Originally Posted by tottigol
I know of at least one medium twin that can cruise at about 130 KIAS on one engine.
Totti -- Yes, first thing that came to mind when I read the article. There are several twins in operation that max out (or come close to maxing out) the xmsn with just one of their engines, therefore potentially avoiding the 'part power' SFC issue.
Originally Posted by chopjock
Or perhaps someone could design a system where by the larger main engine is only used for the cruise and a standby APU is used to power an electric motor to assist in take off and landing
A "little & large" twin engine solution is known to have been studied by at least one OEM in recent years. The downside is having to support two different donks on a single platform. The 'oversized APU' idea could offer an alternative approach (similar to the 'APTU' studied for plank applications), though downsides here include more stringent certification requirements, and poor SFC performance when used in 'APU only' mode.
I/C