Douglas Globemaster, Globemaster II, & Cargomaster (2024)

* After World War II, Douglas Aircraft provided a series of heavy transportsfor the US Air Force. While the Douglas "Globemaster" piston transport wasonly built in small numbers, it led to the improved "Globemaster II", whichwas an airlift workhorse well into the Vietnam War. Douglas also built alarge turboprop transport, the "Cargomaster", that served in the 1960s. Thisdocument provides a history and description of the Globemaster, GlobemasterII, and Cargomaster -- as well as of the comparable Lockheed "Constitution".A list of illustration credits is provided at the end.

[1] C-74 GLOBEMASTER

* In early 1942, the Douglas Aircraft Company began design studies of a newheavy, long-range four engine transport aircraft, with the companydesignation of "Model 415", with an eye towards logistical support ofoperations in the Pacific theater. The work led to a formal US Army AirForces (USAAF) contract in June 1942, specifying delivery of 50 of thetransports. The aircraft was given the military designation of "C-74Globemaster".

Although the design was as straightforward as possible to ensure that theaircraft could be put into production rapidly, the USAAF wanted Douglas togive higher priority to the A-26 Invader medium bomber, and the first C-74wasn't rolled out until July 1945. It didn't perform its first flight untila few weeks after the end of the war, on 5 September 1945. At the time, itwas the biggest land-based transport aircraft in the world.

The C-74 was basically a scaled-up DC-4 / C-54, with a low wing; fourengines; conventional tail; and tricycle landing gear, with twin wheels oneach unit. The engines were Pratt & Whitney (P&W) R-4360-27 Wasp Major28-cylinder four-row air-cooled radials with 2,240 kW (3,000 HP) each,driving fully reversible Curtiss electric propellers to permit shorterlandings and improved taxi maneuverability. The wings featured asophisticated arrangement of flaps to permit shorter take-offs.

The C-74 had a crew of five, including copilot, pilot, radio operator,navigator, and flight engineer. Crew rest quarters were included forlong-duration missions. Passageways were provided in the wing to permit theflight engineer to perform servicing and repairs while the machine was inflight. One unusual feature of initial-build Globemasters was that the pilotand copilot sat in individual "blister" or "bug-eye" type canopies to givethem maximum all-round visibility. Since this scheme also complicatedinteractions between the two men, it was changed to a more conventionalco*ckpit arrangement. Which aircraft had the bug-eye co*ckpit scheme and whichdid not; when it was implemented; and whether the conventional co*ckpit schemewas retrofitted to early aircraft is unclear.

The C-74 could carry 125 fully-equipped troops, 115 litter patients withtheir medical attendants, or up to 22,675 kilograms (50,000 pounds) of cargo.The cargo bay had twin hoists that could be moved on a rail up and down thebay. They could be used to drop a removeable belly section to ease loadingof cargoes, reducing the need for specialized cargo handling equipment.

 ___________________________________________________________________ DOUGLAS C-74 GLOBEMASTER I: ___________________________________________________________________ wingspan: 52.82 meters (173 feet 3 inches) wing_area: 233.18 sq_meters (2,510 sq_feet) length: 37.86 meters (124 feet 2 inches) height: 13.34 meters (43 feet 9 inches) empty weight: 39,087 kilograms (86,172 pounds) MTO weight: 78,018 kilograms (172,000 pounds) max speed at altitude: 500 KPH (310 MPH / 270 KT) cruise speed: 300 KPH (260 MPH / 225 KT) service ceiling: 9,150 meters (30,000 feet) range: 8,350 kilometers (7,200 MI / 6,260 NMI) ___________________________________________________________________

Douglas began discussions with Pan American World Airways in 1944 for sale ofan airliner version of the C-74 for commercial service after the war. The"civilian" C-74 was to be designated the "DC-7", though Pan Am called it the"Clipper Type 9". Pan Am ordered 26 DC-7s in June 1944, but the price keptclimbing and the order was canceled in October 1945. Similarly, althoughthe USAAF contract had specified fifty C-74s, the order was cut back at theend of the war, and only fourteen C-74s were built. There was no "XC-74"prototype, or "YC-74" evaluation aircraft as such. One of the 14 builtcrashed in flight testing in August 1948, while another was a static testarticle that was tested to destruction. The small numbers of C-74s builtmeant that the aircraft's service was limited, but it gave the US Air Force(USAF, as the USAAF had become in 1947) experience with the operation andutilization of large transport aircraft.

The C-74 did achieve distinction during the Berlin Airlift in 1948. On 24June of that year, the Soviets closed all land routes into the divided cityof Berlin, Germany. The next day the USAF began Operation VITTLES, a massiveairlift operation to keep the city supplied. One Globemaster, the 13thbuilt, arrived at Frankfurt Rhein-Main Airfield on 14 August to join in theairlift. The C-74 proved a very useful asset in the effort, hauling largequantities of supplies and often performing several trips in a day. On 18September, the C-74 flew a total of six round trips. The single C-74 wasinstrumental in helping build Tegel Airfield in the French sector of Berlin,hauling in heavy construction equipment that had been broken down intocomponents for air delivery. The aircraft operated as part of the airliftfor six weeks, but it was simply too heavy for the Berlin runways. There arestories that the Soviets complained that it might be used as a bomber becauseof its hoist well in the belly.

With the small number of C-74s in service, maintenance was an increasingheadache as time went on and spares became harder to obtain, forcing thetype's withdrawal from service. The last C-74 was finally retired from USAFservice on 31 March 1956. A handful ended up in civilian hands. None havesurvived.

[2] C-124 GLOBEMASTER II

* The Air Force found the C-74 a very capable and useful aircraft, and beganto consider acquiring much larger numbers of an improved version proposed byDouglas; the result was the "C-124 Globemaster II". The C-124 used the samewings, tail, and engines as the C-74, but featured a new and enlargedfuselage, as well as stronger landing gear to handle higher weights. It waspowered by four P&W R-4360-63A radial engines, with 2,835 kW (3,800 HP) each.

The "YC-124" prototype, rebuilt from a C-74, performed its initial flight on27 November 1949. The Globemaster II had "clamshell" doors in the nose withhydraulically-activated loading ramps. The cargo bay, which was 23.5 meters(77 feet) long, featured the overhead hoist and removeable belly section ofthe C-74. Each hoist had a load capacity of 7,250 kilograms (16,000 pounds).The C-124 could carry most Army field vehicles without requiring that they bedismantled; it could lift 33.560 kilograms (74,000 pounds) of cargo. Itsdouble-decked cabin could also be fitted with 200 seats for troops, or with123 litters for casualty evacuation. Flight crew numbered six.

The first operational C-124 was delivered in May 1950. A total of 204"C-124As" was built, to be followed by 243 "C-124Cs". The C-124C featureduprated engines, an AN/APS-42 weather radar with a distinctive nose "thimble"radome, and wingtip-mounted combustion heaters to provide cabin heating andwing de-icing. The radar was retrofitted to most C-124As; some sources claimthe heaters were as well, but others say not.

A turboprop-powered "KC-124B" tanker variant was considered, which emerged asa single "YC-124B" transport prototype that flew in 1954. The last of 448Globemaster IIs was rolled out in May 1955. At the type's peak in 1963,there were 377 C-124s in service with 20 transport squadrons.

The C-124 provided valuable service in both the Korean and Vietnam Wars,though by the Vietnam era it was regarded as too slow. It was given avariety of nicknames by its crews, such as "Old Shakey", the "Shakemaster",the "Aluminum Cloud", or "Aluminum Overcast". The Globemaster II alsoperformed many other duties, including Antarctic resupply missions, refugeeevacuation, and disaster relief. The type was finally replaced by theLockheed C-5 Galaxy in 1970.

 ___________________________________________________________________ DOUGLAS C-124 GLOBEMASTER II: ___________________________________________________________________ wingspan: 53.05 meters (174 feet) wing area: 232.81 sq_meters (2,506 sq_feet) length: 39.76 meters (130 feet 5 inches) height: 14.74 meters (48 feet 4 inches) empty weight: 45,890 kilograms (101,160 pounds) MTO weight: 88,210 kilograms (194,500 pounds) max speed at altitude: 485 KPH (300 MPH / 260 KT) cruise speed: 370 KPH (230 MPH / 200 KT) service ceiling: 5,610 meters (18,400 feet) range with load: 4,675 kilometers (4,030 MI / 3,500 NMI) ___________________________________________________________________

[3] C-133 CARGOMASTER

* The last of the big Douglas prop transports was the "C-133 Cargomaster",which was designed in response to the Air Force's 1952 "Logistic CarrierSupport System SS402L" requirement, to carry outsize cargoes. Douglas beganwork on the type in early 1953, and was awarded a contract for twelve"C-133As" in 1954.

The first "C-133A" performed its initial flight on 23 April 1956. There wasno formal prototype, with initial delivery to the USAF Military Air TransportService (MATS) in August 1957. C-133As began international flight operationsthe next year, and quickly set several records for transport aircraft. Bythe time of the C-133A's operational introduction, the US was engaged in afrantic race to build ballistic missiles, and one of the primary roles of theC-133A turned out to be ferrying the missiles from the manufacturer tooperational sites.

Conceptually, the C-133 looked much more like an elongated Lockheed C-130Hercules than the C-74 or C-124. The Cargomaster had a high, straight wing,with main landing gear in fairings alongside the aircraft to ensure anunobstructed cargo bay. The cargo bay was 27.5 meters long and 3.7 metershigh (90 feet by 12 feet), had a volume of 1,210 cubic meters (13,000 cubicfeet), and was pressurized, heated, and ventilated.

Early production C-133As were powered by four P&W T34-P-3 turboprops with4,476 kW (6,000 SHP) each, but later machines were fitted with T34-P-7WAturboprops with 4,849 kW (6,500 SHP) each and water-methanol injection forboost power. The aircraft had a crew of four, and could carry 50,000kilograms (110,000 pounds) of cargo, or a fully-assembled Jupiter, Thor, orAtlas ballistic missile. 200 airline-type seats could be fitted forpersonnel hauling, at least in principle.

 ___________________________________________________________________ DOUGLAS C-133A CARGOMASTER: ___________________________________________________________________ wingspan: 54.78 meters (179 feet 8 inches) wing area: 248.32 sq_meters (2,673 sq_feet) length: 48 meters (157 feet 6 inches) height: 14.7 meters (48 feet 3 inches) empty weight: 54,550 kilograms (120,265 pounds) MTO weight: 129,700 kilograms (286,000 pounds) max speed at altitude: 580 KPH (360 MPH / 315 KT) cruise speed: 525 KPH (325 MPH / 280 KT) service ceiling: 9,150 meters (30,000 feet) range with load: 6,480 kilometers (4,025 MI / 3,500 NMI) ___________________________________________________________________

The Cargomaster could be loaded through a side door on the right side of theaircraft, or a rear door. The first 32 C-133As had a two-section rear doorthat opened up and down, with the bottom section forming a loading ramp,while the last three had side-opening "clamshell" doors that extended thecargo bay by 90 centimeters (3 feet), allowing the aircraft to carry anassembled Titan missile. The 35 C-133As were followed by 15 "C-133Bs", withthe clamshell doors and uprated Pratt & Whitney T34-P-9W turboprops providing5,595 kW (7,500 HP) each. The last Cargomaster was rolled out in April 1961.

The C-133 served through the 1960s. It was a big aircraft that gave the AirForce a very useful heavy-lift capability, but it was not very successful.The turboprop engines were unreliable, leading to poor flight availabilityrates, and they also caused excessive vibration. It had a number of otherproblems as well, some of which led to disastrous accidents and groundings.It was never used as a troop transport, and it appears to have been generallydisliked or even feared by anyone who had anything to do with it.

Airframe fatigue problems finally led to the Cargomaster's withdrawal fromservice in 1971, to the relief of all concerned. It was replaced by the C-5Galaxy, which ironically would also suffer from premature fatigue problems.A handful of C-133s remained in commercial air cargo service for a few yearsafter the type's withdrawal from military service. A number remain ondisplay, but none are flying any more.

[4] FOOTNOTE: LOCKHEED R6V CONSTITUTION

* As a footnote to the C-124 story, Lockheed developed a roughly comparableoversized four-piston transport, the "Constitution", though only two weremade. It evolved out of a 1942 US Navy requirement for a large transportaircraft to follow the Navy's big flying boats. The aircraft would bepressurized and able to carry 7,900 kilograms (17,500 pounds) of cargo 8,000kilometers (5,000 miles) at a cruising altitude of 7,600 meters (25,000 feet)and a speed greater than 400 KPH (250 MPH), with a buy of 50 aircraftprojected. Pan Am was also involved in the work, since the aircraft seemedpromising as a commercial airliner.

Initial flight of the "XR6O-1 Constitution" was on 9 November 1946, withthe second following on 9 June 1948. The Constitution had some similaritiesto the earlier Lockheed Constellation airliner, being an all-metal aircraftwith retractable tricycle landing and a low wing with four piston engines.It was, of course, much bigger, with a double deck -- with a "figure 8" or"double bubble" cross-section -- and a conventional tail assembly.

The engines of the Constitutions were originally P&W Wasp Major R-4360-18radials with 2,240 kW (3,000 HP) each, driving four-bladed variable-pitchpaddle propellers. They weren't powerful enough, so they were upgraded toR-4360-22-W engines with water-methanol injection for power boost, raisingthe power output to 2,610 kW (3,500 HP). There were also experiments withrocket-assisted take-off (RATO), using six RATO boosters under the wingsclose to the fuselage, to reduce the take-off field length.

 ___________________________________________________________________ LOCKHEED R60/V CONSTELLATION: ___________________________________________________________________ wingspan: 57.6 meters (189 feet 1 inch) wing area: 335.4 sq_meters (3,610 sq_feet) length: 47.6 meters (156 feet 1 inch) height: 15.4 meters (50 feet 4 inches) empty weight: 51,610 kilograms (113,780 pounds) operating weigh: 72,600 kilograms (160,000 pounds) MTO weight: 83,460 kilograms (184,000 pounds) max speed at altitude: 490 KPH (300 MPH / 265 KT) cruise speed: 420 KPH (260 MPH / 230 KT) service ceiling: 8,700 meters (28,600 feet) range: 8,670 kilometers (5,390 MI / 4,680 NMI) ___________________________________________________________________

The nose gear had twin wheels and retracted forward, while each main gearassembly had four wheels in a 2x2 bogey arrangement, retracting inward fromthe wings towards the fuselage. The Constitution carried 12 crew and 92passengers on the upper deck; the lower deck was intended for cargo carriage,though it could be fitted with 72 passenger seats. The two were delivered tothe US Navy in 1949, operating under the designation of "R6O-1" to fly theCalifornia-Hawaii shuttle. In 1950, their designation was changed to"R6V-1".

The Constitutions proved impractical, being expensive to operate andunderpowered. There was consideration of a turboprop-powered version usingthe Wright T35 Typhoon engine, with 4,450 kW (6,090 ESHP), but the Typhoonprogram was a failure and it didn't happen. No more Constitutions werebuilt. The two machines were retired in 1953, to be sold off to commercialbuyers, with one ending up in Las Vegas, Nevada, as a display, to beultimately scrapped. The other ended in Florida, with nobody having a realplan of what to do with it, until it was finally scrapped as well. The R6Vis said to have been the biggest fixed-wing aircraft ever flown by the USNavy, but ended up with no other distinction.

[5] COMMENTS, SOURCES, & REVISION HISTORY

* This document began life as a set of notes from materials found on THEAVIATION ZONE and THE GLOBEMASTER TRIBUTE PAGE websites. More formalsources include:

• THE COMPLETE ENCYCLOPEDIA OF WORLD AIRCRAFT, edited by David Donald, Barnes & Noble, 1997
• AIRCRAFT OF THE UNITED STATES MILITARY AIR TRANSPORT SERVICE by Nicholas M. Williams, Midland Publishing, 1999

* Illustrations details:

• Douglas C-124C / Warner-Robbins Air Museum GA USA / 2008 / author
• Douglas C-74 Globemaster over Long Beach CA USA / USAF?
• Douglas C-124C Globemaster over Oakland CA USA / USAF?
• Douglas C-133A Cargomaster / USAF Museum OH USA / 2004 / author
• Douglas C-74 Globemaster over Long Beach CA USA / USAF?
• Lockheed R6V Constitution at San Francisco International Airport / author unknown

* Revision history:

 v1.0.0 / 01 feb 02 v1.0.1 / 01 feb 04 / Review & polish. v1.0.2 / 01 mar 05 / Review & polish. v1.0.3 / 01 mar 07 / Review & polish. v1.0.4 / 01 mar 09 / Review & polish. v1.0.5 / 01 feb 11 / Review & polish. v1.0.6 / 01 jan 13 / Review & polish. v1.0.7 / 01 feb 14 / Review & polish. v1.0.8 / 01 jan 16 / Review & polish. v1.0.9 / 01 dec 17 / Review & polish. v1.1.0 / 01 nov 19 / Review & polish. v1.1.1 / 01 sep 21 / Review & polish. v1.2.0 / 01 dec 22 / Added R6V Constitution.