>>13040783>>13040793Raptor FFSC has one pump turned by liquid methane and the other by liquid oxygen. Both are cold. Both don't mix until the combustion chamber. This is hella complicated, but it massively reduces the temperature stress on the turbines and reduces probability of slagging.
SN8 turned green on the combustion cause the engine was throttled from 40% to 100% in a matter of seconds, and the internal copper lining of the combustion chamber was torn through and the combustion of copper with methalox turned the flame green.
With BO's engine design, they take oxygen, ignite it, and pass it back to the turbines chamber, and use it to drive the turbine, which is pulling and pushing fuel into the combustion chamber. Liquid oxygen burns really REALLY FUCKING HOT. 6,000F in the chamber and 700F at the turbo pump. The problem here is that this turbine is doing work, which generates heat and energy. That energy is being contributed to the incoming 700F preburned oxygen. Worse, burning oxygen creates soot. Soot, is a shit at energy transferrence and is really good at energy capture.
So EVENTUALLY, the temperature in the chamber EXCEEDS the cooling potential of the liquid oxygen flowing in from the tanks, and the engine's solitary turbine eats itself alive. The moment the turbine slags, fuel flow in the engine is FUUUUUUCKED. That engine is permanently dead. It cannot be refurbished or recycled back into service.
If this happens during landing of the primary engine, it cuts and New Glenn craters.
BO is retarded for building the biggest fucking oxygen rich flow combustion engine on the planet. It might have a bigger baseline thrust than the raptor out the gate. But the fact that the engine can make it's own heart explode while running normally, is catastrophic.
That's why BE-4 is delayed. Why Vulcan launch is going to get majorly pushed. ULA can't launch payloads on an engine that could die midway into ascent; this core flaw exists in ALL BE-4 engines today.
