Trad Gang
Main Boards => PowWow => Topic started by: Mr.Magoo on June 23, 2007, 05:47:00 PM
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I haven't seen the new TBM, but I decided to look through my old issues to see how the bows in the "bow test" section were actually stacking-up to each other.
I was surprised to see the Predator recurve was the fastest so far at 193 fps (finger release). The A&H ACS-CX is tied with the Morrison Shawnee Arapaho at 192 fps for second place.
However, I really liked the fact that the Bob Lee recurve (that Rodney Dangerfield of bows, which I bought used for $250), with its maple limb cores was only 4fps behind the A&H ACS-CX.
In fact, with only a couple of exceptions, all the bows are very close to each other.
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Really, all bows same exact specs, drawn to the same length and same weight arrows, etc?
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I think they use a 9gr per # formula, wich makes different poundage bows perfom as if they are the same.
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It's a proven fact that bows will perform very differently as arrow weights go up. At 10 grns per pound the adcock would pull ahead of the others. Some bows will shoot light arrows faster than others such as the DAS and warf bows while others will shoot heavier arrows much faster than other bows. I have several top shelf recurves and some handmade hybrid longbows that I have tested. At 9 grns a pound like the TBM tests alot of the bows are the same speedwise but if I shoot a 10-12 grn per pound arrow out of all the bows the hybrid longbows will shoot faster. Mike
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Actually the A&H ACS bow is the king at 84% efficiency, the fps doesn't matter because the draw weight and force draw curve distort the speed. The efficiency is the key.
Jason
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Finger release is also very dependent on the shooter. Differences in grip can make the same shooter shoot a bow that would be faster from a machine slower. That's one of the reasons to match a bow to your style more than what the numbers from tests say. It may shoot great for one person and not for you.
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First, we must assume it's a fair test. The bows aren't all the exact same draw weight, but they're close (all being around 50#@28 +/- a couple pounds). The arrows are kept at 9gpp to even the field.
The whole "proven fact" of bows shooting heavier arrows better is just a old wives tale. If it's faster at 6gpp it's faster at 12gpp.
As for efficiency, I noticed that number too. Not quite sure why a more "efficient" bow would shoot slower at the same gpp (frankly, it shouldn't) ... but saying "fps doesn't matter"??? The guy that crosses the finish line first wins (assuming a fair race); if your engine is more efficient but you cross the line tied for second, you still loose the race.
I quoted the finger release numbers because it's a more realistic expectation for us. The tests post mechanical release numbers and it doesn't change the order, the Predator was still faster by 1fps.
What I found so interesting was that the bows were all very close together and that for all the "aura" surrounding the ACS-CX bows, it was only 4fps faster than a maple core Bob Lee. In fact, the ACS was only 4fps faster than a Bob Lee recurve, a GN Ghost recurve, a Black Widow PSR and a Hummingbird recurve. The ACS was only 3fps faster than a Rose Oak Puma recurve and a Fedora Stalker.
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I'm glad TBM started publishing these tests--probably the closest we'll ever get to an un-biased, real-world test of many different bows.
So far it's like I've experienced, and heard for years--there ain't a big difference (performance-wise) in the better bows.
Chad
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No doubt, though...the Bob Lee is a very underrated performer.
As far as the old "wives tale" Mr Magoo, what you're not taking into account with regard to efficiency and the heavy/light arrow thing is--
Less efficient designs, like the straight or "D" longbow become close the speed gap on the more efficient designs the heavier the arrow gets.
So...an HH bow becomes more efficient with a heavier arrow and closes the speed gap on the more efficient designs.
Will a less efficient design ever be faster than a more efficient design...NO...of course not...
But there are plenty of guys out there who will tell you that at some point, say within 10 fps just for the sake of argument--
...there are qualities of this less efficient design--
Less noise, pointability, stability for starters...
...that make it a darn good choice as a hunting bow from the ground.
LBR, I'm with you though on the publishing of the tests too.
But there are very significant performance differences in bows, the lower you go in arrow weight. Drop that 9 grns per pound down to 6 grns and just like the less efficient designs close the gap on the more efficient designs, the more efficient designs definitely pull away.
Who would shoot 6 grns per pound for hunting purposes?
Well, I shoot a 75 pound recurve at just under over 7 grns per pound...450 grn arrow...and due to the design of the bow and the STS string suppressor I have mounted on it, I do it with NO string silencers, and it's hunting quiet.
A 450 grn arrow traveling at 230 plus fps is plenty KE for even the largest of North American Game. As the wheelie crowd knows well.
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Here is some food for thought. If you compare a 5 horse power motor and a 8 horse. Put both motors on gocarts and run them 100ft, say with the 5 you get a speed of 30mph and with the 8 you get 40mph. Now put these motors in cars and run them 100ft, say with the 5 you now get 10mph and with the 8 you get 12mph. WOW! with the lighter vehickle there was 10mph difference and with the hevear there was a 2mph difference. Is the 5 catching the 8 with more weight? Does the 5 like more weight better?
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Joker, how do you kill a deer with your car if it's only going 10 mph? Lol...
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They are easier to catch with the gocarts but you just hit there legs and they fall on you.
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Actually I look at how fast the arrow is compared to the weight and the last one was 140 fps greated than the weight I think that that is really a good number.
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I agree that it is a question of effeciency. The higher the effeciciency the more energy is going to go into the arrow and less into hand shock and the like. But the other point that you can gain from these tests is that it takes a lot of change in efficiency to change the speed by more than a few fps. You might be able to drop a pound or two by shooting an A&H or similarly effecient bow, but I am not sure that you could drop more than that and stil be ahead of the competitors. I wish that the engineers in the crowd would crunch the effeciency numbers and show us simple folks how these numbers play out in real life...say a 50 pound A&H at 84% effeciency vs a 53 pound bow at 80 or 81%. It is all interesting, and unlike some,I like to see folks making more effecient, yet still simple equipment. At this stage in life, though, I don't notice the 3 extra pounds for the same performance much. I think the best application is for folks like my wife who are only able to pull marginal hunting weights. Here the most effecient bow available makes the most sense. That's my 2 sense...I mean cents :)
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First, this really isn't about "my bow is better than your bow", it's about "all our bows are pretty close to each other" (regardless of the time you spent on a waiting list). So forget the hype and shoot what you like.
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DocBrady brings up an excellent point. Getting the most KE out of the least draw weight is really where bows like the Black Swan, Acs CX, Border, Centaur, Morrison Cheyenne shine.
And no I'm not calling them "girly bows"...lol...
Sure you can kill a moose or an elk with a 45 pound lb, but a 45 pounder that shoots like a 55 pounder at the very least gives you a little peace of mind.
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There's 2 things that go into arrow speed... efficiency and stored energy. The stored energy is the area under the force draw curve. The efficiency is the ratio of the kinetic energy divided by the stored energy. The KE can be the same for 2 arrow/bow setups, but the efficiency and stored energy may be different.
2 bows may have the same draw weight but they can have different force draw curves. It can be explained by the "high early draw weight" or how 2 bows can be the same draw weight but one feel heavier than the other. If you put more reflex into a bow the early draw weight will probably be a little higher and harder to draw than one that has less reflex and has a straight force-draw curve.
You can get around efficiency by increasing the stored energy (more reflex usually) but the bow will feel a little harder to draw.
Clear as mud huh?
Jason
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i have to disagre with jason.
at least about the "hard to pull".
if a bow has a high draw weight at brace height,the chances are high that,given a proper design,that he will be sweeter to pull.
the bow just allready has a higher percentage of his peak draw allready pulled,and therefore less pounds to pull on his way to 28" or what ever.
shantam
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Why not have the bow makers make the same draw weight at 28" and use the same grain arrow? If your bow is worthy, make one bow to the specs for the bow report. I have always paid attention to bow reports from back to my compound days. Now days it's just a pain in the butt to try to keep your math straight with all the different variations.
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Jason brings up an interesting point. Some bows feel heavier to draw, some lighter, at the same draw weight.
I don't know how that would map out on a draw force curve chart, but I know exactly how it feels. I don't see the advantage in a bow that shoots like a bow that is 5# heavier when it feels like you are pulling a bow that is 5# heavier.
I have yet to experience a bow that shot like a comparable bow that is 10# heavier--5# is a stretch, unless it's being compared to something slower than the average good performing bow that today's market offers. Seems the test results in TBM agree with my experience there.
Wish I knew better how to understand how the DFC charts relate to how the bow actually feels when pulling it, if that is possible. Figure that is something you can only tell by actually getting your hands on the bow though.
If anyone has more information (not opinion, but actual test results) on proving or disproving that some bows somehow "catch up" in performance with heavier arrows, I'd love to see it. I've heard it both ways for years, and have my own thoughts on it, but I'll just leave it at that.
Interesting discussion to say the least.
Chad
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You know guys this argument reminds me of Harley motorcylce riders arguing about which of their bikes is faster. In the end your arguing about whos faster in an elephant race. :bigsmyl:
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bowdude...lol...
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Somebody has to have data somewhere that supports or disproves the fact that some bows shoot heavy arrows faster. I know I watched a number of bows shoot through a speed checker at the ETAR a couple of years back all shooting in the 180 fps range with light arows. My son had shot his 80# @ 27" HH Wesley Special through it with 825 gr. arrows @ 181 fps average over 3 shots. He and I both shot my 76# Howatt Hunter with the same arrows and couldn't get to 175 fps. Yet with 2216's my bow consistently shot about 5 fps. faster than his.
I happen to be one of the people who don't fall for the "my bow is more efficient so I can shoot 40# and get the same effect as shooting 50#". I'm sure some bows are built with better efficiency than others but KE doesn't carry that much weight with me either. It's a simple fact. Would you rather be hit in the head with a feather going 50 mph or a ball bat going the same speed? Hit force is a much better test of bow efficiency.
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Originally posted by JOKER:
They are easier to catch with the gocarts but you just hit there legs and they fall on you.
Now that was good for a laugh!!
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Going from 10gpp to 12gpp seems to have less effect on my R/D longbows than it does on my recurves. I think that the thin wide limbs have a harder time accelerating (sp) the heavier weight than do the deep narrow LB limbs. I've always heard that the heavier the arrow the closer the deep cored LB gets to the recurve in the speed department.
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You only have the distance of your draw length to get to the bows full weight.That means when you start with a bow with early draw weight you have less lbs per inch to pull to get there.A gain of less lbs makes a smoother pulling bow.A bow that pulls smooth with less weight gain at and through the end of the draw usually results in more accuracy.You take a bow that gains 4lbs at the end of a draw and one that gains 2lbs for instance.You overdraw or creep 1/2" and the 4lb gain makes a full pound of differance.The 2lb draw bow would be half that.It is easy to see which will have more impact on the arrows flight. :) There is a reason the term "smooth through the clicker" applies to target bows.They are looking to put arrows in little bitty groups. ;) jmo
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I had a predator for sale on the classifieds for $350 and no one looked at it, they are great bows and shoot well.
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It is an interesting topic. In fact, I just picked-up a used recurve (a Horne's Ridge Runner) that really feels like there's a bit of "let off" 2/3's of the way through the draw ... I'm attributing it to the semi-static tips, and it feels very smooth.
As for the "longbow and heavy arrow" debate ... I've never seen any hard numbers or valid tests, but I'd guess it's more a percentage issue. One bow will maintain its percentage advantage, but as the speed falls those numbers will move closer together even though the percentage stays the same. Any given bow can only exert X amount of force on any arrow (it's not like a motor, once that initial push is over the bow is done.) The bow that exerts X+5 is always X+5 and will always shoot faster than X until both fall to zero.
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Maybe it's just me,but I can't see any differance between how a $350 bow or a $1350 shoots.If it's going to cost me $1000 to get 4 more fps. I'll go with the $350 bow thank you. :thumbsup:
BTW.....I shot my 53# Mikuta longbow through a cronogragh just for the hell of it.....
55#-60# Cedar arrow made by Joe Skipp, 29"-BOP, 125gr. field point, and my lousy 3under finger release.
I got 183 fps.....That's fast enough for me!!!!!
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I had the chance to pull back 2 bows around 70# a few years back. The first was an longbow 70# @ 30" and had 5+" reflex. It had high early draw weight. The other was a r/d recurve 70# @ 30 and had a straight force draw curve (low/med early draw weight). The recurve was much easier to draw because there wasn't the high early draw weight like the longbow. Neither stacked, but the early draw weight had an effect on my perception of ease of draw.
Jason
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James, as usual, is right on the money...
But...if you can get a bow to stack right at the end of your draw, it can act as a hard back wall, or built in draw check.
I know one of the best LB shooters around, Redbow, had a couple built that way.
I just happened to luck into a Monarch that did that for me. Accurate as heck, but just a little too slow (have no idea about the newer ones)...okay, a downright dog...
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Hey, if you have 2 60# bows and one is harder to pull than the other one , PUT them on the same scale, 60# is 60# :banghead:
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sorry to bring up an old topic here but magoo is dead on, it's percentages and that's why a HH style SEEMS to catch up the higher the arrow weight gets. not to say it's not observed but it's b/c different arrow shelfs and riser cuts cause arrows to spine differently. spine all the arrows perfectly to each bow and the one that shoots 6gpp fastest will shoot 20gpp faster, however, if the difference at 6gpp is 2fps, the difference at 20 gpp is gonna be a fraction of a percentage of a fps.
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Does this mean that most/all high dollar bows are high dollar mainly because of the craftsmanship and beauty of the bow and the prestige associated with owning one? Not because of superior performance?
Ouch!
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Originally posted by Jason Jelinek:
Actually the A&H ACS bow is the king at 84% efficiency, the fps doesn't matter because the draw weight and force draw curve distort the speed. The efficiency is the key.
Jason
Where did you come up with this theory about draw curve distortion and fps not making a difference? Sounds like gibberish to me...
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Originally posted by Mr.Magoo:
It is an interesting topic. In fact, I just picked-up a used recurve (a Horne's Ridge Runner) that really feels like there's a bit of "let off" 2/3's of the way through the draw ... I'm attributing it to the semi-static tips, and it feels very smooth.
As for the "longbow and heavy arrow" debate ... I've never seen any hard numbers or valid tests, but I'd guess it's more a percentage issue. One bow will maintain its percentage advantage, but as the speed falls those numbers will move closer together even though the percentage stays the same. Any given bow can only exert X amount of force on any arrow (it's not like a motor, once that initial push is over the bow is done.) The bow that exerts X+5 is always X+5 and will always shoot faster than X until both fall to zero.
This may sound pretty basic and not very engineer orientated, but think of it this way. take a stiff tipped fishing rod and put 6 ounces of weight on and cast it.....do the same with a fishing rod with a limber tip.....they will both cast the weight but the stiffer tipped pole handles a heavier weight easier....my comparison would be the long bow has the stiffer tip guys...now go the other way....take that limber tip rod or a recurve with a more limber tip, and put 2 ounces of weight on it.....it will cast that weight faster and more efficiently than using a salmon rod with less effort.....
as far as KE and penitration Light vs Heavy arrows......you'll argue until the day you die with engineers over that one....
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Quote:"There's 2 things that go into arrow speed... efficiency and stored energy. The stored energy is the area under the force draw curve. The efficiency is the ratio of the kinetic energy divided by the stored energy. The KE can be the same for 2 arrow/bow setups, but the efficiency and stored energy may be different." unquote
Jason would you be kind enough to explain this statement a little better....KE is KE ....how can the effeciency be different on two bows shooting an arrow with the same K.E.?
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Kirkll, maby I can help you out with Jason's quote.
When you draw a bow you put a certain amount of stored energy into it (the area under the draw force curve). When you releace that bow the stored energy goes into the KE of the arrow moveing forword, the KE of the limb, string, scilencers going forword, vibrations, ect... The efficiency of a bow is how much of that stored energy in put into the arrow.
So, you can have two bows both with the same draw force curve, both at the same final draw weight, both shooting the same arrow. One may have heavier limbs, string, have more vibratin, ect... it will shoot the arrow slower due to not being as efficient.
I bet it will be as clear as mud now!
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Ok....Now that i understand we are talking about the "Bow's KE" and not the arrows KE..it makes sense....i thought we were back to arguing about slow arrows with heavier weights getting more penitration than a lighter arrow with the same KE. Thanks Joker....
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He was saying that two set ups that give the same KE of the arrow can have vastly different stored enery (potential energy) and efficiency. For example a 45# recurve could shoot the same arrow as a 55# selfbow at the same speed, but the stored energy and efficiency profiles are going to be completely different. I think that's also what he was getting at with the ACS. The one tested is 4# lighter than most of the bows tested with speeds that are 4 fps faster.
There are a lot of factors that go into how a bow's profile and mass distribution in the limb affect the potential energy and efficiency. The Traditional Bowyer's Bible (vol.I I think) had a real good chapter on bow design that explained lots of 'em. Increasing reflex stores more energy by building draw weight earlier. It also effectively stiffens the tips, allowing you to use more taper to make them lighter. That's what OL and John did with the ACS - they took a well known engineering concept (the cross section) and applied it to trad archery, tinkering with the radius until they got really stiff, light tips.
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Think of it this way.
If you lift a book off the table you are giving it Potential (PE) or stored energy, if you drop the book it now has Kinetic energy (KE). Kinetic means in motion, potential is stored.
If you draw the arrow back with the bow the system (bow and arrow) have potential energy, when you let go of the string, the bow will convert the potential energy into kinetic energy in the arrow. Not all the potential energy goes into the arrow, some is lost due to moving the string and moving the limbs. The efficiency is the amount of energy the arrow has (KE) divided by the energy the bow and arrow started with (PE).
Some bows are harder to draw back even though they end up with the same draw weight. The draw weight through the entire draw might not be the same. They will both take the same effort to hold, but not to draw.
Jason
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Hey. I remember this thread. Anyhow, Jeremy said ... "The one (ACS) tested is 4# lighter than most of the bows tested with speeds that are 4 fps faster."
The arrow's gpp was kept constant across the bows so the speed results look valid to me. Nothing wrong with being tied for second place (unless you really want the ACS to be first).
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All I know is that if you can't hit what you're shooting at, it doesn't make a bit of difference how fast your bow is or how heavy your arrow is.
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Hey thank Jason....that was a great engineering lesson in layman's terms...i appreciate it! Kirk
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the simplest way of thinking of this is that when a bow is drawn, it stores a given amount of energy, which is not the peak draw weight. two #55 bows can have a different amount of stored energy. the efficiency is the amount of that stored energy that is imparted to the arrow. once again, different bows will have different efficiency. many things will effect that efficiency, string type, silencers, serving weight, as well as limb and tip design. OL has come up with one way of getting a high efficiency and as far as norb's tests goes, the blackswan was as high if not a miniscule amount higher. sooooooo, in general a recurve will have a higher stored energy than a longbow but generally a lower efficiency and hybrids blur the ground in between. and yes, the difference b/w most high performing bows at 28"amo and 9gpp is about 4-5 fps and the same gpp but 30" amo is about 5-6 fps which is all OL has ever claimed, which is equal to about 1-2" of draw length which means in general, an acs cx or other very high performing bow will allow an archer with a 26" draw to shoot like he had a 28" draw. if that means alot to you, then great, if not.......fine, wouldn't argue about that point of view either. the 20 fps difference many talk about is only b/w the absolute top performing bows and the absolute slowest out there.
once again, if you see tests out there that show it to be a greater than that they're generally highly flawed, and the only way to know is to scientifically test it, feel is subjective and a bows properties on draw and on release an affect how fast an arrow seems to be going so relying on feel or sight is very very misleading in general.