Boeing KC-97 Stratofreighter

History of the Boeing KC-97 Stratofreighter

The events of World War II (1939-1945) made clear to American war planners the value of heavy aircraft in conflict with many unstable fronts. As a result, developers of large aircraft like Boeing have to meet the growing demand for "large" transport aircraft - often based on existing heavy bombers. As early as 1942, Boeing engineers developed the aircraft based on their experience developing what would eventually become the famous four-engine B-29 Superfortress and B-50 Superfortress heavy bombers (both aircraft were found elsewhere). mentioned in this book). detailed on the website). In November 1944, a new four-engine model based on the B-29/B-50 family - the core of its design was transport - made its first test flight.

It eventually entered service in 1947 as the KC-97 "Stratospheric Cargo", albeit only after the war.

The success of the Stratofreighter warranted further variants of the series, with additional work producing the KC-97 Stratofreighter, developed specifically for the new-thinking US Air Force as an aerial tanker. Since many early fuel-guzzling jet fighters and bombers ran out of supplies in a short period of time, it was imperative to equip these combat platforms with air delivery systems to meet demand.

The new aircraft basically used most of the form and function of the C-97 (including the deep fuselage), but also introduced all the components needed to carry and deliver fuel to the aircraft in the air - namely fuel storage, mobile Arms and facilities for pumping fuel to serviceable aircraft. Now, the Air Force's fighters and bombers will not only be limited by internal fuel, but will also need to return to base for refueling -- essentially doubling or tripling their operational range in some cases.

The KC-97 was delivered to the U.S. Air Force as early as 1950, and the series officially launched on July 14, 1951. The service procured a total of 811 KC-97 aircraft from Boeing built between 1951 and 1956. Once in service, the design proved successful, although some higher-flying platforms, such as the soon-to-be Boeing B-52 Stratofortress heavy bomber, had to make special accommodations to accommodate this "slow" fuel Delivery aircraft (still powered by its original 4x Pratt & Whitney air-cooled prop-spin radial engines).

The later introduction of the General Electric J47 turbojet partially offset this design limitation with pods installed under each wing of the KC-97 to create the "KC-97L" designation - these jets used Yu flew a large plane with a short burst of energy hitting the target plane on his crotch.

The KC-97 is used by multiple branches of the U.S. Air Force, including Strategic Air Command (SAC), Air Force Reserve, and Air National Guard. Some examples were retired from front-line service as early as 1956 when the USAF introduced a more efficient solution, but the series continued until mid-1978.

The Israeli Air Force (IAF) and Spanish Air Force see themselves as one of the only other operators in the series.

Variants start with the original KC-97A shipping number and are numbered with three examples applicable to air tanker standards. They lost the rear loading ramp during the modification, but gained a refueling arm to test the effectiveness of the overall aircraft design.

After the testing phase was completed, the trio were converted back to their original form of transport.

The KC-97E was a true tanker form, with 60 built, some of which were eventually transferred back to a transport role under the "C-97E" designation. The KC-97F introduced 4 R-4360-59B engines of 3,800 hp each, with a total of 159 produced.

Likewise, some of these batches were converted to transport form, designated "C-97F".

KC-97G was the final brand, with 592 built. They are specially designed "combination" airframes that can perform the role of an aerial tanker or a cargo transport role as needed. These aircraft are equipped with underwing fuel tanks.

The EC-97G is an Electronic Intelligence (ELINT) conversion for three KC-97G models and equipped with special equipment. The C-97G is a transport conversion using 135 aircraft from the KC-97G roster. The GKC-97G became five KC-97G models designed to be used as ground-level classrooms.

The JKC-97G was a "one-off" variant used to test General Electric J47-GE-23 turbojets in underwing pods - work that culminated in the aforementioned KC-97L, 81 of which became existing KC-97G in stock.

The HC-97G is another offshoot of the G variant, representing 22 aircraft converted to search and rescue (SAR) roles. The KC-97H is another one-off device for testing specific hose and sock fuel delivery systems. The YC-97J represents a pair of KC-97G models equipped with experimental 4 x Pratt & Whitney YT34-P-5 turboprops, but the design was not further developed.

The C-97K became 27 KC-97G aircraft, which were converted into dedicated personnel carriers.

In support of the famous US Apollo (Saturn) space program, a KC-97 example was modified to perform a super heavy lift mission (as "Super Guppy"). The example eventually became NASA property in 1993 and remains airworthy to this day (2018) - one of only two aircraft in the series to claim that status.

Despite serving as an "air tanker", the KC-97 was not designated the "Stratotanker" by the USAF and Boeing, retaining the C-97's original "Stratofreighter" designation.

Specification

Basic

Production

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Performance

Performance

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Changes