They were both model 18s, just like there are different Mustangs. I even think the ones modified with turbines were copied by factory at some point and named Beech Volpar. Originals had Pratt & Whitney radials. There are literally 100 different models of the Beech 18. Heres a list I found :
Variants
Manufacturer models
Model 18A
First production model with seating for two pilots and seven or eight passengers, fitted with Wright R-760E-2 engines of 350 horsepower (260 kW), MTOW: 6,700 lb (3,000 kg)[22][23]
Model S18A
Version of Model 18A capable of being fitted with skis or Edo 55-7170 floats; MTOW: 7,200 lb (3,300 kg)[23]
Model 18B
Improved model with increased range and useful load, fitted with 285 hp (213 kW) Jacobs L-5 engines[22][24][25]
Model S18B
Version of Model 18B capable of being fitted with skis or floats.
Model 18D
Variant with seating for two pilots and nine passengers, fitted with Jacobs L-6 engines of 330 horsepower (250 kW), MTOW: 7,200 lb (3,300 kg).[26]
Model S18D
Version of Model 18D capable of being fitted with skis or Edo 55-7170 floats, MTOW: 7,170 lb (3,250 kg)[13][26]
Model A18D
Variant of 18D with MTOW increased by 300 lb (140 kg) to 7,500 lb (3,400 kg), fitted with Pratt and Whitney R-985 engines with 450 hp each[26]
Model SA18D
Seaplane version of Model A18D, but same MTOW as S18D, fitted with Edo 55-7170 floats[26]
Model A18A
Version fitted with Pratt and Whitney R-985 engines of 450 horsepower (340 kW), MTOW: 7,500 lb (3,400 kg)[26]
Model SA18A
Seaplane version of Model A18A, fitted with Edo 55-7170 floats, MTOW: 7,170 lb (3,250 kg)[26]
Model 18R
Model with Pratt and Whitney R-985-A1 engines with dual-stage blower for increased power at higher operating altitudes, 450 horsepower (340 kW), seven built, one to Sweden as an air ambulance, six to Nationalist China as M18R light bombers[12][22]
Model 18S
Nine-passenger pre-World War II civil variant, served as basis for USAAF C-45C[2]
Model B18S
Nine-passenger pre-World War II civil variant, served as basis for USAAF F-2[2]
Model C18S
Variant of B18S with seating for eight passengers, and equipment and minor structural changes[27]
Model D18S
First post-World War II variant introduced in 1945, with seating for eight passengers and MTOW of 8,750 lb (3,970 kg), 1,035 built[28][29]
Model D18C
Variant with Continental R9-A engines of 525 horsepower (391 kW) and MTOW of 9,000 lb (4,100 kg), introduced in 1947, 31 built.[28][30]
Model E18S
Variant with redesigned wing and MTOW of 9,300 lb (4,200 kg); 403 built[28]
Model E18S-9700
Variant of E18S with MTOW of 9,700 lb (4,400 kg); 57 built[28]
Model G18S
A Model G18S arrives at the 2016 RIAT, England
Superseded E18S, MTOW of 9,700 lb (4,400 kg); 155 built[28][29]
Model G18S-9150
Lightweight version of G18, MTOW of 9,150 lb (4,150 kg); one built[28][29]
Model H18
Last production version, fitted with optional tricycle undercarriage developed by Volpar and MTOW of 9,900 lb (4,500 kg); 149 built, of which 109 were manufactured with tricycle undercarriage[9][28][29]
Military versions
USAAC/USAAF Designations
C-45
Six-seat staff transport based on C18S;[27] 11 built[31][32]
C-45A
Eight-seat utility transport based on C18S;[27] 20 built[31]
RC-45A
Redesignation of all surviving F-2, F-2A, and F-2B aircraft by the USAF in 1948
C-45B
Based on C18S, but with modified internal layout; 223 ordered, redesignated UC-45B in 1943[27][32]
C-45C
Two Model 18S aircraft impressed into the USAAF, redesignated UC-45C in January 1943[2][22][33]
C-45D
Designation given to two AT-7 aircraft converted as passenger transports during manufacture, redesignated UC-45D in January 1943[33][34]
C-45F at the Barksdale Global Power Museum
C-45H/AT-7 CAF, Platte Valley Airpark, Hudson, CO, June 2007
C-45E
Designation given to two AT-7 and four AT-7B aircraft converted as passenger transports during manufacture, redesignated UC-45E in January 1943[33][34]
C-45F
Standardized seven-seat version based on C18S, with longer nose than preceding models;[27] 1,137 ordered, redesignated UC-45F[32]
C-45G
AT-7s and AT-11s remanufactured in the early 1950s for the USAF to similar standard as civil D18S with autopilot and R-985-AN-3 engines; 372 aircraft rebuilt[14][35]
TC-45G
Multiengine crew trainer variant of C-45G; AT-7s and AT-11s remanufactured in the early 1950s for the USAF to similar standard as civil D18S, 96 aircraft rebuilt[14][35]
C-45H
AT-7s and AT-11s remanufactured in the early 1950s for the USAF to similar standard as civil D18S, with no autopilot and R-985-AN-14B engines; 432 aircraft rebuilt[14][36]
TC-45H [28]
RC-45J [28]
In 1962, all surviving U.S. Navy SNB-5Ps were redesignated RC-45J.
TC-45J [28]
In 1962 all surviving U.S. Navy SNB-5s were redesignated TC-45J.
UC-45J [28]
AT-11 at the Barksdale Global Power Museum
AT-7 Navigator
Navigation trainer based on C18S,[27] with an astrodome and positions for three students, powered by 450-hp Pratt & Whitney R-985-25 engines; 577 built[31][32]
AT-7A
Floatplane version of AT-7; six built[31]
AT-7B
Winterised AT-7; nine built[31]
AT-7C
Based on C18S[27] with R-985-AN3 engines; 549 built[31]
AT-11 Kansan
Bombing and gunnery trainer for USAAF derived from AT-7, fuselage had small, circular cabin windows, bombardier position in nose, and bomb bay; gunnery trainers were also fitted with two or three .30-caliber machine guns, early models (the first 150 built) had a single .30-cal AN-M2 in a Beechcraft-manufactured top turret, later models used a Crocker Wheeler twin .30-cal top turret, a bottom tunnel gun was used for tail gunner training, 1,582 built for USAAF orders, with 24 ordered by Netherlands repossessed by USAAF and used by the Royal Netherlands Military Flying School at Jackson, Mississippi.[37][38]
AT-11A
Conversion of AT-11 as navigation trainer; 36 converted[38]
CQ-3
Conversion of UC-45F, modified to act as drone control aircraft, redesignated as DC-45F in June 1948[citation needed]
F-2s in Alaska, 1941
F-2
Photo-reconnaissance version based on B18[2]
F-2A
Improved version
F-2B
US Navy Designations
SNB-1 Kansan
SNB-2 Navigator
JRB-1
Photographic aircraft, based on the C18S,[27] fitted with fairing over cockpit for improved visibility, 11 built[39]
JRB-2
Light transport, based on the C18S;[27] 15 built[39]
JRB-3
Photographic version, similar to C-45B; 23 built[39]
JRB-4
Utility transport version, equivalent to UC-45F'; 328 built.[39]
JRB-6 [28]
SNB-1
Similar to AT-11;[40] 110 built[41]
SNB-2
Navigation trainer[40] similar to AT-7, 299 built
SNB-2C
Navigation trainer[40]
SNB-2H
Ambulance conversion[40]
SNB-2P
Photo-reconnaissance trainer[40]
SNB-3
Navigation trainer
SNB-3Q
Electronic counter-measures trainer
SNB-5 [28]
SNB-2s and SNB-2Cs were remanufactured, and designated SNB-5.
SNB-5P [28]
Photo-reconnaissance trainer
RAF/RCAF Lend-lease Designations
Expeditor I
C-45Bs supplied to the RAF under Lend-Lease.
Expeditor II
C-45Fs supplied to the RAF and Royal Navy under Lend-Lease
Expeditor III
C-45Fs supplied to the RCAF under Lend-Lease
Post-war RCAF designations
C-45Ds delivered between 1951 and 1952.[42]
Expeditor 3N
navigation trainer - 88 built[43]
Expeditor 3NM
navigational trainer that could be converted to a transport - 59 built[44]
Expeditor 3NMT
3NM converted to a transport aircraft - 67 built[45]
Expeditor 3NMT(Special)
navigation trainer/personnel transport - 19 built[46]
Expeditor 3TM
transport with fittings so it could be converted to a navigation trainer - 44 built[43]
Expeditor 3TM(Special)
modified RCAF Expeditors used overseas in conjunction with Project WPB6 - three built.[47]
Conversions
PacAero Tradewind
Conrad 9800
Modification increasing the gross weight to 9,800 pounds with a single piece windshield [48]
Dumod I
Executive conversion with Volpar tricycle landing gear, new wing tips, enlarged fight deck and refurbished 6–7 seat cabin with larger windows. Originally named Infinité I. 37 converted by 1966.[49]
Dumod Liner
Stretched airliner conversion. Similar to Dumod I but with forward fuselage stretched by 6 feet 3 inches (1.91 m), allowing up to 15 passengers to be carried. Originally named Infinité II.[49]
Hamilton HA-1
conversion of a TC-45J aircraft
Hamilton Little Liner
Modification of D18S with aerodynamic improvements and new, retractable tailwheel, capable of carrying 11 seats[50]
Hamilton Westwind
Turboprop conversions with various engines
Hamilton Westwind III conversion at an airfield in Tennessee
Hamilton Westwind II STD
Stretched conversion powered by two 840-hp PT6As, and with accommodation for up to 17 passengers.[51]
Hamilton Westwind III
two 579-hp PT6A-20s or 630-hp PT6A-27s or 630-hp Lycoming LTS101s.
Hamilton Westwind IV
two 570-hp Lycoming LTP101s or 680-hp PT6A-28s or 750-hp PT6A-34s or 1020-hp PT6A-45s
PacAero Tradewind
Conversion of Beech D18S/C-45 to five- to 11-seat executive transport with single fin by Pacific Airmotive
SFERMA-Beechcraft PD.18S
Modification of Beech 18S powered by two Turboméca Bastan turboprops.[52]
Volpar (Beechcraft) Model 18
Conversion of Model 18 with nosewheel undercarriage[53][54]
Volpar (Beechcraft) Super 18
Volpar (Beechcraft) Turbo 18
Beech Model 18s fitted with the Volpar MkIV tricycle undercarriage and powered by two 705-hp Garrett TPE331-1-101B turboprop engines, flat-rated to 605 hp (451 kW), driving Hartzell HC-B3TN-5 three-bladed, reversible-pitch, constant-speed feathering propellers[54]
Volpar (Beechcraft) Super Turbo 18
2x 705 hp (526 kW) Garrett TPE331
Volpar (Beechcraft) C-45G
C-45G aircraft modified with tricycle undercarriage
Volpar (Beechcraft) Turboliner
15-passenger version of the Turbo 18 with extended fuselage, powered by 2 705-hp Garrett TPE331-1-101Bs[55]
Volpar (Beechcraft) Turboliner II
Turboliners modified to meet SFAR 23[55]
I think there were several different planes in that series. I think the main one was a GAF Nomad, but I seen Twin Otters, Aero Commanders and Cessna twins like the 421. Aero Commanders are distinctive because they are usually high winged turboprops and the fuselage is very close to the ground almost car like.
[This message has been edited by rogergarrison (edited 11-19-2019).]
