I was just looking up some aircraft specs for the Avro RJ85 when I noticed something that seems very strange to me: the cruising speed at 35,000 ft is 389 kts (long range) or 412 kts (high speed) while Vne in ISA conditions is 300 kts. I've looked up specs of other aircraft including Boeing and Airbus airliners and they all have cruising speeds higher than their Vne.
Could anyone explain this to me please 'cause its really bothering me.
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RE: A/C Maximum Versus Cruising Speed
Vne is expressed in indicated airspeed/mach. As altitude increases, Vne as a function of indicated airspeed decreases. In jets, Vne is referred to as Vmo/Mmo (maximum operating KIAS/Mach).
Manufacturer specs will make reference to KTAS (true airspeed) as of course the numbers look much better.
Jet aircraft reach their best long range cruise speed while at their best lift/drag configuration. Maximum cruise speed will be just slightly below Mmo, allowing a gust allowance if its turbulent.
Confused?!
Best Regards,
Buff
Manufacturer specs will make reference to KTAS (true airspeed) as of course the numbers look much better.
Jet aircraft reach their best long range cruise speed while at their best lift/drag configuration. Maximum cruise speed will be just slightly below Mmo, allowing a gust allowance if its turbulent.
Confused?!
Best Regards,
Buff
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