我问Google的Gemini AI以下关于普通发动机及冲压发动机转换的问题：

我问：

Suppose I have an aircraft with two separate engines. One is a regular jet engine, the other is a ramjet. Suppose I use the regular jet engine to achieve certain high speed, then shutdown the regular jet engine and start the ramjet, which takes the aircraft to even higher speed. Now I want to slowdown. Can I shutdown the ramjet and restart the regular jet engine?

Google Gemini AI 回答：

No, in this scenario, you would not be able to simply shut down the ramjet and restart the regular jet engine for landing. Here's why:

• Ramjet Limitations:

  • Speed Dependence: Ramjets require a very high forward speed to function. They rely on the compression of air caused by the aircraft's motion to initiate and sustain combustion.   
     

     
  • Low-Speed Inapplicability: At lower speeds, a ramjet will not produce any thrust and may even become a drag source.   
     

• Restarting the Jet Engine:

  • Airflow Disruption: The airflow through the engine would be severely disrupted by the ramjet's presence, making it extremely difficult, if not impossible, to restart the regular jet engine.
  • Potential Damage: The high-speed airflow from the ramjet could damage the internal components of the jet engine during the restart attempt.