Linked Questions

45
votes
3answers
16k views

Why is the Tu-95 so efficient despite having propellers that spin faster than the speed of sound?

I've ready many, many times that propellers are not efficient near the speed of sound because it's so hard to get a tip-speed above Mach 1. Then I came across this: It's the Tu-95 "Bear", a ...
29
votes
2answers
75k views

Which engine is more efficient between turboprop vs jet?

Are turboprops really more efficient than jets? If yes, does that mean that airlines who use jets sacrifice fuel for faster flights?
22
votes
3answers
11k views

Why are propeller engines uncommon on airliners?

My experience in aviation is essentially zero, but looking at Wikipedia it seems like the Tu-95 Bear offers high subsonic speed and extreme range. I assume that turboprop engines are more fuel ...
16
votes
3answers
8k views

Why did the turbojet replace the piston engine?

Many people say that this was because aircraft powered by turbojet engines were faster during WWII. However the Grumman F7F-4N Tigercat, a fighter powered by a piston engine, flew at a maximum speed ...
23
votes
6answers
6k views

In what way are the Concorde's engines considered efficient?

The Concorde is powered by a bunch of Rolls-Royce/Snecma Olympus 593 turbojet engines. Much has been said about how efficient they are at speed, and the fact that they allow long-range cruise at Mach ...
23
votes
3answers
20k views

Can propeller driven aircraft sustain speeds at or above Mach 1?

Has any propeller driven aircraft ever achieved and sustained supersonic speed? If not, why can't propeller airplanes achieve that speed?
13
votes
4answers
62k views

What is the fastest single-engine civil turboprop aircraft with cabin seating?

I was having a discussion with some friends about general aviation aircraft with cabin-class seating. We were discussing cruise speeds and there were some "shop talk opinions" flying around about what ...
13
votes
4answers
11k views

Are turboprops more efficient than piston engines (thrust per fuel consumption)?

I want to compare two types of engines: Turboprops and piston engines. I want to know which one is more efficient. There are many types of efficiencies, so I will specify: thrust (in newtons) per fuel ...
11
votes
2answers
4k views

Why is max endurance different for jet and props?

Max endurance speed is not the same for gliders, propeller planes (also for turbo prop, right?) and jet planes. While for for jet planes max endurance is at the minimum drag speed ($V_{md}$), for ...
10
votes
3answers
1k views

What does the 'hp' rating actually signify, with respect to an aircraft engine?

Let's say I've got a Cessna C172S with a Lycoming IO-360-L2A engine that produces 180 hp (that's the power output for sure). Let's say I've also got a water pump, that is rated at 1 hp (power input or ...
6
votes
3answers
2k views

Can the thrust of a turbofan be increased by increasing bypass ratio?

I read that the CFM56 is based upon the F101. Id on't know how true that is, but it generated the following question: If a larger fan is fitted to a low bypass turbofan, would dry thrust be ...
3
votes
1answer
1k views

Is a turboprop or a turbofan more eco-friendly?

If we compare them, which one wins? Why? And, what about CO2 emissions?