Engines are a tough cookie to crack since the material science need to do it with high performance and economy is a tightly guarded secret and difficult to reve

Engines are a tough cookie to crack since the material science need to do it with high performance and economy is a tightly guarded secret and difficult to reverse engineer. They’ve been dumping billions into this but it’s still a moat (they keep claiming that they have engines ready for high performance/high mileage to overhaul military use, but keep needing to use Russian ones instead).