Effect of arrow speed on distance judging

[niceguy]

Evening all

I was part of a discussion over on Archery talk about whether a fast bow is much more of an advantage when shooting 3D or field. The discussion has got bogged down in mathematics and such so I've bowed out. It's a commonly held view that a faster arrow is a distinct advantage as the flatter trajectory will produce a smaller miss if the distance is mis judged. This is obviously the case if the distance is mis judged to be short as the slower arrow will fall more and hit lower than the faster arrow or miss altogether. Surely it must be the opposite if the distance is mis judged to be long, all arrows will hit high but the slower arrow will not be as high and be nearer the scoring zone. It could turn a complete miss into a hit. Am I missing something here ?. Input please.

Regards

[Chris B]

A slower arrow descends more steeply than a faster one, if they are to reach the same point. So if the trajectory is intercepted ( by an unexpectedly close target), the slower arrow will be seen to land higher than the faster one.

If anyone wants to convince themselves of this, grab a pencil & paper;
Draw two arc-like trajectories, with the same start point (the archer) and the same end point, (the sightmarks for each arrow will be such that the trajectories meet each other (landing in the 10 if your sightmarks for each arrow are correct), and cross over afterwards). Continue the line 'behind the target' to show that the trajectories cross over.
Now, you can draw a vertical line, representing your target, to intercept the two trajectories at any distance, and you will see that the faster arrow (flatter trajectory) will always be closer to the mark if the distance is misjudged.

[English Bowman]

What you're not taking account of is the fact that the sight marks on a faster bow will be closer together than those of a slower bow.
So the fast bow gives a sight mark of 20 on the scale for 20 yards and 30 for 40 yards. On the same scale a slow bow is 20 for 20 yards but 40 for 40 yards.

You guess the distance of a 30 yard target to be 25, so on the fast bow the sight would be set to 22.5 when it should be 25. You end out being 2.5 out on the sight.
If you make the same mistake on the slow bow you'd set the sight to be 25, but it should have been 30, so your sight is out by 5, twice as much.

I hope that makes sense.

Daniel

[niceguy]

Originally Posted by Chris B

A slower arrow descends more steeply than a faster one, if they are to reach the same point. So if the trajectory is intercepted ( by an unexpectedly close target), the slower arrow will be seen to land higher than the faster one.

If anyone wants to convince themselves of this, grab a pencil & paper;
Draw two arc-like trajectories, with the same start point (the archer) and the same end point, (the sightmarks for each arrow will be such that the trajectories meet each other (landing in the 10 if your sightmarks for each arrow are correct), and cross over afterwards). Continue the line 'behind the target' to show that the trajectories cross over.
Now, you can draw a vertical line, representing your target, to intercept the two trajectories at any distance, and you will see that the faster arrow (flatter trajectory) will always be closer to the mark if the distance is misjudged.

It makes more sense when two trajectories are drawn particularly if the curves are exaggerated, the respective impact points become clear. From the ballistic figures I've seen that are agreed to be reasonably correct the actual difference in POI at 40 yards for a speed difference of 20-30 fps is quite small, and is only fractions of an inch so I wont get too hung up about it. Thanks for the input, helpfull.

Regards

[Marcus26]

Interestingly enough arrow speed is often measured at the bow while at the target has a bigger impact on actual effectiveness of the setup.
For example big fat carbons are common in 3D for their line cutting ability. However can be going 10-20fps slower than an X10 at the 40 mark, causing misses on incorrectly guessed target

[SLOWHAND]

Yep you're right. Providing everything else is equal, a fast bow and a fast arrow is best for field.

James Park, a very respected Aussie coach did exhaustive tests to find which was the 'best' arrow for target and field (mainly for compounds but I think the same would apply for recurve). He found that Protours and x10's with tungsten piles were best for target, and Aces were best for field (faster over 60 metres). To be fair, the Nano users complained that their arrows were not tested with the same high quality componants and I am sure that they too would be very good for both disciplines.

[Marcus26]

The key was diametre. The thinner arrows drag less.

Even when tested using the highest level components the Nanos lost to the X10's. Still the difference was minimal.

[bimble]

I once had to shoot an old set of ACE's in a field shoot as I had run out of my regular field arrows (cheap ones, XX75s) and was stunned by how tight my sight marks were. I couldn't get the pins on my multipin sight close enough to have 20/30/40yd marks!!

Apart from the downhill croc shot (which I always miss) I could shot almost every target off the one pin!!

[Devon_Archer]

speed does assist, no doubt about it

however the real secret to being good at field archery is to be good at judging the distance, and executing a good shot

no matter how fast the bow, if you don't have a great set of accurate sight marks and can judge distance all you can end up with is a perfectly executed miss

with the fastest bow, if you are more than a few yards out then the arrow will not hit where you want it to, however if you are skilled in distance judgement and can get that to within a yard or two then you will hit your aimed point with a good shot regardless of how slow the bow is

Now a quick "how to be called the local loony exercise"

when you are out walking pick a lamppost or a car or a sign or a spot on the ground and estimate the distance to it, pace it out and see how close you are to it