Transcript Understanding Bat Performance

High Speed Test Results
ASA Equipment Testing & Certification Committee
Oklahoma, OK April 5-6, 2003
Lloyd Smith, Ph.D., P.E.
High Speed Test
• 110 mph inbound ball speed
• Measure inbound and rebound ball speed
• BBS from 85 mph swing speed and 25
mph pitch speed
• Center of rotation 2.6 inches from knob
• Scale swing speed with bat MOI
• Scan bat every inch to find maximum BBS
New Swing Speed Formula
 d  2.5in  9000inoz
 85m ph

I
 30.5in 
2
Vbat
d=impact location from knob



0.25
Preliminary High Speed Data
• All tests used a pitch speed of 110 mph
• WSU
– measured ball-in and ball-out
– used 44/375 ball, conditioned at 50% RH
• NYU
– measured ball-in and bat-out
– used 47/525 ball
– normalized BBS with ball COR
Si
ng
le
ng
le
al
l
in
um
in
um
W
al
um
al
um
W
oo
d
W
al
G
Do
l
oo
ub
d
le
SP
w
Hi
al
Ba
lT
gh
t
ec
Pe
ho
r fo
no
rm
Hi
lo
gh
in
gy
g
Pe
A
Hi
l
u
r
fo
m
gh
rm
in
pe
um
i
n
Ve
rfo
g
Al
ry
rm
um
hi
in
gh
g
in
um
C
pe
Ve
om
r
ry
fo
p
rm
os
hi
gh
ite
in
g
pe
ba
m
Ve
r
t
ul
fo
ry
t
r
i
-w
m
hi
in
gh
a
ll b
g
co
pe
Ve
at
m
r
fo
ry
po
r
m
hi
sit
in
gh
e
g
ba
pe
co
rfo
t
m
po
rm
sit
in
e
g
ba
co
m
t
po
sit
e
ba
t
Ba
sic
Si
70
's
70
's
Ba
sic
ea
rly
ea
rly
W
oo
d
BBS (mph)
BBS from Era Study (WSU)
110
105
100
95
90
85
80
W
oo
d
Al
um
in
um
M
ul
tiwa
ll
M
ul
tiwa
ll
M
ul
tiwa
ll
M
ul
tiwa
ll
M
ul
tiwa
ll
M
ul
tiwa
ll
Co
m
po
sit
e
Co
m
po
sit
e
Co
m
po
sit
e
Co
m
po
sit
e
BBS (mph)
Era Study (NYU)
104
102
100
98
96
94
92
90
BBS vs. BPF
1.4
1.35
BPF
1.3
1.25
1.2
1.15
1.1
94
96
98
100
BBS (mph)
102
104
Very high
performing
composite
High
Performing
Aluminum
105
Doublewall
Techonology
BBS (mph)
High speed test vs. ASTM 1890
110
High Speed Test
ASTM Test
100
95
90
85
80
Ball Compression
114
112
110
BBS (mph)
108
106
104
102
100
98
96
94
375 lb
525 lb
Ball Conditioning
1.4
9 days
Weight Change (%)
1.2
1
0.8
0.6
0.4
0.44 COR, 375 lb balls
30% to 50% RH
0.2
0
0
50
100
150
1/2
Time (min )
200
Summary
• Current BBS of 85 mph (125 ft/s) not
realistic
• Field observations of high performance
bats captured in high speed test