Boeing 247

Boeing 247
Boeing 247
Type:	Airliner
Design country:	United States
Manufacturer:	Boeing
First flight:	February 8, 1933
Commissioning:	May 22, 1933
Production time:	1932-1935
Number of pieces:	75

The Boeing 247 was a mid -size American airliner built in the 1930s for the aircraft manufacturer Boeing . The twin-engine aircraft , built from mid-1932, is considered to be one of the first modern aircraft of its kind and, in addition to three crew members, offered space for ten passengers .

history

The first flight of the machine took place on February 8th and the approval on March 16, 1933, whereby there was no actual prototype. Only two months later the first machine was delivered to United Air Lines . On October 10, 1933, a machine ( aircraft registration number NC13304) on United Air Lines Flight 23 exploded due to a nitroglycerine bomb in the hold in the air. This plane crash entered the statistics as the first bomb attack in civil aviation history, the background of which has never been clarified.

Although the B-247 was an extremely advanced aircraft for its era, it was denied economic success. The reason for this was a contract that guaranteed the first customer United Air Lines a monopoly on this type of aircraft for a longer period of time . The initially lucrative business turned out to be an own goal for Boeing after potential customers ordered the now much more modern and structurally superior Douglas DC-2 and later the DC-3 from 1934 .

In total, only 75 copies of the B-247 were built, 70 of which were used by United Air Lines. These included 61 machines from the first series. The first example remained with Boeing and was modified after the emergence of competition in the form of the DC-2 to the B-247E (the prototype of the following B-247D). The B-247A, a business jet with a luxurious cabin for six passengers, which also served to test the twin-wasp engines and was scrapped in 1947, also remained a one-off. The B-247D received supercharged and clad P & W Wasp S1H1-G engines, controllable pitch propellers and, instead of the cockpit glazing with forward-sloping windows, aerodynamically optimized ones. Approval took place on October 11, 1934. Despite these improvements, only 13 units were built at a list price of $ 69,000, with United converting 33 of its machines to the D standard.

The German Lufthansa bought 1934 two machines (Code: D-AGAR and D-AKIN). From August 1934 the D-AKIN was used by the Rechlin test center as a test vehicle for course controls. On March 24, 1935, the D-AGAR in Nuremberg was damaged on the ground by an Air France aircraft and scrapped, the D-AKIN crashed on August 13, 1937 when taking off from Hanover-Vahrenwald on the return flight to Rechlin.

By the late 1930s, the machines were already out of date. 27 of them were confiscated as C-73 transporters for two years during the Second World War and were then used in some cases as cargo aircraft until the 1960s and as a military test aircraft with the designation B-247Y.

construction

In addition to an autopilot , the B-247 was also equipped with a de-icing system, a retractable landing gear , variable-pitch propellers (on the B-247D) and motors that were cased and attached to the leading edge of the wing. The fuselage was made from four segments made of duralumin , which were joined with bolts and clad with aluminum sheets. The wings, also made of duralumin, were a modern construction of spars and ribs, the middle section of which was integrally connected to the fuselage and carried the engine mount for the Pratt & Whitney Wasp S1D1 ( P & W R-1340 ) engines . The outer wing segments each contained a fuel tank. In the bow there was a luggage compartment that could be reached through a foldable tip of the nose.

Received aircraft

Boeing 247D at the National Air and Space Museum

Today four B-247s still exist in museums in the United States, Canada, and the United Kingdom.

c / n 1699, CF-JRQ

Exhibited at the Canada Aviation and Space Museum in Ottawa . The aircraft was donated by California Standard Oil in 1967 .

c / n 1722, N18E

National Museum of Science and Industry in Wroughton , United Kingdom.

c / n 1729, N13347

Airworthy on display at the Museum of Flight Restoration Center, Paine Field , Snohomish County, Washington , USA.

c / n 1953, NC13369 / NR257Y

Exhibited at the National Air and Space Museum , Washington, DC , USA, with United Air Lines paint scheme and approval NC13369 on the right and as NR257Y with MacRobertson air race markings on the left.

Technical specifications

cockpit

Three-sided view

Parameter	Data from the 247D
crew	3
Passengers	10
length	16.30 m
span	22.66 m
height	3.70 m
Wing area	77.6 m²
Wing extension	6.6
Payload	1850 kg
Empty mass	4100 kg
Max. Takeoff mass	5950 kg
Cruising speed	304 km / h
Top speed	324 km / h
Landing speed	98 km / h
Climb performance	4.6 m / s
Max. Summit height	7000 m
Service ceiling	3000 m
Range	approx. 1200 km
Engines	two radial engines Pratt & Whitney Wasp S1H1-G (KTW SL) each with 410 kW (557 PS)

Incidents

When this aircraft model was in use, there were a total of 46 accidents with a total of 116 fatalities.

See also

• List of aircraft types

Web links

Commons : Boeing 247  - collection of images, videos and audio files

• Model 247 Commercial Transport. In: History. The Boeing Company, accessed January 14, 2018 . 

Individual evidence

1. ↑ FlugRevue August 2009, pp. 92–95, Modernes Flying - Boeing B-247
2. ↑ Accidents with the Boeing 247 , Aviation Safety Network (English), accessed on March 10, 2019