Science Sunday 09-03-17

A Brief History of Flight – Part 3

The Jet Age

Much like the development of FM radio and television, the development of truly operational military and commercial jet aircraft was delayed by the exigencies of World War II.

The “fathers” of turbojet propulsion and jet aircraft were an Englishman named Frank Whittle and a German named Hans Von Ohain.

Ohain’s work led to the first jet powered fighter aircraft, the Heinkel He 178, which first flew in August of 1939.  Whittle’s work led to the Gloster E.28/39 jet aircraft, which first flew in March of 1941.

The drawings for the Gloster E.28/39 were shared one month later with Major General Henry “Hap” Arnold, commanding officer of the US Army Air Force, who immediately requested that Bell Aircraft design an American equivalent.  Bell Aircraft did this in a mere 6 months, and the first American jet-powered aircraft, the XP-59A (featured in the above video), flew for the first time in October of 1941.

Unfortunately, the speed, handling and reliability characteristics of piston-driven propeller aircraft far outperformed all early jet aircraft, and so jet aircraft development floundered during the war.  The only jet aircraft to make it into action in World War II was the German Messerschmitt Me 262, which flew combat missions in 1944, too late in the war to affect its outcome.

Commercial jet flight first became a household item in the early 1950s, when British manufacturer De Havilland introduced the 36 seat Comet 1 to the public in May of 1952.  Unfortunately, the design of the plane led to some early crashes, which allowed American manufacturer Boeing to capture the jet aircraft market, when it introduced its now famous 707-120, with Pan-Am airlines flying from New York to London in October of 1958.  Rival manufacturer Douglas would introduce its DC-8 aircraft eleven months later.

During this period, Boeing continued its relationship with the US military, manufacturing the B-52 “Stratofortress” long range jet bomber, a plane still in service today.

For a nice summary of early jet aircraft, click here.

 

Cold War Reconnaissance: U2 and the SR-71

After World War II, tension between the United States and the USSR (Russia and its satellite countries) were at the highest level.  Spy satellite imagery was just a dream, decades away.

So it was imperative that the US develop high altitude planes capable of flying over any rival’s territory so as to take pictures of military installations, preparations and the like.

Lockheed Corporation was tasked with developing such planes, and the first one was the U2.  Americans and the world first heard of the U2 in 1960, when one of them was shot down over the USSR.  The pilot, Gary Powers, survived and was captured, much to the embarrassment of then President Eisenhower.

In the vast diaspora of Kennedy assassination conspiracy theories, it has been suggested that Kennedy’s alleged assassin Lee Harvey Oswald, having worked at a secret military airfield in Japan, may have tipped off the soviets as to the altitude at which the planes flew (70,000 ft) when he defected to Russia in 1959.  Certainly the Soviets knew of the flyovers, tracked them, and shot at them prior to Powers’ plane being shot down.

The U2 would prove very useful again during the Cuban Missile Crisis of 1962, when pictures of the missile installations were obtained by flyovers of U2 planes.  One U2 was shot down during the crisis.

It was clear in the early 60s that a new reconnaissance plane was needed, one that could fly higher and faster.  Enter Lockheed’s SR-71, the Blackbird.

The SR-71 was a remarkable plane, as indicated in the video above.  With a crew of 2, it regularly flew at Mach 3.2 (that’s 3.2 times the speed of sound, or 2,458 miles per hour, or 3,600 feet  per second), at an altitude of 80,000 feet.

Because of its speed, the SR-71 would experience temperatures at high altitude of over 900 degrees Fahrenheit, with the inside of its windshield registering a temperature of about 250 degrees Fahrenheit.  These temperatures required that the plane be 90% composed of titanium.

Today, there is much speculation that Lockheed has produced and is testing a SR-71 successor code-named Aurora, with a purported maximum speed of Mach 5 to Mach 6, but there is almost no hard evidence to verify this speculation.

 

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Author: Bob Mahoney

Physics teacher

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