I don't know why the European MALE RPS UAV designers chose to use twin engines?
I know two engines are expensive but add safety...
Does choice is to obtain mass flow @ Medium altitude(low air density)?
especially with relatively low speed(maybe 0.4~0.6 Mach)...
I guess that as density drops off at higher altitudes, the machine ingests less air mass, resulting in reduced power and reduced thrust...
To need larger flow areas (larger diameter)?
Unlike RQ UAV series...