09 October 2015

General Giulio Douhet, the First Air Power Visionary

Giulio Douhet, air power visionary
Those of us interested in aviation take it almost for granted the unyielding pace of technological development that has driven aviation forward through time. But even less heralded are those in aviation history who have shaped the thinking of aviation- it's easy for us to lay eyes on an aircraft or even to put our hands on one. They're very tactile and sensory experiences in aviation- to see one, hear one, feel one, even ride an aircraft. But how do you experience aviation doctrine? How do you grasp the thought processes that have shaped aeronautical progress? They're very abstract and not prone to enjoyment and appreciation by most of us. However, technological progress is a rudderless boat in chaotic waters without visionaries and thinkers to provide steering and direction. Of course we can name designers like Jack Northrop or Andrei Tupolev. Or pilots like Charles Lindbergh or Chuck Yeager. But the subject of today's blog posting is none of those- he didn't design any aircraft, he didn't even fly aircraft. But his writings on air power have left an indelible mark on aviation, if not history itself. 

Born in 1869, Giulio Douhet was a rare breed of Italian army officer who was both an infantry and artillery officer and what we might call a technocrat, having studied science and engineering as well. His earliest writings as part of the General Staff of the Italian Army covered mechanization and the incorporation of what would be come tanks in military doctrine. But with the arrival of lighter-than-air aircraft like dirigibles and the first practical biplanes prior to the First World War, Douhet quickly appreciated the advantages of aviation in war- aircraft could move in three dimensions and operate above and out of the reach of ground and naval forces with relative impunity. In 1912 when the Italians first used aircraft in combat in Libya, he wrote Rules for the Use of Airplanes in War, one of the first efforts to create a doctrine for military aviation- despite his own background as an artillery and infantry officer, Douhet felt that the current military leadership lacked an understanding of the inherent advantages of air power and an almost zealous desire to educate the establishment on air power would be Douhet's mission in his life. 

When the First World War broke out in Europe in August of 1914, Douhet was forty-five years old and no less energetic than officers half his age. With a near-insatiable appetite for the latest developments in aviation, he advocated the building of a force of 500 bombers that could bomb enemy forces from above without having to engage in prolonged combat. He worked closely with the Italian engineer Gianni Caproni in advising him on his own Caproni line of bomber aircraft. But Douhet would find the Italian military leadership incompetent as defeat after defeat was suffered by Italian forces. Convinced that aviation technology could reverse the lagging fortunes of the Italian military, Douhet wrote and spoke frequently to anyone and everyone in the military and government establishment. By 1916 his superiors had had enough when he had ordered construction of Caproni bombers without authorization. He was stripped of his rank and imprisoned on charges of "issuing false news" and "disturbing the public tranquility". It didn't stop him, though. He continued to write and refine his theories from his cell. 

In the fall of 1917, the Italian Second Army was completely routed at the Battle of Caporetto (in modern day Slovenia), suffering over 300,000 casualties. The Italian government in desperation released Douhet from prison and commissioned him as a general in charge of coordinating the nation's aviation strategy and doctrine. It would be too little too late as the entrenched Italian bureaucracy was unwilling to enact his plans and he resigned in protest in June 1918. With the Armistice in November of that year ending the First World War, Douhet's trial verdict was reversed and he was promoted, but by this point in his life he had lost faith in the Italian government and refused to return to duty. During the interwar period he traveled Europe visiting other nation's air arms, consulting with air officers and meeting with aircraft designers. In 1921 he wrote his landmark work Command of the Air which advocated an relentless air campaign of bombing an enemy's population and production centers, reducing their moral and material means of resistance. Properly conducted, he reasoned, such an air assault could force a quick decision and save millions of lives in the long run by avoiding a costly ground war. Douhet also pointed out that the efficient and proper means of carrying out such an air campaign would require an independent air arm led by an aviation-minded general staff. At the time, this was a revolutionary concept and only in Great Britain was the nascent Royal Air Force an independent air arm. For other industrialized nations of the 1920s, their air arms were subordinated to the army. 

Billy Mitchell, USAAC
Reception of Douhet's work outside of Italy was mixed. It wasn't even required reading at the RAF Staff College. But his work would find converts primarily in the United States- at the time the Air Force was part of the Army as the US Army Air Corps. One officer in particular would even meet with Douhet- Brigadier General Billy Mitchell. It was the year after Mitchell had demonstrated the vulnerability of warships to bombers by sinking several captured German warships off the Virginia coast. Mitchell had copies of Command of the Air sent to his superiors and he got banished to Hawaii and then Asia as a result. In 1925 Mitchell wrote a book of his own, Winged Defense, in which he refined Douhet's ideas of a strategic air campaign further and even declared the battleship obsolete as aviation technology matured. As a result, Mitchell was demoted in rank back to colonel. He would later be court-martialed for publicly criticizing the US military following the crash of the airship USS Shenendoah in a storm. But his six week court martial provided Mitchell the perfect forum for advocating views shaped by his mentor, Giulio Douhet. 
Sir Hugh Trenchard, RAF

Douhet died of a heart attack in 1930 and Mitchell himself would die in 1936, neither man living to see how their views of air power would come to fruition in the Second World War. While Command of the Air got little attention in the Royal Air Force, the most influential individual in the RAF at the time fortunately was a proponent of Douhet's theories- Sir Hugh Trenchard, Chief of Staff of the RAF and the man known as the "Father of the RAF". Trenchard, like Mitchell, would refine Douhet's ideas. By the time of the Second World War, Trenchard was every bit the irritant to the establishment as Douhet and Mitchell were, but had enough influence to avoid their fate. Following the disastrous loss of Norway to the Germans in 1940, Trenchard used his position in the House of Lords to criticize Prime Minster Neville Chamberlain's prosecution of the war which contributed to his replacement by Winston Churchill. Trenchard used in influence to put like minded officers in key positions in the Royal Air Force. After the war, Trenchard advised General Henry "Hap" Arnold in his own push for an independent United States Air Force.

The same year Mitchell died in 1936, contracts were issued to both Boeing and Douglas for a large four-engined bomber- while both companies' designs, the XB-15 and the XB-19, respectively, remained experimental, the engineering and design work on such a unprecedentedly large bomber would shape aviation technology throughout the Second World War. 

Source:  Whirlwind: The Air War Against Japan, 1942-1945 by Barrett Tillman. Simon and Schuster, 2010, p9-16.

04 October 2015

Birth of a Breed: The Development of the Douglas DC-1

The Douglas DC-1 at its 1933 handover to TWA
(San Diego Air and Space Museum Archives)
The crash of a TWA (Transcontinental & Western Air) Flight 599 on 31 March 1931 served as a major catalyst in the airline industry for adoption of all-metal aircraft. The Fokker F.10 was on a scheduled flight from Kansas City to Los Angeles when it encountered turbulence on its first leg between Kansas City and Wichita. As the Fokker F.10 airline had wings of wood laminate, accumulated moisture had caused a weakening of the glue used which led to delamination and structural failure. Aboard Flight 599 was the famed Notre Dame head football coach Knute Rockne, who along with five other passengers and two crew, were lost in the crash when the aircraft went down between the rural Kansas towns of Bazaar and Matfield Green. As a result of the crash, the Bureau of Air Commerce required operators of aircraft with wood wing structures to undergo frequent inspections- as this was economically unfeasible for most operators, all-metal designs were procured as soon as possible. TWA nearly shut down for good while its Fokker fleet was grounded for  inspections. Most of the types that were procured were interim types- but in 8 February 1933, a new airliner made its first flight that was a quantum leap over anything that had proceeded it, and that was the Boeing 247 which entered service with United Air Lines just fifty days later. All metal with a retractable undercarriage, the Boeing 247 was sleek and much faster than anything that had flown passenger services up to that point. Even the most current designs were instantly obsolete- for example, the Curtiss Condor biplane airliner had entered service with Eastern Air Lines and American Airlines just five weeks before United put its Boeing 247s into service. 

United's main rival on the transcontinental market was TWA- the Boeing 247 could now make the east to west transcontinental run in only 21 hours 30 minutes including technical stops. By comparison, TWA's Fokkers took 28 hours 43 minutes to fly from New York to Los Angeles. When TWA learned of United's order for the Boeing 247, he contacted Boeing about ordering the aircraft for TWA, but at the time, United and Boeing were part of the same holding company, United Aircraft and Transport Corporation and Boeing was contractually bound to deliver 60 Boeing 247s to United before it could supply airframes to other customers. TWA's vice president for operations, Jack Frye, wasted little time in sending a letter to other aircraft manufacturers soliciting interest in building at least 60 three-engined airliners for the airline. That letter went to Consolidated Aircraft, Curtiss-Wright, Douglas Aircraft, General Aviation Manufacturing, Stout (Ford) Aircraft, and Glenn Martin Aircraft. The letter included general performance specifications that any design had to meet: 

Jack Frye of TWA

1. All metal, trimotor preferred, combination structures and biplane would be considered, but the internal structure had to be metal. 
2. Thee engines of 500-550 hp. 
3. Maximum gross weight of 14,200 lbs. 
4. Weight allowance for radio and mail carriage of 350 lbs. 
5. Weight allowance for full instrumentation, including night flying, fuel to fly 1,080 miles at 150 mph, crew of two, at least 12 passengers in comfort. Payload had to be at least 2,500 lbs with full equipment and fuel for maximum range. 
6. Minimum top speed of 185 mph, cruising speed at least 146 mph. Landing speed not to exceed 65 mph, rate of climb at least 1,200 feet/min, minimum service ceiling of 21,000 feet and a minimum service ceiling with one engine out of 10,000 feet. 

The specifications page also emphasized that any design, fully loaded, "must make satisfactory take-offs under good control at any TWA airport on any combination of two engines." This landmark letter from Jack Frye is considered the "birth certificate" of the DC-1. When Donald Douglas received the letter in Santa Monica, he immediately convened a meeting with his top heads- James "Dutch" Kindelberger (of P-51 Mustang fame) who was his chief engineer, Arthur Raymond who was the deputy to Kindelberger, and Harry Wetzel, the Douglas Santa Monica plant director. With the United States in the midst of the Great Depression, it didn't take long for them to decide this was a tremendous business opportunity for the company. Just ten days after Jack Frye sent his letter of proposal, Douglas dispatched Arthur Raymond and Harry Wetzel with a ten-person team by transcontinental train to New York to meet with TWA. The Douglas team by this point had moved quickly and concluded that even though TWA was leaning towards a three engined design, they would offer a twin engined design that would be equal if not superior to TWA's specifications. The design would be an all-metal monoplane with a retractable undercarriage that would have passenger comfort as a priority. With Kindelberger supervising the design work in California and telephoning design details to Raymond and Wetzel as they were enroute to New York, the design was refined as the team prepared for its presentation to the TWA evaluation team which consisted of Jack Frye, Richard Robbins, president of TWA, and Charles Lindbergh, the airline's technical consultant. Also present were the teams from four other aircraft manufacturers, all of whom tendered three-engined designs. 

Having prior flying experience with other Douglas designs, Frye was favorable to the Douglas proposal, but Lindbergh had his doubts that a twin engined design could meet the airline's stringent specifications. Lindbergh in particular was concerned about single-engined performance at TWA's hot and high airports in the southwestern United States. The Douglas team in consultation with the engineerings staff in California rechecked their calculations repeatedly to be sure that their design could take off with a single engine from any of TWA's airports. With considerable trepidation, Douglas instructed his team meeting with TWA that he would agree to a contract provision guaranteeing this particular specification to satisfy Lindbergh's concerns. On 20 September 1932, TWA signed a contract for the first Douglas DC-1 for $125,000 (about $2 million of today's dollars) with options for 60 more aircraft based on the flight tests and performance of the DC-1. As an insurance policy against a possible failure of the DC-1, General Motors, which owned TWA, had its General Aviation Manufacturing subsidiary work on the GA-38X which was a three-engined larger derivative of the smaller single engined GA-43 airliner. Construction had started on the prototype, but work ceased early on when it became clear the DC-1 would be successful. 

Arthur E. Raymond, chief designer for the Douglas DC-1
(General Aviation News)
With a signed contract in hand, Donald Douglas assigned Arthur Raymond as the DC-1 project manager. Assisting him would be the legendary Jack Northrop, who was at the time managing the Douglas El Segundo division and would be managing the structural design of the DC-1. Other able Douglas engineers were put in charge of various systems and components for the DC-1. In addition and a first for a transport aircraft, extensive wind tunnel testing at Cal Tech's facilities in Pasadena, California, would be an integral part of the design and development process. Cal Tech's aeronautical faculty would head this effort to uncover as many issues as possible before any metal got cut for the prototype- it was wind tunnel testing that found the planned wing design was unstable and further wind tunnel testing at Cal Tech showed that sweeping the wing leading edge back addressed the stability issue. This was how the DC-1 and later DC-2 and DC-3 got their unique wing shape. 

With passenger comfort a priority, it was decided that the benchmark would be the interior noise of a Pullman rail car. The DC-1 cabin had to have the same level of noise or less. As the design effort proceeded, the early specifications for the Boeing 247 were published in Popular Mechanics and Arthur Raymond had copies of the article posted everywhere with the admonition "Do Better than Boeing!" It was vital at every step of the design process that the DC-1 be more comfortable than the Boeing 247 and an important design step was Northrop's wing design that would fit at the bottom of the fuselage without intruding into the cabin as was the case with the Boeing 247. Northrop's wing center section was relatively flat with the engine nacelles at the ends, outboard of which the outer wing panels were attached with the needed dihedral for stability. In a unique feature of the day, the passenger seats could also be reclined. Heating, ventilation, and the aforementioned soundproofing efforts were as considerable as any aircraft system to meet Douglas's desire for the DC-1 to be comfortable. The aisle width was a then-generous 16 inches (Americans in those days were nowhere near as obese as they are now) with a cabin height of 6 feet 4 inches. This would lay down the reputation of Douglas aircraft for years to come to be considered passenger-friendly.

Note the faired struts ahead of the wings on the DC-1
(San Diego Air and Space Museum Archives)
Both the Pratt and Whitney 9-cylinder R-1690 Hornet radial engine and the Wright 9-cylinder R-1820 Cyclone radial engine were evaluated with the Douglas team selecting the Hornet as the DC-1's power plant. Fixed pitch metal propellers were to be used for the prototype. Developments of both engines would figure prominently in American aircraft of the Second World War- the Cyclone would be progressively developed into larger versions that would power the B-17 Flying Fortress, the TBF Avenger, the B-25 Mitchell and in its ultimate development, the B-29 Superfortress and Lockheed Constellation. The Pratt and Whitney Hornet radial engine was a modest success but was developed into a twin row radial as the Twin Wasp which would be used on the DC-3 which in turn was developed into the outstanding Double Wasp and Wasp Major engines. The engine development is of course a future topic here at Tails Through Time! The engines of the DC-1 were one of the first transport aircraft to use the NACA cowling which streamlined radial engines by as much as 60%. When the prototype was rolled out in the summer of 1933, there were also faired struts that connected the forward fuselage with the engine nacelles ahead of the wings- in the prototype these carried sensor cables from the engines for test instrumentation but were later removed. 

On 9 April 1934, Dutch Kingleberger and Arthur Raymond filed for Patent No. 94,427 "Design for an Airplane" which described the layout and configuration of the DC-1 and later DC-2 development. Despite the patent's rather sparse documentation, it was issued by the US Patent Office in the following year. 

On 1 July 1933, the DC-1 would make its first flight as the birth of the Douglas breed of airliners. The story of the flight test program and service history of the DC-1 will be the subject of a subsequent article here, but it should be noted that in 1918, a very young Donald Douglas was working for Glenn L. Martin where he designed bombers for Martin but it was a transport derivative of his bomber designs that fascinated Douglas- the GMT or Glenn Martin Transport was a 15 seat aircraft that had a fully enclosed cockpit. Only one was built and it was destroyed in an accident in March 1920. The GMT was the first Douglas-designed transport and it was where Donald Douglas resolved that his dream was to design and build an aircraft that whose sole purpose was to carry passengers in comfort. That was in 1919-1920, the DC-1 when it made its maiden flight in 1933 was just the start of Donald Douglas's dreams coming true. 

Source: Douglas Propliners: Skyleaders, DC-1 to DC-7 by Rene J. Francillon. Haynes Publishing, 2011, pp 9-11, 46-53. 

29 September 2015

The Cheapest Aircraft of the Second World War: The Focke-Achgelis Fa 330

Poor quality video of the Fa 330 operating from a U-boat (YouTube)

Earlier this month I had written about the aircraft types that were operated off submarines in the First World War, albeit on a very limited operational basis, and some designs that never quite made it to sea. In the interwar period, there were several experiments and attempts at aircraft operations from submarines- some of which will be future topics here at Tails Through Time- but none ever really evolved into a useful operational system. As is often the case in wartime, the pressures and operational needs of combat sometimes rekindle old ideas and this certainly the case for the German Kriegsmarine's Ubootwaffe (U-boat arm) in the Second World War. The initial plans were for a light seaplane from the Arado Flugzeug Werke designated Ar 231. Arado had built observation floatplanes for the larger surface combatants of the Kriegsmarine and in 1940, they were issued a contract for six "U-Bootsaugen" or "submarine eyes". The Ar 231 was the result and it was a single seat high wing monoplane with a 160 hp six-cylinder engine. The wings folded back over the fuselage and the entire aircraft could fit into a container only six feet in diameter. However, sea trials showed the little floatplane couldn't take off in winds greater than 20 knots and much like the problems faced in 1917, only the calmest of sea states was needed for safe flight operations- this was an unrealistic expectation for the planned operational arena for the U-boats, in the harsh North Atlantic interdicting convoys bound for Great Britain from the United States. The idea for the "U-Bootsaugen" was quietly canceled with the Ar 231 fading into the footnotes of aviation history. However, following the entry of Japan into the Second World War after its attack on Pearl Harbor, the directive came down for the Kriegsmarine to find a way to join forces with the Imperial Japanese Navy. In the same year that IJN submarines began operating in the Indian Ocean interdicting British shipping, the idea was passed to the Kriegsmarine in December 1942 to base U-boats in Japanese occupied Malaya and the East Indies. A new U-boat variant based on the large ocean going Type IX submarine, the Type IXD2, was on the drawing boards at that time as an ideal submarine for what the Kriegsmarine called the "Monsun Gruppe" which were U-boats based at Penang in Malaya. 

The Fa 330 at the RAF Museum in Cosford (Wikipedia)
On the broad and calmer Indian Ocean (at least on the trade routes from Africa to Australia), the Kriegsmarine once again issued a limited requirement for some means to extend the visual range of a surfaced U-boat for targets of opportunity on the cruises around the Cape of Good Hope to Penang and back. Simplicity and ease of use were paramount, mindful of past pitfalls with operating aircraft from submarines had shown. The unique demands were met by one of the most unique aircraft of the Second World War, if not the simplest and cheapest, the Focke-Achgelis Fa 330. Heinrich Focke had founded Focke-Wulf in 1923. In the 1930s, Focke-Wulf had license built Juan de la Cierva's autogyro designs and from that experience, Heinrich Focke designed the Fw 61 helicopter. However, in 1936, he was ousted from Focke-Wulf. Several references indicate it was because he was considered politically unreliable the the Nazi regime, but in all likelihood it was to get him out of the way so that Focke-Wulf's production capacity could be used to build more Bf 109 fighters from his rival, Willy Messerschmitt. Despite this, the German Air Ministry was impressed with the Fw 61 which the German pilot Hanna Reisch had ably demonstrated by flying the helicopter indoors. They encouraged Focke to start a new company devoted to the development of his true interest, vertical flight. He teamed up with his helicopter test pilot, Gerd Achgelis (he flew the Fw 61 on its maiden flight in 1936) to start Focke-Achgelis and it was this outfit that created the Fa 330 to meet the Kriegsmarine requirement for an observation aircraft of utmost simplicity for use by the submarines of the Monsun Gruppe

Lacking its own power plant, the Fa 330 was really a gyro kite. It had a three-bladed 24-foot rotor and when fully assembled, the Fa 330 weighed only 180 lbs. The main body was essentially an upright welded steel tube to which the rotor was attached at the top. A longitudinal tube of smaller diameter was attached to the bottom to which the single seat, controls, tail surfaces and outrigger skids were attached. Each of the major components attached together with simple spring loaded pins which also made for easy disassembly. Two vertically-oriented containers attached to the conning tower housed the parts. With each rotor blade 12 feet long, that dictated the maximum depth of each storage compartment. Four men could assemble the Fa 330 in only 3 minutes in a reasonable sea state. A platform sat on the aft part of the conning tower where the Fa 330 was launched and recovered. With the pilot/observer ready, the U-boat would turn into the wind as 20 mph was needed to get the Fa 330 gyro kite airborne as the pilot used his controls to tilt the rotor head back to "catch the wind" like a kite with a steel cable which also carried a telephone line to allow the pilot/observer to communicate with the submarine's bridge. The operating speed was usually about 25 mph but the Fa 330 could stay airborne with as little as 17 mph of forward speed by the U-boat. Typical operating altitudes were between 200 to 500 feet, though in calm weather, the Fa 330 could be flown up to 1000 feet. In good visibility, this extended the U-boat's visual horizon out from the usual 12 miles to 50 miles. At an altitude of 600 feet, the visual horizon was 31 miles. Even at minimum operating speed, the Fa 330 could fly 200 feet up and that still gave the U-boat captain a visual horizon of about 20 miles. The Fa 330 was recovered by simply winding the cable back in until the Fa 330 could alight on the conning tower platform. Though Focke-Achgelis designed the Fa 330, it was built by another company, the Weser Flugzeugbau.

Model kit box art showing an Fa 330 being deployed by a U-boat (Mirage Hobby)
Pilot/observers were trained to fly powered gyrocopters at the French Aeronautical Experimental Establishment outside of Paris. Training on the Fa 330 itself was carried out inside a large wind tunnel with more advanced training taking place with the Fa 330 being towed by trucks on a runway before moving to being towed to higher altitudes by a gyrocopter. A proposal was floated to put a 60 hp engine on the Fa 330, but it never advanced far with the Kriegsmarine. About 200 Fa 330s were built. At sea, the pilot/observer was in an unenviable position should he have spotted a warship as that would have meant an immediate crash dive by the U-boat. If this were to happen, the pilot was to activate his escape mechanism which severed the rotor blades get them away from the pilot who then dropped away from what was left of the Fa 330, his parachute ripcord being pulled automatically by the departing blades as they fell away. That left the pilot to float down to the ocean and hope to be picked up when the submarine resurfaced. It's not known what happened to most Fa 330 pilot/observers, though Royal Navy patrols in the Indian Ocean did come across floating parts from the Fa 330. 

Only the U-boats with Monsun Gruppe in the Indian Ocean used the Fa 330 as the Allied air threat in the Atlantic was too great. Only one sinking is known to be attributed to Fa 330 operations when U-177 used its gyro kite to assist with the interception and sinking of the Greek steamer Ethalia Mari on 6 August 1943. Details of the use of the Fa 330 operationally are scant on account of so few U-boats surviving the war. Several U-boat captains, however, believed using the Fa 330 was too risky which may have ultimately prevented its more widespread use. The Allies found out about the Fa 330 after studying the submarine U-852 after it had run aground on the coast of Somalia after an air attack. While not impressed with its capabilities, they were suitably impressed with its simplicity and ease of use. 
The L-3 Valkyrie Virtual Mast unmanned gyro kite (Popular Science)
Interestingly in 2013, the defense company L-3 proposed a re-imagination of the Fa 330 concept with their Valkyrie "Virtual Mast" in which a carbon fiber gyro kite would carry aloft an electro-optical/IR sensor as high as 5000 feet on a steel cable for ships at sea. 

Sources: Strike From Beneath the Sea: A History of Aircraft-Carrying Submarines by Terry C. Treadwell. The History Press, 2009, pp 103-109. The Smithsonian National Air & Space Museum.

24 September 2015

The Ultimate Superfortress: The B/RB-54A

Concept art of the B/RB-54A in flight
(Boeing Historical Archives)
During the Second World War Boeing worked extensively on further improvements to the B-29 Superfortress. The most important of these improved variants was the B-29D that involved swapping out the Wright R-3350 radial engines with the more powerful Pratt & Whitney R-4360 Wasp Major radial engine. In July 1945 the USAAF signed a contract for 200 B-29Ds, but with the end of the war and the rapid postwar demobilization, the B-29D contract was canceled. With the creation of an independent United States Air Force in 1947, there was a need for interim bombers pending the arrival of more advanced jet bombers. The USAF was already getting the Convair B-36 which took on the mantle of the heavy bomber, but the USAF also wanted the B-29D which would be redesignated as a medium bomber. The USAF had the B-29D redesignated as the B-50 to avoid the appearance of ordering a "wartime" bomber. Making its maiden flight on 25 June 1947, the B-50 Superfortress would eventually result in 320 examples of all variants produced.

Boeing, however, was working on an even more powerful and longer-ranged development of the B-50. Designated the B-50C, this evolution into the ultimate Superfortress was designed to extract as much speed and performance as was possible using a new version of the Pratt & Whitney R-4360 Wasp Major engine that added what was called a "variable discharge turbine" (VDT) to the engine. The standard Wasp Major used on the B-50 developed approximately 3,500 horsepower and a Wasp Major with a VDT could easily produce 4,000 horsepower, making it one of the most powerful production piston engines in the world.

The Wasp Major VDT
(from the Engine History website)
The VDT consisted of two General Electric CHM-2 turbosuperchargers that collected the hot exhaust gases from the 28 cylinders of the Wasp Major. A portion of the hot gases were diverted through an intercooler to provide turbosupercharging at high altitudes. The bulk of the hot gases went through the CHM-2 turbines and were exhausted out a variable area nozzle that resembled a set of eyelids. By adjusting the size of the nozzle, jet thrust could be achieved that had the potential to add as much as 15% to the speed of the B-50C over the production standard B-50. The Wasp Major VDT was already flying at this point on the Republic XF-12/XR-12 Rainbow long range reconnaissance aircraft. 

The scope of the changes needed to for the B/RB-54 resulted in a redesignation to B-54 with the planned reconnaissance variant being the RB-54. The jump in power output from the use of the Wasp Major VDT resulted in a redesign of the wings that resulted in a wingspan that was over 20 feet longer than that of the B-50 with a chord increase as well- an additional six feet of chord at the wing root and an additional four feet of chord at the wing tip. This provided additional fuel capacity along with external fuel tanks which were three times the capacity of the external tanks used on the B-50A on the outboard wings. The wingspan increase was so much that outrigger gears were needed under the outermost engine nacelles. Wind tunnel testing had shown that the new wing and powerful engine output also required a longer fuselage and the B/RB-54's fuselage was stretched 10 feet. Instead of the plexiglass domes used by the gunners on the B-29/B-50, low drag hemispheric sights were used. These used a fish eye hemispheric optical element that the gunner sighted through. Glenn's Computer Museum has some great pictures of the R/RB-54 hemispheric gunsight. The tail gunner also had a hemispheric gunsight but also had a radar to direct the four-gun turret as well which was mounted in fairing above the gun turret but below the hemispheric gunsight. Fairings were also present on the nose and under the forward fuselage for bombing and navigation radars. 

As a comparison, the B-29 weighed 120,000 lbs fully loaded and the B/RB-54 would weighed in at 207,000 lbs at takeoff. The Wright R-3350 engines of the B-29 developed 2,200 horsepower and the bomber had a range of approximately 3,250 miles. The B/RB-54 would have been able to push 8,000 miles of range. The mockups were completed in 1948 and the contract was signed for 43 bombers as an initial production lot. While the Secretary of the Air Force Stuart Symington and the USAF Chief of Staff General Hoyt Vandenberg were supportive of the B/RB-54 project, General Curtis LeMay, the head of the Strategic Air Command, felt that the B/RB-54 was inferior to the Convair B-36 Peacemaker particularly the B-36D that added four J47 jet engines under the outer wings. Pending the arrival of the B-52 Stratofortress, LeMay felt deterrence was better served by the B-36 which could fly faster, farther, higher, and carry a significantly larger bomb load. In the postwar atmosphere of austerity, more B-36s couldn't be accommodated in the Air Force budget and Secretary Symington offered LeMay more B-50s instead of increased numbers of B-36s. This was even more unsatisfactory to the outspoken SAC commander who then argued that if he couldn't get more B-36s, then the funding set aside for the B/RB-54 should be shifted over to get more of the Boeing B-47 Stratojet which made its first flight in December 1947. This was agreeable to all involved, even for Boeing as it meant more funding for the Stratojet program. The B/RB-54 project was cancelled with the prototype approximately 75% complete (it was converted from a B-50A) at Boeing's Seattle facilities. In addition, the addition of the outrigger gears wasn't popular with SAC as many of its bases would need widened taxiways and runways to accommodate the B/RB-54. 

The B-29 lineage would live on, though, in the C/KC-97 Stratofreighter (the last examples being retired in 1978) and in the commercial Boeing 377 Stratocruiser. But neither would have matched the leap in performance of the B/RB-54, the "ultimate" Superfortress.

The Retromechanix page has a series of superb photos via the National Archives that show the B/RB-54A mockup in detail as well as some schematic drawings. It's well worth the time to browse them!

Source: Boeing B-29 Superfortress (Crowood Aviation Series) by Steve Pace. The Crowood Press Ltd, 2003, p166-168. Boeing B-50 (Air Force Legends Number 215 by Geoffrey Hays. Ginter Books, 2012, pp 118-121.

19 September 2015

The XB-15: Getting Boeing Back On Its Feet

Clairmont Egtvedt led Boeing during its most precarious times
(Boeing Historical Archives)
The Boeing Company of the mid-1930s was existing by only a razor-thin margin and at any moment in those times, could have shut down for good with the Boeing name a mere footnote in aviation history. Why one of the dominant aviation companies of today nearly ceased to exist eighty years ago we have to move the clock back to 1929 when President Herbert Hoover appointed Walter Fogler Brown to be the Postmaster General. Within a year, Brown had lobbied Congress for more authority to improve the air mail system which he felt was inefficient and piecemeal in the organization of the existing airline networks that carried the mail. The Air Mail Act of 1930 (also known as the McNary-Watres Act after its Senate sponsors) gave Brown the authority to rationalize the US air mail system, which in effect, led to the rationalization of the US airline system of the day. The details of that controversial move will of course will be the topic of a future blog article here at Tails Through Time- but the key event here was the so-called "Spoils Conference" of 1930 where Brown consolidated the existing air mail routes which by extent led to the consolidation of the US airline system to just three airlines- United, TWA, and American- essentially forcing out of business the other airlines. One of the effects of this move was that Bill Boeing teamed up with Frederick Rentschler of Pratt & Whitney to form a large business conglomerate with diverse interests in aviation called United Aircraft and Transport Corporation. United Aircraft was the holding company for both Boeing Aircraft and Pratt & Whitney and also held ownership of Hamilton Standard, the propeller manufacturer, as well as the aircraft companies of Chance Vought, Sikorsky, and Stearman along with United Air Lines. In late 1933, Senate investigations opened on the 1930 Spoils Conference which led to the Air Mail Scandal of 1934 which led to the Roosevelt Administration canceling all the air mail contracts and handing the air mail delivery to the US Army Air Corps with disastrous results. With no choice but to return air mail service to the airlines, the government did so with punitive conditions that large consolidated aviation firms with airline interests had to be broken up in order to win back air mail contracts. United Aircraft was broken up back into its constituent companies and Bill Boeing resigned from aviation altogether. 

Replacing Bill Boeing was his general manager, Clairmont "Claire" Egtvedt, who had risen up the ranks at Boeing after starting out as a draftsman in 1917 fresh out of college. Of all the pieces of the now-broken up United Aircraft, Egtvedt had to take charge of the smallest and weakest piece- Boeing Aircraft itself which included its Stearman subsidiary in Wichita, Kansas. The first year of Boeing's new independent existence found it operating at a loss of over $200,000, a crushing loss in those days. Egtvedt wanted to get Boeing back into business by building a twin-engined bomber and twin-engined transport, but there was just barely enough money in the company's accounts to make payroll. By the late summer of 1934, Boeing's workforce had fallen from 2,275 a year earlier to only 600. The remaining employees as a testament to their faith in Boeing, offered up a plan to Egtvedt where half the group would work two weeks and then the other half of the group would then work the next two weeks and keep alternating so that only half the employees needed to be paid but the core experience of Boeing could be kept intact. Egtvedt naturally approved of the plan and true to the loyalty of the Boeing employees, some of those where not assigned to work in a particular two week block came to work anyway to help out without asking for payment. 

What Boeing products were available needed to be sold overseas to earn income for the company, so Egtvedt hired a young engineer, Wellwood Beall, who had been an instructor at Boeing's own school of aeronautics. Beall was an enthusiastic and gregarious individual who Egtvedt tasked with selling the Boeing P-26 Peashooter to the Chinese, who ended up ordering eleven aircraft in 1935. But it wasn't enough, and even the in-house company newspaper shut down publication to save money. Ever looking for opportunities to turn Boeing's fortunes around, Egtvedt had always thought the Boeing 247 airliner was too small, which as it turned out, became its biggest liability to the roomier and bigger Douglas DC-3 which proved to be an immense success. Several years earlier Egtvedt actually watched flight operations with Boeing fighters aboard the first US aircraft carrier, the USS Langley. A Navy rear admiral who was hosting the Boeing delegation remarked that battleships made more sense than bombers (this was in the wake of General Billy Mitchell's demonstration where he sank captured German warships with bombers) for US defense because a battleship could defend itself. When pressed further by Egtvedt, the admiral responded that the only practical bomber would be one that would be able to defend itself like a "flying dreadnaught". The remark must have stuck with Egtvedt that bigger was the way to go, but the only large aircraft of the day in the United States was the Barling bomber of 1920 that had a 120-foot wingspan, six engines and needed a tailwind to break 90 mph and had a range of only 300 miles on account of its heavy weight. Large aircraft simply had a lousy track record in those days. But that didn't stop Egtvedt from thinking about the large aircraft problem. Bill Boeing himself once said: 

"I've tried to make the men around me feel as I do, that we are embarked as pioneers upon a new science and industry in which our problems are so new and unusual that it behooves no one to dismiss any novel idea with the statement that 'It can't be done'. Our job is to keep everlastingly at research and experiment, to adapt our laboratory results and those of other laboratories to production as soon as practicable, to let no new improvement in flying and flying equipment pass us by."

The XB-15
(Boeing Historical Archives)
Boeing wasn't just thinking about bigger aircraft. There were also some officers with the US Army Air Corps that saw Billy Mitchell's 1921 demonstrations as prescient and the key to making the United States an aviation power. At the lowest point of Boeing's fortunes in the spring of 1934, Egtvedt got a phone call from Brigadier General Conger Pratt who was head of the Air Corps Materiel Division at Wright Field in Dayton, Ohio (predecessor to today's USAF Systems Command). Pratt wanted Egtvedt's presence at a secret conference in Dayton to which he also invited the heads of several other aircraft companies. Within the Air Corps, many of Mitchell's subordinates were imbuing the USAAC with ideas of long range bombers which received high level support with the command staff in Washington. At the meeting on 14 May 1934, General Pratt informed the aircraft company leaders that the Army wanted proposals for a long range bomber that could carry at least 2,000 lbs of bombs at least 3,000 miles and weigh no more than 32 tons. Nothing like it had been done before and the invited guests were quite startled. 

Egtvedt immediately put Boeing engineers to work on a 150-foot wingspan bomber called "Project A". The speed at which Boeing got to work on Project A resulted in a design contract from the Army. A large hangar at Boeing Field was set aside with a partitioned area only cleared personnel were allowed along with Army representatives from Wright Field. Excitement built quickly at Boeing with word of a mammoth bomber in the works. Despite the Army contract, Boeing's financial state was still quite precarious, but Egtvedt pressed on- Boeing, in his mind, had to learn how to build large aircraft if it was going to survive and Project A would be the company's school house, even if the company ran in the red- which it did. 

With work proceeding on what would become the XB-15, a second proposal was issued by Air Corps Materiel Division at Wright Field. While the first project was to be a technology demonstrator of a large bomber aircraft, the second proposal that was issued on 8 August 1934 just months later called for a production bomber with a 2,000 lb bomb load, a top speed of 250 mph, a range of 2,200 miles and a crew of around six. Companies were asked for designs and bids for an initial production run of just over 200 aircraft. You can imagine Claire Egtvedt's excitement with this second proposal- he had been thinking about larger aircraft and Boeing was learning all about designing and building larger aircraft with the XB-15 demonstrator. He had been thinking about a flying dreadnaught that a Navy admiral referred to years earlier and now the Army was asking for that very aircraft. Egtvedt wanted the Boeing proposal for the production bomber to be a four engine aircraft, but in those days, four engine aircraft were rare and seen as risky from a technological standpoint. He even flew to Wright Field to get further clarification on the production bomber specifications to be sure a four-engined design was acceptable. 

Egtvedt didn't just want to submit a proposal- he wanted to something daring. He wanted to proceed with a prototype of Boeing's proposal and fly it to Wright Field to demonstrate its performance. This was an immense gamble- Boeing was already operating in the red, it was busy working on the XB-15 project and now Egtvedt wanted to build and fly a prototype of Boeing's submission within one year. Egtvedt turned to his friend for guidance- Boeing's company lawyer and future CEO, William M. Allen. Allen came from the University of Montana but had a Harvard law degree- he first worked with Boeing in setting up Boeing Air Transport in 1926 (the predecessor to United Air Lines). Allen was an unusual sort for the Boeing team- he wasn't a pilot and he wasn't an engineer. But he had a remarkable clarity of thought that many at Boeing came to rely on to help with tough decisions and he asked Egtvedt bluntly "Do you think you can build a successful four-engined airplane in a year?" Egtvedt's response evoked the spirit of Bill Boeing: "Yes I know I can." So with Bill Allen's support, on 26 September 1934, Boeing's board of directors authorized Egtvedt to borrow money to the limit to begin work on the Model 299. 

Model 299 prototype
(USAF Museum)
In less than three months the production drawings for the Model 299 were in the hands of assembly shop who began building the prototype, all while work continued on the XB-15 program. As assembly of the Model 299 prototype began, the company ran out of money and the board, putting its faith in Claire Egtvedt, arranged to borrow more money. While it was clear that the XB-15 would never be a production aircraft, what had been learned from the design effort paid dividends for Boeing in the speed at which the design and fabrication of the Model 299 proceeded. Final assembly began in June 1935 and soon workers disregarded their shifts in an all-out effort to finish the Model 299 prototype. At sunrise on a Sunday, 28 July 1935, the Model 299 prototype was rolled out at Boeing Field for its successful maiden flight. Keep in mind the go-ahead to launch the Model 299 program was on 26 September 1934! After a stunning first flight, the Model 299 was then flown to Wright Field on 20 August 1935, taking only nine hours to cover over 2,000 miles with an average speed of 252 mph. Boeing's other competitors also built flying prototypes of their submissions but they paled in comparison to the Model 299. Martin entered the YB-12 which was just a re-engined version of the B-10 twin-engined bomber and Douglas entered the B-18 Bolo which was based on the DC-2 airliner. 

Then tragedy struck. During a flight test out of Wright Field in October, the control locks were left in place and the Model 299 prototype stalled at takeoff and crashed with the loss the pilot and varying degrees of injuries to the rest of the crew. Under the rules of the competition laid down by the Army, the Model 299 had to be eliminated from competition as it was unable to complete its flight tests. It was a somber Christmas 1935 when Douglas won the contract with the B-18 Bolo. But there was a silver lining in the loss of the Model 299 prototype- the flight test program won the Model 299 many advocates within the US Army Air Corps who saw the Boeing design as the future of long range bombers. A service order was placed for thirteen aircraft and a fourteenth aircraft that would be a structural test article. The aircraft's designation would be a name that would echo in the annals in the history of aviation- B-17. When the Seattle Times reporter Richard Williams dubbed the Model 299 a "flying fortress" on account of its six gun turrets, Boeing astutely saw the value of the name and the B-17 became the Flying Fortress. 

Work did continue on the XB-15, though- it made its first flight on 15 October 1937. It was 26 feet longer than the B-17 with a 36-foot greater wingspan and at the time of its rollout, it was the largest bomber ever built. The aircraft was christened "Old Grandpappy" in recognition of the role its design played in the B-17 Flying Fortress. The service history of the XB-15 will also be the subject of a future article here at Tails Through Time, so stay tuned! 

Sources: Boeing: The First Century by Eugene E. Bauer. TABA Publishing, 2000, pp 59-69. Legend & Legacy: The Story of Boeing and Its People by Robert J. Serling. St. Martin's Press, 1992, pp 27-35.

14 September 2015

Operation Drugstore: The 1982 Air Battles Over the Bekaa Valley

In 1976, the Lebanese Civil War had been raging for a year when the Syrian military poured across the border into the region to ostensibly stabilize the situation. Securing the Bekaa Valley and the main Beirut-Damascus highway that crossed the central part of the country with massive numbers of troops and armor, soon the Palestinian Liberation Organization (PLO) and its Muslim allies in Lebanon were receiving support from the Syrians. To cover the Syrian left flank facing Israel, the Syrian 10th Armored Divsion was arrayed across the Bekaa Valley with three brigades of surface-to-air missile units to protect them from an Israeli attack. A total of 19 batteries covered the valley consisting of two SA-2 batteries, two SA-3 batteries, and fifteen new SA-6 batteries. During the next several years the Israelis provided support to the Christian factions in the civil war while maintaining a close eye on the strengthening Syrian integrated air defense system (IADS) that stretched across the Bekaa Valley. Overflights to pinpoint the SAM sites required use of Firebee recon drones due to the dense air defense network that the Syrians had established. In the late May to early June of 1982, the PLO conducted a 12-day artillery and rocket attack on northern Israel that resulted in 60 civilian casualties. The last straw for the Israelis came on 3 June when the PLO attempted to assassinate in London the Israeli ambassador to the United Kingdom.

On 6 June, seven Israeli mechanized divisions with 60,000 troops and 500 tanks crossed into southern Lebanon in three prongs- one up the coastal plain, one through the central mountains, and a third push into the Bekaa Valley to keep the Syrian 10th Armored Division from intervening against the Israeli right flank. On the first three days of the ground invasion, seven Syrian MiG fighters were shot down. By 8 June Israeli forward elements were at the entrance to the Bekaa Valley but weren't able to push any further north as the Syrian forces held steady under the protective umbrella of their IADS, denying close air support to the Israeli ground forces. For several weeks prior to the invasion, though, the IDF/AF had been planning to deal with the Syrian IADS umbrella over the Bekaa Valley. Years of meticulous reconnaissance and eavesdropping gave the IDF/AF the locations, operating frequencies and modes of the SAM batteries in the valley. Operation Drugstore was their plan for not just the suppression of enemy air defenses (SEAD) but what was being called "DEAD"- destruction of enemy air defenses. This is what made Operation Drugstore a landmark operation in air combat- prior to 1982, suppression was the name of the game as it had been practiced in Vietnam by the United States- keep the enemy's heads down while strike packages went in and hit targets. For Israel, nothing less than the complete elimination of the Syrian IADS was acceptable- air superiority against the Syrian fighters was meaningless if the IADS prevented close air support from assisting the ground forces' objectives. 

The opening phase of Operation Drugstore saw large numbers of Delilah ground-launched drones being launched towards the Bekaa Valley, giving the impression of a large Israeli strike force. As the SAM batteries went active to engage what they thought were Israeli aircraft, battlefield surface-to-surface missiles were fired at each SAM battery. One of the missiles used was the Keres, which was an Israeli modification of the AGM-78 Standard anti-radiation missile used by Wild Weasel aircraft. The mobile launcher fired three Keres missiles and even a local modification of the smaller AGM-45 Shrike was used that added a second stage booster to allow a ground launch. In the first ten minutes of the operation, ten of the 19 batteries had been knocked out either due to missile hits or because they had run out of missiles engaging the Delilah drones. Four minutes later, the first wave of ground attack aircraft swept into the Bekaa Valley- 26 McDonnell Douglas F-4E Phantoms and a similar number of IAI Kfir C2s, with the Phantoms using AGM-65 Maverick missiles as well as Shrike and Standard ARMs to hit the remaining SAM sites while the Kfirs targeted the control vans and storage areas of the missile sites. With no losses, a second wave of over forty A-4 Skyhawks and IAI Kfir C2s swept in attacking the SAM sites with cluster bombs while the F-4Es returned using laser-guided bombs against any surviving control vans. In just two hours, 17 of the 19 Syrian SAM sites had been destroyed. 

The next phase of Operation Drugstore saw Israeli strike aircraft next hit the Syrian mobile GCI (ground-controlled intercept) sites that provided directions to the Syrian MiG force. With the destruction of the GCI sites and their radars, the Syrian IADS was now blinded as F-15 Eagles and F-16 Fighting Falcons established combat air patrols over the Bekaa Valley. The timing was perfect- as the Syrian commanders realized that their IADS umbrella was being systematically demolished, three squadrons of MiG-21s and MiG-23s were scrambled from their Syrian bases- it's estimated that up to sixty Syrian fighters raced to the Bekaa Valley where the F-15s and F-16s were waiting. They were tasked to hit the Israeli strike forces that were attacking the components of their IADS, but instead found that Israeli Grumman E-2 Hawkeyes orbiting over southern Lebanon had given the combat air patrols ample warning of the inbound MiGs. Because the Syrians relied on GCI controllers to provide them with vectors and targeting information, the loss of the GCI sites meant they were flying into the Bekaa Valley blind while the F-15s and F-16s' longer ranged radars already had them targeted. With communcations and radars being jammed, most of the Syrian MiGs never saw what hit them- ten MiG-21s fell within minutes. At the end of the day, only one F-15 had been hit, and the pilot managed to recover his Eagle safely to Ramat David AB in northern Israel. 

The following morning the last two Syrian SAM batteries were destroyed while the Syrians scrambled more MiG-21s and MiG-23s to make up for the previous day's losses. Since the MiG-23 Floggers were the most capable of the Syrian fighters, the F-15s were tasked with eliminating them and six were shot down in short order. As Israeli armored units engaged Syrian armor in the valley, two waves of Syrian Sukhoi Su-22 fighter bombers were sent into to attack the Israeli units, escorted by a squadron of MiG-21s. It was a turkey shoot as over 20 Syrian aircraft were shot down by the Israeli fighters patrolling the skies of the Bekaa Valley. The Syrians then tried to send in anti-tank Gazelle helicopters to go after the Israeli armor and those were shot down as well. 

11 June was the last day of continuous fighting as a cease fire was to go into effect later than day. Hoping to stave off defeat and entering the ceasefire at a disadvantage, the Syrians poured their MiG-23 Floggers into the battle against the F-15s and F-16s, leaving the MiG-21s to escort the strike version of the Flogger, the MiG-23BN. Several Syrian MiG-25 Foxbats made high altitude runs over the Bekaa Valley, hoping to distract the Israeli fighters into looking "upward", distracted from the inbound MiG-23s. At lower altitudes, two waves of Syrian MiG-23BNs would attempt to hit the Israeli armored units once again where the Sukhois had failed the previous day. The Syrian fighter sweep failed as their presence was once again known thanks to the E-2 Hawkeyes. Six Floggers were shot down in their first pass over the valley. Another six MiG-21s were shot down as well and the MiG-23BN attacks had little effect on the Israeli positions. 

By the time of the ceasefire took effect, the Syrians lost 30% of their air force in just one week of fighting for a total of 88 aircraft shot down. Of those 88 kills, 44 belonged to F-15 Eagles and 33 belonged to F-16s. Israeli losses have never been fully admitted, but it's believed to include one F-16, one F-4E, one Kfir C2, two A-4s and several helicopters. Following the battle in the skies over the Bekaa Valley, the Israeli Defense Forces Air Force (IDF/AF) was secretly debriefed by US military experts from the US Air Force and other branches of the military. The lessons gleaned from Operation Drugstore would strongly influence Coalition tactics on the opening night of Operation Desert Storm. In what was called "Poobah's Party" (from the callsign of Brigadier General Larry Henry, a leading USAF tactician and expert on air defenses), approximately one-hundred drones were fired from ground sites in Saudi Arabia to trigger the Iraqi IADS into action to they could be targeted for destruction by Coalition air assets. With the stealthy Lockheed F-117A Nighthawks going "downtown" to Baghdad to take out the command and control centers of the IADS, individual radar and SAM sites then were left on their own to find their own targets in the midst of some intense jamming. Iraqi radar sites could burn through the jamming, and when they did, they detected the drones of Poobah's Party. Sites that hadn't expended their missiles on the drones found themselves targeted by F-4G Wild Weasels. 

Source: F-15 Eagle Engaged: The World's Most Successful Fighter by Steve Davies and Doug Dildy. Osprey, 2007, p146-147. Photos: Wikipedia, USAF Featured Art Gallery

09 September 2015

Fall from Triumph: The Sad Story of Tryggve Gran of Norway

1944 Norwegian stamp commemorating Gran's flight
(from Wikipedia)

Aviation history is filled with individuals whose achievements have been eclipsed by history or by their choices later in life. Norwegian aviator Tryggve Gran falls into both categories, having been the first man to fly across the North Sea in 1914 in a fragile Bleriot monoplane only to have the achievement fade into the cataclysm that was the First World War and then to have later in life collaborated with the Nazi occupation government of Norway in the Second World War.

Born in Bergen, Norway in 1889, Jens Tryggve Herman Gran from an early age seemed to have always had a hunger for adventure. By the time he attended the Norwegian Naval Cadet College, he was already an accomplished skier and soccer player who had traveled throughout Europe and South America. He then left college to accompany the explorer Robert F. Scott who had already led one expedition to Antarctica and was racing Roald Amundsen to be the first reach the South Pole. Scott was leading the 1910 Terra Nova expedition to reach the South Pole via the Ross Ice Shelf. Scott and four other men died on their return to their base camp after finding Amundsen had already reached the South Pole. Tryggve Gran was one of the members of the search party sent from the base camp to look for Scott's party.

On his return to Europe in 1913, Gran had a chance meeting with British aviator Robert Loraine who was the first to fly the Irish Channel and the first to fly to the Isle of Wight. Loraine convinced him to take up flying and he enrolled at Louis Bleriot's flying school. Eager for adventure and acclaim, he planned to be the first to fly the North Sea to Norway from the UK. He bought an upgraded Bleriot monoplane from his flight instructor- this aircraft had an 85-horsepower engine compared to the 25- or 50-horsepower engines most Bleriot monoplanes had. He took the plane to Scotland to two different locations that were approximately 300 miles from Norway, eventually settling on Cruden Bay which was the less fog-bound locations of the two.

Gran's flight had to leave by 6pm on 30 July 1914 because on that date because of the looming First World War the British government was imposing a ban on civilian air traffic. He tried to leave the day before the deadline, but had to turn back due to the heavy fog. On the day of the deadline, Gran took off just five hours before the appointed hour of the ban on civil flights. His only navigational instrument was a compass and he used the size and direction of the waves of the North Sea below him as a guide as well. After flying for 289 miles for over four hours, Gran landed in Norway having set world records in time and distance, having made the longest overwater flight until Alcock and Brown crossed the Atlantic five years later. It was also the first air mail flight between Britain and Norway, Gran had with him on the flight a letter from the British publisher Lord Northcliff to Queen Maud of Norway.

Tryggve Gran in 1923
("Tryggve Gran 1923" by Anders Beer Wilse)

The acclaim he sought, though, was dampened by the onset of the war and he did serve in the RAF- having flown a Sopwith Camel, he ended the First World War commanding an RAF squadron at the Russian port of Archangel. In 1919 he left the RAF and tried a trans-Atlantic crossing only to crash right after takeoff. He then toured Scandanavia in a Handley Page O/400 bomber, becoming the first person to fly nonstop between London and Oslo. He crashed that plane too, in Oslo.

During the interwar years Trggyve Gran was restless and disgruntled that his achievements were little noticed by anyone outside of Norway. Though the historical records have thus far failed to show whether he joined the Nazi Party before or after the April 1940 German occupation of Norway, Gran was an easy target by the puppet government of Vidking Quisling who promised him fame and fortune by lending legitimacy to the Quisling government. There is no doubt that the Nazis wanted to use Gran to improve the image of the occupation government in Norway, even issuing a stamp in 1944 on the 30th anniversary of his North Sea crossing. Quisling made Gran the head of flight wing of his government, the Hirdens Flykorps, but with the defeat of Germany in 1945, Gran found himself under trial as a collaborator and sentence to serve 18 months in prison.

For thirty years after his release from prison until his death in 1980, Tryggve Gran lectured about the Antarctic expeditions of Robert F. Scott with little ever said by him of his aviation achievements, his reputation tarnished in his homeland by his association with the Nazis.

Source: Aviation History, March 2010. "Forgotten Pioneer Pilot: The Norwegians never forgave their most famous aviator for collaborating with the Nazis" by Bethany Robinson, p20-21.

04 September 2015

The Aircraft Operated from Submarines in World War I

The Friedrichshafen FF29 on the bow of U-12
(from the War Relics Forum)
 While the combat pinnacle of aircraft-carrying submarines is considered by many to be the big Japanese I-400 class boats of the Second World War that could carry three Aichi Seiran floatplanes, the roots of operating aircraft from submarines has more humble beginnings in the First World War based on the personal initiative of a U-boat captain, Oberleutnant Freidrich von Arnauld de la Periere who was the base commander for the submarine base at Zeebrugge in occupied Belgium. Quite unusually for a submarine officer, he was also an aviator which gave him unique insights into the potential for aircraft that many of his other naval comrades did not possess. Working with a friend who also happened to be a U-boat captain of the submarine U-12, Walther Forstmann, they hatched an plan to launch floatplanes off the foredeck of the submarine to attack British targets. At the time, the only way to attack British targets was either via Zeppelin airship or large bombers like the Gotha G.V. In the last few weeks of 1914, the Germans did try to attack British targets with floatplanes based across the Channel but were largely unsuccessful as the range needed resulted in a very small bomb-load. The first confirmed attack on a British target, in fact, was by Friedrichshafen FF29 floatplane on 21 December 1914 that dropped two bombs and missed against a pier in Dover. 

The two men came from illustrious backgrounds- von Arnauld de la Periere's brother, Lothar, was the most decorated U-boat captain of the First World War and with 194 ships sunk, the most successful submarine captain in history. Walther Forstmann was the second most decorated U-boat captain of the First World War and with a 146 ships sunk, he was the second most successful submarine captain in history after de la Periere. Realizing that there were few Zeppelins and Gotha bombers to prosecute a large scale attack on British targets, the two men surmised that floatplanes with their limited radius when flying from the Continent might have a more utility if launched from the decks of U-boats that could approach more closely to their intended targets. With single engine floatplanes more widely available, they set out to try and prove the concept starting on 6 January 1915 with a Friedrichshafen FF29 floatplane lashed to the foredeck of U-12 to carry out sea trials. Within the Zeebrugge harbor, they had determine that the submarine would have to trim down at the bow with the FF29 floating off and then taking off from the sea. On their first operational mission, with Forstmann captaining U-12 and de la Periere flying the FF29 with an observer, they approached within thirty miles of the British coast when the FF29 was floated off to begin a reconnaissance mission. They flew along the coast undetected, but were unable to rendezvous with U-12 due to deteriorating weather and returned to Zeebrugge instead. 

Emboldened by their success, de la Periere and Forstmann had the FF29 modified with bomb racks to carry 12 kilogram bombs. They determined that calmer sea states were needed to not only allow the FF29 to take off, but to prevent damage to the floatplane as it was lashed to the U-boat's foredeck. Over the course of the year in 1915, the "Zeebrugge Fliers" flew twenty-six raids from U-boats against British and French coastal targets. On Christmas Day 1915, he managed to fly up the Thames Estuary and drop two bombs on London which did little damage. He successfully exited the area to safety despite being chased by three fighter aircraft. This all took place without any sanction or support of the German high command- as the FF29s were light floatplanes, de la Periere and his other pilots he trained often found their biggest issue wasn't British defense but numerous technical issues with the aircraft being subjected to such harsh use. But morale was high amongst the pilots and the U-boat crews- given that the U-boat was a relatively new weapon of war at the time, the crews took special interest in the pilots who were trying a relatively new weapon as well in the same hazardous sea environment. A formal report of their efforts was submitted up the chain of command, but they were told explicitly to stop their efforts. In the words of the German high command, "U-boats operate in the sea, aircraft operate in the air. There is no connection between the two."

Sopwith Schneider floatplanes on the aft deck of the sub E22
(from @RNSubMuseum's Twitter stream)
Across the English Channel, the British were also giving consideration to operating aircraft off submarines, but for a defensive role instead of an offensive role. Germany had opened up a new phase in the war with its strategic bombing campaign against British targets using Zeppelins on 19-20 January 1915. The airships could carry a much more significant bomb-load than most aircraft in the German inventory and they were able to fly at a height that made interception by British fighters difficult. Both the Army and the Royal Navy each proposed their solutions to the "Zeppelin" problem, the Army suggesting fighters with better engines for higher altitude performance and larger caliber anti-aircraft cannon that could reach the airship's bombing altitudes. The Navy, however, came up with a unique solution with the observation that Zeppelins crossed the North Sea on their way to their targets at relatively low altitudes and then climbed to their bombing altitudes once reaching the coast. Although ships had been used to launch floatplanes against the Zeppelin bases in December 1915 in the first "carrier" attack, the Navy proposed the use of submarines which would be less visible to Zeppelin crews as they made their crossing at low altitudes. Such a submarine could launch aircraft that would have had an easier time intercepting the airships at the lower altitudes. Given authorization, the Royal Navy drydocked the 660-ton submarine E22 for the addition of two parallel ramps on the aft deck that extended from the conning tower to the end of the upper deck casing. 

On 24 April 1916, the newly-modified E22 docked at Felixstowe to take on two Sopwith Schneider floatplanes. The Schneider was the floatplane version of the Sopwith Tabloid fighter. The name came from the floatplane Tabloid being used in the 1914 Schneider Trophy race. The land-based Tabloid was used as a fast scout by the Royal Flying Corps (the RAF's predecessor). The E22 took the two aircraft lashed on its modified aft deck for sea trials in the Heligoland Bight, the area where Zeppelins often began their North Sea crossing towards their targets. The effort was near disastrous- the sea state was too rough for the Sopwith Schneiders which had their floats snapped by the waves. On the following day after it was decided to head back to the naval air station at Felixstowe for replacement aircraft, the E22 was torpedoed and sunk by U-18, ending any significant British experiments for the duration of the war. 

The Brandenburg W20 flying boat
(from Their Flying Machines)
Interestingly the two operations of the First World War involving the use of aircraft from submarines didn't involve the most obvious use- reconnaissance. The Germans used it for bombing raids and the British intended to use their aircraft for Zeppelin interception. That didn't stop some German engineers from considering the problems of operating aircraft from submarines. Ernst Heinkel before he would become famous had designed and built a flying boat, the Hansa-Brandenburg W20, designed from the outset to be operated from submarines. As the German naval command began work on larger submarines, Heinkel began work in 1917 on a compact single seat flying boat that could be folded up and stored inside a watertight compartment on a U-boat. Three aircraft were ordered with the prototype flying in the same year that Heinkel began work on the W20 design. A biplane design with a single pusher engine, the W20 was a bit of a weak performer with an 80 hp engine and it took fifteen minutes to climb to 3,000 feet. But the diminutive aircraft could be assembled and disassembled in three minutes and stored in a watertight compartment only 20 feet long and 6 feet in diameter. The design never went to sea trials aboard a U-boat as by late 1917, no spare subs could be afforded to Heinkel and the Hansa-Brandenburg team. 

The LFG Roland V19 "Putbus"
(from Google Snipview)
In 1918, the British returned to the idea of operating aircraft off submarines- only this time they used an SSZ (Sea Scout Zero) class blimp towed by a K-class submarine. It wasn't too successful as the SSZ blimps were too large and it hampered the mobility and flexibility of the submarine. Towed observer kites (large box kites carrying a single very brave observer) were also trialled, but they proved equally unsuccessful in trials as well. That same year, though, the Germans took one more shot at the submarine-compatible aircraft problem. The Luft Fahrzeug Gesselschaft (LFG) Roland company produced a single seat scout plane called the LFG V19 "Putbus". Unlike other aircraft trialed, the Putbus was a monoplane with twin floats with aluminum skin. Fuel was contained in the detachable wings which had shut off valves so the wings could be attached or removed without having to drain the fuel tanks. In flight tests the Putbus could fly up to 112 mph, much faster than any other aircraft flown off submarines thus far and appeared to be quite superior to the Hansa-Brandenburg W20. However, while the W20 could be readied for flight or stowed in as little as three minutes and used a single 20x6 foot compartment, the Putbus took at least thirty minutes for assembly for flight or stowage and required five compartments to stow its components aboard a U-boat. Needless to say, the German naval command was less than enthused but by the time it came to take the Putbus to sea, the war had ended. 

Source: Strike From Beneath the Sea: A History of Aircraft-Carrying Submarines by Terry C. Treadwell. The History Press, 2009, pp 13-24. 

30 August 2015

The Boeing YB-40 Bomber Escort and Its Tall Tales

Boeing YB-40 in flight. Note the second dorsal turret.
It quickly became apparent with the start of daylight strategic bomber missions over Europe that fighter escort was desperately needed to get the heavy bombers to their targets and back. During the design phase of the Boeing B-17 Flying Fortress, air doctrine of the day called for the mutually supporting defensive fire from the bomber formation to be sufficient defense against enemy fighters. Early B-17 missions were against targets in northern France which were well within the range of Royal Air Force Spitfires which could provide escort cover- but as the Eighth Air Force began to dispatch its growing B-17 force against further targets, the Spitfires lacked the range. The Republic P-47 Thunderbolt and North American P-51 Mustang had yet to reach sufficient numbers in Europe to provide long-range escort and the only fighter in theater with the range, the P-38 Lightning, was desperately needed in the North Africa campaign. In those early days of unescorted daylight missions, only a quarter of combat losses were coming from anti-aircraft flak- the majority of bomber losses came from Luftwaffe fighters. The only aircraft with the range to escort the B-17s was quite obviously (at least to planners then) another B-17, so why not swap out a bomb-load for increased defensive armament as a large bomber escort? The passage of time has us not knowing who came up with the idea of a heavily armed B-17 as an escort, but in November 1942 the first XB-40 was ordered- taking a stock B-17F Flying Fortress from the license production line at Lockheed Vega (both Lockheed and Douglas were building Flying Fortresses to augment Boeing's own production), the XB-40 was modified with a chin turret with twin fifty-caliber guns to defeat head-on attacks by Luftwaffe fighters. In addition, the waist positions were staggered so the waist gunners had more freedom of movement and each gunner got a twin fifty-caliber on a flexible mount instead of a single fifty-caliber gun which was standard. Finally, a second dorsal turret was added where the radio room was located, this turret also had twin fifty-caliber machine guns. Space in the bomb bay was devoted to additional ammunition storage and fuel. Compared to a standard B-17F, the XB-40 had three times the ammunition for its beefed up gun armament. 

Interior layout of the YB-40 showing the increased guns.
A further twenty-four B-17Fs were taken from Lockheed Vega's production and delivered to the Douglas B-17 plant in Tulsa for modification to YB-40 standard (the "Y" prefix indicating a service test aircraft as opposed to an experimental prototype which would use the "X" prefix). There were only minor differences between the first XB-40 and the YB-40 series of aircraft. Some sources suggest different armament combinations were trailed including cannons, but the aircraft were sent to Europe standardized on the Browning fifty-caliber machine gun for all the defensive positions. The 92nd Bomb Group at RAF Alconbury would be the first unit to take the YB-40 into combat to prove the concept. Of that group of twenty five aircraft (including the XB-40), thirteen would be sent to Europe- one was lost on the ferry flight, making a forced landing in a Scottish bog, leaving twelve to continue on to Alconbury. The first mission was flown on 29 May 1943 with seven YB-40s accompanying a B-17 force to hit the Kriegsmarine U-boat pens at Saint-Nazaire, France. The YB-40s, loaded with extra guns and ammunition, were slower than regular B-17Fs and handling at altitude was sluggish. The entire formation had to slow down to allow the YB-40s to keep up. On the return leg, the now empty B-17Fs could fly higher and faster no longer burdened with their bomb-loads, but the YB-40s still had their guns as they didn't exactly lighten over the course of the mission as they didn't have a heavy bomb-load to drop. Marauding German fighters focused on stragglers in the bomber formations and while the YB-40s had the defensive fire to fend off the attacks,  no one was thrilled about the prospect of being the formation straggler on every mission. The Eighth Air Force command was less than impressed- the last mission was flown on 29 July 1943 with only two months of operating experience- nine missions were flown with the loss of one aircraft. Five German fighters were confirmed as shot down by the YB-40s with two probable kills. It was hardly a resounding performance and the YB-40 program quietly wound down. Through 1943 until early 1944, the YB-40s returned to the United States. Twelve aircraft of the original twenty four never left the United States and were ultimately scrapped. 

Layout of the YB-40's additional gun armament.
The experience of the YB-40, though, did leave a legacy with the B-17 force. The next variant of the B-17 to follow the B-17F, the B-17G, featured the chin turret and the staggered waist gun positions that were used on the YB-40s. Some sources indicate that the improved "Cheyenne tail turret" (so named from the United Air Lines modification center in Cheyenne, Wyoming) was also an outgrowth of the YB-40 program. 

Two tall tales have sprung up from the YB-40 story that are often repeated on websites, publications and even books. Both of them are just that- fanciful stories and we'll discuss both of them for the record and why they're tall tales and not true historical events. 

The first story concerns a B-17 pilot with the Twelfth Air Force in the Mediterranean named Harold Fischer (in some stories spelled Fisher). Returning to their base in North Africa after a mission against the Italian island of Pantellaria, Fischer's B-17 lagged behind the formation as it had two of its engines shot out. A lone P-38 Lightning formed up on his bomber and offered to escort them. It soon took up position behind the crippled B-17 and shot it down over the sea with Fischer as the only survivor. His story was met with disbelief until USAAF intelligence officers corroborated his story that a P-38 that had gotten lost had fallen into the hands of the Italians and it was being flown by a Regia Aeronautica ace, Guido Rossi, to shoot down B-17 stragglers. Fischer was the first B-17 crewman to have survived Rossi's ruse as he had already downed nine bombers with the captured P-38. Fischer came up with a plan to exact revenge on Guido Rossi and a YB-40 was requested from the Eighth Air Force in August 1943 which Fischer would fly, playing the part of a B-17 straggler to trap Rossi. After two weeks of flying, they hadn't gotten Rossi but the Italian added more kills to his P-38. Determined to get him, Fischer worked with Allied intelligence to find out as much as he could about Guido Rossi and learned his wife and child were living in an Italian city that was in Allied hands. Fischer went to the home of Gina Rossi to meet her and had an artist paint a portrait of her on the side of the YB-40 which he aptly named "Gina". 

On the next mission to Pisa, Italy, Fischer's YB-40 took heavy damage and ended up getting met by Rossi's P-38. Noting the nose art, Rossi asked Fischer if the woman on the nose of the plane was from his own town. Realizing they had Rossi, Fischer confirmed Rossi's suspicions and began to sing the praises of Gina's lovemaking abilities. Filled with rage, Rossi attacked the YB-40 and a running gun duel ensued with Rossi at one point trying to ram the bomber. Rossi was eventually shot down over the sea and survived. As the story goes, Fischer got the Distinguished Flying Cross for it and the two flyers eventually met after the war, but Fischer was killed in a crash during the Berlin Airlift.

Sounds like a great story, but there was no Italian ace named Guido Rossi. A P-38 did fall into Italian hands during the war and its pilot was known and the aircraft as only flown in an evaluation role. There is no record of the YB-40 operating in the Mediterranean theater of operations- while there were two bomb groups with B-17s assigned to the Twelfth Air Force, neither of them operated the YB-40 either. And most damning to the veracity of this story, there is a pilot named Harold Fischer who got the DFC- but he was USAF F-86 Sabre pilot in the Korean War- he was the 25th ace of the war and was imprisoned by the Chinese after getting shot down and wasn't released until 1955. 

The second tale relates to one 1st Lt. Harry Reid with the 95th Bomb Group of the Eighth Air Force who with one of his lead pilots, had noted a lone B-17 that would tail their bomber formations on their missions over Europe. In June 1944 as the story goes, Reid and his lead pilot, Captain Glenn Infield, hatched a plan on their own initiative to use a parked YB-40 at their base to get this lone B-17 which they suspected was a captured Flying Fortress being flown by the Luftwaffe to tail formations and give position, altitude and heading information on the formations to defending Luftwaffe fighters. On a mission against a target in Brussels, Reid and Infield set their plan in motion. Sighting the lone B-17, they closed on it. The aircraft then veered away from them, confirming their suspicions as a one B-17 would have formed up with any other B-17 right away for mutual defensive fire from the gunners. Pursuing the German-flown Flying Fortress, the YB-40 was bounced by six Focke Wulf Fw 190 fighters. Reid and Infield astutely realized if they stayed close to the captured B-17, it made the Fw 190's task harder out of fear of hitting the wrong B-17. Their radio operator happened to speak fluent German and he got on the Luftwaffe's fighter frequency and directed the Fw 190 pilots to attack the captured B-17 while they made a sharp break to the right. Thinking they had gotten direction from their own B-17, the Fw 190 pilots made their attack before their own B-17 could protest! With the captured B-17 damaged, the YB-40 completed a full turn to the right and came up and behind the other Flying Fortress, finishing it off just as escort fighters arrived on the scene. Because their plan was hatched of their own initiative without the approval of their superiors, Reid and Infield were never formally decorated for their actions. 

Again, sounds like a great story, but the last YB-40s were documented to have returned to the United States by March 1944. Most of the original twelve that flew missions had returned through 1943 but three were left in Great Britain at the start of 1944. One returned to the United States in January 1944 and the last two returned in March 1944, making the timeline of this second tale impossible. In addition, while the 95th Bomb Group was co-located with the 92nd Bomb Group at RAF Alconbury, there is no documentation of the 95th BG having flown the YB-40. Only the 91st, 92nd, and 303d BGs ever flew the YB-40. 

Sources: Aerial Gunners: The Unknown Aces of World War II by Charles Watry and Duane Hall. California Aero Press, 1986, p167-174. "Brilliant Mistakes: The YB-40" by Robert Dorr. Defense Media Network at http://www.defensemedianetwork.com/stories/my-brilliant-mistake-the-yb-40/. Photos: USAF Museum, 92nd Air Refueling Wing Historians, Squadron Publications via War Thunder Forums.