or,
m
=
(
225
×
.84
)
−
(
225
×
.1197
)
{\displaystyle m=(225\times .84)-(225\times .1197)}
=
189
−
26.9
{\displaystyle =189-26.9}
=
162.1
{\displaystyle =162.1}
This is the value of
m
{\displaystyle m}
y
{\displaystyle y}
grams; for
y
{\displaystyle y}
m
=
11.5
{\displaystyle m=11.5}
and for the aeroplanes in question,
A
=
.111
{\displaystyle A=.111}
W
=
.372
{\displaystyle W=.372}
∴
c
=
.372
2
.111
×
11.5
×
.0546
=
1.98
{\displaystyle \quad c={\frac {.372^{2}}{.111\times 11.5\times .0546}}=1.98}
This is about the value as determined directly by Duchemin, Dines and Langley for the square plane; it is probably too low for a plane of
n
=
4
{\displaystyle n=4}
Example .—Planes 3 and 4.
m
=
17
2
×
(
.875
−
17
2
n
)
{\displaystyle m=17^{2}\times (.875-17^{2}\ n)}
where
n
=
.000724
{\displaystyle n=.000724}
whence
m
=
192.5
{\displaystyle m=192.5}
or, when absolute units are employed,
m
=
13.6.
{\displaystyle m=13.6.}
A
=
.111
W
=
.418
.
{\displaystyle A=.111\quad W=.418.}
∴
c
=
.418
×
.418
.111
×
13.6
×
.0546
=
2.11
{\displaystyle c={\frac {.418\times .418}{.111\times 13.6\times .0546}}=2.11}
a result which is still probably less than the true value.
Calculation of
β
.
{\displaystyle \beta .}
β
=
y
W
=
m
W
V
2
{\displaystyle \beta ={\frac {y}{W}}={\frac {m}{W\ V^{2}}}}
Taking planes 3 and 4.
β
=
192.5
5.9
×
289
=
.112
{\displaystyle \beta ={\frac {192.5}{5.9\times 289}}=.112\quad }
β
∘
=
6.5
∘
{\displaystyle \quad \beta ^{\circ }=6.5^{\circ }}
or,
β
=
192.5
5.9
×
169
=
.193
{\displaystyle \beta ={\frac {192.5}{5.9\times 169}}=.193\quad }
β
∘
=
11.1
∘
{\displaystyle \quad \beta ^{\circ }=11.1^{\circ }}
