TFOX

Fl,I also put a little more importance on the foc,but it looks like we try for the same thing.I also agree with Sajackson that Easton pretty well keeps it safe for you if you follow their charts.

It has been my experience that for 3d I will keep carbon above 10% as a minimum and aluminum doesn't seem to need as much.Easton reccomends 7%-8% for them.For hunting I like to be up to around 12% for the various obstacles encountered,not just for penetration benefits.

Fl,I also disagree about how much foc helps in the wind.Here in Ky. in the early spring a person can encounter 30-40 mph winds and I have personally watched arrows fly sideways until they hit the target and be right in the 10 ring.The point weight is the main reason but having the least amount of surface area for the wind to catch is a big plus,another reason to use smaller diameter shafts and short,low profile vanes.

FLHunter

TFOX,

It does not matter how large or small your arrow is, it will drift at the rate the of the air mass. However your smaller diameter arrows with the small fletch will weathervane less in a given period of flight time to the target. The faster the arrow is the less drift you will see before it impacts the target due to shorter time airborne in the air mass.

Steve,

I guess I was addressing the faster setups at the time and not stating it. I do agree that getting down to about 8% or below with fixed broadheads is a bit light. I have shot broadheads there before, the arrowspeed was up around 300fps which probably accounted for the stability. The grouping was there with my fieldpoints to 40yds so if it isn't broken well.....

sajackson

55#,

It's hard to say how the 2 arrows would actually compare in all conditions, but I would think that the ACE shafts would definitely have the edge in aerodynamic resistance and therefore downrange performance. For the typical arrow, about half the drag comes from the point, shaft and nock combination, going up in diameter incurs a hefty penalty. The barreled and thinner shaft of the ACE immediately lowers this by a healthy margin(on a side note, Turkish flight arrows were barreled for long range performance). Add to that, Easton produces a wide range of components to tailor arrow weight and FOC.

You can always build an arrow to fly well at distance, what happens in between launch and landing is another story, you are at the mercy of the physical dimensions of the projectile, the more it slows down in flight, the more time it has to drop.

55#recurve

The CXL's are roughly the same weight maybe lighter then ACE's, If I FOC'd the heck out of them do you think they would be more forgiving, even with the thick diameter, plus their components are very flush, leading to less resistance I would think, I don't want to shoot thick, but the benifits of having a more suportive and cheaper company is better for a young person like myself, as I don't have a career going yet.
Good shooting.
Dylan

>>>>--------o-->

Edited by - 55#recurve on 01/07/2002 14:00:09

sajackson

Easton's recommended combos for the ACE show; insert + point weight gives a 12-15% F.O.C. balance with Spin-Wing Vanes and 11-14% F.O.C. balance with plastic vanes.

Perhaps getting those ballpark numbers will give somewhat similar performance, however the big killer in drag is surface area(both shaft and fletches) and to a lesser degree, diameter at the point.

The nocks are pretty much a wash as the feltches "dirty" up the air back there already.

If they are lighter, you might get by jacking the FOC a bit more and try reducing fletch area, and using the extra speed, there's a cost to everything though.

TFOX

Fl


I shoot all my 3d setups about the same speed with about the same foc and I know for a fact that my 395. mags drift more in the wind than when I was using Hyperspeeds.
This shaft is about twice the diameter.It is just arrow dynamics and drag.If the arrow catches more air it will drift more.That is where the foc comes into play.The weight helps to fight the effects of the wind.If you go too far with foc ,you will encounter another set of problems.

I do agree that the faster the arrow the less it may drift but their are other things to take into consideration.

FLHunter

TFOX,

I'm afraid that I can't agree with you. Air and water are both types of fluids. If a fluid moves at a certain rate with an item embodied in that fluid, the object will move at the same rate as the fluid. There maybe factors that effect the amount of drift in a given time period like the speed of the item, or the angle of the crosswind or water current to the intended course path. These factors would influence the amount of possible weathervaning in the fluid. Since there is a certain amount of drag on an object given enough time it will weathervane itself into the current. With an arrow it eventually float in the media with the tip into the current because the greatest amount of drag is on the fletched end. However, the air mass or water mass still moves a certain amount distance in a period of time and will take the object in its flow path. It gets even more complicated when you deal with both water and wind at the same time because of the amount of water displacement that an object has and the size of the freeboard above the waterline for the wind to effect the drift which maybe from another direction. In this case you would end up with an effective composite drift vector from both the effects of the wind and water currents.

A larger arrow will tend to weathervane faster because it has more drag than the smaller sized arrow, but the amount of drift remains the same. This sometimes is misinterputed as more drift, the lateral movement is the same. To understand this more you might want to look at headwinds and tailwinds on an object. If an aircraft has a 40 mph tailwind and it is flying at 200mph of airspeed, it would have traveled 240 miles over the ground in a hour, or the composite sum of the airspeed and the wind. If the aircraft is flying in same speed headwind the aircraft would have traveled 160 miles over the ground and the airspeed would still be 200. In the case of a crosswind the air mass moves the object off course at the speed that the air mass moves in an hour at 90 degrees to the path. If the angle of flight to the wind is less than 90 degrees the drift will vary with the angle of the crosswind component.

Edited by - FLHunter on 01/08/2002 08:58:11

sajackson

This is the effect of FOC where FLHunter and I disagree.

I would submit that the amount of weathervaning is more directly related to the FOC of the arrow(but a large arrow is at a disadvantage). I like to use the example of model rockets when launched in a crosswind(an aerodynamic comparison much closer to an arrow) head directly into the wind in a very pronounced way and do not drift with the wind. There is no rational airplane or boat comparison that can really be made.

The opposition that I normally hear to that argument is that the rocket is powered, but the motors only burn for a short time and yet continue to head into the wind for a time afterward(much like an arrow after launch). As long as the projectile is vectored into the wind and the residual momentum is much greater than the aerodynamic resistance(wind) in that direction it should make headway(at the cost of forward speed) or for lower values possibly hold it's own.

This is most likely why you see the Easton ACE arrow setups with FOC values up around those normally seen with broadheads, or even higher.

Black Frog

I would think that the inertia of the arrow has to be taken into account when discussing cross-wind effects. FL mentioned that once the object in question is embodied in fluid or air- it will move at the speed of the surrounding fluid or air.

BUT, our arrow is launched from a static position in relation to the crosswind. Besides the amount of drag on the arrow, the inertia of the arrow will also play a part. Kind of like dropping a cork and a half-full 55 gallon drum off of a bridge into a river. The cork will be brought up to speed with the river current faster than the drum due to the inertia of the drum resisting the initial flow.

Maybe this effect of inertia is negligible in arrow weight comparisons and crosswinds, but I think it should still be considered?

sajackson

Not a very good analogy at all.