of the same weight, side by side come out of the same bow shooting exactly the same speed was an eye opener at long dstance..... I was shooting two different set ups on a 3D course to check out this EFOC theory. Where i could really see the difference is shooting long distances. I shot 180 yards at the same reference point in the trees with two different radically different FOC one at 12% the other at 30%. The 12% had std helical 4" fletch, and the 30% with two inch straight fletching....
Now common sense tells you the 30% arrow with less fletching drag is going to shoot further at the same degree angle of release than the 12% foc arrow with helical fletching and more drag. but that wasn't the case at all....
The only explanation i have is as the arrow slows down to a certain point, the 12% foc arrow is better balanced and coasts, or planes flatter for a longer distance before the tip weight tips it downward.... Is what you referred to as steepness of the parabolic curve? If so the EFOC arrow was definitely steeper & fell short of the 12% foc arrow....... It was noticeable at 40 yards too just looking at the arrows sticking out of the target. EFOC arrows were tail high.
The only logical explanation i can see is that the helical fletching that spins the arrow mitigates the extra drag and helps stabilize the arrow in flight for a longer distance.
I can see two possible explanations for what you observed, Kirk. If you were shooting broadheads, the EFOC broadhead is probably bigger than the 12% FOC broadhead and therefore would have more wind resistance, so would decelerate faster.
If you were shooting field points, which would have negligible wind resistance, then it is possible that the EFOC arrow was not tuned to the bow, so may have wobbled in flight. This wobble would not be controlled by the 2" straight fletching. To get by with 2" straight fletching, you have to have a perfectly tuned arrow. Or, perhaps neither of the arrows was very well tuned to the bow, but the wobble of the 12% FOC arrow was controlled by the helical 4" fletch. The helical 4" fletch has more wind resistance than the 2" straight fletch, but the wind resistance of either one would not have as much effect on trajectory as wobble of the arrow itself.
a 30% foc arrow also requires a much lower knocking point or you are going to get tail high, tip low flight causing the arrow to hit the dirt sooner rather than later.
The reason I asked is that i have a dozen tapered carbons, I have some that are fletched minimally and some with large feathers. On longer practice shots the ones with small feathers are not as accurate as the ones with the larger fletch, vertically. Also, I have some very heavy tapered cedars with 5.5" feathers that are nearly as heavy as the carbons (watco oil) and shoot out of the same bow, they seem to be more predictable over 40 yards than the tapered carbons, even though from my perspective they both seem to have perfect arrow flight. My son tells me that the carbons fall from the sky like a lead ballon. I have a feeling the longer the nose heavy arrow is in the air and the slower that it is moving the more effect the tugging of the nose will effect the attitude. It would be an interesting test for someone with a bow site or a bow that shoots good out of a Hooter shooter that does not have an agenda to push. My secondary sighting method is not conclusive enough to make a claim one way or the other,but my point on distance is shorter with high efoc than it is with wood arrows or aluminum arrows.
That's what I was talking about Kirk. My thought was a tail high EFOC arrow even though being EFOC it will penetrate more, will actually be penetrating down and not more horizontal thru the target. Probably in small detail though. But if it hits something my thought would be that it would glance even more downward. Sort of like a ricochet only not as pronounced. Worse for killing penetration.
Well i certainly don't have any agenda. i'm just another obsessed archer interested in getting the best possible combo for my hunting and 3D rigs..... and... i'm not afraid to experiment with different set ups.... In my long distance tests, EFOC arrows were bare shaft tuned nicely, and the same spine arrow was used on the 12% FOC shafts. Both arrows flew nicely at close ranges.... BUT... the EFOC arrows were much less forgiving to a pluck or imperfect release..... i got a lot of tail waggers playing with that.....But strangely enough ....it didn't seem to effect my point of impact so much, but it did effect the angle the arrow was at upon impact..... Now that right there is going to effect your penetration. IMO
The EFOC arrows are without question getting better penetration. But there is a trade off with stabilized arrow flight using the tiny fletching prescribed...... So that led me to testing a 27% EFOC arrow with 4" helical fletching. My thoughts were that the heavy EFOC is going to help penetration without sacrificing the flight stability you get with a helical fletch.....
Results were much less tail wag, but they still had a steeper parabolic curve coming back to earth as they slowed down at longer distances..... I think if a guy really likes his EFOC arrows he could get the best of both worlds using decent fletching on the tail end.
The one thing i didn't touch on was wind drift. Shooting in a heavy cross wind, the EFOC arrows would still tail wag a bit, but the wind didn't effect the point of impact near as much as a 12% FOC balanced shaft. It seemed to me the whole arrow would drift more with the larger fletching on the low FOC shaft..... In that side wind test i don't think you can beat a tiny fletched EFOC shaft at close rage.....
Its all real interesting stuff, and everything seems to have a trade off. Same thing is true when designing limbs for a bow. There is always a trade off...
QuoteOriginally posted by Chain2:
That's what I was talking about Kirk. My thought was a tail high EFOC arrow even though being EFOC it will penetrate more, will actually be penetrating down and not more horizontal thru the target. Probably in small detail though. But if it hits something my thought would be that it would glance even more downward. Sort of like a ricochet only not as pronounced. Worse for killing penetration.
I have no doubt you are correct bro... even shooting 3D there was a noticeable difference on the penetration with an EFOC arrow with good arrow flight.... but..... those tiny fletching aren't very forgiving coming of the string less than perfect..... If your arrow is still tail waging on impact, that effects the penetration BIG time.
So why not hedge your bets and put some 3" helical fletching on your EFOC arrows?
This is really something. I love it. But I actually started shooting a longbow to simplify everything. Hah. My biggest issue with the EFOC arrows is us long draw guys. Everything needs to be perfect for good arrow flight. After I've been in a tree for a couple hrs with the temp in the teens, I'm not sure that perfect is attainable. But that's another point to ponder.
As I posted somewhere before, we met a fellow with a long draw with his recurve. He lost quite a lot of his draw when shooting down from a tree stand, for him it greatly affected his arrow flight and his penetration. I am not a long draw person, but using a rather normal tapered cedar arrow and a Hill head, on a rather long shot, my arrow hit a rib square on entry just behind the shoulder and broke a rib on exit. the little ash tree beyond the buck was more than my arrow could take, it snapped it in half. The buck ran for 80 yards and went down hard. Of course ribs on an Iowa whitetail are not ribs on a moose.
I wish I could find wood arrows long enough. I raise bow arm then draw then I bend from the waist or left leg. Ateadt I try to remember to do that
The arrow is following the head, if it is flying well ( tuned).
Whether that is straight forward, or on that "downward trajectory", it is still following the head and flying straight behind it. If you hit a deer from a tree stand, does the arrow penetrate less than if you hit a deer from the ground ( because of angle ) ?
CHuckC
QuoteOriginally posted by ChuckC:
The arrow is following the head, if it is flying well ( tuned).
Whether that is straight forward, or on that "downward trajectory", it is still following the head and flying straight behind it. If you hit a deer from a tree stand, does the arrow penetrate less than if you hit a deer from the ground ( because of angle ) ?
CHuckC
Absolutely no difference whether shooting from the ground or a tree stand.... "IF" the arrow flight is good....
If you come off the string poorly, or don't reach full draw because you are lowering your bow arm instead of bending at the waist, and that arrow is tail high or tail wagging on impact... your penetration is going to be poor.
The point i was trying to make is that a good helical fletching can & will stabilize that arrow a lot quicker than using tiny straight fletch arrows designed for less drag and more FOC. I've watched those tiny straight fletch arrows wag their tails for 30 yards just from a bad release.
There are so many human error factors that can cause poor arrow flight even with well tuned arrows. Why not hedge your bets with good fletching? You can still have a decent EFOC arrow AND good stabilized arrow flight. Win / Win
My thoughts weren't that it would penetrate less. I was thinking that it would penetrate in a downward angle. The angle would seem to steepen after impact.
For me, its not worth the time and mental anguish..... Shoot 10 (ish) gpp in a properly tuned arrow, with the correct brace height on your bow....and spend lots of time shooting, so that you can actually shoot and put them where they need to go, every time.....SHOT PLACEMENT!!! I didn't carry the EFOC, UFOC baggage very far....and lots of dead critters cant argue. I shoot a straight, silent, fast arrow with a sharp broadhead and the job gets done in the woods. Tons of POINT WEIGHT is a "what if" I refuse to concern myself with.
QuoteOriginally posted by Kirkll:
There are so many human error factors that can cause poor arrow flight even with well tuned arrows. Why not hedge your bets with good fletching? You can still have a decent EFOC arrow AND good stabilized arrow flight. Win / Win
I agree. I'm a big fan of higher FOC's and heavy points, but my arrows are helical fletched with four four inch feathers.
I find heavy points no different to tune than a lighter point, it just takes more spine. What I do find is that the heavy points fly and perform better for me.
QuoteOriginally posted by ChuckC:
If you hit a deer from a tree stand, does the arrow penetrate less than if you hit a deer from the ground ( because of angle ) ?
CHuckC
Lots of ifs and maybes in this question/ answer. All other things being equal, I would say no. I shot a doe from a treestand a few weeks back. It was a fairly close and pretty quartered shot. I hit her high about mid way back and the arrow exited between the chest and front shoulder. In this case I had more deer to shoot through but what affected penetration was the ribs being closer and heavier up high. I cut two ribs going in, one of them pretty deep. Still, the arrow almost made it all the way thru, breaking just in front of the fletch.
You can barely see the entry in this pic, the exit is clear. My form on the shot was good and the arrow well tuned. I don't regret my choice of a 235 gr Grizzly Kodiak and 620 grains of arrow for 50 lbs.
(http://img.photobucket.com/albums/v450/Fletcher610/20151017_091907.jpg) (http://smg.photobucket.com/user/Fletcher610/media/20151017_091907.jpg.html)