SPIN
Spin is a good thing! When an arrow is launched all kinds of errors enter the picture. The arrow bends and oscillates (wet noodle), the vanes deform under load to spin up the arrow, and the broadhead is constantly changing the position of the blades causing wind planning in different directions. Yikes! How does anything like that fly straight. The spin of an arrow averages out all the induced errors that the bending of the arrow causes and the changing wind planning of the broadheads blades. In effect, the spin causes the arrow to corkscrew in to itself and not allow the arrow to take off in one particular direction.
The debate is how much spin? It is just a matter of physics the more the spin the more energy it took to achieve it. Having a 1 1/4 inch blade spinning like a propeller causes funny things to happen. It takes energy to overcome the air resistance (blades pushing the air out of the way to spin) which causes the front of the arrow to have more load. Back to physics, That energy has to come from somewhere (loss of speed) and the same energy has to go somewhere (load on the front of the arrow).
Not enough spin (with a broadhead) and the arrow will just fly off in some random direction with little or no control. As far as the FOB goes, An instant slow roll is what we have found to provide best broadhead flight without causing instability issues and loss of energy (speed) at long range. The spin of a FOB at say 30 yards is about the same as a normal fletch. But the spin-up occurs much faster. The idea is not to create a lot of spin, just to spin things up to speed faster. It is that first 10 yards out of the bow that is important (in my humble opinion). That is when the corkscrewing takes places and the arrow is still oscillating (wet noodle bending back and forth).
Drag
Drag is also a good thing! It keeps the back of the arrow from catching the front. Again, the question is how much? There are obviously a lot of factors that go into this one but generally speaking, the larger the blades on the front of the arrow, the more drag is required to keep the back of the arrow where is belongs. Ideally a stabilizer should produce as little drag as possible when the arrow is flying straight and true and as much as possible the instant the back of the arrow tries to catch the front. The FOB does just that. When the arrow leaves true and flat, the FOB has about the same drag as a vane. When the back end tries to catch the front, the FOB produces about 3 times the force a vane produce to keep thing flying like a laser.
Best of luck on the hunt!
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