ESDU 77012:2013

ESDU 77012 gives a method for estimating the forward shift of
aerodynamic centre by treating the nacelle as an annular wing of
diameter equal to the nacelle spanwise width. A graph gives the
lift-curve slope for an annular wing as a function of its width to
length ratio, the lift is assumed to act at the nacelle lip, and a
correction term for the effect of the wing upwash field is added.
The method is validated by comparing predictions with wind-tunnel
data taken from the literature for both free-flow nacelles and
nacelles with variable mass flow and is found to predict the shift
to within 0.02 of aerodynamic mean chord. The wing lift-curve
slope, also required in the method, is obtained from ESDU 70011 and
the aerodynamic centre of the wing-fuselage combination, to which
the forward shift is applied, is obtained from ESDU 76015.

The effect on aerodynamic centre due to rear-fuselage
pylon-mounted nacelles is obtained from ESDU 78013.

The computer program ESDUpac A1309, associated with ESDU 13009,
evaluates the chordwise position of the aerodynamic centre of
wing-fuselage-nacelle combinations at subsonic speeds.