The button tuning method in the paper you highlighted is interesting insofar as it ignores bracing height variables. I had thought that in order to obtain the highest speed with a standard fletched arrow it was necessary for the nodes of the arrow to be aligned when the arrow left the string and, to turn the argument on its head, that this "ideal" arrangement resulted in the highest arrow speed thereby confirming the tune of the bow.A method for using a chronograph for recurve bow tuning is mentioned here:
https://sites.google.com/site/archerybibliography/documents-1/tuningwithspeed.pdf?attredirects=0
Proposed explanation of the basis of the method is presented here:
Speed Variation Tuning
Hi JoetapleyI think what your really adjusting with BH is the string exit path to the alignment of the nock.
I agree that there is a speed penalty via nock - arrow separation but is it 5fps or 0.05fps? Unless you can quantify it to some reasonable degree then you don't know whether there's any mileage in it. With the Frangilli method, I considered it many years ago and discounted it as the (calculated) speed difference was too small to be of practical use. The bright (Frangilli) idea was to interpolate the tuning setting from speed values that were (just about) measurable.Hi Joetapley
I agree that BH directly affects nock alignment and that was the point that I was trying to make. If the nock is not in line with the string at exit point I had assumed that the arrow speed would be reduced to some measurable degree.
If that's not the case and the button adjustments makes such a small difference then perhaps using a chronograph might be a bit of a waste of time
Seems that the only way to find out would be to get a chronograph and shoot a lot of arrows at differing brace heights.I agree that there is a speed penalty via nock - arrow separation but is it 5fps or 0.05fps? Unless you can quantify it to some reasonable degree then you don't know whether there's any mileage in it. With the Frangilli method, I considered it many years ago and discounted it as the (calculated) speed difference was too small to be of practical use. The bright (Frangilli) idea was to interpolate the tuning setting from speed values that were (just about) measurable.
The problem is that changing brace height changes measured arrow speed in a number of different ways - can't see the tree for the wood.Seems that the only way to find out would be to get a chronograph and shoot a lot of arrows at differing brace heights.
Many thanks for all the information. I'll probably get a chrono and go from thereThe problem is that changing brace height changes measured arrow speed in a number of different ways - can't see the tree for the wood.
That's why in in the Frangilli speed method you compare (the difference between) a bare shaft with a fletched shaft. Speed difference depends only on the tuning (variable) and slight arrow mass difference (constant). All other speed affecting variables are going to affect the bare and fletched shafts equally assuming arrows shot close together in time. You could in theory just shoot fletched arrows and measure the speed change with tuning but then you are not allowing for other speed affecting variables messing up the measurements.
Using a chronograph to tune a bow will most probably get you a nice fast efficient bow set up, but it's very likely not going to be the best set up in terms of being the most accurate one for getting good consistent groups.Anyone got any experience of using chronographs in bow tuning? If you have which is the best and how useful is it?
I realise that tuning a bow is subject to more variables than just arrow speed but it thought would give a starting point for the only variable that is not clearly defined - other than by trying to decide where the bow is quietest - bracing height. I find that I'm never sure where it is quietest and sort of go with what feels smoothest.Are you talking compound or recurve...
Id think Bow tune would best suit compounds, due to some variables being fixed due to design and tweaking of allen keys ect.
But I would have thought Chrono's would be better used to tune the archer to repeatability, Consistancy of release, and maybe even tab face tests, than bow tune, since there are dozens of "other" variables in recurve bow tune (cant coment on compounds) that can effect speed on a recurve. Such as Arrow tune, draw length, ect.
I can see the one result if speed is your goal, Limbs wound in, Low brace hieght, and a light weight point and a loss of FOC.
If you were going for consistancy, id look at the human/bow interface with a chrono...
Other than that use a chrono to try and find out what gives a faster setup to find the cause and effect of each part of bow tune. but not to tune a bow.
Just our 2p's worth...
Worth playing with though...
I think with BH you take the split the difference approach. For me there is around a half inch range of BH where noise/vibration is low and no detectable difference is noticeable. So if you can detect noise change (increase) at 8.5" and 9" limits then around the mid point, 8.75" is about where you want to be. Don't think BH setting is that critical as it sort of comes out in the wash when you do the bow set up (initial bare shaft) check and the draw weight, if necessary, is adjusted.I realise that tuning a bow is subject to more variables than just arrow speed but it thought would give a starting point for the only variable that is not clearly defined - other than by trying to decide where the bow is quietest - bracing height. I find that I'm never sure where it is quietest and sort of go with what feels smoothest.
Simon Needham thinks differently in his book suggesting that BH is very important. I tend to agree with you in that you can pretty much get a bow into tune providing it isn't making a huge crash each time you release it. It would be nice, though, to know the optimum BH for a given setup - which, I think, is where I came in.I think with BH you take the split the difference approach. For me there is around a half inch range of BH where noise/vibration is low and no detectable difference is noticeable. So if you can detect noise change (increase) at 8.5" and 9" limits then around the mid point, 8.75" is about where you want to be. Don't think BH setting is that critical as it sort of comes out in the wash when you do the bow set up (initial bare shaft) check and the draw weight, if necessary, is adjusted.