v1.0.1 / 01 jun 02 / greg goebel / public domain
* Two of the most prominent jet transport aircraft in US military service are the Lockheed "C-141 Starlifter" and its "big brother", the huge "C-5 Galaxy". This document provides a short history of these two aircraft.
* In the 1950s, the US Air Force's Military Air Transport Service (MATS) was reliant on piston-engined cargolifters, such as the Douglas C-124 Globemaster. By the end of the decade, MATS had decided that they needed a more capable cargolifter, and in the spring of 1960 the USAF issued a request for proposals under the designation "Specific Operational Requirement 182 (SOR 182)".
SOR 182 specified an aircraft with a cargo capacity of 27,200 kilograms (60,000 pounds) and a range of 6,480 kilometers (4,025 miles). Lockheed's proposal was selected, with an initial contract for five "development, test, and evaluation (DT&E)" aircraft awarded on 13 March 1961. The aircraft was given the designation "C-141 Starlifter".
The Starlifter incorporated ideas from Lockheed's earlier C-130 Hercules cargolifter, including a high wing; a loading ramp that dropped down from the rear fuselage; clamshell rear doors that could be opened in flight for airdrops; and main landing gear that retracted into fairings alongside the fuselage to ensure an unobstructed cargo hold.
The Starlifter differed from the Hercules in having wings with a sweepback of 25 degrees and a tee tail, rather than straight wings and a conventional tail; and four Pratt & Whitney TF33-P-7 turbofans with 9,525 kilograms (21,000 pounds) thrust each mounted in pods on underwing pylons, instead of turboprops mounted on the wing. The flight crew numbered five, including pilot, copilot, navigator, and two loadmasters.
Initial flight of the Starlifter was on 17 December 1963. The first production "C-141A" was delivered to the USAF Military Airlift Command (MAC, successor to MATS) on 23 April 1965. A total of 284 C-141As were built through February 1968.
Once in service, the Starlifter immediately began daily shuttle flights from the continental US to VietNam, carrying 138 passengers in rearward-facing seats (a configuration that the Air Force decided provided better safety in crashes) or up to ten standard "463L" pallets with a total of 28,880 kilograms (62,700 pounds) of cargo to the war zone, and returning with casualties. The aircraft could carry 80 litters with 23 medical attendants. A few Starlifters were modified to carry Minuteman ICBMs from the factory to operational bases.
* In practice, MAC found that the Starlifter's cargo hold volume was small compared to its weight-lifting capability. The aircraft often ran out of space well before it met its weight limit.
To resolve this problem, in 1976 the USAF began a program to "stretch" the Starlifter with fuselage "plugs" in front of and behind the wing, increasing the length of the aircraft by 7.11 meters (23 feet 4 inches) and providing space for three more standard pallets, for a total of 13. The upgrade also involved the addition of a boom-refueling receptacle behind the cockpit.
The first "YC-141B" conversion performed its initial flight on 24 March 1977.
A total of 270 "C-141B" conversions were performed through June 1982. The
Air Force was very pleased with the conversion program, since it came through
ahead of schedule and under budget, and gave MAC an increased airlift
capacity equivalent to 90 C-141As.
LOCKHEED C-141B STARLIFTER:
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spec metric english
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wingspan 48.74 meters 159 feet 11 inches
length 51.29 meters 168 feet 4 inches
height 11.96 meters 39 feet 3 inches
empty weight 677,200 kilograms 148,120 pounds
loaded weight 155,600 kilograms 343,000 pounds
max cruise speed 910 KPH 565 MPH / 490 KT
normal cruise speed 800 KPH 495 MPH / 430 KT
service ceiling 12,500 meters 41,000 feet
loaded range 4,725 kilometers 2,935 MI / 2,555 NMI
_____________________ _________________ _______________________
KAO was primarily intended to perform infrared observations of cosmic objects with a 91 centimeter (36 inch) telescope, mounted to perform observations out a hole in the fuselage. Such observations must be performed at high altitude, since the atmosphere absorbs infrared radiation. KAO went into service in 1974, and obtained many significant astronomical observations.
The flying observatory was retired in 1995, as NASA was beginning work on a much more sophisticated flying observatory based on the Boeing 747SP, designated the "Stratospheric Observatory for Infrared Astronomy (SOFIA)". Retiring KAO freed up funds for the SOFIA effort.
* In 1994, the Air Force began a program to refit 13 C-141Bs to the "Special Operations Low-Level II (SOLL II)" standard, with a total program cost of $41 million USD. These aircraft are operated by the USAF in behalf of the US Special Operations Command, and include gear for low-level night flying, as well as defensive countermeasures.
The SOLL II Starlifters are also sometimes referred to as "Special Operations Forces Improvement Modification (SOFI-Mod)" Starlifters. Exactly what "SOLL I" was is unclear, unsurprising given the clandestine nature of the Special Operations Command, and it may have been an MC-130 or HC-130 Special Operations Hercules variant.
The SOLL II Starlifter looks much like any other C-141B, but it can be recognized by three "knobs" on its chin. One knob is directly under the nose and is a turret for a Texas Instruments AAQ-17 "forward looking infra-red (FLIR)" imager, which gives the aircraft the ability to "see in the dark". The FLIR imagery is displayed on a CRT at the navigator's station, and on an auxiliary display for the pilot. The navigator points the FLIR turret using a joystick. The FLIR turret can be removed for maintenance.
The other two knobs are for ALE-40 chaff-flare dispensers, and are mounted on the "cheeks" of the aircraft. There are also chaff-flare dispensers in the landing-gear wheel wells and on the wingtips. In addition, the defensive countermeasures suite includes an AAR-44 infrared missile warning sensor fitted under the fuselage, and an ALR-69 radar warning receiver with unobtrusive antennas tacked on to the nose and tail.
The defensive countermeasures system can be set to an "automatic" mode to dispense chaff and flares without crew intervention. The amount of chaff and flares to be dispensed can be preprogrammed. The sensors also provide an audible warning to the crew through their earphones, with the crew dispensing chaff and flares themselves when the system is in "manual" mode. Even the loadmaster can activate the dispensers, as he or she often keeps a "SAM (surface to air missile) watch" from the rear ramp.
The SOLL II Starlifter also includes an enhanced suite of communications equipment and Global Positioning System (GPS) navigation gear. The enhancements of the SOLL II increase its weight by about 680 kilograms (1,500 pounds) compared to a "stock" C-141B. Crews are handpicked for night operations, which are conducted with night vision goggles (NVGs). All SOLL II Starlifter cockpit and exterior lighting is NVG-compatible.
Additional crewmembers are included for missions of long duration or with high workload requirements. Passengers on SOLL II flights tend to find the low-level flight of the aircraft in pitch darkness, often in formation with another SOLL II aircraft, to be a little unnerving.
* In recent decades, the Starlifter has been a major player in airlift operations to Haiti, Bosnia, Somalia, and Rwanda. It was used very heavily in the Gulf War in 1991. After the Gulf War, structural problems led to the imposition of flight restrictions, though these problems were quickly resolved by a comprehensive repair program.
However, the Starlifter is in its twilight years with the USAF's Air Mobility Command (AMC), the current incarnation of MATS and MAC, with all C-141s expected to be out of first-line Air Force service by 2003 and retired from Reserve and Air National Guard service by 2006. They will be replaced by the much more capable and modern Boeing C-17 cargolifter on a roughly two-for-one basis. SOLL II C-141Bs will be replaced by C-17s configured for the special operations mission.
Although 63 Starlifters are being upgraded to the "C-141C" standard, with improved avionics, including GPS navigation gear and digital "glass" cockpits, this program is intended to merely obtain incremental life out of the aircraft, rather than keep it in service over the long term.
* In 1963, MATS issued a requirement for a "Cargo Experimental Heavy Logistics System (CX-HLS)" that specified a heavy long-range cargolifter to complement the Starlifter. The CX-HLS was to be capable of carrying 56,700 kilograms (125,000 pounds) of cargo over a range of 12,875 kilometers (8,000 miles).
In mid-1964, the USAF issued short-term contracts to Lockheed, Boeing, and McDonnell-Douglas for design studies of the CX-HLS, as well as to General Electric and Pratt & Whitney for design studies of new, highly efficient "high bypass ratio" turbofans to power the aircraft.
GE won the engine competition in August 1963 with what would become the "TF39" turbofan, and Lockheed won the CX-HLS competition in October 1965 with their "L-500" design. The first Lockheed "C-5A Galaxy" flew on 30 June 1968. Deliveries began in 1970. A total of 81 C-5As were built.
* The C-5A had the same overall configuration as the C-141, with high wing with a sweep of 25 degrees, four jet engines in pods on underwing pylons, a rear loading ramp, a high tee tail, and main landing gear retracting into fairings. However, it was massively scaled up, with the capability of lifting two main battle tanks or transporting 345 fully-equipped troops. The Galaxy was the largest operational aircraft in the world for 15 years, until it was surpassed by the Soviet Antonov "An-124 Condor".
The C-5's nose hinged upward to allow "drive-through" access through the unobstructed cargo bay, which was pressurized and climate-conditioned. The upraised nose cleared the cockpit, permitting the aircraft to be taxied with its nose open. The cockpit was placed at the front of an upper flight deck on top of the huge cargo hold, and accommodated a crew of five, including pilot, copilot, flight engineer, and two loadmasters. The upper deck also included a 15-person crew-relief compartment with bunks in front of the wing, and a passenger compartment behind the wing with 73 rearward-facing seats.
The C-5A was powered by four General Electric TF39-GE-1 turbofans with 19,500 kilograms (43,000 pounds) thrust each. The aircraft had a four sets of main gear, each with two-axle bogies with two wheels in front and four in the rear, and a four-wheel nose gear. The landing gear could "kneel" to assist in loading cargoes, and featured a system to help land in crosswinds. The C-5A had a boom refueling capability from the start, as well as a computerised "Malfunction Detection, Analysis and Recording (MADAR)" diagnostic system that monitored 800 test points in flight or for ground servicing.
* The C-5A proved its worth in the fall of 1973, in OPERATION NICKEL GRASS, the massive airlift to support Israel during the Yom Kippur war, with the big cargolifter carrying massive quantities of ammunition and weapons to assist Israeli forces. The Galaxy also performed reliable service in the last years of the Vietnam War, though one was lost on 4 April 1975, while trying to evacuate orphans from Saigon. 206 of the 382 people aboard were killed, many of them infants.
* The C-5A's design specifications had been very aggressive and hard to meet. The program did not go smoothly, and in fact the program is said to have coined the term "cost overrun". One of the long-term problems that resulted was that the aircraft did not live up to its fatigue-life specifications, with the wings having barely a quarter of the 30,000 hour lifetime specified.
In 1975, Lockheed was awarded a contract to provide new wings to all surviving aircraft to increase the wing service life to the specified 30,000 hours. The first re-winged aircraft was delivered to the USAF in 1983, with the re-winging program complete by July 1987.
* In 1982, the Air Force awarded Lockheed a contract for a 50 "C-5Bs" that
included the new wing; uprated TF-39-GE-1C turbofans; improved alloys and
fasteners; and improved avionics, including a MADAR II diagnostic system,
Bendix weather radar with a color display, and a Delco triple-redundant
inertial navigation system. The landing-gear crosswind landing system of the
C-5A, which had proven unreliable, was eliminated. Initial flight of the
prototype was on 30 September 1985. Initial deliveries were in 1986 and all
deliveries were completed in 1989.
LOCKHEED C-5B GALAXY:
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spec metric english
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wingspan 67.88 meters 222 feet 9 inches
length 75.54 meters 247 feet 10 inches
height 19.85 meters 65 feet 2 inches
empty weight 169,650 kilograms 374,000 pounds
loaded weight 379,700 kilograms 837,000 pounds
max cruise speed 910 KPH 565 MPH / 490 KT
service ceiling 10,900 meters 35,750 feet
fully-loaded range 5,525 kilometers 3,435 MI / 2,990 NMI
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Two C-5As were modified for NASA to carry space shuttle payload bay container cargoes, and were given the new designation of "C-5C". They are also known as the "Space Container Transport System (SCTS)", "Space Container Modifications (SCM)", "SCM Birds", or "Scum Birds".
They are flown by Air Force crews but under NASA's operational control, and the USAF has to ask NASA for permission to use them for non-NASA-related missions. They are also rumored to be used for ferrying top-secret cargoes to isolated bases for testing, but of course the government has no comment on such matters.
* The Galaxy, or "Fred (Fantastic Ridiculous Economic Disaster)" as it is known to its crews, has been a valuable asset for US military overseas deployments for three decades, and served with particular distinction in the Gulf War, lifting in a little more than two weeks more than the entire Berlin Airlift in 1949. One was lost in a crash at Ramstein Air Force Base in Germany on 29 August 1990. The accident was a misfortune, but at least it was the only loss of a transport during the Gulf War airlift, and only the fifth Galaxy lost during its entire operational history.
* As of 2000, the AMC operated 126 C-5s, including 74 C-5As, 50 C-5Bs, and two C-5Cs. The C-5s represent a valuable asset that has a lot of life left in it. Estimated structural life of the airframe is 80,000 hours, while the current flight time on a high-time C-5A is only about 22,000 hours and on a high-time C-5Bs is only about 15,000 hours. The "Fred" has an excellent safety record, but at present its reliability leaves much to be desired. In November 1998, the "mission capable rate" of the AMC C-5 fleet was only 61.8%.
The USAF is now working on programs to upgrade the C-5s to keep them flying until at least 2040. The most prominent part of this effort is the $7 billion USD "Reliability Enhancement & Reengining Program (RERP)", which will replace the current GE TF39 turbofan engines with modern GE CF6-80C2 turbofans.
The CF6-80C2 is well-proven, being used on the Boeing 747 and 767, and normally offers 27,210 kilograms (60,000 pounds) thrust each, though the engines will be derated to 22,675 kilograms (50,000 pounds) thrust. Lockheed-Martin, which expects to receive a formal contract award for RERP from the USAF in 2001, chose the GE engine over the Pratt & Whitney PW4650 and the Rolls-Royce Trent 500. GE is expected to perform off-wing maintenance on the engines for the USAF.
RERP will also involve a few structural enhancements to deal with a new pattern of airframe loads; a new auxiliary power unit (APU); new engine pylons; and improvements to the aircraft's antiskid landing gear and climate-conditioning systems.
Reengining will begin in 2003, with the first reengined aircraft flying in 2005, and initial operating capability in 2008. From 12 to 15 C-5s would be reengined every year, once the program goes into full operation. The reengined C-5s will have much improved performance, with over twice the top payload capacity and a faster climb rate, and the new engines will be significantly quieter as well.
RERP is only a part of a suite of upgrades for the C-5. Another element, the $500 million USD "Avionics Modernization Program (AMP)", was begun in 1999, with the first C-5 fitted with an AMP upgrade, consisting of a Honeywell "traffic alert and collision avoidance system (TCAS)", returned to Air Force service in August 2000.
The initial AMP phase features installation of the Honeywell TCAS, with its own dedicated cockpit display. When the full AMP upgrade is finished, the TCAS will be a integrated part of the new cockpit system, which will feature a digital flight-control system; a state-of-the-art communications and navigation system; an ARINC-standard data bus; and six color flat-panel displays. According to Lockheed-Martin, which is implementing the AMP program, all the new equipment is based on commercially-available products. Once installed, the AMP upgrade will allow the C-5 to meet Global Air Traffic Management standards anywhere in the world.
* During the late 1960s and early 1970s, I used to see C-141s coming into Fairchild Air Force base near Spokane, Washington, on an occasional basis. Some claim it is an ugly aircraft, but I've always found it somewhat elegant myself. As far as the C-5 goes, I have a memory of one flying over Spokane in the same timeframe, with the thing so huge that it appeared to float in the sky like an airship.
In 1973, when I was stationed at Fort Hood, Texas, I also watched C-5s swallowing up M-60 tanks as part of the NICKEL GRASS airlift to Israel during the Yom Kippur War. It is an interesting memory to have observed history in progress, though the details have largely faded away.
* Sources include:
Some details on the C-5 were also obtained from a web document by Jason Hodgkiss, as well as THE AVIATION ZONE website, which is refreshingly dedicated to "big lifters" instead of the usual assortment of fighters and bombers more commonly favored on the web.
* Revision history:
v1.0 / 01 jul 01 / gvg
v1.0.1 / 01 jun 02 / gvg / Minor update with corrections.