|
Page 1 of 1
|
[ 11 posts ] |
|
Research into loose 'efficiency'
| Author |
Message |
|
Mike Hardman
Joined: Tue Oct 30, 2007 5:53 pm Posts: 21 Location: Bristol, UK
|
 Research into loose 'efficiency'
Dear All,
I'm attempting to compare (using a chronograph) the initial arrow speeds of arrows shot from the same bow, with the same draw length etc, where I vary the lock, on the string. For example, thumbdraw versus three finger draw. Both with and without tab/ring.
From my first set of data, I see little difference between styles, and little difference within a style when different equipment is used. I'm in very early stages as of yet, but I suspect much depends on the skill of the archer, rather than the technique the archer uses (is that a paradox?).
I wonder, has anyone here done similar experiments and come to the same conclusion? Or failing that, does anyone here know of anyone else interested in researching arrow speeds?
Regards
Mike Hardman
|
| Wed Jul 16, 2008 1:52 pm |
|
 |
|
Bede
Joined: Sat Jan 21, 2006 2:25 am Posts: 36 Location: Sydney, Australia
|
Mike,
I have done similar experiments and have had strong correlations between release type and arrow speed. It is hard to find someone proficient in several different styles of shooting. Standardising the equipment can also be problematical.
What I attempted recently was to minimise the skill based component of the release. The way I did this was to use the chronograph to measure my performance with each style and try to improve it independently of the other modes. Then I selected a bow that limited my draw length and reduced the effect of individual bad releases. Lastly I looked at doing several series of tests each based on an arrow optimised for one particular style.
This way I think that a real comparison could be made. However, it is tedious and will take time to complete. My current chronograph supports multiple tests so I think that I might be able to finish the process.
_________________ Bede
|
| Sun Oct 12, 2008 6:32 am |
|
 |
|
Mike Hardman
Joined: Tue Oct 30, 2007 5:53 pm Posts: 21 Location: Bristol, UK
|
Bede,
What sort of percentage differences did you find? I found differences between fingers and thumb lock in the order of 1 % or less. I was using a bow of only 26lb (lots of readings taken in one session) and draw length 31". My error could easily be larger than 1%. If you want to see my raw values I can send you the excel file. I'm afraid I gave up after the first sitting of 32 arrows on each.
I put this experiment away to think about several months ago, due to several factors. I would only be happy with a conclusion if I could draw on a comprehensive set of data, which I am not able to produce (lack of varied equipment, time, decently designed experiment). I feel that in order to be scientific about it, one needs the following:
Data, varying technique, keeping all other variables constant.
However, if you vary technique, you also vary how the arrow, string, and bow interact. Thus any 'constants' you have in place, chiefly how the arrow oscillates (as you have mentioned) might be subject to change. By optimising the arrow, do you mean, optimising for direction (the arrows then oscillate the same) or for velocity? I think the first one would be the most helpful one, though they might of course coincide (I'm assuming you're changed arrow spine to this end). Will you be keeping arrow mass constant (and mass distribution)?
Most worrying, is the factor of archer's skill, which is the factor which most of all put me off. Any data I find is just applicable to me, and any other archer could argue that quite honestly, unless the data covers multiple archers. Even then, how do we know that this group of archers we have used are not all equally well skilled in one area, and poorly skilled in another?
I am however, more optimistic about comparing the ring and tab, as protective measures for the fingers and thumb respectively. If the differences between no tab, tab and no ring ,ring could be shown to be similar, that might enable the thumbring to be reclassified. One hitch with this though, is that your ability is influenced by the protective devices. If you are less comfortable, a bad shot is more likely, thus averages are dragged down in certain areas.
I agree with your idea of optimising the arrow, but do not see how you are eliminating the skill factor. Improving your own abilities in each area (if that is what you mean in your 2nd para) to a maximum is not guranteed to reach The maximum effectiveness, just your own at that point in time. It will still be human archers operating the equipment. You will still be measuring how efficient your own methods are, not the general entity.
If however, it were possible to model mathematically the release mechanisms, and any predictions made by that were backed up by consistant evidence, I would be forced to change my current conclusion.
Nevertheless, after all that scepticism, if you are able to design a true test of each technique, I look forward to seeing the results.
Regards
Mike
|
| Sun Oct 12, 2008 7:49 pm |
|
 |
|
Bede
Joined: Sat Jan 21, 2006 2:25 am Posts: 36 Location: Sydney, Australia
|
Mike,
I have been able to get differences above 10% which were backed up by the required aiming points.
To make this clearer, I have taken high speed photographs of the thumb release in action and discovered that the string leaves the thumb just after the index finger clears the tip of the thumb nail. That means that very small variations in thumb release can cause drag. This is not apparent to the user because we do not perceive variations is pressure as short as 1/60 second.
The variation in speed between a thumb ring, a leather thumb tab and a bare thumb are small to non-existent with light bows. I am not sure how FITA rules are observed everywhere. Here we regard a thumb ring as nothing more than a hard tab. In flight shooting in the US some classes are specified as three-finger release events and even two fingers are disqualified.
I have tried a Sassanid two finger release and got higher speeds than three fingered shooting.
You can only shoot as well as you can so, at best, your results will only refer to you. However, if you take all due care to make sure that you are executing the shots with the best technique possible to you, then there must be some level at which it is generalisable. Attaining a fast release is easier than making a consistent one in each style.
_________________ Bede
|
| Mon Oct 13, 2008 4:41 am |
|
 |
|
Pierre
|
Here in France a thumbring is considered as a mechanical release by the FFTA.
By the way, I haven't tried tum ring release And I only shoot using a mediteranean (3 fingers) release but through various tests my chrono showed me that there could be a difference of as muche as 10 to 15 fps between a good and a bad mediteranean release.
I wondered if there could be such a difference with a thumb ring release?
|
| Mon Oct 13, 2008 8:01 am |
|
 |
|
Bede
Joined: Sat Jan 21, 2006 2:25 am Posts: 36 Location: Sydney, Australia
|
There can be large variations in speed due to poor releases with the thumb. The timing of the movements of the index finger and the thumb are critical. Even the degree of tension in the thumb can affect the speed. Having said that, it is relatively easy with practice to get variation below one foot per second in speeds of 160 to 210 FPS.
It is amusing that some authorities see a thumb ring as a mechanical release when it has no moving parts and performs exactly the same function as a tab if used in the traditional manner. Of course there have been some misleading articles written about how it performs, particularly one from several decades ago, and you can't blame officials from being confused.
The one ring that does qualify as a mechanical release in my view is the so-called male ring of the Koreans. It moves in relation to the thumb when used, pivoting on the ring section. In that case, it is not just acting to protect the thumb.
_________________ Bede
|
| Mon Oct 13, 2008 11:02 pm |
|
 |
|
Mike Hardman
Joined: Tue Oct 30, 2007 5:53 pm Posts: 21 Location: Bristol, UK
|
I put the strange ruling down to the issue over numbers. It appears that very few archers here actively use the ring, (although there is an archery club of 30 or so in Croydon that seems to use the thumb ring exclusively) and thus there is no real need to revise the ruling (especially as 'Archery GB' this new trendy entity appears to have little or no interest in non-modern forms). I doubt any of the members of the upper echelons have ever seen a ring, let alone used one.
Is the situation any different in Australia? Or do you have more open minded officials?
I'm curious as to why my % difference is much lower than yours. Is the best method for a fast thumb lock loose that described by Kani?
I too found that I could be very consistent on a good day, most values were within 0.5%.
How many archers have you studied? If you require readings from other archers, I could provide some.
|
| Tue Oct 14, 2008 4:19 pm |
|
 |
|
Bede
Joined: Sat Jan 21, 2006 2:25 am Posts: 36 Location: Sydney, Australia
|
Mike,
I would say the officials seem to be reasonably tolerant when there is no chance of unfair advantage. However, it could just be the attitude of my club which is very open-minded. Perhaps, there has been so little use of thumb rings here that they were unfamiliar with the implications. I don't shoot competition target and have only asked for opinions.
I use a release very close to Kani's. I use a short thumb ring and a fully flexed thumb with a low pressure index finger. There is high pressure between the thumb and the middle finger, the other two fingers are tightly curled as well. The problem might be that my Mediterranean release is much worse than yours.
I have basically only tested myself. Testing multiple archers introduces too many variables in a study that has a lot of noise already as you pointed out.
_________________ Bede
|
| Wed Oct 15, 2008 3:46 am |
|
 |
|
Rod
Joined: Thu Jul 16, 2009 5:10 pm Posts: 5 Location: Lincolnshire
|
 Arrow speeds
There was a time when we did some shooting through a chronograph for two reasons.
This was using fingers, mediterranean loose, and in my case a slick pony-buck tab.
One was to practice getting a consistent arrow speed.
When I was at my best I could do no worse than plus or minus 1 fps for a good while.
The other was to settle an argument over the effect of holding time on arrow speed using a wooden bow.
Our conclusion was that a brief holding time had little effect, but after about 5 seconds there was a drop in cast which stabilised after 15 to 20 seconds.
The loss in arrow speed was on average around 9 mph in the hands of the more consistent archers.
The variation in recorded arrow speed using the same equipment used by different but reasonably competent archers was in the range of up to plus or minus 5 fps, significantly more if we include the less competent participants, in excess of plus or minus 12 fps.
The benchmark speed I set with this bow was 165 fps if held briefly at anchor, 172 fps with a fluent but not slashing loose.
I daresay a skilled flight shooter might get as much as another 10 - 15 fps out of the same gear.
Rod Parsons.
|
| Fri Jul 17, 2009 10:13 am |
|
 |
|
Bede
Joined: Sat Jan 21, 2006 2:25 am Posts: 36 Location: Sydney, Australia
|
Rod,
That is an interesting result and is consistent with theory. In a flight bow, which is highly stressed, I would expect a greater variation. However, I have not had time to test this even with ordinary horn-wood-sinew composites so I can't really comment further. I am looking forward to doing this in a month or two when the hot weather returns down here.
_________________ Bede
|
| Fri Jul 31, 2009 12:13 am |
|
 |
|
Hugh Soar
Joined: Sat Jan 21, 2006 2:05 pm Posts: 106 Location: England
|
 Re: Research into loose 'efficiency'
Read with growing interest. Surely there is another factor in play here. The thumb ring offers minimal contact with the string, thus maximising the string angle at full draw and by doing so improving cast. Also in theory and in practice I would expect a sharper loose from a thumb draw than with a two or three finger Mediterranean loose. Would not the slight relative reduction in string angle at full draw using the latter also mean a slight comparative reduction in limb bend and thus cast ? . Or am I barking up the wrong tree.
|
| Sat Jul 31, 2010 11:04 am |
|
|
|
Page 1 of 1
|
[ 11 posts ] |
|
Who is online |
Users browsing this forum: No registered users and 1 guest |
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum
|
|