slater_just_slater t1_irq4gst wrote

What is interesting is that it's the same principle to how single crystal silicone is grown for microchip substrates. However the blades are hollow.

Since they have no grain structure, nothing responds to an acid etc, on a metallograph it's just a white blob.
They do have a thermal barrier coating (TBC) One of my jobs as a process engineer at Rolls Royce was the TBC coating. If you are bored here is a link about it.


slater_just_slater t1_irq3c05 wrote

The fans don't actually spin very fast (compared to the compressor) fans only spin about 3000 rpm so the tips don't go supersonic. The compressor spins much faster (12,000 rpm is typical however small engines can spin much faster up to 50,000 rpm) they do this by using 2, sometimes 3 shafts in the engine (one shaft inside the other). The fan is powered by 1 or 2 turbine at the very back, the compressor is powered by separate turbines at the front of the turbine section, just ahead of the fan turbines