Headlight lens
Just a bit of trivia if I may. When we deployed to Saudi Arabia in Desert Storm 17 years ago we had nothing on the blades of our AH-64 Apaches and the blades were getting ate up. In less than a few weeks the blades had to be replaced.
The leading edges were just disintegrating!
A contact team came over and applied a clear film strip (similar to 3m) to the leading edges of the main rotor blades and it was amazing. We really never had to change another blade in 8 months.
I don't know who made the film but I think the principle is the same. The dirt and abrasives just bounce off. I don't know what the speed of the blades were in MPH but probably faster than your normal driving.





