Question

At low subsonic speed, we should select _________

(a) low bypass Turbofan engine

(b) turboprop always

(c) always use ram jet

(d) subsonic speed cannot be achieved

The question was asked during an online interview.

The doubt is from Propulsion topic in chapter Propulsion of Aircraft Design

Answer 1

Right option is (a) low bypass Turbofan engine

For explanation I would say: At low subsonic speed, low bypass Turbofan engine should be adopted among the given options. Turboprop has speed limitation due to propeller. Ram jet engine cannot be used at low subsonic speed as ram jet will require assistance to achieve adequate design condition. Ramjet can be used for speeds above Mach 2.8.