Journal ArticleDOI
Extended range operations of two and three turbofan engined airplanes
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In this paper, a comparative analysis of the behavior of two and three turbofan engined airplanes after engine failure is presented, taking into account the increase in parasite drag, and considering variations of thrust and specific fuel consumption with altitude and Mach number.Abstract:
The objective of the present work is a comparative analysis of the behavior of two and three turbofan engined airplanes after engine failure. A simple but fairly realistic treatment of the range equation allows study of extended range operations of airplanes after any prescribed decrease in thrust. The approach takes into account the increase in parasite drag, and considers variations of thrust and specific fuel consumption with altitude and Mach number. All peculiarities of the powerplant are translated into a few nondimensional parameters. The model provides the long-range cruise conditions after engine failure, namely altitude and Mach number, and the additional fuel needed to reach the final destination. Results for a typical 5000-km route show the relative disadvantage of twins. Nomenclature A = aspect ratio of wing AF = extra fuel needed to reach destination due to engine failure aQ = speed of sound at sea level of = normalized extra fuel, AF/W* C = specific fuel consumption CDO = parasite drag coefficient CL = lift coefficient C0 = increment factor in parasite drag due to engineread more
Citations
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Journal ArticleDOI
Cruise performance and range prediction reconsidered
TL;DR: In this paper, a unified analytical treatment of the cruise performance of subsonic transport aircraft is derived, valid for gas turbine powerplant installations: turboprop, turbojet and turbofan powered aircraft.
Book
Advanced Aircraft Flight Performance
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References
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Journal ArticleDOI
Reducing fuel consumption of subsonic aircraft by optimal cyclic cruise
TL;DR: For the compressible flight regime, it is shown that drag rise effects represent a key factor limiting the improvements possible by optimal cyclic cruise, and results are presented for endurance flight, which is more improved by optimal cycling control than is range cruise.
Journal ArticleDOI
Fuel optimal trajectory computation
TL;DR: In this paper, the shape of the trajectory in the vertical plane is treated, and spline fits to the drag and fuel flow functions are described, and a suboptimal trajectory is found using the maximum principle of optimal control and singular perturbation theory.
Journal ArticleDOI
Optimum cruise lift coefficient in initial design of jet aircraft
TL;DR: In this article, the average lift during the ramp-down motion is the dominant factor in the decline of the total average lift at high amax, while decreasing amax is advantageous from the standpoint of average drag reduction.