A Century in Review - The 1940s: First jets, big war

 - January 30, 2008, 9:16 AM

The year 1939 saw not only the outbreak of World War II but also the first flight of a jet airplane –both events that were rapidly to change aviation beyond recognition. Just eight years later, man would fly faster than the speed of sound for the first time.

As noted in last month’s column, Germany and Italy had been making preparations for war, cloaked in nationalism, through most of the 1930s. Despite the World War I Versailles Treaty, which forbade Germany from building military airplanes, air superiority was a central Nazi strategy.

America had scaled back military spending in the 1920s and pursued a policy of isolating itself from foreign skirmishes, concentrating on defensive spending. Since the sea provided the most obvious avenue of attack against America, the Navy received most in the trimmed military budgets of that decade. In 1926 the Army Air Service became the Army Air Corps, but it remained an underfunded offshoot of an underfunded Army during the 1930s. The best civilian airplanes of the 1930s outperformed the U.S. military’s equipment.

U.S. Navy airpower fared better in the 1930s, however, following the introduction of the first aircraft carriers in the 1920s. How ironic it was that in 1932, more than 150 airplanes from the USS Lexington and USS Saratoga carried out a mock attack on the naval base at Pearl Harbor. The total surprise of the exercise led U.S. strategists to conclude that an enemy power such as Japan could strike a devastating blow. Japan had reached the same conclusion, with only too infamous results.

When Britain and Germany declared hostilities in 1939, Reginald Mitchell had been dead for two years but his determination to develop the Spitfire despite his government’s infatuation with “peace in our time” was immediately vindicated. Born of Mitchell’s work on the Schneider Trophy-winning Supermarine seaplanes, the Spitfire was a masterpiece of fighter design in an era dominated by biplanes and fat-winged monoplane derivatives such as the Hawker Hurricane. The Spit’s characteristic thin, elliptical wing housed eight Colt/Browning .303 machine guns, and its large root chord provided great strength despite the thinness of the wing section. The multi-layered wing spar combined strength and taper with the resilience of a leaf spring.

Overall, the Spit and the Messerschmitt Bf-109 were well matched in the Battle of Britain. The Bf-109’s fuel-injected Daimler-Benz DB601 V12 (installed inverted to make room for nose-mounted guns above its crankcase) allowed Luftwaffe pilots under pursuit to nose over into a dive without the engine cutting out, whereas the early Spit’s carbureted Rolls-Royce Merlin would cough unless the pilot half rolled before diving. Either way, the Spit lost ground.

The Spit’s was not a simple structure to build in a time of urgent need, and its stressed skin made it less damage tolerant than the Hurricane. But while the Hurricane bore the brunt of the Battle of Britain, the Spitfire took the glory, spitting fire indeed as it swooped through the hot skies of summer 1940 on those timelessly elegant wings.

Willy Messerschmitt was also a highly talented designer. He based the Bf-109 (the Bf standing for Messerschmitt’s company, Bayerische Flugzeugwerke) on his Bf-108 Taifun, an advanced civil tourer that lived up to his credo of clean, simple, lightweight, monoplane design. Lacking an engine as efficient as the Merlin, Messerschmitt designed the Bf-109 to be the smallest, lightest, cleanest wrapping for a Junkers Jumo, a heavy engine that produced a meager 600 hp. Messerschmitt gave the Bf-109 leading-edge slats so that he could design a wing thin enough to reach the necessary top-end speeds while preserving low-speed handling. In 1938 it was married to the DB601.

Four days before the start of World War II, however, an airplane made its first flight that was to be far more significant than anything with a propeller on it. It was on Aug. 27, 1939, that the first jet aircraft took off, from Marienehe Airfield in Germany. Erich Warsitz was at the controls for the six-minute maiden hop of the Heinkel He-178, a retractable-gear taildragger powered by a turbojet engine created by Hans von Ohain–one of a number of researchers into jet propulsion in the 1930s. Another was Flt. Lt. Frank Whittle of the Royal Air Force, who struggled with bureaucratic indifference and a shortage of money despite his filing a patent for jet propulsion in 1930, and did not see his jet engine fly until 1941 aboard the Gloster E.28/39.

By contrast, von Ohain and his assistant, Max Hahn, enjoyed backing by both Ernst Heinkel and the German Air Ministry. After the historic first flight, Heinkel commented: “The hideous wail of the engine was music to our ears.”

The He-178 was capable of reaching 400 mph. To put this in perspective, consider that the world air speed record at the time was 469.22 mph, set four months earlier by Fritz Wendel in a Messerschmitt Bf-109R. Even taking its first tentative steps, then, the jet was hot on the heels of the fastest propeller-powered airplane.

Germany was a hotbed of not only nationalist fervor but also of aeronautical research. Apart from the jet engine, the swept wing also had its origins in that country in the work of Alexander Lippisch and Adolph Busemann, as did rocketry with Wernher von Braun.

The world’s first operational jet fighter, the Messerschmitt Me-262, entered operational service in October 1944 with Maj. Walter Nowotny’s Kommando Nowotny after a protracted development program dating back to 1941. The swept wings and pair of 1,980-pound-thrust Junkers Jumo turbojets helped the Me-262 reach a top speed of 540 mph. Nowotny’s career with the Me-262 was brief: on November 8 one of his engines caught fire and he died in the subsequent crash.

In March 1944 the Me-163 Komet entered service, bearing fruit from a program that began in 1938. The Me-163 had limited success when it finally saw combat, but it did demonstrate the impressive results of combining plenty of thrust with a swept wing. Its 3,750-pound-thrust liquid-fueled rocket motor was mated with a swept flying wing in a tailless aircraft capable of 600 mph and blistering climb performance as it streaked upward toward enemy bombers.

The night after Japan attacked Pearl Harbor on Dec. 7, 1941, British Prime Minister Winston Churchill is said to have slept better than he had in years. America’s isolationist stance was history, the sleeping giant had indeed been awakened, and before long America’s factories would be turning out airplanes on a scale previously unimaginable. In the process, the names of many industrialists, designers and pilots were etched into the history of aviation. Among the industrialists was Reuben Fleet of Consolidated, whose B-24 Liberator was produced in larger numbers than any other American military airplane (more than 18,000 of them). The designers’ ranks included Edgar Schmued for the North American P-51 Mustang (originally created for the British with an Allison engine but short on performance until it met the Rolls-Royce Merlin); and Clarence “Kelly” Johnson for the Lockheed P-38 Lightning (and later the Constellation, F-104 Starfighter, U-2 and SR-71). Among the pilots were Curtiss LeMay, toughest of the tough in the U.S. Army Air Force, father of the 305th Bomb Group in England, and later in charge of bombing missions against Japan in the Pacific theater; and Richard Ira Bong, American ace of aces with 40 confirmed kills in 200 combat missions in P-38s (he died after engine failure in a Lockheed P-80 jet he was flight-testing for Lockheed on the very day the atomic bomb fell on Hiroshima).

By the standards of modern air warfare, losses in World War II were appalling. The British chose to conduct their bombing raids on Germany at night with Avro Lancaster and Handley Page Halifax heavy bombers, and the Americans, their mighty Eighth Air Force based on the island fortress of Britain, pounded the enemy homeland by day with Boeing B-17 Flying Fortresses and B-24 Liberators. On Aug. 17, 1943, for example, of the 376 USAAF B-17s that raided the ball-bearing factory in Schweinfurt and the aircraft factory in Regensburg, 60 were shot down and 11 were damaged badly enough to be nothing more than a source of parts upon their return.

The raids were punishing for the crews as well as those on the receiving end of the payload: unheated and unpressurized, the bombers were slow and vulnerable, despite early hopes that they would be impregnable to fighters with their heavy armament. But the intensity of combat would soon have the crews sweating in subzero temperatures.

Edgar Schmued’s P-51 Mustang, a failed fighter in its original form for the RAF, became the “little friend” to these USAAF bomber crews when introduced in December 1943, providing cover for not only the outbound journey but the return too, thanks to its prodigious range and altitude capabilities once married with the Merlin at the suggestion of Rolls-Royce test pilot Ronald Harker. Equipped with drop tanks, the Merlin Mustang could fly to Berlin and back, and its laminar-flow wing allowed a top speed of 440 mph. It outclassed the Bf-109 and Focke-Wulf Fw-190 in combat, and was probably the finest fighter of World War II. By the spring of 1944 the USAAF was sending 1,000 fighters on escort for its bomber missions.

The P-51 was unusual for a U.S. fighter in having V12 power (a distinction it shared with the P-38 and Curtiss P-40), most of its fellow American aircraft being powered instead by radial engines– the Republic P-47 Thunderbolt (“Jug”) and all the Grumman cats that excelled in naval aviation. In the end, the radial proved to be the road to more power when, in its final form, it was turning out close to 4,000 hp from 28 cylinders in four rows (the Pratt & Whitney R4360). V12s, on the other hand, were hard pushed to produce much more than 2,000 hp in military service. The Rolls-Royce Griffon was the pinnacle of the V12, and it produced a relatively modest 2,400 hp. (Unlimited air racers at Reno, Nev., have since managed to force 3,500+ hp out of the Merlin, but they operate within a gnat’s whisker of self-destruction, which is all part of the excitement for the punters.) The in-line proponents conceded that while radials could develop more power, the reduced drag of the V12 more than compensated.

The Pacific theater inspired another great American bomber, the Boeing B-29 Superfortress. When it entered service in the summer of 1944, the B-29 ended the two-year dearth of attacks on Tokyo after Jimmy Doolittle’s famous April 1942 raid with B-25 Mitchells launched from the carrier USS Hornet. The B-29 represented a major advance over the capable but lumbering B-17, offering more than double the range and twice its 150-mph cruise speed.

The B-29 would evolve into the Boeing Stratocruiser and the DC-3/C-47 sired the Douglas DC-4/6/7 series, which became mainstays of postwar airline travel. (The P-38’s wing, at least, lived on in scaled-up form on the Constellation.) Corporate aviation’s early years relied on converted military surplus equipment such as C-47s, B-26s and Lodestars.

But the reign of the propliners was cut short by the limitations of their powerplants and the readying of the jet engine for service beyond the flight-suited ranks of the military. The late 1940s were rich with a new sort of progress, different from the desperate pace of advancement and production that marked the first half of the decade. Chuck Yeager’s 1947 breaking of the “sound barrier” and the 1948 first flight of the world’s first turbine-powered airliner, the Vickers Viscount, happened in the 1940s, but they better belong in the chronicling of the 1950s that will follow next month. Different forces were at work then: the Cold War and commercial competition to capitalize on everything learned while aviation had been at war.