This paper presents the effect of certain powerplant characteristics which must be considered in selecting the engine for a VTOL airplane. Selection factors discussed include: power matching, disc loading, aircraft control provisions, weight trades, and transition.
The interrelationship of propulsion and airplane characteristics are based on subsonic considerations with emphasis on VTOL rather than STOL. The discussion is applicable to engines for VTOL aircraft of 0.3 to 0.9 Mach number and of the fixed wing category.
Powerplant selection for VTOL demands timely attention to many details not existing in conventional aircraft.