Why Supersonic Is So Hard

Throughout aviation history, only two aircraft have entered commercial service as supersonic transportations (SST). The first was the Soviet built Tupolev Tu-144. The Tu-144 made only 55 passenger flights in only one year of service, but continued hauling cargo through 1983, totaling just 102 flights. Concorde found much more success during its 27 years of commercial service, although only 20 were ever built, at a tremendous cost and with large government subsidies. Concorde eventually became profitable for a while when it found an elite customer base that was willing to pay a premium for the novelty of traveling on the world's fastest airliner. The economic downturn in the late 1990's combined with the Concrode's only crash in 2000 and rising maintenance cost on the aging fleet, finally led to its retirement following the very last flight in November of 2003.

Here are the top four problems for companies trying to revive supersonic transport:

Sonic Boom

One of the most obvious byproducts of supersonic flight is the loud boom. The shockwave that creates it is like an invisible boat wake that sounds like a loud clap to those on the ground and can even rattle and crack window panes. This has led to strict regulations governing allowable levels of sonic boom, and in 1973, supersonic flight over land in the United States was officially prohibited. Many people have tried to invent a wing or fuselage design that creates a "quiet" sonic boom. Another tactic to reduce how much the boom is heard on the ground is to fly at much higher altitudes. Unfortunately this solution leads to the next obstacle.

Propulsion

Most modern aircraft propulsion systems are air breathing, meaning they burn oxygen from the ambient air mixed with fuel. At the extreme altitudes required for practical supersonic flight, the air density would not be adequate to feed such an engine and still produce sufficient thrust to accelerate the aircraft beyond the speed of sound. This has lead many designers to look elsewhere for non-conventional propulsion like rocket engines and ramjets.

Aerodynamics

Supersonic planes would need to use the same airports as other aircraft. But a supersonic jet's need to be as slippery as possible often results in poor stability at slower speeds. SSTs need very fast takeoffs and landings that require an unusually long runway. This can severely limit where a supersonic plane can operate.

Costs

This all costs an extreme amount of money not only to develop but also to operate. Fewer routes due to sonic boom restrictions and airport runway limitation reduces the potential customer base. Add the exorbitant fuel costs and increased maintenance needed due to the extreme conditions, all of which make supersonic transportation cost prohibitive.