Regimes of Flight
After the invention of the airplane, designers and engineers created new aircraft for a variety of uses. Airplanes became a part of daily life. Aircraft were used regularly to ship cargo and to transport people. Over time, the speed of aircraft has increased. We put aircraft into groups based upon how fast they can fly. We call these groups the speed regimes (pronounced ``ra-jeems'') of flight. There are five basic speed regimes. These include the earliest aircraft to the most modern.
The first speed group flies in the low speed regime. Aircraft in this group travel at speeds between 0 and 100 miles per hour (mph). These tend to be lightweight vehicles with a small engine or no engine at all. The aircraft in this group include the earliest types of aircraft, such as kites, balloons and early airplanes. Modern aircraft in this speed regime are hang gliders, balloons, ultralights and airships (blimps, dirigibles).
The second group flies in the medium speed regime. These aircraft fly between 100 and 350 mph. These vehicles are usually airplanes with straight, thick wings. This category includes sailplanes, biplanes, propeller planes, helicopters and autogyros. Early German-made planes like the Fokker and the Junkers are in this category. Small planes, like the modern Cessna and Beechcraft, are also grouped within this speed regime.
The third group flies in the high speed regime. The aircraft in this category are the powerful propeller airplanes and jet planes that fly between 350 and 700 mph. These vehicles usually have thin, sweptback wings. The greater the sweep, the faster they can go. The fuselage is a sleek shape.
The Boeing 747 Jumbo Jet, the Lear Jet, the Sikorsky Blackhawk helicopter and many fighter planes fly within this speed regime.
The fourth group flies in the supersonic speed regime. This group includes aircraft that can go faster than the speed of sound, which is approximately 760 mph. The supersonic speed regime goes up to 5 times the speed of sound. These vehicles have high-powered jet engines, a sleek fuselage and super thin, sweptback or delta wings. The Concorde, the F-15 Eagle, and the SR-71 Blackbird are some examples of airplanes that can fly at supersonic speeds. The X-1 was the first plane to fly faster than the speed of sound.
The last speed regime is hypersonic flight, which is between 5 and 10 times the speed of sound. This is 3,500-7,000 mph. These vehicles have high-powered rocket engines with short, thin wings. They have highly advanced heat protection systems to protect the aircraft from the extreme heat faced during re-entry. Rockets travel at these speeds as they accelerate into Earth orbit. Also, re-entry capsules like Apollo travel at these speeds as they descend from orbit. The best known examples of hypersonic aircraft are the X-15 and the space shuttle