Boeing B-17: The Fifteen Ton Flying Fortress

By Graham M. Simons and Harry Friedman

“Fascinating insight into the early development of the B-17 Flying Fortress . . . undoubtedly outshines other books on this significant WWII aircraft.” —Air Mail
 
The Boeing B-17 was the first American heavy bomber to see action in World War II when it was supplied to the RAF. The design originated in 1934 when the US Air Corps was looking for a heavy bomber to reinforce air forces in Hawaii, Panama and Alaska. For its time, the design included many advanced features, and Boeing continued to develop the aircraft as experience of the demands of long-distance flying at high altitude was gained.
 
When the United States entered WWII, production of the aircraft was rapidly increased and it became the backbone of the USAAF in all theaters of war. This book describes how it was built and utilizes many hitherto unpublished photographs from the design studio and production lines. It illustrates and explains the many different roles that the aircraft took as the war progressed. Heavy bomber, reconnaissance, antisubmarine, and air-sea rescue operations; there were few roles that this solid design could not adopt.

• Language: English
• Publisher: Open Road Integrated Media
• Release date: Dec 1, 2011
• ISBN: 9781783461011

Graham M. Simons

Graham M. Simons is a highly regarded Aviation historian with extensive contacts within the field. He is the author of Mosquito: The Original Multi-Role Combat Aircraft (2011), B-17 The Fifteen Ton Flying Fortress (2011), and Valkyrie: The North American XB-70 (also 2011), all published by Pen and Sword Books. He lives near Peterborough.

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INTRODUCTION

The history of what is possibly the most famous of all United States military aircraft from the Second World War era, the Boeing B-I7 Flying Fortress, has been substantially documented. In fact, an understandable reaction to this book could be - ‘Oh no, not another book on the Flying Fortress!’

In recent years the design and use of the B-17 has achieved an almost mythical, ‘god-like’ status through the activities of a few so-called ‘third generation veterans’ - whatever that means - who love to over-glamourise the war-horse of their ancestors. To read some authors, one would have to believe that this huge bomber sprang fully formed out of the box it was delivered in clad in more armour than a tank and carrying more guns than a battleship!

As a result of the critical acclaim our ‘Memphis Belle - Dispelling the Myths’ received, we decided that there was a need for a similar work on the B-17 - to subject the design, in all its forms, to close scrutiny. Without doubt there is a clear, strong requirement to ‘put the record straight’ using primary source documentation to record the undoubted achievements alongside and in context with the shortcomings to the types design and operation that have otherwise received scant attention. There is also a matching need to look into the murky world of power politics and intrigue that hovered around the design through the early years.

This is not a book that details the many thousands of combat operations flown by incredibly brave aircrew in both the European and Pacific theatre of operations - we prefer to leave that to the likes of good friend and colleague Martin W Bowman, who does a far better job at that than we could ever do!

The B-17’s capacity to repel enemy attacks and still inflict heavy damage to the German war machine and production centres is imaginatively rendered by Colonel C Ross Greening in this caricature completed while he was a prisoner at Stalag Luft I Germany in 1944-1945. (USAF)

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Throughout the research and writing of this book we could not help but carry in our minds the late Bob Stevens’ marvelous ‘think what a tale this will make for future reunions’ cartoon. Bob gave us the OK to use this many years ago, and it’s as pertinent now as when it was first drawn. Perhaps this book with ensure that the tales told may be that little bit more accurate!

For around the first six years of its life the Boeing 299 design received what appears to be only grudging support from the Army Air Corps. It was Great Britain who took the design into battle with what was then an un-developed machine, operating outside the original design envelope with only a small a number of aircraft instead of the massed formations of a few years later.

Lessons were learned and soon the ‘big assed bird’ - the B-17E appeared. Production increased dramatically with the Model F and G - so much so that the Boeing-Lockheed Vega - Douglas conglomerate was created, that in turn brought into being the Block Numbers and later Staging Lists systems that helped keep track of what modification state each aircraft was at.

Post-war, some Flying Fortresses had a brief but colourful career with the US Navy, the US Coastguard, and a few overseas air arms, while others were used for research projects or converted into pilotless drones and Borate bombers, all of which we decided to look at in some detail.

For many years there have been endless battles as to which was ‘best’, the B-17 or the Consolidated B-24 Liberator. We decided to carefully study not only those two designs in comparison, but also to put the B-17 up against other Axis and Allied designs of the time - the results were interesting to say the least!

‘The overall result is...’, as David Lee, the former Deputy Director of the Imperial War Museum at Duxford said upon reading the final proofs ‘...all you never knew about the B-17!’

Graham Simons

Peterborough UK

Dr Harry Friedman

Memphis, USA.

ORIGINS

The Boeing Aircraft Corporation has its origins in Seattle, Washington State USA when on 15 July 1916, William E Boeing, incorporated the ‘Pacific Aero Products Co.’ following the maiden flight on the same day by of one of the two ‘B&W’ seaplanes built with the assistance of George Conrad Westervelt, a U.S. Navy engineer.

William Edward Boeing was born in Detroit, Michigan, to a wealthy German mining engineer named Wilhelm Böing who had made a fortune developing large low-grade penuckle taconite iron ore deposits and who had a sideline as a timber merchant. Anglicizing his name to ‘William’ after returning from being educated in Switzerland in 1900 to attend Yale University, Boeing left Yale in 1903 to go into the lumber side of the business. He bought extensive timberlands around Grays Harbor on the Pacific side of the Olympic Peninsula in Washington State, and also bought into lumber operations.

While president of Greenwood Logging Company, Boeing, who had experimented with boat design, travelled to Seattle, where, during the Alaska-Yukon-Pacific Exposition in 1909, some reports say that he saw a manned flying machine for the first time and became fascinated with aircraft. Other sources differ, and there are records which suggest that he attended an aviation meet held in Los Angeles County, California at Dominguez Field in present day Carson, California over January 10 to January 20, 1910. Spectator turnout numbered approximately 254,000 over 11 days of ticket sales.

The 1910 Air Meet drew many famous aviators, most of whom were American. Glenn Curtiss, American aviation pioneer and founder of the Curtiss Aeroplane and Motor Company, was the most famous. Other participants included Roy Knabenshue, Charles Willard, Lincoln Beachey and Charles K. Hamilton, Howard Warfield Gill, and Clifford B. Harmon, many of whom are listed among the Early Birds of Aviation. French aviators at the event included Louis Paulhan and Didier Masson.

The founder of the company, William Edward Boeing (October 1, 1881 – September 28, 1956)

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Paulhan gave William Randolph Hearst his first experience of flight and it is alleged also promised to give Boeing a flight, but despite waiting for four days, Paulhan left before taking Boeing up.

In 1914, Thomas Hamilton, later founder of Hamilton Metalplane Co. (acquired by Boeing in 1929), introduced Boeing to U.S. Navy Lieutenant George Conrad Westervelt. Boeing and Westervelt became close friends and when flier Terah Maroney brought a Curtiss-type hydroplane to Seattle later that year, the pair took turns riding above Lake Washington. A year later , Boeing went into business with Westervelt as B & Wand founded the Pacific Aero Products Co. When America entered the First World War in April 1917, Boeing changed the name of Pacific Aero Products Co. to the Boeing Airplane Company and obtained orders from the United States Navy for fifty machines. At the end of the war, Boeing began to concentrate on commercial aircraft, securing contracts to supply an airmail service which was built up into a successful airmail operation.

On 30 June 1927 Boeing created an airline named Boeing Air Transport, which merged a year later with Pacific Air Transport and the Boeing Airplane Company. The company changed its name to United Aircraft and Transport Corporation in 1929. United Aircraft then purchased National Air Transport in 1930.

Boeing also built a number of different designs for the military, including a number of flying boats and a family of fighters. In 1933 the revolutionary Boeing Model 247 was introduced, a design that would lay claim to the title of the first truly modern airliner. It was much faster, safer, and easier to fly than other passenger aircraft. For example, it was the first twin engine passenger aircraft that could maintain height on one engine. In an era of unreliable engines, this vastly improved flight safety. Realising what it had created, Boeing built the first sixty aircraft exclusively for its own airline operations, something that badly hurt competing airlines, and was typical of the anti-competitive corporate behaviour that the US government sought to prohibit at the time.

In 1934, the United States government accused William Boeing of monopolistic practices and so brought in the Air Mail Act which prohibited airlines and manufacturers from being under the same corporate umbrella, so the company was forced to split into three smaller companies - the Boeing Airplane Company, United Airlines, and the United Aircraft Corporation, which was the precursor to United Technologies. As a result, William Boeing sold off his shares in the company and left Boeing. Clairmont L ‘Clair’ Egtvedt, who had became Boeing’s president in 1933, thus became the chairman as well. He believed the company’s future was in building bigger and more technologically advanced aircraft.

Ancestors to the B-17...

To trace the ancestry of the B-17 back to an origin is not an easy task. The design had many influences from not only the talented designers within the company, but also from many other different manufacturers.

The Boeing Monomail

In 1930, Boeing created the revolutionary Monomail, which made traditional biplane construction a design of the past. The Monomail wing was set lower, was of cantilevered construction, smooth, made entirely of metal and had no struts. The retractable landing gear, the streamlined fuselage and the engine covered by an anti-drag cowling created a machine that was built to an advanced, extremely aerodynamic design.

The first Monomail took to the skies on 6 May 1930 - the Monomail Model 200 was a mailplane, and the Model 221 was a six-passenger transport. Both were later revised for transcontinental passenger service as Model 221As.

The major drawback of the Monomail was that its design was too advanced for the engines and propellers of the time. The aircraft required a fine-pitch propeller for takeoff and climb and a much coarser -pitch propeller to cruise. By the time the variable-pitch propeller and more powerful engines were available, the Monomail was being replaced by larger, multi-engine aircraft it had inspired.

Clairmont L ‘Clair’ Egtvedt, (18 October 1892 – October 1975) who became Boeing’s President in 1933.

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The Boeing Model 200 mailplane (right) and the Model 221 transport. The design with retracting landing gear and all-metal construction was very advanced for the time. (Simon Peters Collection)

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The Boeing B-9

The Boeing B-9 bomber was the earliest company aircraft based on the Monomail design. It had a top speed of 186 mph and could out-run the fighters of the day by 5 mph. The monoplane bomber reached this speed although it had a five-man crew and carried a 2,400 lb bomb load.

Designed by John Sanders, the design, nicknamed the ‘Death Angel’ by Popular Mechanics of August 1931, was originally tested and developed as the XB-901 and first flew on April 29, 1931. The YB-9 was an enlarged modification of Boeing’s Model 200 Commercial Transport. The Pratt & Whitney R-1830-13 radial engines used on the YB-9 gave it a top speed of 163 mph. The second test model, named the Y1B-9 (Y1 indicating funding outside normal fiscal year procurement), evolved into the Y1B-9A and Boeing built a total of seven prototype bombers at company expense to show their design potential to the military. This high-speed aircraft inspired other aircraft manufacturers to launch a new generation of bombers, such as the Martin B-10. Because fighters were expected to be faster than bombers, the B-9 also led to the first monoplane fighters.

Y1B-9 32-302 is seen undergoing evaluation for the United States Army Air Corps. (Simon Peters Collection)

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The Martin B-10

The XB-10 began as the Martin Model 123, a private venture by the Glenn L Martin Company of Baltimore, Maryland. It had a crew of four: pilot, copilot, nose gunner and fuselage gunner. As in previous bombers, the four crew compartments were open, but it had a number of design innovations as well. The most important of these were the first known example of a powered gun turret in a military aircraft, located in the nose position. There was also a deep belly for an internal bomb bay and retractable main landing gear. Its 600 hp Wright Cyclone engines provided significant power. It first flew on 16 February 1932 and was delivered for testing to the US Army on 20 March.

The B-10 began a revolution in bomber design. Its all-metal monoplane build, along with its features of closed cockpits, rotating gun turrets, retractable landing gear, internal bomb bay, and full engine cowlings, would become the standard for decades. It made all existing bombers completely obsolete. In 1932, Martin received the Collier Trophy for designing the XB-10.

The XB-10 delivered to the Army was slightly different from the original aircraft. Where the Model 123 had NACA cowling rings, the XB-10 had full engine cowlings to decrease drag. It also sported a pair of 675 hp Wright R-1820-19 engines, and an eight-foot increase in the wingspan. When the XB-10 flew during trials in June, it recorded a speed of 197 mph at 6,000 ft. This was an impressive performance for 1932.

Following the success of the XB-10, a number of changes were made, including reduction to a three-man crew, addition of canopies for all crew positions, and an upgrade to higher horsepower engines. The Army ordered 48 of these on 17 January 1933. The first 14 aircraft were designated YB-10 and delivered to Wright Field, starting in November 1933. The production model of the XB-10, the YB-10 was very similar to its prototype.

At the time of its creation, the B-10B was so advanced that General Henry H. Arnold described it as the air power wonder of its day. It was half as fast again as any biplane bomber, and faster than any contemporary fighter. However, advances in bomber design during the 1930s meant that the B-10 was rapidly eclipsed by later designs before the United States entered World War Two.

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Martin B-10 ‘57’ seen during a training flight from Maxwell Field, Alabama. (Simon Peters Collection)

The Boeing 247

Meanwhile, Boeing had been building the revolutionary Boeing Model 247. Developed in 1933, it was an all-metal, twin-engine aircraft and the first modern passenger airliner. It had a gyro panel for instrument flying, an autopilot, pneumatically operated de-icing equipment, variable-pitch propellers and retractable landing gear.

It took the Model 247 20 hours, with seven stops, to fly between New York and Los Angeles. However, because the 247 flew at 189 mph, its trip was seven and a half hours shorter than that made by any previous airliner.

Seventy-five 247s were built. Boeing Air Transport flew 60 Model 247s. United Aircraft Corp. flew 10, and the rest went to Deutsche Lufthansa and a private owner in China.

As Boeing had monopolised so much of the production run for their own airline, rival companies had been forced to look elsewhere - and turned to the Donald Douglas and the Douglas Aircraft Corporation. This act became very much a double-edged sword for Boeing, for in blocking out Transcontinental & Western Air (TWA) from the Model 247 they inadvertently allowed the creation of a rival that evolved into the best selling airliner in the world.

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The Boeing Model 247 airliner.

NC13369 of United Air Lines. The aircraft bears the markings celebrating its participation in the Mildenhall, England to Melbourne, Australia MacRobertson Air Race.

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A unidentified 247 with the nose cargo hatch open.

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A Boeing 247D ‘7635’ of the Royal Canadian Air Force. (All Simon Peters Collection)

Douglas Commercial 1, 2 and 3

TWA wanted a similar aircraft to the Model 247 and so asked four manufacturers to bid for construction of a three-engine, 12-seat aircraft to meet the specifications stipulated by the Civil Aeronautics Board: All metal wings and structural members, retractable landing gear and capable of remaining in flight, even if one engine failed.

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The sole DC-1 X223Y in the colours of TWA.

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DC-2 PH-AJU of Koninklijke Luchtvaart Maatschappij (KLM - Royal Dutch Airlines).

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United Airlines DC-3 Mainliner NC16072 is seen on high. (Simon Peters Collection)

Donald Douglas was initially reluctant to participate in the invitation from TWA. He doubted there would be a market for 100 aircraft, the number of sales necessary to cover development costs. Nevertheless, he submitted a design consisting of an all-metal, low-wing, twin-engine aircraft seating twelve passengers, a crew of two and a flight attendant. The aircraft exceeded the specifications of TWA even with two engines. It was insulated against noise, heated, and fully capable of both flying and performing a single-engined takeoff or landing.

Only one prototype aircraft was produced. It made its maiden flight on July 1, 1933, flown by Carl Cover, and was given the model name DC-1. During a half year of testing, it performed more than 200 test flights and demonstrated its superiority versus the most used airliners at that time, the Ford and Fokker Trimotors. It was flown across the United States, making the journey in a record time of 13 hours 5 minutes.

TWA accepted the model with a few modifications, such as increasing seating to fourteen passengers and adding more powerful engines, and then ordered 20 aircraft. The production model was called the Douglas DC-2.

The design impressed a number of American and European airlines so that a number of further orders followed. The US Army Air Corps also were impressed, and operated the DC-2 as the C-39. A total of 156 DC-2s were built.

The DC-2 was re-engineered into the DC-3 by a team led by chief engineer Arthur E. Raymond and first flew on December 17, 1935 (the 32nd anniversary of the Wright Brothers’ flight at Kitty Hawk). The aircraft was the result of a marathon phone call from American Airlines CEO Cyrus Smith to Donald Douglas requesting the design of an improved successor to the DC-2. The amenities of the DC-3 (including sleeping berths on early ‘DST’—Douglas Sleeper Transport—models and an in-flight kitchen) popularized air travel in the United States.

The Douglas B-18 Bolo

The twin-engined B-18 Bolo was the first Douglas medium bomber. It was a combat version of the DC-2 commercial transport, absorbed punishment well and was especially useful during the early days of World War Two

The prototype (Douglas Bomber 1 or DB-1), finished in 1935, was designed around the DC-2’s wings, but had a deeper and fatter fuselage with a bomb bay under its centre section. The single DB-1 was used later to test the firing of large cannons from an aircraft.

The Douglas DB-1/B-18 Bolo derived from the DC-2. (Simon Peters Collection)

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Douglas produced 370 of the production model B-18 Bolos, and their availability during the late 1930s allowed the Army Air Corps to train bomber crews. The B-18 Bolos made up most of the bombers deployed outside the country as the United States entered World War Two

B-18 Bolos were used for anti-submarine operations in American and Caribbean waters and as trainers and transports. Twenty served as general reconnaissance bombers with the Royal Canadian Air Force as Digby Mk1s.

In November 1938, Douglas used the stronger wings of the DC-3, a new and better streamlined fuselage, and large fin and rudder for the Bolo’s successor - the B-23 Dragon. The first of 38 B-23 Dragons built flew 27 July 1939. The 26,500-pound B-23 bomber incorporated the first tail turret installed in an Air Corps bomber and was powered by two 1,600-horsepower Wright R-2600-3 engines.

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The Douglas DB-1/B-18 Bolo aircraft design had the bomb-aimers position above the nose-gunner,

The Boeing Model 294/XBLR-1/XB-15/XC-105

This design came about with a request on 14 April 1934 from the United States Army Air Corps for a ‘Long Range Airplane suitable for Military Purposes’ - Boeing decided to see if it would be possible to build a heavy bomber with a 5,000 mile range, using the concept of the Model 247 as the starting point - and then thinking bigger- MUCH bigger!

The design was originally designated the XBLR-1 (eXperimental Bomber, Long Range). When it first flew, it was the most massive and most voluminous aircraft ever built in the United States. It set a number of load-to-altitude records, including a 31,205-pound flight to 8,200 feet on 30 July 1939.

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The enormous Model 294 comes together at Seattle. (Simon Peters Collection)

The XB-15 in flight, a view that shows just how big it really was, especially the chord of the wings. (Simon Peters Collection)

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The aircraft’s immense size allowed for passages within the wing, which the crew of ten could use to make minor repairs in flight. Due to the technology of the time, a 5,000 mile flight took thirty-three hours at its 152-mph cruising speed; the crew was made up of several shifts, and bunks allowed them to sleep when off duty.

The XB-15 was designed to be powered by liquid-cooled 1,000 hp Allison V-3420 liquid-cooled engines, but were later changed to 1,000 hp Pratt and Whitney R-1830 twin row radial engines. Before these were developed, 850 hp Twin Wasp radial air-cooled engines were used instead. These engines left the bomber significantly underpowered; its top speed of 200 mph - 145 mph with bombs on board - was far too slow for a combat aircraft, and the project was abandoned.

Despite its cancellation, the XB-15 did feature a number of significant innovations: it had an Automatic Pilot, De-icing equipment, Auxiliary power units that were independent of the main engines to power two 110 volt AC electrical generators used to power the electrical system; the engines could be serviced in flight using an access tunnel inside the wing; there was a crew compartment with rest bunks, galley and lavatory and it had double-wheel main landing gear. Many of the mechanical duties of the pilot were taken away from him, to be done instead by a flight engineer who had his own crew position in the cockpit.

The XB-15 comes in to land, showing off the double wheeled landing gear to advantage. (Simon Peters Collection)

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The ‘family resemblance’ between the XB-15 and the B-17 - which was designed later, but flew first - is very clear in this view. (Simon Peters Collection)

The machine’s statistics were impressive: span - 149 feet; length 87 feet 7 inches; height: 19 feet 5 inches and weighed in at 65,068 lbs gross. The aircraft carried three .30-cal. machine guns and three .50-cal. machine guns as armament, along with a maximum of 12,000 lbs of bombs. It was powered by four Pratt & Whitney R-1830-11 Twin Wasp radials of 1,000 hp each which gave the aircraft a maximum speed of 197 mph. Its cruising speed was 171 mph, service ceiling: 18,850 feet and had a range of 3,400 miles with 2,500 lb. bomb load.

The XB-15 with unit markings ‘89’ on the nose and BB89 on the tail. (Simon Peters Collection)

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XB-15 DETAILS

The nose of the aircraft showing the single .30 machine gun ‘turret’.

The complexity of the aluminium structure used to create the nose-glazing must have been very labour-intensive to create.

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The interior of the XB-15, showing top turret along with the .50 calibre machine gun in its mount.

The picture clearly shows just how large the aircraft was inside.

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The interior of the XB-15, showing the inside of the waist-gunner’s position.

The picture reveals the incredibly complex, bulky structure that masked the gunner’s view of a large amount of sky that could hide an attacking enemy aircraft.

The complexity of the mechanism would also be very hard for the gunner to quickly operate. (All USAF Museum)

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Technical Data - XB-15

The single prototype aircraft, serialled 35-277, was assigned to the 2nd Bombardment Group at Langley Field, Virginia. Commanded by Major Caleb V Haynes; it flew an earthquake relief mission, carrying medical supplies to Chile in February 1939, earning its crew the MacKay Trophy.

Even without the improved defensive armament that would have been needed in service, the XB-15 had a maximum takeoff weight 5,000 pounds greater than the later B-17G, but with a total engine output of 1,800 less horsepower. Because of its experimental nature and low performance when compared to later models, the XB-15 was not used as a bomber during World War Two. The Army Air Forces converted it into a cargo carrier under the changed designation of XC-105 to capitalize on its great load-carrying capacity.

Two service test models, ordered as Y1B-20 with slightly larger Pratt & Whitney R-2180 engines, were cancelled and the single XB-15 was used as a research and development aeroplane and not as the prototype of a line of production bombers.

In service for eight years, the aircraft carried more than 5,200 passengers, 440,000 pounds of cargo and 94,000 pounds of mail. It flew seventy cargo trips and sixty missions including some anti-submarine patrols.

The eventual fate of the aircraft is somewhat unclear. Some sources say it was finally scrapped at Kelly Field, Texas, shortly before the end of the war. Other records state that the XC-105 was eventually scrapped at Howard Air Force Base in Panama in 1945.

It was time for the Boeing design team to go back to the drawing board.

THE MODEL 299 AND YB-17

On 8 August 1934, the US