Hello all, my daughter and I have recently been getting into archery, and bought our first bows (she got a Bear compound hunting-style bow and I got a takedown longbow by Tradtech). I'm sure there are probably some great folks at archery on this site, since the bow and arrow have played such a significant role in history.

I got thinking about the efficiency of bows as they've developed over the centuries, and now I'm curious as to just how far we've come from something used in, say, the medieval ages. I know that the typical draw weights were much higher back then than even the heaviest modern hunting compounds. On the other hand, I've heard that modern materials and workmanship has made newer bows far more efficient.

Do you guys have any guesses as to how an ancient bow would compare in efficiency to a modern one? Let me give examples; Say a 120 pound "war bow" or English Longbow, versus a 60 pound Hoyt Buffalo hunting recurve. I'm sure that the ancient bow at 120 pounds would be far more "powerful" but is it really a pound for pound gain? Or do you think that the 60 lb Hoyt would be roughly comparable to an 80 or even 90 pound bow of the medieval ages, simply due to advances in geometry, limb design, materials, craftsmanship, etc.? And how about a modern compound, such as a 70 # Hoyt Charger, launching arrows in the 325 FPS range?

Granted, I know that the modern, fast and light carbon arrows play a huge role in velocity too, and I wonder how some of them would fare in a medieval setting. My thought is some would probably be crap, and others might fare just fine. I can't imagine that a modern arrow designed for taking down some of the largest game on earth would be completely ineffective on the medieval battlefield.

Anyways, these are just a few things I've been pondering since getting into archery, and I'd love to hear other's thoughts on it. After all, even though the equipment is modern, the history behind the bow is certainly what led me, and probably most of us, to become interested in it.

Bow efficiency depends on arrow weight - the heavier the arrow, the higher the efficiency, but you don't want the arrow to be too heavy or it will be too slow. So it's hard to compare numbers with risking apples vs oranges. But anyway, wood has higher hysteresis than good modern bow materials, so modern bows can beat wooden bows of the same geometry. Modern bowstrings make a difference too. A good modern bow should be able to manage an efficiency of 90% or so with reasonable arrows. A good traditional wooden bow with traditional string should manage over 70%, but will probably be below 80%. Traditional composite bows can exceed 90% efficiency, so can be as efficient as modern bows. (Modern bows will win in terms of cost, maintenance, and weather-proofness.)

Note that the energy vs speed compromise means that bows are often used at about 70-75% efficiency.

So, for a given draw weight, a modern bow can deliver about 20% more energy than a historical wooden bow of the same geometry. So, a modern 60lb bow might be comparable to a historical 70lb bow, in terms of energy delivered. Compared to a good composite bow, about the same.

Note that efficiency is not the same as energy stored per pound of draw weight. Efficiency tells you how much of the stored energy ends up as kinetic energy of the arrow. The bow geometry affects the energy stored per pound of draw weight. A recurve can be better in this than a straight bow, and a strongly reflexed bow can be much better than a non-reflexed bow (so might beat modern recurves in terms of energy delivered to the arrow per pound of draw weight). Compound bows (i.e., the modern ones with the pulleys and cams) are enormously better at storing. I expect they are not as efficient as good modern recurves, but they will make up for that just by storing so much more energy.

Modern arrows? Comparable in weight to historical Turkish, Indian, and Korean arrows (and probably to Mongol arrows pre-1600), so should be OK. Should be stronger and more uniform than historical light-weight arrows. If the intent is armour-piercing, a key question is whether the arrow survives impact. A friend tested a modern aluminium alloy arrow on a 1.7mm breastplate of mine. Left a tiny mark and destroyed itself. This was with a target point rather than an armour-piercing point or broadhead, but still, energy that goes into destroying the arrow is not energy going into piercing armour.

Excellent post Timo! I wasn't aware that a bow's efficiency was so different from it's stored energy potential, but it makes sense.

Please keep the opinions (and facts) coming. This is great stuff to read about.

This is an interesting question, I've been doing a bit of research on this, eager for peoples opinions, found a lot of background here

http://www.huntersfriend.com/bow-review-400-f...nd-bow.htm

The industry standard way to look at is to compare IBO numbers, a agnostic metric centered around a 70lb draw

http://www.archeryexchange.com/shopcontent.asp?type=amoibo

This means for an average arrow (5 grains per weight of draw) for a 30 inch draw at 70 lb pull you will shoot at the ibo = speed in fps

http://www.stickemarchery.com/stickemcart/arc...ators.aspx

A modern compound bow will genrally have an IBO of around 350, topping out at 366 or so for production bows. The world record was 600

http://www.archerytalk.com/vb/showthread.php?t=1401321

Longbows and recurves, even modern ones are in the 200 range

http://www.archerytalk.com/vb/showthread.php?t=1465946

so very very roughly a compound bow shoots things about twice as fast as a non-compound bow

things get very wacky once you move past 70lbs draws though, there is a lot of diminishing returns that kick in for traditional archery.

If i were to guess i would say that a 70lb compound shoots better/faster then any tradtional bow ever made in the history of man and that a 40lb compound will outshoot anything you will likely ru into in real life

if you put them on the IBO scale the Karpowicz bows look like they are coming in at around 215-220

It's not just a matter of efficiency though, you are actually able to store more overall energy into a compound bow I beleive

it is interesting how they scale out at the higher arrow grains though, i wonder how real that is?

According to Weapons of Warre, the most common Mary Rose arrows - poplar - were around 700 grains. The birch arrows reached maybe 1000. I don't know of any direct evidence for 1500-grain English arrows at all, much less as the standard. I suspect they did get up to 1750 grains - the quarter-pound arrow - based on context, but it's far from clear.

King Charles bemoaned the fact that, during his time, nobody could shoot quarter-pound arrows any more. Here is an example of quarter-pound arrows being shot with Mary Rose replicas out to a distance of almost 200 yards.
http://www.theenglishwarbowsociety.com/wye2008_EN.html

if you are going to keep the comparison clean though you would also have to see how compound bows handle that size arrow. Compound bows are generally only 80-85% efficient but might also improve with heavy arrows

what you need is a warbow-IBO generalize everything around 140lb draw and 1000 grain arrow (-:

Are the big arrows used with the weak bows though, that is the question? I could say the same thing about the modern US military with regards to.50 caliber ammunition and .45 handguns.

Bow + arrow is an integrated weapon system...

Benjamin H. Abbott wrote:

Bartek Strojek wrote: 1500 grains arrows are not ridiculous, but they most certainly weren't shot from 70 pound bows. 140 pound ones are different matter. 18th-century Manchu sources give 80lbs as an acceptable military draw weight and Manchu war arrows are sometimes over 1500 grains.

Well, there's no doubt that modern compounds severely outperform historical bows in many ways. That's not surprising. In someways, I think if someone had figured out compound bows in the late middle ages, we might not have developed rifles for a long time.

On the other hand, a modern compound bow is as far from traditional archery as you can get while still hurling long thin objects from a stringed object. It's really hard and almost unfair to compare the two because of the massive differences in mechanics and material and even motivation. I've also seen it distort what people expect from archery. It's not really that hard with a properly set up compound to get quarter-sized spreads from 30 yards in a few weeks. Doing that with a wooden long bow takes years of dedicated practice. So I've heard "modern" archers opine that ancient archers must have been terrible (basically the same argument that pyramids couldn't have been built because people without iPads must have been/be stupid). On the other end, I've heard people give almost reverential respect to ancient archers, to the point that they will resolutely maintain that every Englishman could hit a French knight in the eye at 400 paces (a variation of every samurai was almost Mushashi). Just as aggravating because of the tendency to make any attempt to impose actual limitations that exist are seen as somehow demeaning an entire art that they've become emotionally invested in, which never makes pleasant conversations.

In any case, don't take this as "don't you dare try to compare the two!!!" Any archer gets respect from me and best wishes. But I usually find its more productive to keep comparisons in context and as close to an "apples to apples" comparison as we can. Its hard enough to do "red delicious" English Warbow to "granny smith" Turkish Composites, but in this case it seems we are trying to compare "grape flavored pear/apples" (recently seen, still confused). Our points of reference are getting a little strained...

As far as I understand, most of 'affordable' compound bows also have around 70% of efficiency.

They are obviously just able to store so much more energy for the same draw, that this 70% ends up being a lot of energy.

Thanks for the great replies, folks! This is what I was hoping for...please keep it coming.

Ben Coomer wrote:

In any case, don't take this as "don't you dare try to compare the two!!!" Any archer gets respect from me and best wishes. But I usually find its more productive to keep comparisons in context and as close to an "apples to apples" comparison as we can. Its hard enough to do "red delicious" English Warbow to "granny smith" Turkish Composites, but in this case it seems we are trying to compare "grape flavored pear/apples" (recently seen, still confused). Our points of reference are getting a little strained...

Ben, I totally get your point, and I'm not offended by it. Although your point is valid, as a new student of archery, I love hearing the comparisons, even the apples -oranges ones. The reason is, it actually helps me better understand the history of archery to see where it has come to today. I have a hard time explaining it, but if someone were only to ask about comparisons in the same time period, I feel like we'd only be getting a small snapshot of the bow and arrow, taken out of context. By comparing apples to oranges throughout history, I feel like we get to see more of the whole picture.

On another forum I've recently been reading on, Archerytalk.com, I often read the opinion that modern top of the line compound bows shouldn't even be considered archery, or nearly that strongly worded of an opinion. They cite that the energy to launch an arrow is now coming from pulling the limbs together, as opposed to the limbs pulling away from the archer. I get the distinction. But at the same time, I believe it is still every bit as much a bow and arrow, just using different forces to produce the energy. If I remember right, there has even been a historical Native American example of a "compound bow" (4 limbs instead of two). Would that bow all of a sudden be "real" because it is an ancient weapon? That's my take on the argument at least.

When my daughter got her new Bear compound for her 12th birthday, I tried really hard to like compounds, so I could shoot it with her. I even narrowed it down to two choices, the Bear "Assassin" and the Hoyt "Charger". I tried shooting both. But as luck would have it, I also tried a Tradtech take-down longbow and fell instantly in love. The Longbow has nowhere near the performance of the compounds, but when I used it, I immediately thought, "now THIS is what a bow is supposed to feel like". By the way, I can't hit the broad side of a barn door with the thing, but it is still a blast. :)

Anyways, back to the discussion...

it's kinda funny i had the same experience as D. S. Smith, just don't like compound bows much even though my wife and kid both use them. There is something about the feel of it I don't like, the pull and release is a pretty different experience. I just started shooting a compound two months ago though, been shooting traditional on and off since my teens

It's a good conversation though since anyone getting into archery is going to have to choose between the two at some point.

I think the "easiness" of compound is a bit overstated though. Sure with sights that are zeroed in at a known range with no windage, however even then you need proper form and quarter spreads are not a common site. Dinner plate spreads they seem to get to pretty fast

Also a big part of traditional archery is learning how the bow shoots at different ranges, instinctively. That kind of skill is not picked up quickly, if you ignore it, you ignore a big part of the sport