Arrow stiffness?

[Dave]

<font size="2">Shirt mentioned in one of the other forums that he was using G3 limbs and they've made his arrows weaker. I seem to have the opposite problem! I'm shooting 3L-04 ACC arrows from my 34lb G3s (according to the Easton chart, they're the right spine for the weight and draw length)#and although the fletched arrows are grouping nicely my bareshaft is flying quite far to the left, indicating, so I've been told,#that they're too stiff! I've tried various button tweaks (but nothing too extreme yet) and that hasn't helped.</font></p>

<font size="2">So, does it look like I'm going to need to get some weaker arrows or is it nothing that can't be solved by gratuitous button tweaking?</font></p>

<font size="2">Any advice, as usual, gratefully received </font></p>

<font size="2"></font></p>

[Barry C]

Many people find the Easton charts to come out slightly stiff. Its ok to shoot stiff arrows. If they are flying well its not much of a problem. Or you can buy some heavier points and also benefit from the higher FOC.

[Shirt]

Agree with Barry. If they're flying OK, who cares. If not, buy some heavier points and enjoy the extra FOC.

[joetapley]

Dave

If you can't get the bare/fletched arrows to group by moving button centreshot the only real option is to up the draw weight if possible.

Unfortunately if you have the wrong arrow - you have the wrong arrow

[Jerry Tee]

Use heavy points . Or shoot compound ,no problem for me I just up the poundage to match the arrow.

[Dave]

I managed to solve the problem of stiff arrows by replacing the brass nocking points with cotton ones.#Thanks to everyone for their advice

[Yew Bow]

Although this is not strickly about arrow stiffness it may be of some interest to those who advocate the use of bare shaft tuning.
In 2000 I was supervising 2 PhD students, who, finding themselves with a little time on their hands, were involved in a discussion regarding the flight and mechanical characteristics of bare and fletched arrows. We decided to test a hypothesis that there was no difference between the two arrow types or the difference was minimal as advocated by coaches at the time. We mounted a Yamaha Alpha X riser with Super Ceramic Carbon Limbs to a modified steel frame previously used for testing balance recovery in subjects with long term head injury. The frame was a triangular construction of 75mm dia steel pipe , 5mm wall thickness secured to 1 cubic meter of isolated (mechanical and acoustic) concrete The frame was secured at 12 locations using 12mm bolts. The draw was achieved by the use of a linea displaced actuator secured to a free motion gimble mechanism The release mechanism for the arrow was a cartel release aid attached to a Z beam load cell (range 100 - 999 N) with a small servo motor activating the release cam. .The load cell activated the release at 18kg load (+/- 0.003 kg) with a draw speed of 0.2 meter/ sec. In order to dertmin the position of the arrow after firing a custom target was printed . The target had 72 radial lines (5 degree increments) and 30 concentric circles at 5mm intervals. This recording system would provide a two co-ordinate location system i.e. distance from the centre in mm and deviation in degrees. The entire mechanism was mounted on micrometer adjustments giving adjustment in all three cardinal planes.
We began by shooting a single fletched Easton A.C.E. and aligning the mechanism untill the shot was consistantly in the centre 5mm ring (n= 50 arrows). We then carefully removed the fletchings and repeated the test shots recording the location of the unfletched arrow The unfletched arrow was consistantly 35 - 40mm at 285 degrees away from the centre. We repeated the testing again changing a single perameter on each occasion of a) button stiffness, b) botton position,c) nocking point . At each set of tests, we could not find a configureation that would put the bare shaft and the fletched shaft in the same location.
We concluded that fletching an arrow changes the flight characteristics in such a way that setting up a bow with a bare shaft gave dissimular location results. If a bow was to be setup witha bare shaft, then using fletched arrows would give different results.

[joetapley]

"The unfletched arrow was consistantly 35 - 40mm at 285 degrees away from the centre."

Yew Bow - what was the zero angle position re say a clock face? And what was the target distance?

It's stating the obvious but the reason bareshaft arrows can be used for arow selection or tuning is that they behave differently to fletched arrows.

[Yew Bow]

The zero position for the fletched shaft was the centre of the target face Omm O degree determined by moving the entire assembly . I agree entirely that the two arrow configureations behave in adifferent ways , But my question is... why set up the bow to arrow A, and then in competition shoot arrow B that you know to be different?.

[joetapley]

"The zero position for the fletched shaft was the centre of the target face Omm O degree determined by moving the entire assembly "

Maybe I'm being dense but this 285 degrees - it means the the bareshaft was hitting to right of the fletched shaft at whatever distance?

. I agree entirely that the two arrow configureations behave in adifferent ways , But my question is... why set up the bow to arrow A, and then in competition shoot arrow B that you know to be different?.

You are essentially adjusting to a null position. Although the two arrows behave differently you are looking for the setting at which the difference between the two arrows is a minimum. Same approach as speed tuning, your finding the setting at which the speed difference between the fletched and bareshaft arrows is a minimum.