" why do the airbuses usually have lower speed limit than boeings?"
See my previous answers!
This question is only true at the long-range end of the product line. At short & medium, it depends which aircraft you compare - A320 vs 737 or 757vs A321 or A332 vs 767 or 767 vs A300/A310.
I am certain that both Airbus & Boeing could design aircraft at whatever speed they so chose - they have just arrived at different conclusions concerning the value of speed.
As I said previously, it is in the balance that the airframers make.
Airbus could have selected a higher wing sweeo for the A330/A340 sweep to achieve a cruise Mach similar the 777 (777 has 1.6 degrees more sweep than the A330/A340).
In balance mentioned earlier, Boeing pushed the speed a bit and Airbus opted for fuel economy.
That said, the A330/A340 are not slow and the 777 is not a fuel guzzler, just that the fine balance between the two issues is different.
The high speed of a 747 may come from the fact that the basic aerodynamics were designed in the 1960's - i.e. fuel was cheap. Although they have been subsequently improved, the basic speed is a function of the wing sweep and aerodynamic sections.
So Ferrydud, your opinions are deafening me!
Last edited by Noise Unit; 8th Aug 2003 at 00:18.