Experiments of air resistance with models of above-water portion of 4 typical warships were carried out in the Wind tunnel of the Naval Research Institute and the following are the formulae deduced.
For battle ship, battle cruiser and destroyer :
Ra=.0332
A V.
2For aeroplane carrier : -
Ra=.024
AV,
2in which
Ra=air resistance in kg.,
A= transverse projected area of ship above water line in m
2.,
V=relative velocity between wind and ship in m./sec.
Secondly, in view of obtaining the formula for calculating the air resistance of aeroplane carrier advancing obliquely to the direction of the wind, one model of this type tested in the same tunnel, and from the results of experiment next formula deduced : -
Ra=
C'
R (
Acos
2θ+Bsin
2θ)
V,
2where
Ra air resistance in kg.,
C'
R=coefficient of air resistance,
A=transverse projected area of ship above water line in m
2.,
B=longitudinal projected area of ship above water line in m
2.,
θ=direction of relative wind to middle line of ship measured from the bow in degrees.
Some remarks on the tendency of variation of the coefficient
C'
R in the above formula influenced by other elements, etc. are described; in addition tables and curves of the result of experiments are appended.
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