Home Forums Bows and Equipment A heavy arrow that shoots flatter than a lighter arrow! Reply To: A heavy arrow that shoots flatter than a lighter arrow!

Ed Ashby
Post count: 816

My pleasure Jason,

Just to save other folks the need to go back and forth, here’s the reply.

“In the simple demonstration arrrow used the dynamic spine on ALL the shots would be grossly over-spined. The propulsion system was a short section of modest strength bunge cord, drawn less than 10 inches. The shaft was a 20” section of dowel rod. The mass weight of the sliding weight is small. None of the shots represented a ‘tuned vs. untunes’ setup. All were ‘untuned’. It was a demonstration of the effect EFOC has on the flight characteristics of even a poorly tuned arrow setup.

I have, however, used matching arrows (same total mass and external profile, varying only in degree of FOC), equally well tuned, from the same bow and achieved the same results – the higher FOC shoots measurably (and significantly) flatter than the lower FOC arrow. To do so the higher FOC arrow has to be making better use of the force derived from the bow. This has been a 100% occurrance when testing with such matching setups.

Conversely, I have yet to see an equally well tuned lower FOC arrow that can totally recover from paradox as quickly (with the smaller fletching) as an arrow of higher FOC. That means that more of the arrow’s force is being loss to arrow flex. These results are not based on conjecture, but on repeated actual testing, from several different types of bows.

With big traditional broadheads (like the 190 Grizzly), Wesley Mulkey is getting total stability and can consistently hit 1″ dots at forty yards using a 2″ A&A pattern 3-fletch on a 28% FOC arrow setup. At lower FOC he can’t do that, even with considerabley more fletching and regardless of the tuning. That’s from actual testing too. Why does it happen? Because of the inate stability of a higher FOC projectile in flight. (Wesley is a three time Georgia 3-D champion, and by far the most accurate shooter I personally know.)

Talking with the folks at Win Win, most all of the South Korean FITA shooters are using well upwards of 19% FOC … and they’re the ones ‘taking the gold’.

Just as I told everyone at the seminar, there’s no trick or no magic. When we’re finished, feel free to come up and try it for yourself.

Hope that helps clarify,