7 votes

What would be the minimum number of engines required to climb in a 747?

We use the polar of the 747 as given in this answer: Let's suppose that it took off at its MTOW of 377'000kg and that the accident happened somewhere midway i.e. with half of its 198'000 liters of ...
  • 5,926
6 votes

What is the purpose of variable stator vanes in the power turbine part of a free shaft gas turbine?

When you take a turboshaft engine and subject it to large and sudden load changes, that it doesn't have to cope with in an aircraft, like during gear ratio changes in a tank, you get very sudden ...
  • 117k
5 votes

Why does Engine Pressure Ratio (EPR) rise as thrust levers are pushed forward?

What makes you think the EPR should be 1.0? Note that we are using stagnation/total pressures to determine the EPR, we are not using the static pressures. Although the nozzle expands to ambient ...
  • 1,564
3 votes

Why the green inside newer turbofan engine nacelles?

This is a part of the fan case and is integral with the engine - it is not a part of the nacelle. On PW GTF engines, the fan case is manufactured using composite materials. So why is it painted green?...
2 votes

Why does ITT drop drastically after startup?

Yes, the increase in airflow has a cooling effect.
  • 21.7k
2 votes

What is the GE90-115b turbine power output in horsepower?

TLDR The number given for the Trent engine is only for a specific engine component and is not representative for the total output of that engine. The 110000 hp for GE90 is plausible. Full answer It is ...

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