SIZING OF AIRCRAFT ACCORDING TO MANEUVARING REQUIREMENT

In this post I am going to introduce about the sizing of aircraft according to their maneuvering requirement .

Specific requirement for sustained maneuvering capability (including sometimes specific turn rate) are often contained in the mission specification for agricultural ,aerobatic or for military aircrafts.

Sustained maneuvering requirement are usually formulated in terms of a combination of sustained load factor (n) at some speed and altitude.

The sustained maneuvering capability of an aircraft depends strongly on its maximum lift coefficient and on its trust.

For equilibrium in vertical direction of flight , it Is necessary that:-

n*W =C_L*q*S ———–(1)

where n= load factor and, q= dynamic pressure

the maximum load factor can be capability of an aircraft (n_max)can be found from above equation(1) ;

n_max = C_L*q /(W/S)

this load factor can be sustained as long as there is sufficient thrust, since:-

THRUST = DRAG

T= C_DO + KC_L²,

T= (q*C_D0*S )+( C_L²*q*S/∏e*A.R)

After dividing above equation by W we get :-

T/W = (q*C_DO/(W/S)) + (W/S)(n_max)²/(∏*e*A.R )

NOW,

If some maximum load factor is desired on a sustained basis at a given speed and altitude then , the above equation can be used to find out the relation between (T/W) and (W/S) for a given value of c_d0.

so we can find out the wing loading for a specific thrust by weight ratio and hence design the wing /aircraft accordingly.