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.
A light aircraft is an aircraft that has a maximum gross takeoff weight of 12,500 lb (5,670 kg) or less.
Beechcraft is a brand of Textron Aviation since 2014. Originally, it was a brand of Beech Aircraft Corporation, an American manufacturer of general aviation, commercial, and military aircraft, ranging from light single-engined aircraft to twin-engined turboprop transports, business jets, and military trainers. Beech later became a division of Raytheon and later Hawker Beechcraft before a bankruptcy sale turned its assets over to Textron.
During and after World War II, over 4,500 Beech 18s were used in 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, and 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.
World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from more than 30 countries. The major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World WarII was the deadliest conflict in human history, marked by 70 to 85 million fatalities, most of whom were civilians in the Soviet Union and China. It included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, and the only use of nuclear weapons in war.
The United States Army Air Forces, officially known as the Army Air Forces, was the aerial warfare service component of the United States Army during and immediately after World War II (1939/41–1945), successor to the previous United States Army Air Corps and the direct predecessor of the United States Air Force of today, one of the five uniformed military services. The AAF was a component of the United States Army, which on 2 March 1942 was divided functionally by executive order into three autonomous forces: the Army Ground Forces, the Services of Supply, and the Army Air Forces. Each of these forces had a commanding general who reported directly to the Army Chief of Staff.
The United States Navy (USN) is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. It is the largest and most capable navy in the world and it has been estimated that in terms of tonnage of its active battle fleet alone, it is larger than the next 13 navies combined, which includes 11 U.S. allies or partner nations. It has the highest combined battle fleet tonnage and the world's largest aircraft carrier fleet, with eleven in service, and two new carriers under construction. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the U.S. Navy is the third largest of the U.S. military service branches in terms of personnel. It has 290 deployable combat vessels and more than 3,700 operational aircraft as of June 2019, making it the third-largest air force in the world, after the United States Air Force and the United States Army.
An agricultural aircraft is an aircraft that has been built or converted for agricultural use – usually aerial application of pesticides or fertilizer ; in these roles they are referred to as "crop dusters" or "top dressers". Agricultural aircraft are also used for hydroseeding.
The sterile insect technique (SIT) is a method of biological insect control, whereby overwhelming numbers of sterile insects are released into the wild. The released insects are preferably male, as this is more cost-effective and the females may in some situations cause damage by laying eggs in the crop, or, in the case of mosquitoes, taking blood from humans. The sterile males compete with wild males to mate with the females. Females that mate with a sterile male produce no offspring, thus reducing the next generation's population. Sterile insects are not self-replicating and, therefore, cannot become established in the environment. Repeated release of sterile males over low population densities can further reduce and in cases of isolation eliminate pest populations, although cost-effective control with dense target populations is subjected to population suppression prior to the release of the sterile males.
Cloud seeding is a type of weather modification that aims to change the amount or type of precipitation that falls from clouds by dispersing substances into the air that serve as cloud condensation or ice nuclei, which alter the microphysical processes within the cloud. The usual intent is to increase precipitation, but hail and fog suppression are also widely practised in airports where harsh weather conditions are experienced.
Design and development
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.
The term semi-monocoque refers to a stressed shell structure that is similar to a true monocoque, but which derives at least some of its strength from conventional reinforcement. Semi-monocoque construction is used for, among other things, aircraft fuselages, car bodies and motorcycle frames.
Landing gear is the undercarriage of an aircraft or spacecraft and may be used for either takeoff or landing. For aircraft it is generally both. It was also formerly called alighting gear by some manufacturers, such as the Glenn L. Martin Company.
The Lockheed Model 10 Electra is an American twin-engined, all-metal monoplane airliner developed by the Lockheed Aircraft Corporation in the 1930s to compete with the Boeing 247 and Douglas DC-2. The type gained considerable fame as one was flown by Amelia Earhart on her ill-fated around-the-world expedition in 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-hp (447-kW) Pratt & Whitney R-1340 powerplant configuration. With the added weight of about 200lb (91kg) per engine, the concept of a Model 18 fitted with R-1340 engines was deemed unsatisfactory due to the weakest structural area of the aircraft being the engine mounts. Nearly every airframe component has been modified.
In 1955, deliveries of the Model E18S commenced; the E18S featured a fuselage that was extended 6in (150mm) higher for more headroom in the passenger cabin. All later Beech 18s (sometimes called Super 18s) featured this taller fuselage, and some earlier models (including one AT-11) have been modified to this larger fuselage. The Model H18, introduced in 1963, featured optional tricycle undercarriage. Unusually, the undercarriage was developed for earlier-model aircraft under an STC by Volpar, and installed in H18s at the factory during manufacture. A total of 109 H18s was built with tricycle undercarriage, and another 240 earlier-model aircraft were modified with this.
The fuselage is an aircraft's main body section. It holds crew, passengers, and cargo. In single-engine aircraft it will usually contain an engine, as well, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage, which in turn is used as a floating hull. The fuselage also serves to position control and stabilization surfaces in specific relationships to lifting surfaces, which is required for aircraft stability and maneuverability.
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 Pacific Airmotive as the PacAero Tradewind. This featured a lengthened nose to accommodate the tricycle nosewheel, and the Model 18's twin tailfins were replaced by a single fin.
The Lockheed Constellation ("Connie") is a propeller-driven, four-engine airliner built by Lockheed Corporation between 1943 and 1958 at Burbank, California. Lockheed built 856 in numerous models—all with the same triple-tail design and dolphin-shaped fuselage. Most were powered by four 18-cylinder Wright R-3350 Duplex-Cyclones. The Constellation was used as a civil airliner and as a military and civilian air transport, seeing service in the Berlin and the Biafran airlifts. The Constellation series was the first pressurized-cabin civil airliner series to go into widespread use. Its pressurized cabin enabled large numbers of commercial passengers to fly well above most bad weather for the first time, thus significantly improving the general safety and ease of air travel. Three of them served as the presidential aircraft for Dwight D. Eisenhower.
Production got an early boost when Nationalist China paid the company US$750,000 for six M18R light bombers, but by the time of the U.S. entry into World War II, only 39 Model 18s had been sold, of which 29 were for civilian customers. Work began in earnest on a variant specifically for training 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. The United States Air Force (USAF) Strategic Air Command had Model 18 variants (AT-11 Kansans, C-45 Expeditors, F-2 Expeditors (the "F" standing for "Fotorecon", short for "photographic reconnaissance"), and UC-45 Expeditors) from 1946 until 1951. From 1951 to 1955, the USAF had many of its aircraft remanufactured with new fuselages, wing center sections, and undercarriages to take advantage of the improvements to the civil models since the end of World War II. Eventually, 900 aircraft were remanufactured to be similar to the then-current Model D18S and given new designations, constructor's numbers, and Air Force serial numbers. The USN had many of its surviving aircraft remanufactured, as well, these being redesignated as SNB-5s and SNB-5Ps. The C-45 flew in USAF service until 1963, the USN retired its last SNB in 1972, while the U.S. Army flew its C-45s until 1976. In later years, the military called these aircraft "bug smashers" in reference to their extensive use supplying mandatory flight hours for desk-bound aviators in the Pentagon.
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 10,200lb (4,600kg). 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 10,286lb (4,666kg).
The wing spar of the Model 18 was fabricated by welding an assembly of tubular steel. The configuration of the tubes in combination with drilled holes from aftermarket STC modifications on some of these aircraft have allowed the spar to become susceptible to corrosion and cracking while in service. This prompted the FAA to issue an Airworthiness Directive in 1975, mandating the fitting of a spar strap to some Model 18s. This led, in turn, to the retirement of a large number of STC-modified Model 18s when owners determined the aircraft were worth less than the cost of the modifications. The corrosion on unmodified spars was not a problem; it occurred due to the additional exposed surface area created through the STC hole-drilling process. Further requirements have been mandated by the FAA and other national airworthiness authorities, including regular removal of the spar strap to allow the strap to be checked for cracks and corrosion and the spar to be X-rayed. In Australia, the airworthiness authority has placed a life limit on the airframe, beyond which aircraft are not allowed to fly.
Version of Model 18B capable of being fitted with skis or floats.
Variant with seating for two pilots and nine passengers, fitted with Jacobs L-6 engines of 330 horsepower (250kW), MTOW: 7,200lb (3,300kg).
Version of Model 18D capable of being fitted with skis or Edo 55-7170 floats, MTOW: 7,170lb (3,250kg)
Variant of 18D with MTOW increased by 300lb (140kg) to 7,500lb (3,400kg), fitted with Pratt and Whitney R-985 engines with 450 hp each
Seaplane version of Model A18D, but same MTOW as S18D, fitted with Edo 55-7170 floats
Version fitted with Pratt and Whitney R-985 engines of 450 horsepower (340kW), MTOW: 7,500lb (3,400kg)
Seaplane version of Model A18A, fitted with Edo 55-7170 floats, MTOW: 7,170lb (3,250kg)
Model with Pratt and Whitney R-985-A1 engines with dual-stage blower for increased power at higher operating altitudes, 450 horsepower (340kW), seven built, one to Sweden as an air ambulance, six to Nationalist China as M18R light bombers
Nine-passenger pre-World War II civil variant, served as basis for USAAF C-45C
Nine-passenger pre-World War II civil variant, served as basis for USAAF F-2
Variant of B18S with seating for eight passengers, and equipment and minor structural changes
First post-World War II variant introduced in 1945, with seating for eight passengers and MTOW of 8,750lb (3,970kg), 1,035 built
Variant with Continental R9-A engines of 525 horsepower (391kW) and MTOW of 9,000lb (4,100kg), introduced in 1947, 31 built.
Variant with redesigned wing and MTOW of 9,300lb (4,200kg); 403 built
Variant of E18S with MTOW of 9,700lb (4,400kg); 57 built
Superseded E18S, MTOW of 9,700lb (4,400kg); 155 built
Lightweight version of G18, MTOW of 9,150lb (4,150kg); one built
Last production version, fitted with optional tricycle undercarriage developed by Volpar and MTOW of 9,900lb (4,500kg); 149 built, of which 109 were manufactured with tricycle undercarriage
Six-seat staff transport based on C18S; 11 built
Eight-seat utility transport based on C18S; 20 built
Redesignation of all surviving F-2, F-2A, and F-2B aircraft by the USAF in 1948
Based on C18S, but with modified internal layout; 223 ordered, redesignated UC-45B in 1943
Two Model 18S aircraft impressed into the USAAF, redesignated UC-45C in January 1943
Designation given to two AT-7 aircraft converted as passenger transports during manufacture, redesignated UC-45D in January 1943
Designation given to two AT-7 and four AT-7B aircraft converted as passenger transports during manufacture, redesignated UC-45E in January 1943
Standardized seven-seat version based on C18S, with longer nose than preceding models; 1,137 ordered, redesignated UC-45F
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
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
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
Based on C18S with R-985-AN3 engines; 549 built
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.
Conversion of AT-11 as navigation trainer; 36 converted
Conversion of UC-45F, modified to act as drone control aircraft, redesignated as DC-45F in June 1948
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 605hp (451kW), driving Hartzell HC-B3TN-5 three-bladed, reversible-pitch, constant-speed feathering propellers
The Sikorsky H-19 Chickasaw was a multi-purpose helicopter used by the United States Army and United States Air Force. It was also license-built by Westland Aircraft as the Westland Whirlwind in the United Kingdom. United States Navy and United States Coast Guard models were designated HO4S, while those of the U.S. Marine Corps were designated HRS. In 1962, the U.S. Navy, U.S. Coast Guard and U.S. Marine Corps versions were all redesignated as H-19s like their U.S. Army and U.S. Air Force counterparts.
The Lockheed Model 18 Lodestar is a passenger transport aircraft of the World War II era.
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The Yankee Air Museum is an aviation museum located at Willow Run Airport in Van Buren Township, Michigan. The museum has a small fleet of flying aircraft and a collection of static display aircraft outdoors.
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The Stinson L-5 Sentinel was a World War II era liaison aircraft used by all branches of the U.S. military and by the British Royal Air Force. It was produced by the Stinson Aircraft Company. Along with the Stinson L-1 Vigilant, the L-5 was the only other American liaison aircraft of World War II that was purpose-built for military use and had no civilian counterpart. All other military liaison airplanes adopted during World War II were lightly modified "off-the-shelf" civilian models.
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The Naval Air Station Wildwood Aviation Museum is an aviation museum located at the Cape May Airport in Lower Township, in Cape May County, New Jersey, United States.
The Vintage Flying Museum is a non-profit aviation museum located at Meacham International Airport, Fort Worth, Texas. The primary mission of the museum is to preserve America's flying heritage in word, deed and action.
The Chico Air Museum is a nonprofit aviation museum located at the Chico Municipal Airport in Chico, California. Its mission statement is to "collect, preserve, document and display aircraft, and aviation and space artifacts. The museum’s primary purpose is to educate and inspire people of all ages about aviation and the history of flight".
↑ Bauschspies, James S. and William E. Simpson, "Research and Technology Program Perspectives for General Aviation and Commuter Aircraft", NASA Contract NASW-3554 for NASA, Sept. 1982, N83-17454#. Retrieved: Dec. 18, 2014. (In particular, see: Table 2.4 "COMMUTER CARGO FLEET IN 1981 - TOP TEN AIRCRAFT MODELS - NUMBER IN FLEET," which notes Beech 18 units are more than the next two aircraft combined (Convair 500/680 and Douglas DC-3), and more than the next three general aviation aircraft combined.