Dynamics of high-bypass-engine thrust reversal using a variable-pitch fan

The test program demonstrated that successful and rapid forward-to reverse-thrust transients can be performed without any significant engine operational limitations for fan blade pitch changes through either feather pitch or flat pitch. For through-feather-pitch operation with a flight inlet, fan stall problems were encountered, and a fan blade overshoot technique was used to establish reverse thrust

Hybrid Aircraft for Improved Off-Design Performance and Reduced Emissions

The exceptionally high efficiency of electric motors makes them an enabler for flexible hybrid energy management, which can be used to optimize off-design aircraft operation, such as taxi and descent. The off-design operation contributes to a significant part of the global fuel usage of air transport vehicles as well as to the NOx emissions around airports. Thus, a hybrid chain designed for efficient idle operation could be an economical short-term solution for reduced global environmental impact. This paper focuses on providing and assessing such a design using a conventional 165-PAX-class transonic airliner with an assumed entry into service year of 2035 as a baseline