Glossary

Mach Speed

Mach speed is the ratio of an aircraft’s true airspeed to the speed of sound. For instance, a Gulfstream G650 jet charter, which temporarily held the record as the world’s fastest civilian jet (the title currently belongs to the Citation X+), has a maximum operating speed of about 710 mph. The speed of sound is about 761 mph, so in terms of Mach speed, the G650 flies at Mach .925.

Private jet manufacturers like Gulfstream, Cessna and Dassault have long tried to outdo one another in designing the world’s fastest civilian plane. The speed of sound is the current benchmark towards which these teams of engineers are striving.

Flight of the Concorde

However, there is one jet that eclipsed this magical barrier, and it did it twice! The Concorde, which is no longer in service, flew at a staggering Mach 2.04, or 1,354 mph! It could complete the London-to-New York run in a paltry three hours and 30 minutes.

So while a Gulfstream G650 jet charter is plenty fast, it has a ways to go to catch up to the Concorde. There are also several advanced aeronautics manufacturers attempting to build new supersonic and hypersonic jets, such as:

  • Aerion
  • HyperMach Sonicstar
  • Gulfstream X-54
  • Reaction Engines A2
  • Spaceliner

For the record, the fastest airplane in existence is the Lockheed SR-71 “Blackbird,” which flew more than three times the speed of sound.

Ernst Mach, an Austrian philosopher and physicist, introduced Mach numbers in the late 1920s.