涉猎 & 无尽
Most of the improvements over the past 40 years have been as a result of propulsion technology, primarily higher by-pass ratios and turbine inlet temperatures, nearly tripling seat mules per gallon. Advanced configuration concepts have, in general not been investigated in depth nor implemented.
The thickness ratio is the ratio of the maximum thickness of an airfoil to the chord and often varies between the root and tip.
“A phugoid or fugoid ( /ˈfjuːɡɔɪd/) is an aircraft motion where the vehicle pitches up and climbs, and then pitches down and descends, accompanied by speeding up and slowing down as it goes “uphill” and “downhill.” This is one of the basic flight dynamics modes of an aircraft (others include short period, dutch roll, and spiral divergence), and a classic example of a positive feedback system.”
- Shock waves in supersonic flow create a new source of drag called wave drag.
- To minimize the strength of the shock wave, all supersonic airfoil profiles are thin, with respect relatively sharp leading edges.
- Total drag = Skin friction drag + Pressure drag (due to flow separation) + wave drag (only for transonic and supersonic speeds)
- Skin friction drag + Pressure drag called Profile Drag
Pilot Induced Oscillations (PIO) are defined as sustained or uncontrollable oscillations resulting from the pilot’s efforts to control the aircraft.
Pilot Handling Qualities are quantitative measures of the acceptability of the stability, controllability and manoeuvring performance of an aircraft which can be utilised by an engineer during the aircraft design process.