It was on this day in aviation history that the first air to air refuelling took place between two jet aircraft
A specially modified YB-47F Stratojet was refuelled in flight from a KB-47G tanker aircraft.
The two aircraft were specially modified for the trials with the in-flight refuelling, using the Probe and Drogue refuelling system. This system consists of a tanker aircraft, which extends a hose from the fuselage or a pod in/under the wing. At the end of the hose is the Drogue. The fuel receiving aircraft as a probe installed on it connected to its fuel tanks. when the Probe connects with the Drogue a fuel tight connection is established and the refuelling can start.
Basic sketch of a Probe and Drogue aerial refuelling system
The two aircraft used for this first air to air refuelling experiment between jet aircraft were B-47B's.
The tanker aircraft was fitted with a British built drogue refuelling system and was designated as a KB-47G, its crews gave it the nickname "Maw". The receiving aircraft was designated as YB-47F, nicknamed "Paw" by its crews. After a limited amount of tests, the program was cancelled in 1954 as the KB-47G could not carry enough fuel for practical mission fulfilment. After a short re-examination of the project in 1957, it was still deemed uneconomical and unpractical to use a KB-47G for inflight refuelling. Boeing in the meantime was busy developing its aerial refuelling aircraft the KC-135 Stratotanker which offered must better performance! That aircraft actually made its flight yesterday in 1956, on the 31st of August! The B-47B was the first operational version of the B-47. Previous versions were the B-47A (10 built) they were evaluation models and the two prototypes, the XB-47. Many more versions of the B47 would be built, a total of 2042 B-47's would be built. 2040 of these aircraft were in active service with the US Air Force, and two were in active service with the US Navy between 1952 to 1977 The US Navy aircraft were modified to Electronic Warfare aircraft, these were the last B-47's in active service, the last flight being performed on the 20th of December 1977.
399 B-47B aircraft were built, the first flight of this model was on the 26th of April 1951. Initially, the B-47B was powered by General Electric J47-GE-11 engines (5200 lbs thrust), later models were powered by the J47-GE-23 turbojets with 5800 lbf thrust. The first production aircraft would later be modified with the J47-GE-23 turbojets. To increase the take-off performance all B-47B's were fitted with a built-in RATO (Rocket-Assisted Take Off) system.
A B-47B performing a RATO Take-Off
Some specifications for a B-47B:
Span: 116 feet (35.36 meters)
Length: 107 feet 1 inch (32.64 meters)
Height: 28 feet (8.53 meters)
MTOW: 226.000 lbs (102512 kg)
Powerplant: 6x General Electric J47-GE-23 turbojets with 5,800 lbf (2630 kg) thrust each.
Vmo: 547 knots (630 mph - 1013 kph)
Cruise Speed: 487 knots (560 mph - 900 kph)
Range: 3040 nm (3500 miles - 5633 km)
Service Ceiling: 39.300 feet (12.000 meters)