Editing Lockheed Model 18 Lodestar (section)

==Variants==
;18-07
:Powered by two 875 hp Pratt & Whitney Hornet S1E2-G engines; 25 built plus two prototypes.{{sfn|Francillon|1982|pp=186, 488}}
;18-08
:Powered by two 1,200 hp Pratt & Whitney Twin Wasp S1C3-G engines; 33 built.{{sfn|Francillon|1982|pp=185, 488}}
;18-10
:Powered by two 1,200 hp Pratt & Whitney Twin Wasp S1C3-G engines; 39 built.{{sfn|Francillon|1982|pp=186, 488–489}}
;18-14
:Powered by two 1,200 hp Pratt & Whitney Twin Wasp S4C4-G engines; four built.{{sfn|Francillon|1982|pp=186, 488}}
;18-40
:Powered by two 1,200 hp Wright Cyclone G-1820-G104A engines; 26 built.{{sfn|Francillon|1982|pp=186, 488}}
;18-50
:Powered by two 1,200hp Wright Cyclone G-1820-G202A engines; 13 built.{{sfn|Francillon|1982|pp=186, 488–489}}
;18-56
:Powered by two 1,200hp Wright Cyclone GR-1820-G205A, R-1820-40 or R-1820-87 engines.{{sfn|Francillon|1982|p=186}}<ref>{{cite web |title=Lockheed 18 Lodestar specs |website=Aviation Safety Network |date=8 August 2013 |url=https://aviation-safety.net/database/types/Lockheed-18-Lodestar/specs |access-date=24 May 2019}}</ref>

===US Army Lodestars===
;C-56
:Powered by 1,200 hp [[Wright R-1820|Wright 1820-89]] engines, one Model 18-50 for evaluation.<ref name="Serials77">Andrade 1979, pp. 77–78.</ref>
;C-56A
:One impressed Model 18-07 with two [[Pratt & Whitney R-1690|Pratt & Whitney R-1690-54]] engines.<ref name="Serials77" />
;C-56B
:Thirteen impressed Model 18-40s with two [[Wright R-1820|Wright 1820-97]] engines.<ref name="Serials77" />
;C-56C
:Twelve impressed Model 18-07.<ref name="Serials77" />
;C-56D
:Seven impressed Model 18-08.<ref name="Serials77" />
;C-56E
:Two Model 18-40s impressed in 1943.<ref name="Serials77" />
;C-57
:As Model 18-14 powered by two 1,200 hp [[Pratt & Whitney R-1830|Pratt & Whitney R-1830-53]] engines.<ref name="Serials77" />
;C-57A
:Allocated for impressed aircraft, not used.<ref name="Serials77" />
;C-57B
:Based on Model 18-08 fitted for trooping; seven aircraft built.<ref name="Serials77" />
;C-57C
:Repowered C-60A with Pratt & Whitney R-1830-51 engines; three aircraft converted.<ref name="Serials77" />
;C-57D
:Repowered C-57C with Pratt & Whitney R-1830-92 engines; one aircraft converted.<ref name="Serials77" />
;C-59
:Based on Model 18-07 powered by [[Pratt & Whitney R-1690|Pratt & Whitney R-1690-25]] Hornet engines; 10 aircraft built, transferred to Royal Air Force as '''Lodestar IA'''.
;C-60
:Model 18-56 powered by Wright R-1820-87 engines; 36 aircraft built, some transferred to RAF as '''Lodestar II'''.
;C-60A
:As the C-60 but fitted out as a paratroop transport powered by Pratt & Whitney R-1830 Twin Wasp engines; 325 aircraft built.<ref name="Serials77" />
;XC-60B
:One C-60A fitted with experimental de-icing equipment.<ref name="Serials77" />
;C-60C
:Proposed 21-seat troop transport aircraft, never built.
;C-66
:Powered by Wright R-1820-87 engines; one aircraft built, 11-passenger interior for transfer to the [[Brazilian Air Force]].<ref name="Serials77" />
;C-104
:Original designation for C-60C

===US Navy Lodestars===
;XR5O-1
:One Model 18-07 acquired for evaluation powered by 1,200&nbsp;hp (895&nbsp;kW) Wright R-1820-40 engines.<ref name="Serials77" />
;R5O-1
:Staff transport powered by 1,200&nbsp;hp (895&nbsp;kW) Wright R-1820-97 engines; three aircraft built, two for the USN and one for the [[United States Coast Guard]] (USCG).<ref name=":0">{{Cite web |title=Lockheed R5O-1/4/5 "Lodestar" (1940) |url=https://cgaviationhistory.org/aircraft_/lockheed-r5o-145-lodestar/ |access-date=2025-01-13 |website=Coast Guard Aviation History |language=en-US}}</ref>
;R5O-2
:Navy version of the C-59 powered by 850&nbsp;hp (634&nbsp;kW) Pratt & Whitney R-1690-25 engines; one aircraft built.
;R5O-3
:Powered by 1,200&nbsp;hp (895&nbsp;kW) Pratt & Whitney R-1830-34A engines. Originally 4-seater VIP transports; three aircraft built.
;R5O-4
:Powered by 1,200&nbsp;hp (895&nbsp;kW) Wright R-1820-40 engines. Impressed. 7-seater staff transports; 12 aircraft built. The USCG acquired four in late 1942.<ref name=":0" />
;R5O-5
:Navy version of the C-60 powered by 1,200&nbsp;hp (895&nbsp;kW) Wright R-1820-40 engines. Similar to the R5O-4 but had 14-seats; 38 aircraft built and three former NEIAF aircraft.<ref name="Serials77" /> Three were acquired by the USCG in late 1942.<ref name=":0" />
;R5O-6
:Navy version of the C-60A for the [[US Marine Corps]], equipped with 18 paratroop seats; 35 built.<ref name="Serials77" />