Originally Posted by
KiloB
Even though I sat at the back, I did listen in (some) lectures, so I understand the ‘Critical Mach Number’bit. What I don’t understand is how this super duper new design hits Critical Mach at a SLOWER speed than thousands of existing airliners?
As Boeing's proposal has a very narrow chord and only a small amount of sweep, the thickness to chord ratio may well be higher than current airliners, so the pressure drop on the upper surface will be high and the lower critical mach number lower than current designs.
Airbus gave a presentation to employees back around 2005, at which they showed proposals for A320 series replacements. They stressed that low cost airlines are interested in the maximum flights per day, not maximum speed, and that bigger time savings can be achieved by avoiding reliance on jet bridges and airport supplied steps, hence the aircraft should be low to the ground and carry its own steps. Potentially the cabin crew could unload any hold baggage for passengers to carry, avoiding the need for baggage handlers too. The Airbus design looked a bit like an Ilyushin 76 but with rear fuselage-mounted engines (as per DC-9 etc.) Presumably Boeing are getting the same message from their Lo-Co customers.
By the way, what is wrong with calling a strut a strut? Are struts only found on Cessnas and old aeroplanes?