4 ms·
Flight with inoperative engine(s) is altitude constrained. The aircraft is going to be able to fly with one engine operative, but not at its usual altitude, so
by nemetroid 7y ago
Flight with inoperative engine(s) is altitude constrained. The aircraft is going to be able to fly with one engine operative, but not at its usual altitude, so the 200/150/133 idea doesn’t really hold.
Further, larger engines are more efficient than smaller ones. You pretty much want to install the largest engines you can fit. It’s the underlying reason for the 737 Max debacle.
- burfog 7y agoEngines are sized for failure at take-off. At that time they are at maximum power, the aircraft is heavy with fuel, and the ground is mighty close. I see no evidence that larger engines are more efficient than smaller ones. Larger total frontal area (counting all engines together) is more efficient, as is a higher bypass ratio. Both of those tend to lead toward larger engines, but you could leave those unchanged while modifying the number of engines. For example, switching from 2 engines to 8 engines, you could maintain the same frontal area by changing the diameter from 10 feet to 5 feet. The bypass ratio, which is the portion of air that bypasses the combustion, could be 12-to-1 or 10-to-1 or whatever, and need not change with engine diameter.