The C-141 is possibly The Most Significant Aircraft in History of Jet Airlifter Design. Here’s why. (2024)

The C-141 Airlifter

The C-141 Starlifter was the US Air Force’s first major jet aircraft designed to meet military standards as a troop and cargo carrier. Lockheed (now Lockheed Martin) built a total of 285 C-141s, and for more than 40 years, C-141s performed numerous airlift missions for the USAF. With its great range and high speed, the Starlifter projected American military power and humanitarian efforts rapidly across the globe.

The Starlifter originated from a 1959 requirement for a fast, strategic transport aircraft that would serve as a “work horse” for moving U.S. Army troops rapidly anywhere in the world. The C-141 made its maiden flight on December 17, 1963, and the C-141A became operational in April 1965 with the 1501st Air Transport Wing at Travis Air Force Base, Calif.

During its early operational service, the C-141A demonstrated that it had the potential to transport larger cargo loads, and the USAF lengthened the C-141A’s fuselage by 23.3 feet and added aerial refueling capability.

Layout

Looking back to Starlifter’s layout, Lockheed’s Wilfred C. Garrard recalls in George Cox and Craig Kaston bookAmerican Secret Projects Vol 2:

`During the preliminary design phase of the C-141 aircraft a small team was given the task of comparing all configurations that could be conceived for performing the C-141 mission. The hope was that a new configuration could be developed which would be superior … either in speed or cost or some other major characteristic. One factor in our minds was that something new or different would catch the imagination of USAF and if it offered one or more advantages, we would have an overwhelming competitive advantage. Unfortunately our hopes were dashed in this endeavor..’

Lockheed opted for a high-wing, T-tailed configuration with four turbofans slung on wing-mounted pylons. The wing’s moderate sweep (25° at quarter chord) traded a reduction in cruise speed for an increase in payload for the same size wing. The reduced sweep also decreased approach speeds, allowing Lockheed to eliminate leading edge slats.

In March 1961 the Air Force ordered the building of five development aircraft under the designation C-141A. Even before the first of these had flown, a contract was placed for 132 production aircraft, which was subsequently increased to 248. Lockheed delivered the first C-141A to the USAF in October 1964 and the final example in February 1968.

Starlifter limitations

Lockheed also designed a version of the Starlifter aimed at the civil market, known as the L-300 Super Starlifter. The company built a demonstrator that flew in 1963, but it attracted no orders.

The C-141 was arguably the USAF’s first strategic jet airlifter. It was not, however, without its limitations. A report published in January 1973 by the USAF’s Office ofMAC (Military Airlift Command)History, noted that it had ‘a shorter fuselage than the C-133 and DC-8F; its maximum payload of 34 tons less than that of the Boeing 707-300 series (44.9 tons) andDouglas DC-8F(38.7 tons); its economy cruise speed fell 35mph short and 64mph below the 707-320B and DC-8F respectively; while its maximum range was some 500 miles less than that of either the 707 or DC-8F. In addition … the C-141 was incapable of carrying the outsized cargo that the C-124 or C-133 could.’

The C-141, The Most Significant Aircraft in History of Jet Airlifter Design

Nevertheless the report makes clear that the C-141 gave MAC what it had long wanted: a fast cargo aircraft, with a troop-carrying capability. It may not have had the outsize cargo capability of the C-124, but it did cruise at twice the speed and, compared with the other fast aircraft, the 707 and DC-8, it could carry cargo that they could not. Like all designs, it was a compromise, and overall it proved a successful one. Having entered service in 1964, the last examples of the C-141 were not retired until September 2004.

This very lengthy operational life was in no small part due to a substantial mid-life modification programme. The process extended the fuselage by adding two plugs, one of 13ft 4in (4.07m) ahead of the wing, the other of 10ft (3.05m) aft of it. It also added in-flight refuelling capability by inserting a boom receptacle in the top of the fuselage aft of the co*ckpit. These changes were tested on a prototype (designated the YC-141B) in 1977, and over the following five years 270 C-141As were converted into C-141Bs. Some of these aircraft received avionics and co*ckpit display upgrades, becoming C-141Cs.

The C-141 is also significant in the history of airlifter design for its configuration, which would become the norm for virtually every future large military transport: high-mounted swept wings, T-tail, and fuselage-attached main undercarriage. In years to follow theLockheed C-5, McDonnell Douglas Boeing C-17, Ilyushin IL-76,Kawasaki C-1 and C-2, EmbraerKC-390, Xi’an Y-20, andAirbus A400Mwould all embrace the C-141’s basic design features.

American Secret Projects Vol 2 is published by Crecy and is available toorder here.

Photo credit: U.S. Air Force