3 ms·

I believe it's more complicated than that. Take a look at this image for example: https://www.skybrary.aero/images/Erosion_due_to_Volcanic_Ash.jpg https://www

by ta4399 9y ago

I believe it's more complicated than that. Take a look at this image for example: https://www.skybrary.aero/images/Erosion_due_to_Volcanic_Ash.jpg https://www.skybrary.aero/images/Erosion_due_to_Volcanic_Ash...

ars 9y ago
That's an amazing photo! But it still does seem like it could be dealt with - the abrasion does not completely destroy it, so it seems just incremental hardness improvement would handle it. Or even ablative tips.
- sooper 9y ago
  True, but ablative tips would likely mean engine overhauls at increased frequency, significantly increasing cost. At that cost vs benefit, likely better to just go back to piston and prop.
- davidgould 9y ago
  The damaged blades in the photo are turbine inlet guide vanes. They are attached to the static part of the engine in front fo the rotating turbine and are the first thing the hot (1500C) gasses from combustion hit. To prevent them from melting the blades are hollow and compressor bleed air (300C) flows through them and out the holes visible on the blades. This cooling air forms an insulating layer to protect the blade surfaces. Additionally they will have a ceramic thermal barrier coating. The actual turbine blades are similar except that they have to cope with tremendous loads from centrifugal force and the power transfer from the the gas stream to the shaft. The damage shown indicates loss of the thermal barrier coating at the leading edge and deformation of the leading edge and the cooling holes. The precise shapes are critical to maintaining the cool air film on the blade. Basically these vanes are toast and in a short time would be burnt melted toast. Let me recommend the book: “The Jet Engine” published by Rolls-Royce. Jet engines are pretty amazing. They seem simple in principle, but the optimizations needed to make a good one are beyond most countries and companies capabilities.

by ta4399 9y ago

ars 9y ago

That's an amazing photo! But it still does seem like it could be dealt with - the abrasion does not completely destroy it, so it seems just incremental hardness improvement would handle it. Or even ablative tips.

sooper 9y ago
True, but ablative tips would likely mean engine overhauls at increased frequency, significantly increasing cost. At that cost vs benefit, likely better to just go back to piston and prop.
davidgould 9y ago
The damaged blades in the photo are turbine inlet guide vanes. They are attached to the static part of the engine in front fo the rotating turbine and are the first thing the hot (1500C) gasses from combustion hit. To prevent them from melting the blades are hollow and compressor bleed air (300C) flows through them and out the holes visible on the blades. This cooling air forms an insulating layer to protect the blade surfaces. Additionally they will have a ceramic thermal barrier coating. The actual turbine blades are similar except that they have to cope with tremendous loads from centrifugal force and the power transfer from the the gas stream to the shaft. The damage shown indicates loss of the thermal barrier coating at the leading edge and deformation of the leading edge and the cooling holes. The precise shapes are critical to maintaining the cool air film on the blade. Basically these vanes are toast and in a short time would be burnt melted toast. Let me recommend the book: “The Jet Engine” published by Rolls-Royce. Jet engines are pretty amazing. They seem simple in principle, but the optimizations needed to make a good one are beyond most countries and companies capabilities.