Can modern airliners fly faster than the speed of sound ?
Question asked by Gerald
The simple answer is no. Airplanes must be specifically designed for speeds faster than the speed of sound, the engines as well as the aerodynamics and structure of the airframe. Therefore, airplanes capable of flight at supersonic speeds have a unique shape. So far the only commercial airliners that had the capability of supersonic flight were the Anglo-French Concord and the Russian Tupolev TU-144. Both of these airplane types are no longer in service and are interesting museum pieces to admire.
An airplane in flight pushes waves of air in front of it. Although we cannot see the waves, they are similar to waves generated by the front, or bow, of a boat moving through water. As the speed of the airplane increases, these waves become more and more compressed. At the speed of sound, they form a high pressure barrier, as the air molecules are pushed aside with great force, by the airplane.
Airplanes need additional thrust from the engines to push through this pressure barrier. Engines on subsonic airliners do not have this additional thrust, nor are those engines designed to operate at supersonic speeds. This pressure barrier, or shock wave, also generates a sonic boom, which is a loud, gunshot-like noise heard by a person on the ground. Because of the sonic boom, airplanes like the Concord, were not allowed to fly at supersonic speeds over land. Only over water.
I remember one instance several years ago, when I was sailing in the Atlantic ocean just south of Bermuda. I was standing in the cockpit of the sailboat and suddenly I heard a noise, like a double gunshot blast. I looked around, I did not see any pirate boats. Then I looked up and sure enough there was a Concord airliner on the way from USA to Europe.
Research is continuously being done on how to reduce or eliminate this undesirable sonic boom and window-rattling effects of supersonic flight. In addition, fuel consumption at supersonic speeds is high. For example, the Concord airliner, which only carried 100 passengers in first class comfort, burned as much fuel to fly from North America to Europe, as a Boeing B747 does on the same route with four times as many passengers. However, the Concord would do that trip in less than half the time of the B747.
A bit more about Captain Dan:
Captain Dan Baz enrolled in Flight School at the age of 16.
He has completed studies in Aircraft Engineering and Master of Business Administration. He has been at the controls of many different types of aircraft, from single engine Cessnas to large intercontinental jets on global routes.
Over the last four decades he has flown thousands of hours up in the blue sky.
Have a question for the Captain ? Send it to Captain Dan Baz firstname.lastname@example.org Every week a question from the readers will be selected and answer posted in this column.