Long Range Turboprop Aircraft

Question

Why are turboprops not as efficient as jets on long range flights, say over 1,000 miles? Seems to me if they are more efficient on short haul flights (2 planes, same number of passengers, flying the same distance) the same should apply to long haul flights. Everything I read says this is not so. Why is that? Does it have to do with cruise altitude?

What about the turboprops that CAN fly above 30,000 ft; wouldn't they be more efficient on long haul flights?

JD

Answer 1

Turboprops and jets have roughly equal efficiency at moderate speed, but turboprops aren't as efficient at high speed - in other words, turboprops fly, in practice, slower than jets. Thus, turboprops tend to be used on short-haul flights; jets on longer-haul flights where travel time might be a factor.

Answer 2

Remember at higher altitudes, the air is less dense thus the propellers have less to work with as compared to a jet engine that compresses the air first.