3 ms·

Nonsense. Look at 90,000 lb. thrust high bypass turbofan engines that makes flying long distances cheap, even for poor people with moderate savings rates. Loo

by aj7 10y ago

Nonsense. Look at 90,000 lb. thrust high bypass turbofan engines that makes flying long distances cheap, even for poor people with moderate savings rates. Look at avionics and control systems that make the flight safer than the drive to the airport. You want spectacular. You missed the real advances.

gaius 10y ago
Turbofans and avionics didn't exist in 1915, but they did in 1965. I get what you are saying but those are incremental improvements, not huge jumps.
- dredmorbius 10y ago
  And the gas turbine itself (steam variant) had been created by the late 19th century. Going from steam turbine to kerosene-fueled jet engine took some doing, but the fundamental concept had been validated. What needed to happen were improvements in fluid mechanics, in materials science, in machining, and in the iterative process of design, build, test, and refinement that simply takes build cycles. Both the Germans and British were flying jet-powered aircraft by the end of WWII (though only the Germans flew these in combat IIRC). So again, the fundamental principles had been worked out, but iterating on design took more development. I'm kicking around an ontology of technological mechanisms (or dynamics), which tries to detail what the specific bases of technological change are. https://ello.co/dredmorbius/post/klsjjjzzl9plqxz-ms8nww https://ello.co/dredmorbius/post/klsjjjzzl9plqxz-ms8nww Taking the case of the jet engine: * The engine itself is an energy transformation system (converting fuel to thrust), and relies on numerous other energy transmission and transformation components (shafts, bearings, fan blades, turbine blades, actuators). * It relies on fuel -- vast amounts of cheap liquid hydrocarbons, or similarly energy-dense fuels which are safe and convenient to handle. * It requires a fundamental understanding of fluid dynamics -- systemic scientific knowledge. * It requires materials capable of supporting operation under the conditions of a jet engine: very high RPM, high stress, high thermal load, high pressure load, resistance to material creep, resistance to vapour or cavitation damage, etc. Containment that is light but effective for the fan casing itself. * High levels of precision in specification, machining, and inspection of components. * Specific imaging and sensing capabilities (multiple x-ray, acoustic, and other sensing beyond mere human abilities) are required. * Organisational structures capabile of designing, producing, operating, and maintaining highly technical equipment. * Information recording, processing, and transmission of the technical requirements for building, operating, and maintaining highly technical equipment. * The technical domain skills required to design, build, operate, and maintain HTE. * Understandings and mitigation of adverse consequences of design and operations. Vaclav Smil has a book dedicated to the two most significant prime movers of the 20th century, diesel engines and gas turbines, which might have a better breakdown of power output over time. In his earlier Energy in World History (1994), his plot of gas turbine outputs from about 1940 - 1990 increases from about 10^5 watts to 10^8 watts, with a distinct trailing off toward the last decade or two of the plot. (Steam turbines exceed these with maximum power in the gigawatt range.) The gas turbine plot on a log-linear scale (log power, linear time) is largely linear through the 1970s, though detail is low. Sources aren't provided, I suspect this is Smil's own compilation.

by aj7 10y ago

gaius 10y ago

Turbofans and avionics didn't exist in 1915, but they did in 1965. I get what you are saying but those are incremental improvements, not huge jumps.

dredmorbius 10y ago
And the gas turbine itself (steam variant) had been created by the late 19th century. Going from steam turbine to kerosene-fueled jet engine took some doing, but the fundamental concept had been validated. What needed to happen were improvements in fluid mechanics, in materials science, in machining, and in the iterative process of design, build, test, and refinement that simply takes build cycles. Both the Germans and British were flying jet-powered aircraft by the end of WWII (though only the Germans flew these in combat IIRC). So again, the fundamental principles had been worked out, but iterating on design took more development. I'm kicking around an ontology of technological mechanisms (or dynamics), which tries to detail what the specific bases of technological change are. https://ello.co/dredmorbius/post/klsjjjzzl9plqxz-ms8nww https://ello.co/dredmorbius/post/klsjjjzzl9plqxz-ms8nww Taking the case of the jet engine: * The engine itself is an energy transformation system (converting fuel to thrust), and relies on numerous other energy transmission and transformation components (shafts, bearings, fan blades, turbine blades, actuators). * It relies on fuel -- vast amounts of cheap liquid hydrocarbons, or similarly energy-dense fuels which are safe and convenient to handle. * It requires a fundamental understanding of fluid dynamics -- systemic scientific knowledge. * It requires materials capable of supporting operation under the conditions of a jet engine: very high RPM, high stress, high thermal load, high pressure load, resistance to material creep, resistance to vapour or cavitation damage, etc. Containment that is light but effective for the fan casing itself. * High levels of precision in specification, machining, and inspection of components. * Specific imaging and sensing capabilities (multiple x-ray, acoustic, and other sensing beyond mere human abilities) are required. * Organisational structures capabile of designing, producing, operating, and maintaining highly technical equipment. * Information recording, processing, and transmission of the technical requirements for building, operating, and maintaining highly technical equipment. * The technical domain skills required to design, build, operate, and maintain HTE. * Understandings and mitigation of adverse consequences of design and operations. Vaclav Smil has a book dedicated to the two most significant prime movers of the 20th century, diesel engines and gas turbines, which might have a better breakdown of power output over time. In his earlier Energy in World History (1994), his plot of gas turbine outputs from about 1940 - 1990 increases from about 10^5 watts to 10^8 watts, with a distinct trailing off toward the last decade or two of the plot. (Steam turbines exceed these with maximum power in the gigawatt range.) The gas turbine plot on a log-linear scale (log power, linear time) is largely linear through the 1970s, though detail is low. Sources aren't provided, I suspect this is Smil's own compilation.