Beechcraft Model 18

https://en.wikipedia.org/wiki/Beechcraft_Model_18

The Beechcraft Model 18 (or "Twin Beech", as it is also known) is a 6- to
11-seat, twin-engined, low-wing, tailwheel light aircraft manufactured by the
Beech Aircraft Corporation of Wichita, Kansas. Continuously produced from 1937
to November 1969 (over 32 years, a world record at the time), over 9,000 were
built, making it one of the world's most widely used light aircraft. Sold
worldwide as a civilian executive, utility, cargo aircraft, and passenger
airliner on tailwheels, nosewheels, skis or floats, it was also used as a
military aircraft.

During and after World War II, over 4,500 Beech 18s saw military service—as
light transport, light bomber (for China), aircrew trainer (for bombing,
navigation and gunnery), photo-reconnaissance, and "mother ship" for target
drones—including United States Army Air Forces (USAAF) C-45 Expeditor, AT-7
Navigator, AT-11 Kansan; and United States Navy (USN) UC-45J Navigator, SNB-1
Kansan, and others. In World War II, over 90% of USAAF bombardiers and
navigators trained in these aircraft.

In the early postwar era, the Beech 18 was the pre-eminent "business aircraft"
and "feeder airliner." Besides carrying passengers, its civilian uses have
included aerial spraying, sterile insect release, fish seeding, dry-ice cloud
seeding, aerial firefighting, air mail delivery, ambulance service, numerous
movie productions, skydiving, freight, weapon- and drug-smuggling, engine
testbed, skywriting, banner towing, and stunt aircraft. Many are now privately
owned, around the world, with 240 in the U.S. still on the FAA Aircraft Registry
in August 2017.

By the late 1930s, Beechcraft management speculated that a demand would exist
for a new design dubbed the Model 18, which would have a military application,
and increased the main production facilities. The design was mainly conventional
for the time, including twin radial engines, all-metal semimonocoque
construction with fabric-covered control surfaces and tailwheel undercarriage.
Less conventional was the twin-tailfin configuration. The Model 18 can be
mistaken for the larger Lockheed Electra series of airliners which closely
resemble it. Early production aircraft were powered either by two 330-hp
(250-kW) Jacobs L-6s or 350-hp (260-kW) Wright R-760Es. The 450-hp (336-kW)
Pratt & Whitney R-985 became the definitive engine from the prewar C18S onwards.
The Beech 18 prototype first flew on January 15, 1937.

Construction of the Beechcraft Model 18 ended in 1970 with a final Model H18
going to Japan Airlines. Through the years, 32 variations of the basic design
had flown, over 200 improvement modification kits were developed, and almost
8,000 aircraft were built. In one case, the aircraft was modified to a triple
tail, trigear, humpbacked configuration and appeared similar to a miniature
Lockheed Constellation. Another distinctive conversion was carried out by
PacAero as the Tradewind. This featured a lengthened nose to accommodate the
tricycle nosewheel, and the Model 18's twin tailfins were replaced by a single
fin.


Role
Trainer and utility aircraft

National origin
United States

Manufacturer
Beech Aircraft Corporation

First flight
January 15, 1937

Introduction
1937

Primary users
United States Army Air Forces
United States Navy
Royal Air Force
Royal Canadian Air Force

Produced
1937–1970

Number built
9,000+

Unit cost

D18S: US$78,050 in 1952

Beech 18s were used extensively by Air America during the Vietnam War; initially
more-or-less standard ex-military C-45 examples were used, but then the airline
had 12 aircraft modified by Conrad Conversions in 1963 and 1964 to increase
performance and load-carrying capacity. The modified aircraft were known as
Conrad Ten-Twos, as the maximum takeoff weight (MTOW) was increased to 10,200 lb
(4,600 kg). The increase was achieved by several airframe modifications,
including increased horizontal stabilizer angle-of-incidence, redesigned
undercarriage doors, and aerodynamically improved wingtips. Air America then had
Volpar convert 14 aircraft to turboprop power, fitted with Garrett AiResearch
TPE-331 engines; modified aircraft were called Volpar Turbo Beeches, and also
had a further increase in MTOW to 10,286 lb (4,666 kg).

Specifications (UC-45 Expeditor)

General characteristics
Crew: 2 pilots
Capacity: 6 passengers
Length: 34 ft 2 in (10.41 m)
Wingspan: 47 ft 8 in (14.53 m)
Height: 9 ft 8 in (2.95 m)
Wing area: 349 ft² (32.4 m²)
Empty weight: 6,175 lb (2,800 kg)
Loaded weight: 7,500 lb (3,400 kg)
Max. takeoff weight: 8,727 lb (3,959 kg)
Powerplant: 2 × Pratt & Whitney R-985-AN-1 "Wasp Junior" radial engines, 450 hp
(336 kW) each

Performance
Maximum speed: 225 mph (195 knots, 360 km/h)
Range: 1,200 mi (1,000 NM, 1,900 km) at 160 mph (260 km/h)
Service ceiling: 26,000 ft (7,930 m)
Rate of climb: 1,850 ft/min (9.4 m/s)




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