In the soft refueling method, the aerodynamic instability of the refueling hose taper sleeve is affected by the airflow, which seriously affects the success rate and safety of aerial refueling/refueling. The wake field of the tanker affects the stability of the hose taper sleeve. major factor.
The full name of APU is Auxiliary Power Unit. Its core part is a turbine engine, which is generally installed in the tail cone part of the rear end of the aircraft.