# Military Aircraft Design: Takeoff

Because military aircraft mostly have a single engine, there is no requirement for one engine being inoperative; ejection is the best solution if the aircraft cannot be landed safely. Therefore, Equation 11.6 can be directly applied (for a multiengine design, the one-engine inoperative case generally uses measures similar to the civil – aircraft case).

In the FPS system, this can be written as:

(W/S) = (TOFL x (T/ W)(1 – D/ T – лW/ T + лЦ T)] x CLtaii)/18.85 (11.10a) In the SI system, it becomes:

(W/S) = 8.345 x (TOFL x (T/ W)(1 – D/T – ^W/ T + лЦ T)] x CLstaii) (11.10b)

Military aircraft have a thrust, TSLS/W, that is substantially higher than civil aircraft, which makes (D/T – л^/T + лЦ/T) even smaller. Therefore, for a single-engine

Figure 11.2. Aircraft climb trajectory

aircraft, no correction is needed and the simplified equations are as follows:

In the FPS system, this can be written as:

(W/S) = [TOFL x (T/W) x Cbstaii]/18.85 (11.11a)

In the SI system, this becomes:

(W/S) = 8.345 x (TOFL x (T/ W) x C^taii) (11.11b)