Symbol W_1
is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
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where a is the local speed of sound, M is cruise Mach number, g is standard gravity, is thrust-specific fuel consumption, L/D is the lift-to-drag ratio, and and are the aircraft’s weight at the start and end of the cruise segment [ 1 ] . Three of those four factors — speed, engine efficiency, and aerodynamic efficiency — are where a century of aeronautical engineering has already done most of its work and where further gains now come in single-digit percentages per generation, the flattened tail of aviation’s S-curve. The fourth factor, the mass-ratio term , is where the aviation lineage’s entire battery-versus-kerosene argument actually lives, because / is set…
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Symbol W_2
is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
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Published contexts (3)
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Equation 9 · Technological Evolution
Flight at the Energy Floor: Transport Selection to 2100
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.
where a is the local speed of sound, M is cruise Mach number, g is standard gravity, is thrust-specific fuel consumption, L/D is the lift-to-drag ratio, and and are the aircraft’s weight at the start and end of the cruise segment [ 1 ] . Three of those four factors — speed, engine efficiency, and aerodynamic efficiency — are where a century of aeronautical engineering has already done most of its work and where further gains now come in single-digit percentages per generation, the flattened tail of aviation’s S-curve. The fourth factor, the mass-ratio term , is where the aviation lineage’s entire battery-versus-kerosene argument actually lives, because / is set…
Equation guide → · Article →Equation 11 · Technological Evolution
Flight at the Energy Floor: Transport Selection to 2100
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.
where a is the local speed of sound, M is cruise Mach number, g is standard gravity, is thrust-specific fuel consumption, L/D is the lift-to-drag ratio, and and are the aircraft’s weight at the start and end of the cruise segment [ 1 ] . Three of those four factors — speed, engine efficiency, and aerodynamic efficiency — are where a century of aeronautical engineering has already done most of its work and where further gains now come in single-digit percentages per generation, the flattened tail of aviation’s S-curve. The fourth factor, the mass-ratio term , is where the aviation lineage’s entire battery-versus-kerosene argument actually lives, because / is set…
Equation guide → · Article →Equation 12 · Technological Evolution
Flight at the Energy Floor: Transport Selection to 2100
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.
Jet fuel carries about 43 megajoules of chemical energy per kilogram, or roughly 11,944 watt-hours per kilogram [ 2 ] . A modern commercial lithium-ion cell, by contrast, runs 160 to 300 watt-hours per kilogram at the cell level, with specialty laboratory cells using silicon-anode and graphene-enhanced chemistries reaching a record of roughly 450 watt-hours per kilogram [ 3 ] — figures that describe a bare cell, not a certified aircraft pack, which must add cooling, structure, wiring, and safety margin on top. A widely cited 2018 estimate for a packaged aviation battery, including that overhead, put usable specific energy at around 160 watt-hours per kilogram, or about two percent of…
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