The Boeing Model 247 is an early American airliner, and one of the first such aircraft to incorporate advances such as all-metal (anodized aluminum) semimonocoque construction, a fully cantilevered wing, and retractable landing gear. Other advanced features included control surface trim tabs, an autopilot and de-icing boots for the wings and tailplane. The 247 first flew on February 8, 1933, and entered service later that year.

Design and development

thumb|The Boeing 247 production line

thumb|Early versions had the windshield raked forward, to avoid reflecting light off the cockpit instruments. It was later changed to a backward slope because it reflected landing lights on the ground.

Boeing introduced a host of aerodynamic and technical features into a new commercial airliner building on work with the earlier Monomail (Models 200, 221, 221A) mailplanes and B-9 bomber designs. The Boeing 247 was faster than the best U.S. fighter of its day, the open-cockpit biplane Boeing P-12. The low landing speed of avoided the need for flaps, and pilots learned that at speeds as low as , the 247 could be taxied "tail high" for ease of ground handling.

The 247 could fly on one engine. With controllable-pitch propellers, the 247 could maintain at maximum gross weight on one engine. Aside from its size, much lower wing loading, and the wing spar obstructing the cabin, many of its features became the norm for airliners, including the Douglas DC-1, before World War II.

One concern of the pilots was that in their view, few airfields could safely take an eight-ton aircraft. Pratt & Whitney's chief engineer, George Mead, knew the problem would be resolved eventually,

The slope of the early 247's windshield was reversed from normal. This was a design solution, also used on other contemporary aircraft, to the problem of control panel instrument lights reflecting off the windshield, but the reversed windshield reflected ground lights instead, especially during landings, and it also increased drag. By the introduction of the 247D, the windshield was sloped normally, and the glare was resolved with a glarescreen extension over the panel.

Boeing incorporated design elements to enhance passenger comfort, such as the thermostat controlled, air conditioned, and noise-proofed cabin. The crew included a pilot and copilot, as well as a flight attendant (then known as a "steward"), who could tend to passenger needs. The main landing gear did not fully retract; the wheels extended slightly below the nacelles, typical of designs of the time, as a means of reducing structural damage in a wheels-up landing. The tailwheel was not retractable. While the Model 247 and 247A had speed-ring engine cowlings and fixed-pitch propellers, the Model 247D incorporated NACA cowlings and variable-pitch propellers.

Operational history

thumb|[[United Airlines crew members and employees stand in front of a Boeing 247.]]

thumb|A Boeing 247D in its MacRobertson Air Race markings, . Note the dramatic pose in this fanciful 1935 illustrated card art.

thumb|A [[stewardess points to the markings on a Boeing 247 that commemorate finishing third in the MacRobertson Air Race.]]

As the 247 emerged from its test and development phase, the company further showcased its capabilities by entering a long-distance air race in 1934, the MacRobertson Air Race from England to Australia. During the 1930s, aircraft designs were often proven in air races and other aerial contests. A modified 247D was entered, flown by Colonel Roscoe Turner and Clyde Pangborn.

Being the winner of the 1934 U.S. Collier Trophy for excellence in aviation design, the first 247 production orders were earmarked for William Boeing's airline, Boeing Air Transport. The 247 was capable of crossing the United States from east to west eight hours faster than its predecessors, such as the Ford Trimotor and Curtiss Condor. Entering service on May 22, 1933, a Boeing Air Transport 247 set a cross-country record of hours on its San Francisco to New York City inaugural flight.

Boeing sold the first 60 247s, an unprecedented $3.5 million order, to its affiliated airline, Boeing Air Transport (part of the United Aircraft and Transport Corporation, UATC), at a unit price of $65,000. The Lockheed Model 10 Electra had a similar configuration, and while it was a more compact design, the Electra managed to carry the same number of passengers at a slightly better overall performance, and at a lower cost-per-mile. and one went to a private owner in China. While the industry primarily standardized on Boeing's competitors, many of United's aircraft were later purchased by Western Air Express at "bargain-basement prices".

thumb|left|No. 121 [[RCAF Squadron Boeing 247D, c. 1939]]

The 247 remained in airline service until World War II, when several were converted into C-73 transports and trainers. The Royal Canadian Air Force's 121 Squadron operated seven 247Ds as medium transports during the early part of the war. One of these aircraft was donated to the Royal Air Force (RAF) for radar testing, where it was renumbered DZ203. DZ203 was passed among several units in the RAF before being used to make the world's first fully automatic blind landing on 16 January 1945.

Warlord "Young Marshal" Zhang Xueliang ordered two Boeing 247Ds for his air force. He used one of them, named Bai-Ying (White Eagle), during the Xi'an incident in 1936, during which he flew into the opposing Nationalist army's camp at Sian (now rendered as Xi'an) under a secret truce, and had their leader, Generalissimo Chiang Kai-shek, arrested, ending the civil war between the Communist and Nationalist armies, so they could fight together against the Japanese invaders.

A number of specially modified variants included a Boeing 247Y appropriated from United for Air Corps use as a test aircraft fitted with two machine guns in the nose. The same installation later was fitted to a 247Y owned by Generalissimo Chiang Kai-shek. This aircraft also featured a Colt machine gun in a flexible mount. A 247D purchased by the British RAF became a testbed for instrument approach equipment and received a nonstandard nose, new powerplants, and fixed landing gear. Some 247s were still flying in the late 1960s as cargo transports and business aircraft.

Variants

thumb|Boeing 247 prototype at [[Boeing Field, ]]

thumb|right|A 247 in the 1950s

;Model 247

:Twin-engined civil transport airliner, initial production version

;247A

:Powered by new P&W Wasp, on special order for Deutsche Luft Hansa in 1934

;247E

:This designation was given to the first Boeing 247 aircraft, it was used to test a number improvements that were later incorporated into the Boeing 247D.

;247D

:Original one-off was a race aircraft designed for the MacRobertson Air Race; use of Hamilton Standard variable-pitch propellers allowed for a gain; the 247D configuration incorporated in production series bearing the same name.

;247Y

:Armed version, one exported to China, second used for trials

;C-73

:Designation for Boeing 247D airliners impressed into military service in USAAF, 27 in total

;Model 280

:Proposed development of Boeing 247 with 14 seats and P&W Hornet engines

Operators

Civil operators

thumb|right|A C-73 during World War II

;

  • Viação Aérea Bahiana operated one aircraft.

;

  • Canadian Pacific Airlines
  • Quebec Airways

;

  • Private owner operated one aircraft.

;

  • Avianca as SCADTA operated 10 aircraft.

;

  • Lufthansa operated one aircraft and used a second for spares/testing. All seven on board were killed.

;November 9, 1933:A Pacific Air Transport 247, NC13345 (c/n 1727), crashed on takeoff after the pilot became disoriented in fog and low visibility; four of ten on board died.

;November 24, 1933:A National Air Transport 247, NC13324 (c/n 1705), was being ferried from Chicago to Kansas City when it crashed near Wedron, Illinois, killing all three crew.

;February 23, 1934: A United Air Lines 247, NC13357 (c/n 1739), crashed in Parley's Canyon in fog near Salt Lake City, killing all eight on board.

;December 20, 1934: United Air Lines Flight 6, a 247 (NC13328, c/n 1709), struck a tree and crashed near Western Springs, Illinois, due to carburetor icing; all four on board survived. The aircraft involved was repaired and converted to 247D standard in July 1935 and returned to service; the aircraft was pressed into USAAF service in 1942 and redesignated as C-73 with tail number 42-57210. The aircraft was damaged in a wind storm at Duncan Field, Texas, on August 30, 1942, and was written off.

;March 24, 1935: The sole 247 operated by Lufthansa (D-AGAR, c/n 1945) was damaged beyond economical repair in a collision with an Air France aircraft on the ground at Nuremberg and then scrapped

;October 7, 1935: United Airlines Flight 4, a 247D (c/n 1698), went down about west of Cheyenne, Wyoming due to pilot error. Three crew and nine passengers killed, there were no survivors.

;October 30, 1935:United Air Lines Boeing 247D, NC13323 (c/n 1704), crashed during an instrument checkflight near Cheyenne, killing the four crew members aboard.

;December 15, 1936:Seven died when Western Air Express Flight 6, a 247D, en route from Burbank, California, to Salt Lake City via Las Vegas, crashed just below Hardy Ridge on Lone Peak in Utah. The major parts of the aircraft were hurled over the ridge and fell over into a basin below.

;August 13, 1937 :A 247 being operated by the Luftwaffe's proving ground at Rechlin (formerly D-AKIN of Lufthansa, c/n 1944) crashed at Hannover, Germany, during a test flight,

;February 27, 1940 :A SCADTA 247D, C-140, struck El Mortino mountain near Tona, Santander, Colombia, killing all 11 on board.

;July 30, 1942:A Northwest Airlines C-73, 42-68639 (c/n 1717, former NC13335), crashed and burned on takeoff from Wold Chamberlain Field, near Minneapolis, Minnesota, killing all 10 on board.

Surviving aircraft

thumb|right|Boeing 247D at the [[National Air and Space Museum showing United Air Lines markings in this view.

;c/n 1722, N18E

:Exhibited in the National Museum of Science and Industry, Wroughton, UK

thumb|The Boeing 247 at the Museum of Flight in the city of Tukwila, just south of Seattle

;c/n 1729, N13347

:Static display, flown after restoration at the Museum of Flight Restoration Center, Paine Field, Snohomish County, Washington, USA, to the Museum of Flight main facility on 26 April 2016 where it was subsequently installed in that museum's Air Park.

;c/n 1953, NC13369 / NR257Y

:Exhibited in the Hall of Air Transportation at the National Air and Space Museum, Washington, D.C., USA, with United Air Lines colors and registration as NC13369 on its right fuselage and wing and as NR257Y with MacRobertson Air Race markings on its left side.

|prime units?=imp

|crew=Three

|capacity=10 passengers + baggage and of mail

|length ft=51|length in=7

|span ft=74|span in=1

|height ft=12|height in=1.75

|wing area sqft=836.13

|airfoil=Boeing 106B

|empty weight lb=8921|max takeoff weight lb=13650

|fuel capacity=

<!-- Powerplant -->

|eng1 number=2|eng1 name= Pratt & Whitney R-1340 S1H1-G Wasp|eng1 type=9-cylinder air-cooled radial piston engines|eng1 hp=500|eng1 note=at 2,200 rpm at

|prop blade number=2 |prop name=variable-pitch propellers (3-bladed propellers shown in line drawing)

|prop dia ft=|prop dia in=<!-- propeller aircraft -->

<!--

Performance

-->

|max speed mph=200

|cruise speed mph=189

|cruise speed note=at

|range miles=745

|ceiling ft=25400

|ceiling note=<br>

  • Absolute ceiling:

|climb rate ftmin=1150

|more performance=

Notable appearances in media

<!-- All content about the aircraft in fictional and gaming use has been moved to Aircraft in fiction, please see WP:AIRPOP -->

See also

Notes

Bibliography

  • Bowers, Peter M. Boeing aircraft since 1916. London: Putnam Aeronautical Books, 1989. .
  • Bryan, C.D.B. The National Air and Space Museum. New York: Harry N. Abrams, Inc., 1979. .
  • Fernandez, Ronald. Excess Profits: The Rise of United Technologies. Boston, Massachusetts: Addison-Wesley, 1983. .
  • Gould, William. Boeing (Business in Action). Bath, Avon, UK: Cherrytree Books, 1995. .
  • Mondey, David, The Concise Guide to American Aircraft of World War II. London: Chancellor, 1996. .
  • Pearcy, Arthur. Douglas Propliners: DC-1–DC-7. Shrewsbury, UK: Airlife Publishing, 1995. .
  • Pedigree of Champions: Boeing Since 1916, Third Edition. Seattle, Washington: The Boeing Company, 1969. No ISBN. WorldCat.
  • Seely, Victor. "Boeing's Grand Old Lady." Air Classics, Vol. 4, No. 6, August 1968.
  • Serling, Robert J. Legend & Legacy: The Story of Boeing and its People. New York: St. Martin's Press, 1992. .
  • Taylor, H. A. "Boeing's Trend-Setting 247". Air Enthusiast, No. 9, February–May 1979, pp.&nbsp;43–54. .
  • Taylor, H. A. "Talkback". Air Enthusiast, No. 10, July–September 1979, p.&nbsp;80.
  • van der Linden, F. Robert. The Boeing 247: The First Modern Airliner. Seattle, Washington: University of Washington Press, 1991. . Retrieved: July 26, 2009.
  • Yenne, Bill. Boeing: Planemaker to the World. New York:, Crescent Books, 1989. .

Further reading

  • Holden H.M., The Boeing 247, TAB Books, Blu Ridge Summit (PA.), 1991
  • Scott W.B., The Boeing 247, Flying Classic Serie no. 1, TAB Aero Books, Blu Ridge Summit (PA.)
  • Film of United Airlines Boeing 247 NC13364 taking off from Vancouver Airport 1934
  • Gallery: Boeing 247 Images, including two of the interior and one of the retracted main gear
  • Boeing Model 247: First modern airliner
  • "From Mock Up To Latest Airliner," Popular Mechanics, October 1932, early article on future Model 247
  • "Keeping Them In The Air" Popular Mechanics, July 1935 photos and colored artwork of 247 pp.9–16
  • Maintenance & service manual for the Boeing Model 247 transport airplane