Beechcraft 18 - Expeditor - Navigator - Kansan.
The Beechcraft Model 18, or "Twin Beech", as it was better known, is a 6-11 place, twin-engine, low-wing, conventional-gear aircraft that was manufactured by the Beech Aircraft Corporation of Wichita, Kansas. This model saw service during and after World War II in a number of versions including the United States Army Air Forces C-45 Expeditor, AT-7 Navigator, AT-11 Kansan, and for the United States Navy, UC-45J Navigator and the SNB-1 Kansan. An estimated aggregate total time in service for the aircraft time is in excess of 20,000,000 hours of flight time.
The Beech 18 is the most modified US-certified aircraft design, with over 200 FAA approved Supplemental Type Certificates on record for the aircraft.
The aircraft uses have included aerial spraying, sterile bug release, fish seeding, dry ice cloud seeding, aerial fire fighting, airborne mail pick up and drop, ambulance service, numerous movie productions, skydiving, freight, gun and drug smuggling, engine test bed, skywriting and banner tow. A number of Model 18s were operated as passenger aircraft, The Model 18 was also the first aircraft flown by Philippine Airlines, Asia's first and oldest airline. Many are now in private hands as highly prized collectibles.
By the late 30s, the winds of war had blown across Europe. Beechcraft management knew the company would be called upon to help the allied cause and they bet the future on increased production facilities and a new design dubbed the Model 18. The design was mainly conventional for the time, including twin radial engines, all-metal semi-monocoque construction with fabric covered control surfaces and "taildragger" undercarriage, while less common were the twin tail fins. Early production aircraft were either powered by two 225kW (or 300hp) Jacobs L6s or 260kW (or 350hp) Wright R760Es. The Pratt & Whitney Wasp Junior became the definitive engine from the prewar C18S onwards. The Beech 18 prototype first flew on 15 January 1937.
The aircraft has used a variety of engines and has had a number of airframe modifications to increase gross weight and speed. At least one aircraft was modified to a 600 horse power R-1340 Pratt and Whitney powerplant configuration. The added weight of approximately 200 pounds per engine with R-1340 engine was not satisfactory due to the weakest structural area of the aircraft being the engine mounts. With the exception of the center truss, the central component around which the entire aircraft is built, nearly every airframe component has been modified at one time or another.
Construction of the Beechcraft Model 18 ended in 1970 with the last Model 18 built going to Japan Airlines. Beechcraft set a record that still stands today for longest continuous production of a piston engine aircraft. Through the years, 32 variations of the basic design had flown, over 200 improvement modification kits were developed, and almost 8,000 aircraft had been built. Some aircraft were almost unrecognizable as having originated as a Beech 18. In one case the aircraft was modified to a triple tail, tri-gear, hump backed configuration and appeared similar to a miniature Lockheed Constellation.
Operational history
China sent the company $750,000 in return for light bombers based on the Model 18 design, but by the beginning of the war, only 39 Model 18s had been sold. Work began in earnest on a variant specifically for training fledgling military pilots, bombardiers and navigators. The effort resulted in the Army AT-7 and Navy SNB. Further development led to the AT-11 and SNB-2 navigation trainers and the C-45 military transport. There was even, eventually, an experimental XA-38 attack version with a huge cannon in the nose, although it never went into production. The USAF Strategic Air Command had Beechcraft Model 18 (AT-11 Kansans, C-45 Expeditors, F-2 Expeditors, the "F" standing for "Fotorecon", and UC-45 Expeditors) from 1946 through 1951. The C-45 flew in US Air Force service until 1963, the US Navy retired their last SNB in 1972 while the US Army flew their C-45s through 1976.
Some of the modifications created by independent engineering entrepreneurs were adopted in concept by the factory in later production versions in similar fashion to the current practice Harley Davidson copying of custom motorcycles built in the 1960s and 1970s. Among the most notable cooling air and exhaust modifications were those engineered by Benjamin Israel while employed by Conrad Conversions. His modifications were based largely on creating a more efficient use of cooling air to reduce cooling drag, a major detriment to aircraft cruise performance. The difference in cruise performance was a significant 10% or better at the same power settings as before the modifications. These modifications were largely copied on the factory produced G and H models.
A factory option at one point was the addition of JATO bottles on each engine nacelle which added the equivalent of 200 hp per engine for about 12 seconds. The most successful powerplant upgrade was that of the Pratt and Whitney turbine PT-6 engine and Hartzell propellor. This combination of engine and propellor successfully extended the commercial life of the aging aircraft.
Manufacturer models
Unless otherwise noted, the engines fitted are Pratt & Whitney R-985 radials.
- 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).
- Model S18A : Version of Model 18A capable of being fitted with skis or Edo 55-7170 floats; MTOW: 7,200 lb (3,300 kg).
- Model 18B : Improved model with increased range and useful load, fitted with 285 hp (213 kW) Jacobs L-5 engines.
- 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).
- Model S18D : Version of Model 18D capable of being fitted with skis or Edo 55-7170 floats, MTOW: 7,170 lb (3,250 kg).
- 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.
- Model SA18D : Seaplane version of Model A18D, but same MTOW as S18D, fitted with Edo 55-7170 floats.
- Model A18A : Version fitted with Pratt and Whitney R-985 engines of 450 horsepower (340 kW), MTOW: 7,500 lb (3,400 kg).
- Model SA18A : Seaplane version of Model A18A, fitted with Edo 55-7170 floats, MTOW: 7,170 lb (3,250 kg).
- 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.
- Model 18S : Nine-passenger pre-World War II civil variant, served as basis for USAAF C-45C.
- Model B18S : Nine-passenger pre-World War II civil variant, served as basis for USAAF F-2.
- Model C18S : Variant of B18S with seating for eight passengers, and equipment and minor structural changes.
- 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. Two hundred and eighty 280 D Models were made for the Royal Canadian Air Force (RCAF), given the service name 'Expeditor' and delivered between 1951 and 1952. Seating for RCAF was for five passengers, or two RCAF Navigator students and one RCAF navigator instructor. MTOW for RCAF was 9300 lbs.
- 3N : Fitted as a navigation trainer with astrodome and two trainee stations in the cabin; 88 built.
- 3NM : Fitted primarily as a navigational trainer, and is fitted with floor lugs to accept transport seats on removal of navigation equipment; 59 built.
- 3NMT : Basically a 3NM, converted to a transport aircraft; 67 built 3NMT(Special): Fitted as a navigation trainer personnel transport. First navigation training position retained, slightly modified ie: removal of air position indicator and replaced with radio compass and indicator from removed second navigation position; in addition, three reclining-type chairs fitted; 19 built.
- 3TM : Normally fitted with transport type seats, but has the necessary wiring, plumbing, and fittings for conversion to a navigation trainer, including provisions for fitting an astrodome; 44 built.
- 3TM(Special) : Specifically modified RCAF Expeditor under Project WPB6, and refers specifically to overseas Expeditors; three built.
- 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.
- Model E18S : Variant with redesigned wing and MTOW of 9,300 lb (4,200 kg); 403 built.
- Model E18S-9700 : Variant of E18S with MTOW of 9,700 lb (4,400 kg); 57 built.
- Model G18S : Superseded E18S, MTOW of 9,700 lb (4,400 kg); 155 built.
- Model G18S-9150 : Lightweight version of G18, MTOW of 9,150 lb (4,150 kg); one built.
- 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.
Military versions
- C-45 : Six-seat staff transport based on C18S; 11 built.
- C-45A : Eight-seat utility transport based on C18S; 20 built.
- 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.
- Expeditor I: Some C-45Bs were supplied to the RAF under Lend-Lease.
- C-45C : Two Model 18S aircraft impressed into the USAAF, redesignated UC-45C in January 1943.
- C-45D : Designation given to two AT-7 aircraft converted as passenger transports during manufacture, redesignated UC-45D in January 1943.
- 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.
- C-45F : Standardized seven-seat version based on C18S, with longer nose than preceding models; 1,137 ordered, redesignated UC-45F.
- 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.
- 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.
- 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.
- 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.
- TC-45H.
- RC-45J : In 1962, all surviving U.S. Navy SNB-5Ps were redesignated RC-45J.
- TC-45J : In 1962 all surviving U.S. Navy SNB-5s were redesignated TC-45J.
- UC-45J.
- AT-7 Navigator : Navigation trainer based on C18S, with an astrodome and positions for three students, powered by 450-hp Pratt & Whitney R-985-25 engines; 577 built.
- AT-7A : Floatplane version of AT-7; six built.
- AT-7B : Winterised AT-7; nine built.
- AT-7C : Based on C18S with R-985-AN3 engines; 549 built.
- 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.
- AT-11A : Conversion of AT-11 as navigation trainer; 36 converted.
- CQ-3 : Conversion of UC-45F, modified to act as drone control aircraft, redesignated as DC-45F in June 1948.
- F-2 : Photo-reconnaissance version based on B18.
- F-2A : Improved version.
- F-2B.
- JRB-1 : Photographic aircraft for the U.S. Navy, based on the C18S,[27] fitted with fairing over cockpit for improved visibility, 11 built.
- JRB-2 : Light transport for the U.S. Navy, based on the C18S; 15 built.
- JRB-3 : Photographic version, similar to C-45B; 23 built.
- JRB-4 : Utility transport version, equivalent to UC-45F; 328 built.
- JRB-6.
- SNB-1 : Variant for the U.S. Navy, similar to AT-11; 110 built.
- SNB-2 : Navigation trainer for the U.S. Navy, similar to AT-7, 299 built.
- SNB-2C : Variant for the U.S. Navy, similar to AT-7C.
- SNB-2H : Ambulance conversion for the U.S. Navy.
- SNB-2P : Photo-reconnaissance trainer for the U.S. Navy.
- SNB-3 : Variant for the U.S. Navy, similar to AT-7C.
- SNB-3Q : Electronic counter-measures trainer for the U.S. Navy.
- SNB-5 : SNB-2s and SNB-2Cs were remanufactured, and designated SNB-5 by the U.S. Navy.
- SNB-5P : Photo-reconnaissance trainer for the U.S. Navy.
Conversions
- PAC Super 18S Tradewind : Custom conversion of Beech D-18S/C-45 to five- to 11-seat executive transport by Pacific Airmotive.
- 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.
- Hamilton Westwind : Turboprop conversions with various engines.
- Hamilton Westwind II STD : Stretched conversion powered by two 840-hp PT6As, and with accommodation for up to 17 passengers.
- 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.
- Volpar (Beechcraft) Model 18 : Conversion of Model 18 with nosewheel undercarriage.
- 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.
- 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.
Volpar (Beechcraft) Turboliner II : Turboliners modified to meet SFAR 23.
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