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Model 299 Prototype


The Boeing Model 299 Prototype of The B-17

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On August 16, 1934, Boeing began construction of a four engine heavy bomber with which it hoped to win a twin engine competition for the U.S.A.A.F.'s new standard bearer. Financed by the company itself, the Boeing Model 299 lifted into the air on July 28, 1935, and led the way for one of the world's most famous series of airplanes.
This new design appeared as a scaled down version of the, as yet unfinished, XB-15, since much of the latter's engineering principles had been applied to the smaller craft. Performance of the 299 immediately overshadowed that of its two engined competitors. The four Pratt & Whitney R-1690-E Hornets, each offering 750 hp, provided a top speed of 250 mph and a service ceiling of 25,000 feet. Among the new features incorporated into the Model 299 were control locks designed to keep the wind from buffeting the large moveable surfaces while on the ground. On October 30, 1935, during Air Corps tests, this innovation was tragically overlooked and, after taking off with the controls locked, the 299 fell to its destruction.
But Boeing's gamble paid off when on January 17, 1936, thirteen planes were ordered. As the YB-17, the first Flying Fortress (A.F. serial number 36-149), was accepted in January, 1937. Power was supplied by Wright R-1820-39 Cyclones of 930 hp, and a 'top speed of 256 mph was achieved. Service ceiling was 30,600 feet. The maximum range was 3,320 miles. Five and a quarter tons of bombs could be carried 1,377 miles. The six crewmen were armed with five .30 or .50 cal. guns.

The YB-17 had an empty weight of 24,468 pounds and a gross of 34,873 pounds. The 103 foot 9 inch wing had an area of 1,420 square feet and remained basically unchanged in the subsequent models. One YB-17 was fitted with Wright R-1850-21 supercharged engines giving 1,000 hp on take-off and a speed of 295 mph at 25,000 feet. This was the sole YB-17A and was distinguished by the removal of the fairings over the engine nacelles.

The Fortress design was subjected to many modifications in the never ending quest for improved performance. The original 68 foot 4 inch length of the YB-17 differed on some of the later models. The basic changes in the B-17B are as follows: removal of nose blister and bombardier's indentation, length reduced to 67 feet 11 inches, R-1820-51 engines, empty weight of 27,650 pounds, gross 37,810 pounds, fuel capacity 1,700 gallons, top speed of 291 mph, cruising speed 231 mph, service ceiling 36,000 feet, 8,000 pounds of bombs, armament of one .30 cal. and six .50 cal. guns. Thirty-nine B-17B's were built. The "D"'s had self-sealing fuel tanks.

The Air Corps was quick to apply the lessons the Allies had learned since World War II started in Europe in September, 1939; the B-17C incorporated armor for the crew stations and self-sealing fuel tanks. Improved R- 1820-65 engines delivered 1000 h.p. at 25,000 feet and increased the top speed at that altitude to 323 mph. The range with a 4000-lb. bomb load increased to 2400 miles.

Boeing engineers also began working up some ideas for a smaller Army bomber and a civil transport that would use many common parts. These received the model numbers 299 and 300, respectively, and were roughly half-way between the 247 and Project A's Model 294 in size and appearance. With a need for a new airliner to replace the 247 and surpass the DC-2, priority was given to the Model 300, which used four engines, not to get a bigger airplane into the air as had been the case with the B-15, but to use the additional power to give a smaller airplane greater speed.


News Release

The War Department press release for the Model 299 - July 5, 1935




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Hailed as the fastest and longest range bomber ever built, a giant four-engined all-metal airplane, today was brought to light by the Boeing Aircraft Company of Seattle after more than a year of work on the project.

Known merely as the Boeing 299, the huge craft shortly will undergo test flights before being submitted to the United States Air Corps in open competition with other types at Dayton, Ohio. These tests, it was announced, are expected definitely to stamp the plane as the most formidable aerial defense weapon ever offered this country, with far more speed and a substantially greater cruising range than any bomber ever before produced.

Military secrecy necessarily shrouds many details of the Model 299. Boeing officials said, however, that it would meet or exceed specifications of the Air Corps as set forth in a public call for bids and equipment.

Among other things, these requirements are known to call for a high speed of from 200 to 250 miles an hour at 10,000 feet altitude, for an endurance at operating speed from six to ten hours, and for a service ceiling of from 20,000 to 25,000 feet.

The Boeing "aerial battle cruiser" has a wing span of approximately 100 feet, length of 70 feet, height of 15 feet, and gross weight of about fifteen tons. It is of the all-metal mid-wing type, equipped with four Hornet engines of over 700 horsepower each and with the new Hamilton Standard three-bladed constant speed propellers. Clean streamlining is a feature, with retractable landing gear and tail wheel as further aids to speed. Officials declare the plane to be the first military type which will be able to complete a mission in the event one engine ceases to function.

A number of new armament installations, developed by Boeing engineers, are carried in addition to the latest types of flight and engine instruments, including an automatic pilot, two-way radio telephone equipment and a radio "homing" device. Air brakes are used for the first time in any American aircraft, with these as well as the craft's wheels and tires having been especially developed.

Construction is of typical Boeing semi-monocoque type, the structure consisting of longerons, skin stiffeners, bulkheads and smooth outside metal skin.

The Model 299 makes its bow as the latest in a long line of Boeing achievements dating from 1916. Among these in recent years have been the company's high-speed twin-engine bomber of 1931 and commercial transport plane of 1933, both of which established the current trend in aircraft design and construction.

An entire fleet of the transports, known as the Model 247-type, today is operating on the routes of United Air Lines, Pennsylvania Airlines, National Park Airways, Western Air Express and Wyoming Air Service. In addition, single-seater Boeing fighters are regular equipment at Army Air Corps bases, at Navy shore stations and on Uncle Sam's aircraft carriers.


WAR DEPARTMENT - July 5, 1935.



General information and specifications


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The 299 was the prototype of the B-17 Flying Fortress, probably the most significant air weapon of its time. In 1921, Army bombers in a special demonstration for the Navy, sank the captured German Battleship Frankfurt by air bombing. At that time there was a great deal of discussion about the role of the airplane as a weapon. It was recognized that an airplane which could carry a large bomb load a considerable distance from its base, and be able to defend itself from enemy fighters, would be desirable. However, neither aircraft design nor materials had advanced enough to make such a thing possible.

In 1930, C.L. Egtvedt, of Boeing, who had been present when the Frankfurt was sunk delivered a Boeing fighter to the Navy. A Navy officer remarked to him that, despite all the progress aviation had made, there still was no aerial counter part for the battleship --- an airplane that could operate far from its base, deliver a heavy blow to the enemy, and protect itself from attack.

In 1934, when the Army first announced its competition for "multiengine" bombers, Boeing engineers went to work to give shape to the design that Egtvedt had formed as a result of these discussions. The project was financed entirely with company funds.

Span: 103 feet 9 3/8 inches
Length: 68 feet 9 inches
Height: 14 feet 11 15/16 inches
Weight: 32,432 pounds, gross
Speed - top: 236 mph
Speed - cruising: 140 mph
Range: 3010 miles, maximum
Service ceiling: 24,620 feet
Power: Four Pratt & Whitney R-1690 radials of 750 hp. each
Armament: Five .30, or five .50 caliber machine guns and eight 600 pound bombs

Approximately a year later, on a flight from Seattle to Wright Field in Dayton, Ohio, for the Army tests, the 299 averaged 252 mph, setting a nonstop record for the distance.

Although the airplane later was destroyed, when an Army pilot took off with the controls locked, the Army was sufficiently impressed in the potential of this new bomber to place a service order for thirteen. It was then that the bomber received its designation, B-17.



Development History Of The Boeing Model 299


William Boeing had gone into business building seaplanes in Seattle, Washington, in 1916. In the decades after World War I, the Boeing Company became successful selling aircraft to the US military and commercial airlines. In those decades, the US military returned to the weak state that had been its tradition in peacetime years, and the arrival of the Great Depression did nothing to improve its health. The military leadership tended to be conservative, and US Army Air Corps (USAAC) visionaries who believed in air power received uncertain support. However, commercial aircraft development was leading to great advances in aircraft design that would benefit the military.

In 1930, the Boeing Company introduced a single-engine, all-metal, low-wing monoplane named the "Model 200 Monomail" that featured the new innovation of retractable landing gear. The Monomail led to the twin-engine "Model 215 / YB-9" bomber, which lost an Air Corps competition against the Martin B-10 and did not enter production. The YB-9 in turn led to the sleek twin-engine "Model 247" airliner. All these aircraft were powered by air-cooled Pratt & Whitney (P&W) radial engines and gave Boeing experience in building advanced, strong aircraft from aluminum.

The Model 247 in particular defined ideas that Boeing would exploit in the future. It is generally regarded as the first modern airliner, an all-metal, low-wing monoplane with retractable landing gear; twin P&W Wasp S1D1 engines with 410 kW (550 HP) each and driving three-bladed fixed-pitch propellers; a crew of three, including a pilot, copilot, and stewardess; and seating for ten passengers. It also featured pneumatic de-icer boots in the wing leading edge, which were inflated to knock ice off the wing.

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Initial flight of the Model 247 was on 8 February 1933. A total of 59 were built for United Air Lines, plus two for the German LuftHansa airline. A single "Model 247A" was built as well, featuring P&W Twin Wasp Junior engines with 465 kW (625 HP) each, and provided long service to the United Aircraft Corporation as an executive transport. Boeing also built 13 "Model 247Ds", which featured a number of refinements, including P&W Wasp 51H1-G radials with 375 kW (500 HP), installed in modified cowlings and driving three-bladed variable-pitch propellers; a significant increase in fuel capacity; fabric-skinned rudder and elevators; and replacement of antique-looking forward-sloped cockpit windscreen of the Model 247 / 247A with a modern backward-sloped windscreen.

The Model 247D offered improved speed, about half again as much range, and better looks than the Model 247 / 247A, and most of the older machines were brought up to 247D standard. One 247D was fitted with machine guns as an armed VIP transport for a Chinese warlord and redesignated "Model 247Y".

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                22.56 meters        74 feet
   wing area               77.68 sq_meters     836.13 sq_feet
   length                  15.72 meters        51 feet 7 inches
   height                  3.6 meters          12 feet 2 inches

   empty weight            4,150 kilograms     4,150 pounds
   MTO weight              6,190 kilograms     9,145 pounds

   cruise speed            305 KPH             190 MPH / 165 KT
   service ceiling         7,740 meters        22,400 feet
   range                   1,200 kilometers    745 MI / 650 NMI
   _____________________   _________________   _______________________

27 247Ds were impressed into US military service during World War II as "C-73s", and a number were also flown by the Royal Canadian Air Force during the conflict. At least one Model 247D survives today at the Smithsonian National Air & Space Museum in Washington DC.

In the meantime, Boeing was also working on more warlike flying machines. In February 1934, the USAAC issued a request for an experimental aircraft with the designation "Experimental Bomber Long-Range 1 (XBLR-1)". The requirement specified an aircraft capable of carrying a 900 kilogram (1 US ton) bomb load over 8,050 kilometers (5,000 miles). In keeping with America's basically isolationist policies of the time, the aircraft was intended as an experimental demonstrator for a long-range bomber that could protect the US from foreign fleets, and help guard Hawaii and the Philippines. Since money was tight, only one aircraft was funded.

Boeing President Claire Egtvedt was eager to push the state of the art in large-aircraft technology, and Boeing responded with a design called the "Model 294". The Air Corps accepted the Boeing proposal over a Martin offering in June 1934, giving the Boeing aircraft the designation "XB-15". It was the biggest aircraft built in the US to that time, much on the scale of the big propaganda planes built for the Soviet state by the Antonov design bureau, but somewhat more elegant. The XB-15 was a sleek machine, made mostly of aluminum; was powered by four 745 kW (1,000 HP) Pratt & Whitney Twin Wasp engines; and had very large fuel capacity.

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The XB-15 was to have a crew of ten. It was fitted with streamlined gun blisters in the style of the time and was to be armed with six machine guns, though pictures of the machine do not show it to have actually been fitted with defensive armament. The big bomber had sleeping quarters and a galley, and a thick, broad wing that contained tunnels into which a flight engineer could crawl to tinker with the engines.

 The sole XB-15 finally performed its first flight on 15 October 1937. Since it had been designed for a new 1,500 kW (2,000 HP) radial engine under development by Allison that would never really materialize, the XB-15 proved to be very underpowered, with a top speed of only 315 KPH (195 MPH). In the war years, it was fitted with cargo doors and used as a freight hauler, under the designation "XC-105".

   BOEING XB-15:
   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                45.42 meters        149 feet
   wing area               258.26 sq_meters    2,780 sq_feet
   length                  26.80 meters        87 feet 11 inches
   height                  5.49 meters         18 feet

   empty weight            17,105 kilograms    37,710 pounds
   MTO weight              41,730 kilograms    92,000 pounds

   max speed at altitude   315 KPH             195 MPH / 170 KT
   service ceiling         5,760 meters        18,900 feet
   range                   8,255 kilometers    5,130 MI / 4,460 NMI
   _____________________   _________________   _______________________

Despite the fact that only one XB-15 was built, the design proved influential. Its wing was reused in the Boeing Model 314 Clipper flying boat. Much more significantly, it led to a new bomber that would be one of the most famous in aviation history.


The Model 299 "Flying Fortress"

Even while the XB-15 was moving off the drawing board, both the Air Corps and Boeing were looking for a more practical bomber to replace the Martin B-10s then in service. In August 1934, the Air Corps issued a request for a multi-engined bomber aircraft that could carry a "useful bombload" at a cruising speed of 354 KPH (220 MPH) at an altitude of 3.05 kilometers (10,000 feet) for ten hours. Top speed was to be 400 KPH (250 MPH).

The potential production quantity was a hundred aircraft, and Boeing officials were eager for the business. The company quickly responded with a design with the designation "Model 299". The Model 299 had four engines instead of the two implied in the request, but the Air Corps assured Boeing that wasn't a problem. The USAAC approved the construction of a prototype of the Model 299 on 26 September 1934. Boeing allocated initial funding of $275,000 USD, but this sum would double before the prototype flew. The design team was led by E. Gifford Emery, along with Edward C. Wells. The design they came up with looked something between a scaled-down version of the XB-15, then in design, and a scaled-up, four-engine version of the Model 247.

The Model 299 was a mid-wing monoplane of aluminum construction, powered by Pratt & Whitney R-1690 Hornet single-row nine-cylinder radial engines. The engines could each produce 560 kW (750 HP) at 2,135 meters (7,000 feet) and drove three-bladed Hamilton Standard propellers with a diameter of 3.5 meters (11 feet 6 inches). The aircraft had a wingspan of 31.6 meters (103 feet 9 inches) and a length of 20.95 meters (68 feet 9 inches). The nose was glassed-in to give the bombardier a good view. There was a nock under the nose where the bombsight was placed, as well as a bubble on top of the nose glass where a machine gun could be mounted.

The pilot and copilot sat side-by-side, each within reach of a clever new central throttle arrangement that allowed them to control all four engines with one hand. There was a bomb bay behind the cockpit, with twin vertical bomb racks accommodating up to 2,177 kilograms (4,800 pounds) of bombs. There was a flight engineer / radioman position behind the bombbay, connected to the cockpit by a narrow catwalk through the bombbay. There was a machine-gun blister above the radioman's position, with a tub on the belly a little further to the rear for another machine gun, and then twin blisters on either side of the fuselage, to be each fitted with a single machine gun. Either 7.62 or 12.7 millimeter (0.30 or 0.50 caliber) Browning machine guns could be mounted, giving the Model 299 defensive armament of five machine guns.

The aircraft was a "taildragger" with a semi-retractable tailwheel. The main gear retracted to a half-recessed position in the inner engine nacelles.

The Model 299 was publicly rolled out at Boeing field in Seattle on 17 July 1935. The new aircraft was big and impressive, with a gleaming arc-deco THRILLING WONDER STORIES pulp-fiction look to it. Reporter Richard Williams of the SEATTLE DAILY TIMES was inspired to call it a "flying fortress". Boeing public relations men liked the name so much that they adopted it and registered it as the aircraft's official name. First flight was on 28 July, and on 20 August 1935 the aircraft flew from Seattle to Wright Field near Dayton for Air Corps evaluation. The flight was made in 9 hours 3 minutes at an average speed of 375 KPH (235 MPH). This was much faster than its rivals in the Air Corps competition, the Douglas DB-1 and the Martin 146. However, the Model 299 cost almost $200,000 USD, more than twice as much as either of its two competitors.

The evaluation program went well up until very near the end. On 30 October 1935, the Model 299 crashed on takeoff. The pilot, Air Corps Major Ployer Hill, and Boeing test pilot Leslie Tower were killed, though there were two survivors. The accident was not due to any inherent fault in the design of the aircraft. The Model 299 had a set of control surface locks that could be set from the cockpit to prevent wind damage to the control surfaces while the aircraft was parked. Major Hill had failed to release this control during take-off and Tower had failed to notice the error. Unfortunately, the ruined Model 299 could not finish the Air Corps evaluation, and the Army selected the Douglas DB-1 instead. The DB-1 was a derivative of the Douglas DC-2 commercial transport, and was be designated the B-18 in service. 350 were built, though the design was effectively obsolete within a few years.

Despite the Model 299's high cost and the accident, the Air Corps thought the design had obvious merit, and so on 17 January 1936 the Army ordered 13 flying Model 299s and a static test airframe from Boeing for the sum of $3,823,807 USD, funds that the overstretched company badly needed to stay afloat. The 13 aircraft were to be designated "YB-17".

Greg Goebel /Public Domain



History Of The Boeing Model 299


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The B-17 Flying Fortress was perhaps the most well-known American heavy bomber of the Second World War. It achieved a fame far beyond that of its more-numerous stablemate, the Consolidated B-24 Liberator. A total of 12,677 Fortresses was built before production came to an end. In August of 1944, the B-17 equipped no less than 33 overseas combat groups. The B-17 was to achieve lasting fame in the daylight precision-bombing campaign over Germany in 1943, 1944, and 1945. It achieved a reputation as being capable of absorbing a tremendous amount of battle damage and still continuing to fly. In later variants, it had an exceptionally-heavy defensive armament. It had an excellent high-altitude performance. It was able to win the affection of the crews who flew in it, since it was often able to bring them home safely when other aircraft would have fallen. However, the B-17 generally had a performance inferior to that of its B-24 stablemate and it could not carry nearly as large a bomb load. In typical missions over Europe, B-17s usually carried a bombload only as large as that which a twin-engined Mosquito could carry.

B-17s dropped 640,036 tons of bombs on European targets during the war, as compared to 452,508 tons dropped by the Liberator and 463,544 tons dropped by all other US aircraft. Boeing records claim that the Fortress destroyed 23 enemy aircraft per thousand sorties as compared to 22 for Liberators, eleven by US fighters, and 3 by all US light and medium bombers. However, the "kill" claims by both Fortress and Liberator gunner crews are probably greatly exaggerated, largely because the same enemy aircraft was being fired at by many different people. Approximately 4750 B-17s were lost on combat missions, which is about one out of three of all B-17s built.

The origin of the Boeing Fortress can be traced to a February 1934 Army Air Corps requirement for a bomber with a range of 5000 miles at 200 mph while carrying a bombload of 2000 pounds. This became known as "Project A", and was more of a feasibility study than it was a serious proposal for a production bomber. However, there was always a possibility that production examples would be ordered if the design proved successful. Both Martin and Boeing submitted preliminary designs in response to the "Project A" requirement. The Martin project was cancelled before anything could be built, but the Boeing design (assigned the company designation of Model 294) was awarded a contract for a single example under the designation XBLR-1. The XBLR-1 was later redesignated XB-15.

In May of 1934, the Army announced another bomber competition. This time, it was for a multi-engined bomber capable of carrying a ton of bombs at more than 200 mph over a distance of 2000 miles. As opposed to the "Project A" requirement, this Army requirement envisaged from the start that the winning design would have a production run of as many as 220 planes. Several manufacturers (including Boeing) were invited to submit bids, with the entries being flown at Wright Field in a final competition to select the winner. Preliminary work by Boeing on the design began on June 18, 1934. Boeing engineers came up with what was basically a scaled-down version of the Model 294. Like the Model 294, it was to be powered by four engines. Four-engined bombers were a novelty at the time, most contemporary bomber designs having only two engines. Construction began on August 16, 1934 under the company designation Model 299.

The Model 299 was based heavily on the company's experience with the all-metal Model 247 commercial airliner. It was basically a marriage between the aerodynamic and structural features used by the Model 247 and the basic four-engined format used by the Model 294 bomber. The aircraft was to be powered by four 750 hp Pratt & Whitney R-1690-E Hornet nine-cylinder air-cooled radials, each driving a three-bladed propeller. The large, thick-section wing was to be mounted low on the cylindrical-section fuselage. The main landing gear was to retract forward into the inner engine nacelles, with the lower edge of the wheel protruding into the airstream.

The Model 299 aircraft was painted with the civilian registration X-13372, since it was a company-owned aircraft. It carried a crew of 8, a pilot, copilot, bombardier, navigator/radio operator, and four gunners. There were four blister-type flexible machine gun stations, each of which could accommodate a 0.3-inch or 0.5-inch machine gun. One was in a dorsal position in the fuselage just above the wing trailing edge, a second was in a ventral fuselage position just behind the wing trailing edge, and a blister was mounted on each side of the rear fuselage in a waist position. There was an additional station for a machine gun in the nose. All of the guns were manually swung. Up to eight 600-pound bombs could be carried internally. Loaded weight was 43,000 pounds.

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In order to prevent damage by wind to the tail surfaces while the plane was on the ground, the elevators were locked in position. Before takeoff, the pilot would unlock the tail surfaces by releasing a spring lock in the cockpit.

First flight of the Model 299 took place on July 28, 1935 at Seattle with Boeing test pilot Leslie R. Tower at the controls. According to legend, a reporter having seen the 299 for the first time remarked, "Why, it's a flying fortress!". The name stuck.

After a short period of factory testing, the Model 299 was flown by Boeing test pilot Leslie Tower and three other crewmen out to Wright Field on August 20 for Air Corps evaluation. During this flight, it flew the 2100 miles nonstop at an average speed of 232 mph at an average altitude of 12,000 feet, breaking all records for the distance.

The prototype was submitted to the Army as Model X-299, but the Army objected to the designation as being too similar to its experimental military project numbers, so it was officially changed to B-299.

The competitors of the B-299 were the Martin 146 and the Douglas DB-1, which were both twin-engined designs. The Model 299 was clearly superior to both the Martin and Douglas designs, surpassing all the Army requirements for speed, climb, range and bombload. The Army decided to purchase 65 service test examples under the designation YB-17.

On October 30, 1935, the Model 299 crashed during takeoff at Wright Field and burned. Three of the crewmen managed to crawl out of the wreckage with only minor injuries, but pilot Ployer P. Hill (chief of Wright Field's Flight Testing Section) and Boeing test pilot Leslie Tower (who was riding as an observer) both died later of their injuries after being dragged from the burning aircraft. An investigation later showed that the crash was caused by the crew forgetting to unlock the tail surfaces before takeoff, the aircraft losing control immediately after leaving the ground.

Although the aircraft itself was blameless in the crash, the Air Corps got cold feet about the wisdom of acquiring so many YB-17s with the limited funds that were then available, and cut their order back to only 13 examples on January 17, 1936. The designation was changed to Y1B-17 on November 20, 1936, the "Y1" designation indicating that they were purchased from "F-1" funds rather than from regular appropriations.

As insurance, the Army decided at the same time to order 133 examples of the competing twin-engined Douglas DB-1 under the designation B-18. The B-18 was substantially slower than the Flying Fortress, had a shorter range, carried fewer bombs, and had a poorer defensive armament. However, it was only half as expensive as the B-17 and since the B-18 was based on a proven design (the DC-2 commercial airliner), the amount of risk was deemed to be smaller.

The wreckage of the B-299 was salvaged and a section of the fuselage containing the side blisters was used at Wright Field for the evaluation of new types of gun mounts.

The Model 299 never carried a US Army serial number.

Specification of Model 299:

Four Pratt & Whitney R-1690E S1EG Hornet radials rated at 750 hp at 2250 rpm at 7000 feet. Performance: Maximum speed 236 mph at 10,000 feet. Cruising speed 204 mph. Service ceiling 24,620 feet. Range 2040 miles with 2573 pounds of bombs. Maximum range 3101 miles. Dimensions: Wingspan 103 feet 9 3/8 inches, length 68 feet 9 inches, height 14 feet 11 15/16 inches, wing area 1420 square feet. Weights: 21,657 pounds empty, 32,432 pounds normal loaded, 38,053 pounds maximum. Armament: Armed with five 0.30-inch machine guns, with one gun in each of nose, dorsal, ventral, and two waist positions. A maximum of eight 600 pound bombs could be carried in an internal bomb bay.

By Joe Baugher


  1. Flying Fortress, Edward Jablonski, Doubleday, 1965.
  2. Famous Bombers of the Second World War, Volume One, William Green, Doubleday, 1959.
  3. Boeing Aircraft Since 1916, Peter M. Bowers, Naval Institute Press, 1989.
  4. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.
  5. McDonnell Douglas Aircraft Since 1920: Volume 1, Rene Francillon, Naval Institute Press, 1988.
  6. American Combat Planes, Ray Wagner, Third Edition, Doubleday, 1982.
  7. Jane's Fighting Aircraft of World War II, Military Press, 1989.



Photo Gallery


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Nose turret with gun

Bomb sight window (ext.)

Bombers and front gunners compartment

Streamline gun turret (ext. - waist gunner)

Streamline gun turret (int.)

B-299 three view


The Boeing Model 299 Crash

"The Cause Of The Crash"

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(15 November 1935)

The findings of the Board of Officers convened at Wright Field, Dayton, Ohio, to investigate the cause of the crash on October 30, 1935, of the Boeing Aircraft Company Bombardment plane, model 299, were to the effect that the accident was not due to structural failure, or to the malfunctioning or failure of any of the four engines, the airplane control surfaces or the automatic pilot, but to the locked condition of the rudder and elevator surface controls (primarily the latter), which made it impossible for the pilot to control the airplane.

These findings were based on the locked condition of the controls after the crash; the testimony of Lieut. Donald Putt, co-pilot; of Mr. Leslie R. Tower, Boeing Aircraft Company test pilot, as to the behavior of the airplane in the air, and the testimony of eyewitnesses as to the behavior of the airplane on take off and flight.

From the evidence submitted the Board reached the conclusion that the elevator was locked in the first hole of the quadrant on the "up elevator" side when the airplane took off, for had the elevator been in either of the "down elevator" holes on the quadrant or the extreme "up elevator" hole, it would have been impossible for the airplane to be taken off in the former case, and in the latter case the pilot could not have gotten into the seat without first releasing the controls. With the elevator in this position they are inclined at an angle of 12.5 degrees.

During the take-off run the airplane could not assume an angle of attack greater than the landing angle of the airplane (7.5 degrees) plus the angle of incidence of the monoplane wing to the fuselage (3 degrees) or a total angle of 10.5 degrees. This would not be particularly noticeable to the pilot during the ground run.

However, as soon as the airplane left the ground, which several witnesses testified was in a tail low attitude, the elevators, with increasing power, varying as the square of the air speed (approximately 74 miles per hour at take-off), tended constantly to increase the angle of attack, until the stall was reached. The trim tab on the elevator also tended to aggravate this extreme tail heavy position, since with locked elevators, and the pilot pushing forward on the control column, the trim tabs were up, and themselves acted as small elevators on the fixed elevator proper.

Due to the size of the airplane and the inherent design of the control system, it is improbable that a pilot, taking off under these conditions, would discover that the controls were locked until too late to prevent a crash.

The locked condition of the controls was due either to the possibility that no effort was made to unlock the controls prior to take-off, and as a result the controls were fully locked; the possibility that the pilot only partially depressed the locking handle and as a result the locking pin was only partially withdrawn from its hole in the face of the locking quadrant; or the possibility that the locking handle was fully depressed prior to take-off and, due to the malfunctioning of the system, did not fully disengage the locking pin. There is no evidence to show that the system had ever malfunctioned, but due to the inherent design it must be considered a possibility.

Model 299
Number Built/Converted
Crashed 30 October 1935



The Boeing Y1B-17




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