An airplane has tail efficiency η = 0.95, horizontal-tail volume ratio VH = 0.453, downwash slope dε/dα = 0.35, wing lift slope 4.8 rad⁻¹ and tail lift slope 4.4 rad⁻¹. Find the neutral-point shift as percentage of mean aerodynamic chord, to 2 decimals.
The tail contribution to nondimensional neutral-point position is $\Delta h_n=\eta V_H(a_t/a_w)(1-d\epsilon/d\alpha)$. Substitute to get $0.95(0.453)(4.4/4.8)(0.65)=0.256406$. In percent chord the shift is 25.64%. It is the tail-induced shift, not an absolute neutral-point coordinate.
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