Cargo Aircraft Designations

Last revised August 11, 2007




Here are the designations of US Army and US Air Force transport aircraft. The C for Cargo designation for Army transport aircraft was originally introduced in May of 1924

There were two series of C-planes, one beginning in 1924 and ending in 1962, and another one beginning in 1962 and continuing to the present day.



Original C-Series (1924-1962)


Here are the aircraft in the original C-series, beginning with the C-1 and ending in 1962 with the C-142.

Douglas C-1			Single-engine biplane military transport.
				One 435 hp Liberty V-1650-1 water-cooled engine.
				Best known for participation in early mid-air
				refuelling experiments (1929).  26 built.
				Standard USAAC transport until 1929.

Fokker-Atlantic C-2		Military version of Fokker F-VIIA/3m trimotor
				transport.	Eleven built.

Ford/Stout C-3			Designation given to eight 4-AT-B commercial 
				trimotor transports acquired by USAAC.  
			
Ford/Stout C-4			Designation given to 5-AT trimotor commercial 
				transports acquired by USAAC.  5 built.
				radials.

Fokker-Atlantic C-5 		Military version of 12-passenger commercial   
				Fokker F-10A.  Three Wright R-975 radials
				in place of the P&W Wasps of the commercial
				version.  Only one ordered.

Sikorsky C-6			Military version of 12-seat S-38A twin-engined
				sesquiplane amphibian.  Two 450 hp R-1340-7
				radials.  112 mph crusing speed at sea level.
				Total of eleven procured.

Fokker-Atlantic C-7		Ten-passenger military transport.  XC-7 was
				a C-2A with engines replaced by 3 330 hp
				Wright R-975 radials.  It and four other 
				similarly re-engined C-2As were redesignated
				C-7.  C-7A was designation given to six 
				production planes which had a slightly larger
				wing, new vertical fins, and fuselages patterned
				after the commercial F-10A.
				Max. speed: 136 mph.

Fairchild C-8			Designation given to commercial Model 71 single-
				engine light cabin monoplanes used by USAAC as
				light transports and photographic survey 
				aircraft.  Some were briefly designated F-1.
				An unusual feature was a folding wing.

Ford/Stout C-9			Designation given to C-3 trimotor transports
				after being re-engined with 300 hp. R-975-1
				radials.	

Curtiss XC-10			Designation given to one Curtiss Robin W 
				delivered to USAAC.  As compared to standard
				civil Robins, C-10 had increased wing 
				dihedral, enlarged vertical tail surfaces,
				raised thrust line.  Used for early 
				experiments in radio-controlled unpiloted
				aircraft.

Consolidated Y1C-11		Designation given to a single Consolidated 
				Model 17 Fleetster 6-7 seat passenger and
				mail transport monoplane acquired by USAAC in
				1932.  One Wright R-1820-1 radial.

Lockheed Y1C-12			Designation given to a single Lockheed Vega DL-1
				commercial monoplane acquired by USAAC for
				tests as fast command transport. 

C-13				Designation not used.  Either for superstitious reasons
				or to avoid confusion with the Curtiss O-13B, a transport
				version of the O-13. 

Fokker-Atlantic C-14		Military version of six-seat Fokker F-14 single-
				engine parasol-wing commercial transport.
				20 ordered as Y1C-14s with 525 hp Wright
				R-1750-3 Cyclone radial.  

Fokker-Atlantic C-15		Ninth Y1C-14 was converted as a specialized
				ambulance aircraft and was redesignated
				Y1C-15.  Single C-15 was a commercial Fokker
				F-14 acquired from General Aviation.

Fokker-Atlantic C-16		Designation given to one commercial F-XI
				amphibian acquired by USAAC for tests.

Lockheed Y1C-17			Designation given to a single Lockheed Vega 
				DL-1B Special commercial monoplane acquired by
				USAAC for tests in 1930.  All-metal fuselage,
				wire-braced single strut landing gear, NACA
				cowling, and wheel pants.  At the time, the
				Y1C-17 was the fastest aircraft of any type
				in USAAC service (221mph). 

Boeing C-18			Designation given to commercial Model 221
				Monomail acquired by USAAC for tests.

Northrop C-19			Designation given to three Alpha 1 light
				transports acquired by USAAC.

Fokker-Atlantic C-20		Designation given to F-32 commercial transport
				acquired by USAAC for tests.

Douglas C-21			Designation given to military version of Douglas
				Dolphin commercial amphibian transport.  Two
				350 hp Wright R-975-3 radials mounted in 
				separate nacelles above the high-mounted wing.

Consolidated Y1C-22		Military version of Model 17 Fleetster 6-7 seat
				passenger and mail transport.  Improved version
				of C-11. Three built.

Lockheed Y1C-23			Designation given to a single Lockheed Altair
				DL-2A two-seat single-engined commercial 
				monoplane acquired by USAAC in 1931 for use as 
				transport for high-ranking military and civil 
				officials. 

American Y1C-24			Military version of commercial American Pilgrim
				single-engined transport.  One 575 hp Wright
				R-1820-1 Cyclone.  Ten seats.  Used by USAAC
				as general utility aircraft.  Four built.

Lockheed Y1C-25			Designation given to prototype Lockheed Altair 
				8D two-seat single-engined commercial monoplane
				acquired by USAAC in 1931. 

Douglas C-26			Extensively revised version of C-21 amphibian
				transport.  Two 300hp P&W R-985-1 radials in
				nacelles above the high-mounted wing.  Larger
				wing area, longer fuselage, higher vertical
				tail, auxiliary fins removed.  Later 
				redesignated OA-4.  8 built. 

Bellanca C-27			Adaptation of civilian Airbus four-seat
				cabin sesquiplane light tranport to military
				transport/cargo requirements.
				Total of 15 built

Sikorsky C-28			Commercial S-39C with R-985-1.  Only one built.

Douglas C-29			Version of C-26 amphibian transport with more
				powerful 550 hp P&W R-1340-29 radials. Two 
				built.

Curtiss YC-30 Condor		Military version of T-32 Condor biplane civil
				transport. Two supplied to US Army.

Kreider-Reisner C-31		High-wing freighter.  R-1820-25 engine.  Only
				one built.

Douglas C-32			Original XC-32 was a military version of the 
				DC-2 commercial airliner.  Differed from the
				the commercial airliner only in minor details
				and in being powered by 750 hp Wright R-1820-12
				radials.  Only one built.  Designation C-32A
				given to 24 DC-2 commercial airliners acquired 
				by the Army in 1942 from civilian sources
				(including 5 aircraft previously acquired by the
				British Purchasing Commission).

Douglas C-33			Military cargo version of DC-2 series.  Enlarged
				vertical tail, reinforced cabin floor, large
				cargo door.  18 built.

Douglas C-34			Military version of DC-2 commercial airliner.
				Similar to XC-32 except for minor revisions in 
				interior arrangements. Two built.

Lockheed XC-35			Experimental high-altitude adaptation of Model
				10E Electra light transport.  Completely 
				circular cross-section fuselage, smaller cabin
				windows. 

Lockheed C-36			Three Lockheed Model 10A Electra twin-engined 
				light transports were purchased by USAAC "off-
				the-shelf" in 1937 
				In 1942, 15 12-place Model 10As were "drafted"
				by USAAC and designated C-36A.  2 450 hp.
				P&W R-985-13s.  Surviving aircraft were 
				returned to civil register beginning in 1944.
				Four similar Model 10Es became C-36B.  Two
				600 hp P&W R-1340-49 radials.
				Seven 10-place Model 10Bs (450 hp Wright R-975
				Whirlwinds) became C-36C.
				Maximum speed: 205 mph.
				Redesignated UC-36 in 1943.

Lockheed C-37			Designation given to a single Lockheed Model 10A
				Electra ten-passenger commercial transport
				ordered "off-the-shelf" by War Department in 
				1937.  450 hp P&W R-985-13 radials.  Assigned
				to National Guard as staff transport.
				Redesignated UC-37 in 1943. 

Douglas C-38			Military version of DC-2 twin-engine commercial
				airliner.  Had DC-3 outer wing "married" to a
				DC-2 fuseslage and center section.  Prototype
				of the series of aircraft sometimes known
				as "DC 2 1/2".  One built. 

Douglas C-39			Twin-engine military transport.  Production 
				version of C-38 aerodynamic prototype.  Had     
				DC-3 outer wing "married" to a DC-2 fuselage
				and center section.  Two 795 hp Wright
				R-1820-55 Cyclone radials.  Used primarily as
				cargo transport.  35 built. 

Lockheed C-40			Military version of Lockheed Model 12-A Electra
				Junior commercial light transport. 

Douglas C-41			C-41 was a "one-off" version of C-39 intended as
				staff transport for Chief of Staff of Army Air
				Corps.  Two 1200 hp P&W R-1830-21 radials.
				Generally similar to C-39.  One built.
				C-41A was military version of DC-3A reequipped
				with military instruments and communication
				equipment.  Two 1200 hp P&W R-1830-21 radials.
				Served as staff transport.  One built.

Douglas C-42			Staff transport for use by Commanding General
				of the Air Force GHQ.  Similar to C-41 but
				powered by two 1000 hp. Wright R-1820-21   
				radials.  One built.

Beechcraft UC-43		Designation given to civilian Model 17 five-seat
	Traveller		staggerwing biplane cabin transport acquired
				by Army and used as light personnel transport.

Messerschmitt C-44			Designation given to one Bf 108B Taifun single-
				engine cabin monoplane purchased in Germany
				for use by US military attache in Berlin. 

Beechraft C-45			Military transport version of civilian Model 18S
	Expeditor			twin-engine, twin tail light transport.

Curtiss C-46 Commando		Twin-engine personnel/cargo transport.  Two
				P&W R-2800 radials.  3182 built

Douglas C-47 Skytrain		Redesign of civilian DC-3 twin-engine commercial
				airliner for role of military cargo transport.
				Most widely used military transport
				in World War 2.  Used by RAF as Dakota, by 
				U. S. Navy as R4D. 

Douglas C-48			Designation given to 36 DC-3As taken over from
				the airlines and used by the Army as personnel
				transports. 

Douglas C-49			Designation given to 138 DC-3s taken over from
				the airlines and used by the Army as personnel
				transports. 

Douglas C-50			Designation given to 14 DC-3s taken over from
				airline orders and used by the Army as personnel
				transports. 

Douglas C-51 			Designation given to a single DC-3 taken over 
				from airline order and used by the Army as 
				paratroop transport. 

Douglas C-52			Designation given to 6 DC-3s taken over on the
				production lines before delivery and fitted
				as paratroop transports

Douglas C-53			Paratroop transport version of C-47.  Fixed
Skytrooper			metal seats, no large cargo door, no reinforced
				floor, no astrodome. 

Douglas C-54 Skymaster		Military version of DC-4 four-engine commercial
				transport.  Both cargo and troop transport
				versions built.  Navy version was R5D.
				Total of 1084 built.

Curtiss C-55			Prototype CW-20T civil transport purchased by
				US Army for use as troop transport

Lockheed C-56 Lodestar		Military version of civilian Model 18 Lodestar
				twin-engine commercial airliner.  Crew 3, 14 
				passengers.  36 acquired in 1942-43 from various
				civilian sources and used by Army as general
				personnel transport

Lockheed C-57 Lodestar		Military version of civilian Model 18 Lodestar
				twin-engine commercial airliner.  Crew 3, 14
				passengers.  Impressed under different contracts
				than C-56 series. 20 acquired from various
				civilian sources and used by Army as general
				personnel transport. 

Douglas C-58			Designation given to two B-18A bombers modified
				as unarmed cargo transports.

Lockheed C-59 Lodestar		Designation given to 10 civilian Model 18-07 
 				Lodestar commercial airliners acquired by Army  
				from various sources and used as general 
				personnel transport.  

Lockheed C-60 Lodestar		C-60 was designation given to 36 Model 18-56 
				twin-engine commercial airliners acquired from
				civilian sources and used by Army as general
				personnel transport.  C-60A was designation
				given to 325 aircraft of the same general type
				built from scratch as military paratroop
				transports. 

Fairchild UC-61			Military version of Model 24 civilian four-seat
	Forwarder			high-wing single-engine cabin monoplane.  
				Used by Army as general light utility transport.

Waco C-62				Projected twin-engined, high-wing cargo
				transport.  Order for 253 was cancelled before
				any could be built.

Lockheed C-63			Proposed transport variant of A-29 Hudson
				light attack bomber.  Cancelled before any
				could be produced.

Noorduyn C-64 Norseman		Light transport and communication aircraft.
				Single engine, high wing cabin monoplane powered
				by 600 hp P&W R-1340 Wasp radial.  Crew 2,
				up to 8 passengers.  746 built.

Stout C-65			Designation given to Stout Skycar used by USAAC
				for tests.

Lockheed C-66 Lodestar		Designation given to a single civilian Model 
				18-10 Lodestar twin-engine commercial airliner
				impressed by the Defense Supply Corporation.

Douglas UC-67			Designation given to 18 B-23 Dragon bombers  
				converted to transport role and stripped of all
				armament. 
 
Douglas C-68			Designation given to two DC-3A twin-engine
				commercial airliners taken over from the
				airlines and used by Army as personnel 
				transports.  Two P&W R-1830-92 radials.

Lockheed C-69			Originally initiated as the L.049 four-engined
	Constellation		commercial airliner explicitly designed to meet
				the requirements of TWA.  Taken over as a 
				military project following Pearl Harbor, and
				modified to meet troop transport needs..
				Only 20 were delivered as C-69 to
				USAAF before end of World War 2.  At the end
				of the war, USAAF decided to standardize on the
				Douglas C-54 as its four-engined transport of
				choice, and most of the C-69s were promptly
				declared surplus and sold on the commercial market. 
				Production of the basic design was turned over 
				to the civil market, which was to lead to the
				famous Constellation series of airliners.  

Howard UC-70			Designation given to 20 Howard DGA-8,9,12, and 
				15 commercial four-seat high-wing cabin 
				monoplanes acquired from various sources and 
				used by Army for general light utility transport
				duties.

Spartan UC-71			Designation given to 16 Model 7W Executive
				civilian 5-seat cabin monoplanes acquired by the
				USAAF.  One 450 hp P&W R-985 radial.  212 mph.

Waco UC-72			Designation given to 44 Waco civilian cabin
				biplanes impressed by USAAF for use as staff
				transports and station ferries.  Sixteen
				different Waco models were included, some with
				tricycle undercarriage.

Boeing C-73			Designation given to 27 Boeing 274 twin-engined
				commercial transports "drafted" by USAAF in
				1942.  Small airline cabin and doors prevented
				use as heavy cargo and troop transport, so they
				were used primarily for crew ferrying and later
				for training.

Douglas C-74 			Long range heavy transport aircraft.  Four 3250
	Globemaster		hp P&W R-4360-69 Wasp Major radials.  312 mph at
				20,800 feet.  Max range of 7250 mi.  Could carry
				125 troops or up to 48,000 lbs of cargo.
				Only 14 built.  Served only briefly with USAAF,
				then declared surplus and sold on the commercial
				market.		

Boeing C-75 Stratoliner		Designation given to 5 Boeing 307 Stratoliner
				commercial airliners impressed into USAAF 
				service.  Four Wright GR-1820 Cyclone radials.
				Pressurized cabin, 33 passengers.  241 mph at
				6000 feet.  Returned to commercial users after
				the war.

Curtiss C-76 Caravan		Twin-engined transport.  Structure largely made
				of wood to minimize use of critical materials.  Aluminum
				shortage failed to materialize and program was
				canceled after only 25 had been built.

Cessna C-77			Designation given to eleven Model DC-6
				planes impressed by USAAF.

Cessna UC-78 Bobcat		Military version of T-50 civilian 5-seat twin
				engine cabin monoplane.  Used by Army as light
				personnel transport.  3356 built.

Junkers C-79			Designation given to one Junkers Ju 52/3m
				acquired by USAAF as war prize from Brazil.

Harlow C-80			Designation given to four Harlow PJC-2 civilian
				aircraft impressed into service with USAAC.

Stinson UC-81 Reliant		Designation given to 47 privately-owned Stinson
				Reliant commercial 5-seat high-wing monoplanes 
				impounded by USAAF and used for general utility
				transport duties.  Wartime production of Reliant
				was under designation of AT-19.

Fairchild C-82 Packet		Twin-engined high-wing, twin boom, twin-tailed
				tactical freighter and troop transport.  Total of 220 built.

Piper C-83			Designation given to seven Cub aircraft
				impressed into service with USAAC in 1942.
				Later redesignated L-4F.

Douglas C-84			Designation given to four DC-3Bs taken over from
				the airlines and used by the Army as personnel 
				transports. 

Lockheed UC-85			Designation given to a single Model 9-D2 Orion
				six-passenger commercial transport impressed into
				service by USAAF in 1942.  

Fairchild C-86			Designation given to nine commercial F-24-R-40
				aircraft acquired by USAAF.
 
Consolidated C-87			Transport version of B-24 Liberator.  Bomb bay
	Liberator Express		and rear fuselage replaced by passenger
				compartment.  Loading door cut into rear
				fuselage.  286 built.

Fairchild C-88			Designation given to two F-45 low-wing
				commercial aircraft acquired by USAAF.

Hamilton C-89			Designation given to H-47 high-wing commercial
				aircraft acquired by USAAF.

Luscombe C-90			Designation given to two Model 8 high-wing
				commercial planes acquired by USAAF.

Stinson C-91			Designation given to SM-6000 trimotor transport
				acquired by USAAF.

Akron-Funk UC-92		Designation given to one B-75-L commercial
				aircraft acquired by USAAF.

Budd C-93A Conestoga		Twin-engined stainless-steel transport.  
				Cancelled by Army but ordered by Navy as
				RB-1.

Cessna C-94			Designation given to three C-165 commercial
				aircraft acquired by USAAF.

Taylorcraft UC-95			Designation given to 7 commercial BL-65 light
				high-wing monoplanes taken over by USAAC and
				used as light communications aircraft.  Later
				redesignated as L-2F.  One Lycoming O-145-B1
				engine.

Fairchild UC-96			Designation given to three Model 71 commercial
				single-engined cabin monoplanes "drafted" by
				USAAF in 1942 and used for photographic survey
				duties.

Boeing C-97			Four-engined aerial refuelling aircraft.
	Stratofreighter		Four P&W R-4360 radials.  375 mph at 25,000 ft.
				Midair refuelling boom under rear fuselage.
				Can be converted into transport role.  When
				acting as transport, can carry up to 96 fully-
				equipped troops.  888 built.

Boeing C-98			Designation given to four examples of Model 314
				flying boat requisitioned by USAAF from PAA.
				Later transferred to US Navy.

Convair XC-99			Transport version of Convair B-36 strategic
				bomber.  Two decks.  Capable of carrying 400
				equipped troops, 300 stretchers, or 100,000
				pounds of cargo.  Six R-4360-41 radials.
				Only one built

Northrop UC-100			Designation given to one commercial 2D Gamma
				single-engine mail-carrying and special 
				purpose aircraft acquired by USAAF from Texaco.
				in 1942.  Used as utility transport until 1943.

Lockheed UC-101			Designation given to a single civilian Lockheed
				Model 5C Vega single-engine light transport 
				"drafted" by USAAF in 1942.  Returned to civil
				register in 1944

Rearwin C-102			Designation given to three Speedsters acquired
				by USAAF.

Grumman UC-103			Designation given to two Grumman G-32 two-seat
				demonstration aircraft (conversion of single
				seat F3F biplane fighter) impressed by USAAF
				and used as utility light transports and ferry
				pilot trainers.

Lockheed C-104			Model 118 transport derived from civilian
				Lodestar transport.  Redesignated C-60C, then
				cancelled.

Boeing C-105			Conversion of XB-15 experimental long-range
				bomber to cargo transport. 

Cessna C-106			High-wing twin-engine transport.  Two used
				for tests.

Stout C-107			Skycar III commandeered in 1942 for tests.

Boeing YC-108			Transport version of B-17 bomber.  XC-108
				was B-17E converted as VIP transport for 
				General McArthur. All armor and armament was
				removed (except for nose and tail guns) and
				interior was fitted out as office.
				YC-108 was B-17F converted to VIP transport
				in similar manner as XC-108.
				XC-108A was B-17E converted to experimental
				cargo transport.
				XC-108B was tanker conversion of B-17F.

Consolidated C-109			Designation given to 200 B-24 Liberator bombers
				converted for use as aerial tankers to support 
				China-based B-29 squadrons.

Douglas C-110			Designation given to three DC-5 twin-engined
				commercial transports impressed by Army in Australia
				from Dutch operators. 

Lockheed C-111			Designation assigned to three Model 14-WF62
				Super Electra commercial airliners flown to
				Australia in 1942 to avoid capture by Japanese.
				Purchased by USAAF for service with Allied
				Directorate of Air Transport. 

Douglas XC-112			Pressurized development of C-54E Skymaster
				military transport.  Longer fuselage, larger
				rectangular windows in place of circular
				portholes of C-54.  Four 2100 hp P&W R-2800-34
				radials.  End of war resulted in lack of
				production orders.  Became basis of DC-6 series
				of commercial airliners.

Curtiss XC-113			Conversion of C-46G to test General Electric
				TG-100 turboprop.  The turboprop was in star-
				board nacelle, original R-2800 radial in port
				nacelle.  Arrangement found to be completely
				unmanageable.  Program terminated by a ground
				accident.  Aircraft never flown.

Douglas XC-114			Proposed Allison V-1710 powered version of C-54.
				Not built.

Douglas XC-115			Projected Packard Merlin V-1650-209-powered
				version of XC-114.  Not built.

Douglas XC-116			Proposed Allison V-1710 powered version of C-54.
				Similar to XC-114, but with thermal deicers.  Not built

Douglas C-117			Twin-engine staff transport externally similar
				to C-47, the military version of the DC-3
				commercial airliner.  Combination of original
				features developed for DC-3 with latest 
				improvements developed for C-47. 

Douglas C-118A			Military version of commercial DC-6A freighter.
				Can carry up to 76 fully-equipped troops or
				up to 27,000 pounds of cargo.  Four 2500 hp
				P&W R-2800-52W radials.  372 mph at 18,000 ft.
				101 built.  74 troops or 27,000 lbs. of cargo.
				40 R6D-1 (Navy logistic transport versions of
				DC-6A) were also transferred to USAF. 

Fairchild C-119 			Twin-engine, twin boom, twin tail cargo and
	Flying Boxcar		troop transport.  Evolved from C-82 by 
				relocating the flight deck, widening the
				fuselage, and providing more powerful engines.
				Two Wright R-3350 radials.  296 mph at 17,000
				feet.  Can carry up to 62 fully-equipped troops
				or a 30,000 pound cargo load.  Clamshell doors
				in rear cockpit can accommodate wheeled or
				tracked vehicles.

Fairchild XC-120 			Experimental version of C-119 with detachable
	Packplane			cargo pod.  Aircraft could be flown with or
				without the pod. Only one built.

Lockheed C-121			C-121A was military version of commercial Model
				749 Constellation.  Military transport versions and
				radar picket versions both built.
				One was used by President-elect Eisenhower as 
				*Colombine II* in 1952.  

Chase YC-122			Twin-engined assault transport evolved from
	Avitruc			the all-metal XCG-18A 30-seat troop transport
				glider.  Only nine built.  After evaluation by USAF,
				declared surplus and disposed of on the
				commercial market.

Fairchild C-123 			Twin-engined assault transport  Two P&W R-2800
	Provider			radials.  Can accommodate up to 60 fully-
				equipped troops or a 24,000 lb cargo load.
				300 built.  Achieved some notoriety in Vietnam
				as carrier plane for "Agent Orange" defoliant.

Douglas C-124			Four-engine long-range military transport.
	Globemaster II		Based on C-74 wing, engines, and tail, married
				to a new, deeper fuselage.  Clamshell doors
				in lower fuselage for cargo loading.

Northrop YC-125 Raider		Short-field light assault transport and Arctic
				rescue aircraft.  Three 1200 hp Wright
				R-1820-99 radials. 
				Used mainly for mechanical training until
				disposed of as surplus in 1955.

Cessna LC-126			Designation given to 78 civilian Model 195
				high-wing 4/5-seat cabin monoplanes ordered
				by USAF.  Used primarily for instrument
				training and light transport duties.  One
				Jacobs R-775 air-cooled radial.  180 mph.

C-127				Initial designation given to DeHavilland 
				Beaver single-engine utility monoplane.
				Later redesignated L-20 and then eventually
				to U-6.
				Designation later reassigned to Boeing-built
				four-engined turboprop transport.  Cancelled
				while still on drawing board.

Fairchild C-128			Variant of C-119.  Redesignated C-119D and E.

Douglas YC-129			Designation given to a single Super DC-3 ordered
				by USAF in 1951 for trials.  Larger horizontal
				and vertical tail surfaces with squared tips.
				New outer wing panels with squared tips.  

Lockheed C-130 			The famous Hercules assault transport!!!
	Hercules			Four Allison T-56 turboprops.  High wing,
				cargo door in rear fuselage.  345 mph at 
				18,000 ft.  Probably the most successful
				military transport since the Douglas C-47.
				Used by just about every air force in the 
				Production still continues today.

Convair C-131			Military version of Convair 240-440 series of
	Samaritan			twin-engine commercial airliners.  Used by USAF
				as general aeromedical, cargo, and personnel transport

Douglas XC-132			Proposal for heavy cargo aircraft.  High-
				mounted wing with 25 degree sweepback and
				four 15,000 hp. P&W T-57 turboprops  Cancelled in
				1956 after only a mockup was built. 

Douglas C-133 			Four-engine, long-range military cargo 
	Cargomaster		transport.  Clamshell-type cargo loading doors
				in rear fuselage.  Four 5700 hp P&W T34-P-3 
				turboprops.  Total of 50 built 

Stroukoff C-134			Modification of C-123B to test a boundary 
				layer control system.  Two Wright R-3350-89A 
				radials with four bladed props.  Longer and
				wider fuselage, much-modified undercarriage.
				Small endplane fins and rudders replaced the
				dorsal fin.

Boeing KC-135			Four engine midair refuelling tanker.
	Stratotanker 		Four P&W J-57 jets/TF-33 turbofans.  Versions for
				Midair refuelling, long range transport, cargo,
				photo mapping, electronic
				reconnaissance, readiation measuring, space
				communication, weather reconnaissance, nuclear
				blast detection, aerial command posts, and
				laser weapons testing.

Fairchild C-136			Proposed improved version of C-123B Provider.
				Cancelled early in the design stage

Boeing VC-137			Military version of commercial 707 transport.  Used by
				USAF for use as personnel and high-priority
				cargo transports.  Two used by President as "Air 
				Force One".  

C-138				Reserved for Fairchild F-27 but not taken up

Lockheed SC-139			Reserved for USAF transport version of Navy P2V Neptune.
				Cancelled before anything could be built
 
Lockheed C-140 Jetstar		Four-engined jet utility transport and trainer.
				Four P&W J-60 turbojets.  573 mph at 36,000 ft.

Lockheed C-141			Four-jet long-range strategic transport.
	Starlifter		Four P&W TF-33 turbofans.  570 mph at sea level.
				High mounted swept wing, high mounted t-tail.
				Clamshell cargo doors in rear fuselage.

LTV-Hiller-Ryan XC-142A		Four-engined V/STOL tactical transport.  Four
				General Electric T-64 turboprops mounted on a
				wing which can be tilted vertically for VTOL.  Not
				ordered into production. 
				
Curtiss-Wright XC-143		Reserved for Model 200 VTOL but not approved.  Became X-19 instead.
The original C-series seems to end here.




New C-Series (1962-Present)


In 1962, the Defense Department introduced a scheme under which Army, Navy, Marine Corps, and Air Force aircraft would all be designated in exactly the same manner. In addition, they decided to start the C-series over again from one. However, Air Force transports in the C- category still in service (such as the C-141) had their designations unchanged.

Here are the post-1962 C-series aircraft:

New Transport Series



Designation Description
Grumman C-1A Trader Transport version of S-2 Tracker twin-engine carrier-based antisubmarine aircraft. Used by Navy as general utility shipboard transport and training aircraft
Grumman C-2A GreyhoundTransport version of E-2A Hawkeye shipboard early-warning aircraft
Martin VC-3ATwo commercial Martin 4-0-4 airliners acquired by US Coast Guard in 1951. Redesignated VC-3A in 1962. Later transferredto US Navy.
Grumman C-4A Academe Military version of Gulfstream twin-engine business transport intended for U. S. Coast Guard and U. S. Navy as VIP transport and training aircraft
Lockheed C-5 Galaxy Four-engined long range military strategic transport. Four General Electric TF-39 turbofans.
Beechcraft VC-6A One King Air 90 commercial executive aircraft delivered to USAF as VIP transport.
DeHavilland Canada C-7A Designation given to 134 US Army DHC-4 Caribou twin-engined light tactical transports taken over by USAF.
DeHavilland Canada C-8A Designation given to 4 US Army DHC-5 twin- turboprop light tactical transports taken over by USAF
Douglas C-9A/B Nightingale/Skytrain II C-9A Nightingale is aeromedical evacuation transport. Basically similar to commercial DC-9-32CF convertible freighter.
McDonnell-Douglas KC-10A Extender Flight refueling tanker and military freighter adaptation of commercial DC-10 airliner. Three General Electric CF6 turbofans. C-10 designation was originally allocated to a military version of British Aerospace HP-137 Jetstream 3 executive transport and feederliner. Order cancelled before any could be delivered.
Gulfstream VC-11A Designation given to Gulfstream II executive aircraft purchased by US Coast Guard for use as a VIP transport.
Beechcraft C-12 Huron Designation given to versions of the Beechcraft Super King Air 200 ordered for use by all the services.
C-13 Not used (I assume for superstitious reasons)
Boeing YC-14 Advanced Medium STOL transport (AMST) prototypes. Two built. Two CF6-50 turbofans and USB system. Did not go beyond prototype stage.
McDonnell-Douglas YC-15 Advanced Medium STOL Stransport (AMST). Four JT8D-17 turbofans and EBF systems. Did not go beyond prototype stage.
C-16 Designation assigned to Cessa Caravan CE-208 intended for use by Army in FLIR missions against leftist rebels in El Salvador and the forces of Nicaragua. Aircraft not accepted.
McDonnell-Douglas C-17 Globemaster III Long-range heavy airlifter project. Four 37,000 lb. st. P&W F117-PW-100 turbofans.
Boeing C-18Designation given to eight ex- airline Boeing 707-320Cs acquired by USAF in 1981.
Boeing C-19 Version of commercial Boeing 747 personnel cargo transport ordered for Air National Guard. Order cancelled before any could be acquired. One of my references has 19 examples being modified for Civil Reserve Air Force use in case of national emergencies. Planes remain in civilian service until called up by the Secretary of Defense.
Gulfstream C-20A Designation given to military version of Gulfstream III business jet used for special mission support and electronic surveillance roles.
Gates Learjet C-21A Military version of Gates Learjet Model 35A executive jet. Used for delivery of high- priority and time-sensitive cargo, as well as for general light transport and medevac duties
Boeing C-22C-22A was ex-airline 727-100 operated by USAF as VIP transport for US Southern Command in Panama. C-22B was designation given to four ex-airline Boeing 727-100 three-jet transports used by Air National Guard to carry inspection and training teams from Washington to various points in the USA.
Shorts C-23A Sherpa Light freighter and utility aircraft based on Shorts 330-200 30-passenger commercial transport.
Douglas EC-24A Designation given to DC-8-54F acquired by US Navy for use as "electronic aggressor" aircraft with fleet electronic warfare support group.
Boeing VC-25A Extensively-modified Boeing 747-200 used as presidential aircraft
Fairchild C-26A Military version of 19-seat Metro 3 twin- turboprop light commercial transport. Used as operational support transport by Air National Guard units.
Alenia C-27A Alenia G-222-710 twin-turboprop transport acquired for use as short takeoff transport in the Canal Zone.
Cessna C-28 One commercial Model 404 Titan ordered for use by US Navy as personnel transport.
British Aerospace C-29A Military version of British Aerospace 125-800 light corporate executive transport. Six ordered by USAF for the combat flight inspection and navigation mission roles.
C-30 Designation skipped for unknown reasons.
Fokker C-31A Designation applied to two Fokker F-27s used by US Army for Golden Knights parachute team.
Boeing C-32A Designation applied to four Boeing 757-200s acquired for USAF for use as executive VIP transports.
C-33 Non-Developmental Airlift Aircraft project for a commercial freighter to supplement the C-17. Project cancelled before anything was ordered. At the time, the C-17 project was in trouble and Boeing proposed a version of the 747-400F to supplement a reduced C-17 acquisition. The proposal was rejected. Lockheed made a similar proposal (C-5D) which was also rejected.
C-34 Designation skipped at the request of the US Army when the latter requested the MDS for what later became th UC-35A. The Army wanted to avoid confusion with "T-34"
Cessna UC-35A Military version of Citation V Ultra (Model 560)
YFC-36A Reserved for a four-engined aircraft, but not used. Believed to have been the original designation for the YAL-1A airborne laser prototype
Gulfstream Aerospace C-37A Gulfstream Vs acquired by USAF for technical and logistics support.
Galaxy Aerospace C-38A Military version of Model 1125A Astra SPX business jet for ANG.
C-39 Initial designation for Navy Unique Fleet Essential Aircraft. Designation changed to C-40 for reasons that remain unclear. Perhaps the Navy never noticed that C-40 was not next in the sequence.
Boeing C-40A Designation applied to three Boeing 737-700Cs For Navy Unique Fleet Essential Airlift Replacement Aircraft to replace C-9B Skytrain II
CASA C-41A Military version of CASA C.212-200
Canadair C-43 Military version of CL-641 Challenger for US Coast Guard
Boeing CT-49A Designation given to NATO 707s.

Sources:

  1. The Aircraft of the World, William Green and Gerald Pollinger, Doubleday, New York, 1962

  2. Jane's Fighting Aircraft of World War II, Military Press, 1989.

  3. The "C" Planes-US Cargo Aircraft 1925 to the Present, Bill Holder and Scott Vadnais, Schiffer Military History, 1996.

  4. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian Institution Press, 1989.

  5. E-mail from Jasper Versteeg on C-110

  6. E-mail from David Shiflett on C-16A designation.

  7. E-mail from Andreas Parsch on C-41, C-138, C-139, C-143, C-34, C-36.

  8. E-mail from GOMACjdm on C-22 designation.

  9. E-mail from Vahe Demirjian on reason for skipping C-13 in pre-1962 series, and C-39 in post-1962 series.

  10. E-mail from Jos Heyman on C-43 designation.

  11. E-mail from John Holt on CT-49 designation.