quote:
Originally posted by 08Dad:
Of course, the way the BESR was supposed to work was to make metal bats and wood bats equal on the exist speed off of the bat - something which I believe worked at first but the engineers have since figured out how to shift the balance towards metal. With a perfect formula, you would still see kids picking wood bats rather than metal.
Given the way metal bats are made today, there is no perfect formula. Wood bats and metal bats have fundamentally different characteristics.
A wood bat is made of a solid constant density material, which means that most of the weight of the bat is located at the barrel. Conversely, a metal bat is hollow, and has a thick wall near the handle, and a very thin wall in the region of the barrel. For bats of the same weight and length, it is much easier to swing the metal bat quickly (in technical terms, the metal bat has a lower moment of inertia about the handle), and the bat speed is higher. So the ball should come off the metal bat faster, except there is less mass behind the ball, and that more than compensates for the higher bat speed. On the other hand, the trampoline effect of a thin wall metal bat tends to make the ball exit speed higher.
So there are three competing effects--MOI, mass behind the ball, and trampoline. For the particular bat/ball collision velocity used in the BESR tests (which at first glance seem low, but are actually pretty close to college speeds) and for a ball hit on the sweet spot, a typical metal bat matches a good wood bat pretty well, now that lower limits have been placed on the MOI. But the match doesn't hold up as we vary the conditions: For a higher collision velocity, a metal bat tends to give a higher exit speed, because the trampoline effect dominates. Facing slow pitching, a wood bat may drive the ball farther. Or increase the size/strength of the batter enabling him to swing a heavier bat, and the advantage likely switches back to wood.
The point is that no formula will cause a metal bat to perfom identically to a wood bat, when we consider different lengths and weights of bats, different collision velocities, and a varielty of hitting capabilities.
If we required a metal (or any other material) bat to have the same weight distribution as a wood bat, and got rid of the trampoline effect, then the bat would perform just like a wood bat. For metal bats, that would require a very different type of construction, which would likely be fairly expensive. A metal skin covering a hex cell interior comes to mind (folks who were skiers in the 70s/80s may recall Hexcell skis). Or we could just laminate up a low density wood with plastic resin, and have a durable bat at a low price. A bamboo bat comes to mind.
I'm not so pessimistic about the resurgence of wood or wood-like bats. I wouldn't be surprised if in 10 years, metal bats were used only before high school, or in beer softball leagues. The NFHS, on a national or state level could drive that, and might do so for safety reasons. The NCAA could do the same on a national or conference basis. Sponsorship of college teams would still continue. Of course, a switch to wood-like bats would help professional baseball identify potential hitters better. Maybe they'd like to set up a bat fund for all the college teams!