Twin Bonanza
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The Beechcraft Model 50 Twin Bonanza is a small twin-engined aircraft designed by
Beechcraft Beechcraft is an American brand of civil aviation and Military aircraft, military aircraft owned by Textron Aviation since 2014, headquartered in Wichita, Kansas. Originally, it was a brand of Beech Aircraft Corporation, an American manufacture ...
as an executive transport for the business market. It was developed to fill a gap in Beechcraft's product line between the single-engined Model 35 Bonanza and the larger Model 18. The Twin Bonanza is dissimilar to the Bonanza, being much larger and heavier and using more powerful engines, while in its earliest form having only half the passenger capacity of the Model 18.


Development

The Twin Bonanza was first flown on November 15, 1949 after rapid development, begun only in April of that year. The aircraft was first designed to use
Franklin Franklin may refer to: People and characters * Franklin (given name), including list of people and characters with the name * Franklin (surname), including list of people and characters with the name * Franklin (class), a member of a historic ...
engines with
supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement (engine), displacement. It is a form of forced induction that is mechanically ...
s, but engine company owner
Preston Tucker Preston Thomas Tucker (21 September 1903 – 26 December 1956) was an American automobile entrepreneur who developed the innovative Tucker 48 sedan, initially nicknamed the "Tucker Torpedo", an automobile which introduced many features that ...
diverted all of its aviation resources to support his ill-fated
Tucker 48 The Tucker 48, commonly but incorrectly referred to as the Tucker Torpedo, was an Car, automobile conceived by Preston Tucker while in Ypsilanti, Michigan, and briefly produced in Chicago, Chicago, Illinois, in 1948. Only 51 cars were made inclu ...
automobile project, and the aircraft was hastily modified to accept the Lycoming GO-435. However, the engine
nacelles A nacelle ( ) is a streamlined container for aircraft parts such as engines, fuel or equipment. When attached entirely outside the airframe, it is sometimes called a pod, in which case it is attached with a pylon or strut and the engine is know ...
were not redesigned to fit the smaller Lycoming, creating unusually generous internal clearances that facilitate engine maintenance. The Model 50's
type certificate A type certificate signifies the airworthiness of a particular category of aircraft, according to its manufacturing design (''type design''). Certification confirms that the aircraft of a new type intended for serial production is in compliance w ...
was awarded in 1951, and production began the same year. The Twin Bonanza is one of only a few light twin-engined civil aircraft certificated in the utility category, and was the first production light aircraft to feature shoulder belts. Despite its name, the Twin Bonanza is a substantially larger and heavier aircraft that is mostly dissimilar to the single-engined
Bonanza ''Bonanza'' is an American Western television series that ran on NBC from September 12, 1959, to January 16, 1973. Lasting 14 seasons and 431 episodes, ''Bonanza'' is NBC's longest-running Western, the second-longest-running Western series on ...
; the only major shared parts are the front fuselage sides and windows, and on early models, the main cabin door. The Twin Bonanza fuselage is wider than that of the Bonanza. The United States Army adopted the Twin Bonanza as the L-23 Seminole utility transport, making it the largest fixed-wing aircraft in its inventory at that time. According to Ralph Harmon, the airplane's designer, during an initial demonstration flight for the Army, Beechcraft
test pilot A test pilot is an aircraft pilot with additional training to fly and evaluate experimental, newly produced and modified aircraft with specific maneuvers, known as flight test techniques.Stinton, Darrol. ''Flying Qualities and Flight Testin ...
Claude Palmer crashed while trying to land over a tree line with the aircraft full of soldiers and sandbags. Everyone on board walked away from the crash. The Army was impressed with the structural strength of the Twin Bonanza, eventually purchasing 216 of the 994 examples produced. It was also the first twin-engined aircraft in its class to be offered to the business market, but the
Korean War The Korean War (25 June 1950 – 27 July 1953) was an armed conflict on the Korean Peninsula fought between North Korea (Democratic People's Republic of Korea; DPRK) and South Korea (Republic of Korea; ROK) and their allies. North Korea was s ...
was raging in the early 1950s and the US Army took almost the entire production for 1952 and 1953. The Beechcraft Model 65 Queen Air and Model 90 King Air are both direct descendants of the Model 50 Twin Bonanza. All three aircraft share the same basic wing design, as well as landing gear, flaps, instrument panels, fuel cells, and more. The Queen Air added a larger cabin to the design, while the later King Air added turbine power and
pressurization Pressurization or pressurisation is the application of pressure in a given situation or environment. Examples Industrial Industrial equipment is often maintained at pressures above or below atmospheric. Atmospheric This is the process by which a ...
. Twin Bonanza production ended in 1963 while the King Air was under development.


Design

The Twin Bonanza is an all-metal
low-wing monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplane (aeronautics), multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowes ...
with a
cantilever wing A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilev ...
and retractable
tricycle landing gear Tricycle gear is a type of aircraft undercarriage, or ''landing gear'', that is arranged in a tricycle fashion. The tricycle arrangement has one or more nose wheels in a single front undercarriage and two or more main wheels slightly aft of th ...
, initially powered by two wing-mounted
geared A gear or gearwheel is a rotating machine part typically used to transmit rotational motion and/or torque by means of a series of teeth that engage with compatible teeth of another gear or other part. The teeth can be integral saliences or c ...
Lycoming GO-435 piston engines, each with a wooden two-bladed propeller. The standard cabin seats six people on bench seats, three in the front and three in the rear, and several other seating configurations were offered, including club seating and a three-person sideways-facing couch. Early models had a single right-hand door above the wing, accessed by trailing edge steps, while later aircraft added a rear airstair door with retracting steps. The GO-435 was replaced by the
Lycoming GO-480 The Lycoming GO-480 is a family of six-cylinder, horizontally opposed fixed-wing aircraft engines of 479.6 cubic inch (7.86 L) displacement, made by Lycoming Engines. The engine is a six-cylinder version of the four-cylinder Lycoming O-320. Desi ...
in 1954; this engine was subsequently upgraded with
fuel injection Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of a fuel injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All c ...
and then superchargers, increasing power to in 1956 and in 1957. In addition to its seating configuration, the Twin Bonanza has several other unusual design features. The main landing gear wheels retract only partially into the engine nacelles, leaving the tires exposed to assist in the event of a
belly landing A belly landing or gear-up landing occurs when an aircraft lands without its landing gear fully extended and uses its underside, or belly, as its primary landing device. Normally the term ''gear-up landing'' refers to incidents in which the pilo ...
and allowing the pilot some directional control using
differential braking Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing, takeoff or landing. For aircraft, it is generally needed for all three of these. It was also formerly called ''alighting gear'' by some manufacturers, s ...
. The aircraft is equipped with a tailskid to mitigate damage from a badly executed or belly landing. The exposed main wheels and tailskid potentially allow a Twin Bonanza equipped with two-bladed props to be belly-landed with minimal damage if the props are stopped horizontally. In many Twin Bonanzas, the
copilot In aviation, the first officer (FO), also called co-pilot, is a Aircraft pilot, pilot in addition to the Pilot in command, captain, who is the legal commander. In the event of incapacitation of the captain, the first officer will assume command ...
's seat and
rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...
pedals are not on the right as is customary, but instead are positioned in the center of the front seat; the pilots pivot the single "throwover"
control yoke A yoke, alternatively known as a control wheel or a control column, is a device used for piloting some fixed-wing aircraft.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 563. Aviation Supplies & Academics, 1997. . ...
to the center for the copilot to fly. Instead of conventional
cowl flaps A cowl is an item of clothing consisting of a long, hooded garment with wide sleeves, often worn by monks. It was developed during the Early Middle Ages. The term may have originally referred to the hooded portion of a cloak, though contemporar ...
for low-speed engine cooling, the engines are equipped with exhaust augmenter tubes that create a low-pressure area inside the engine nacelles, drawing in additional cooling air. The combination of the augmenter tubes and low propeller
RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 def ...
and high engine RPM from the geared engines gives the Twin Bonanza a characteristic sound. "Junior
JATO JATO (acronym for jet-assisted take-off) is a type of assisted take-off for helping overloaded aircraft into the air by providing additional thrust in the form of small rockets. The term ''JATO'' is used interchangeably with the (more specific ...
" rocket motors mounted to the tops of the engine nacelles were briefly offered as a factory option for the Twin Bonanza. Unlike most JATO systems intended to shorten takeoff distance, the Twin Bonanza motors were nominally intended to keep the aircraft aloft during in-flight emergencies or
forced landing A forced landing is a landing by an aircraft made under factors outside the pilot's control, such as the failure of engines, systems, components, or weather which makes continued flight impossible. However, the term also means a landing that has ...
s. However, it is unclear whether this feature was ever installed on a production aircraft or used in any instance other than test flights.


Operational history

The Twin Bonanza had trouble competing with the similarly capable but substantially lighter
Cessna 310 The Cessna 310 is an American four-to-six-seat, low-wing, twin-engine monoplane produced by Cessna between 1954 and 1980. It was the second twin-engine aircraft that Cessna put into production; the first was the Cessna T-50. It was used by the ...
and
Piper PA-23 The Piper PA-23, named Apache and later Aztec, is an American four- to six-seat twin-engined general aviation light aircraft, used also in small numbers by the United States Navy and military forces in other countries. Originally designed as the ...
, so Beechcraft used the basic single-engined Bonanza fuselage and many other Bonanza parts to create the Twin Bonanza's effective replacements: the
Travel Air The Travel Air Manufacturing Company was an aircraft manufacturer established in Wichita, Kansas, United States in January 1925 by Clyde Cessna, Walter Beech, and Lloyd Stearman. An early leader in single-engine, light-aircraft manufacturing, ...
and the closely related
Baron Baron is a rank of nobility or title of honour, often Hereditary title, hereditary, in various European countries, either current or historical. The female equivalent is baroness. Typically, the title denotes an aristocrat who ranks higher than ...
. The Twin Bonanza has been plagued by a reputation for slow cruise speed, poor fuel economy and high engine overhaul costs relative to other six to eight-seat light piston twins; this has historically kept resale values low, but many owners praise its reliability, good outwards visibility, stable flying qualities and generous interior space, particularly when the three-wide seats are not fully occupied. The Twin Bonanza is popularly known as the "Twin Bo" or the "T-Bone". In January 2012, the Australian
Civil Aviation Safety Authority The Civil Aviation Safety Authority (CASA) is an Australian statutory authority responsible for the regulation and safety oversight of Australia's civil aviation. CASA was formed on 6 July 1995 under the ''Civil Aviation Act 1988'' when the Civil ...
issued an airworthiness directive grounding all Bonanzas, Twin Bonanzas, and Debonairs equipped with a single pole-style yoke, having forward elevator control cables more than 15 years old, until they could be inspected. The AD was issued based on two aircraft found to have frayed cables, one of which suffered a cable failure just prior to takeoff, and resulting concerns about the age of the cables in fleet aircraft of this age. At the time of the grounding, some Bonanzas had reached 64 years in service. Aircraft with frayed cables were grounded until the cables were replaced, and those that passed inspection were required to have their cables replaced within 60 days regardless. The AD affected only Australian aircraft and was not adopted by the airworthiness authority responsible for the
type certificate A type certificate signifies the airworthiness of a particular category of aircraft, according to its manufacturing design (''type design''). Certification confirms that the aircraft of a new type intended for serial production is in compliance w ...
, the US
Federal Aviation Administration The Federal Aviation Administration (FAA) is a Federal government of the United States, U.S. federal government agency within the United States Department of Transportation, U.S. Department of Transportation that regulates civil aviation in t ...
. The FAA instead opted to issue a ''Special Airworthiness Information Bulletin'' (SAIB) requesting that the elevator control cables be inspected during the annual inspection.


Variants

;Model 50: Initial production version powered by two Lycoming GO-435-C2 engines, 13 built (six for the US Army, remainder civilian versions, with the first two production numbers for factory evaluation). As of 2010, only one Model 50 is still registered and flying (serial number H-7). As of June 2016, Serial Number H-7 is owned by W. Hulsey Smith through his holding company Archangel Technologies, LLC, as part of the Archangel Collection. ;Model B50: Upgraded Model 50 with increased takeoff weight, extra cabin windows and improved cabin heating, 139 built (40 for the US Army). ;Model C50: Superseded the B50; fitted with Lycoming GO-480-F1A6 engines, 155 built (one to
United States Air Force The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...
). ;Model D50: Superseded the C50; fitted with Lycoming GO-480-G2C6 engines, 154 built (six to US Army). ;Model D50A: Upgraded D50 fitted with GO-480-G2D6 engines, 44 built. ;Model D50B: Upgraded D50A with new passenger steps and improved baggage area, 38 built. ;Model D50C: Upgraded D50B with starboard
airstair An airstair is a set of steps built into an aircraft so that passengers may board and alight the aircraft. The stairs are often built into a clamshell-style door on the aircraft. Airstairs eliminate the need for passengers to use a Ground s ...
entry door, three rows of seats, improved air conditioning, larger baggage area, 64 built. ;Model D50E: Upgraded D50C with extra portside window, squared-off rear starboard window, pointed nose and Lycoming GO-480-G2F6 engines, 47 built. ;Model E50: Supercharged version of the D50; with increased takeoff weight and supercharged GSO-480-B1B6 engines, 181 built (mostly for the US Army). ;Model F50: Supercharged version of the D50A with GSO-480-B1B6 engines, 26 built including one converted to G50 standard. ;Model G50: Supercharged version of the D50B with IGSO-480-A1A6 engines, increased fuel capacity and increased takeoff weight, one conversion from F50 plus 23 built. ;Model H50: Supercharged version of the D50C with increased takeoff weight and IGSO-480-A1A6 engines, 30 built. ;Model J50: Supercharged version of the D50E with IGSO-480-A1B6 engines and increased takeoff weight, 27 built. ;Model K50: Unbuilt variant. Serial numbers KH-1 through KH-38 were allocated for this variant. ;Excalibur 800 :A modification designed originally by
Swearingen Aircraft Swearingen may refer to: *Swearingen Aircraft, or one of several aircraft manufactured by this company and its successors, including: **Swearingen Merlin, a twin turboprop business aircraft **Fairchild Swearingen Metroliner, a twin turboprop airli ...
and taken over by the Excalibur Aviation Company which re-engines the Twin Bonanza with two 400 HP (298 kW) Avco Lycoming IO-720-A1A flat-eight engines in a new cowling and revised exhaust system. Other optional improvements were also available. ; L-23 Seminole: Military version


Operators


Military operators

;:
Chilean Air Force The Chilean Air Force () is the air force of Chile and branch of the Chilean military. History The first step towards the current FACh is taken by Lieutenant Colonel, Teniente Coronel training as a pilot in France. Although a local academy was c ...
(5 x C50, 4 x D50) ;:
Colombian Air Force The Colombian Aerospace Force (FAC, ) is the air force of the Republic of Colombia. The Colombian Aerospace Force is one of the three institutions of the Military Forces of Colombia charged, according to the 1991 Constitution, with working to exe ...
(1 x D50) ;:
Royal Jordanian Air Force The Royal Jordanian Air Force (RJAF; Arabic: سلاح الجو الملكي الأردني, ''Silāḥ al-Jaww al-Malakī al-ʾUrdunī'') is the aerial warfare branch of the Jordanian Armed Forces. Founded in 1955, the RJAF serves as the primary ...
(1 x F50) ;:
Royal Moroccan Air Force The Royal Moroccan Air Force (; ; ) is the air force of the Moroccan Armed Forces. History The Moroccan air force was formed on 14 May 1956 as the Sherifian Royal Aviation (). Its modern installations and bases were inherited from France (Bass ...
;:
Swiss Air Force The Swiss Air Force (; ; ; ) is the air component of the Swiss Armed Forces, established on 31 July 1914, three days after the outbreak of World War I, as a part of the Swiss Army, army and in October 1936 as an independent service. In peaceti ...
(3 x E50) ;:
Uruguayan Air Force The Uruguayan Air Force (, abbreviated FAU) is the air service branch of the Armed Forces of Uruguay. Originally created as part of the National Army of Uruguay, the Air Force was established as a separate branch on December 4, 1953. It is the ...


Accidents and incidents

The Beechcraft Twin Bonanza has been involved in the following notable accidents and incidents: *On 24 July 1966, American professional golfer
Tony Lema Anthony David Lema (February 25, 1934 – July 24, 1966) was an American professional golfer who rose to fame in the mid-1960s and won a major title, the 1964 Open Championship at the Old Course at St Andrews in Scotland. He died two years later ...
, his wife, and two others were killed when the aircraft struck terrain during an apparent
ditching In aviation, a water landing is, in the broadest sense, an aircraft landing on a body of water. Seaplanes, such as floatplanes and flying boats, land on water as a normal operation. Ditching is a controlled emergency landing on the water sur ...
attempt in a lake near their intended destination, Lansing Municipal Airport.


Specifications (D50)


See also


References

* * * *


Further reading

* Aviation Media, Inc. ''Wonderful World of Flying.'' New York: Aviation Media, Inc, 1992. * Beech Aircraft Corporstion. ''Beechcraft Bonanza.'' Wichita, Kan. : Beech Aircraft Corp., 1947. * Beech Aircraft Corporation. ''The Story of Beechcraft.'' Wichita, Kan., 1969. * Beech Aircraft Corporation. ''The World of Beechcraft.'' Wichita, Kan. : Beech Aircraft, 1973. * Christy, Joe. ''Beechcraft Guide: Bonanza, Debonair, Musketeer.'' New York : Modern Aircraft Series, 1962. * McDaniel, William Herbert. ''The History of Beech.'' Wichita, Kan. : McCormick-Armstrong Co. Pub. Division, 1982. * Pelletier, Alain J. ''Beech Aircraft and Their Predecessors.'' Annapolis, MD. : Naval Institute Press, 1995. * Ward, Richard I. ''Beechcraft Twin Bonanza, Craft of the Masters: The Story of the Beech Civilian Model 50 & Military L-23/U8.'' Destin, FL. : Aviation Heritage, 1996. * Wixey, Kenneth E. ''Beechcraft.'' Stroud: Tempus, 1999.


External links

{{Beechcraft
Twin Bonanza The Beechcraft Model 50 Twin Bonanza is a small twin-engined aircraft designed by Beechcraft as an executive transport for the business market. It was developed to fill a gap in Beechcraft's product line between the single-engined Model 35 Bona ...
1940s United States civil utility aircraft Low-wing aircraft Aircraft first flown in 1949 Twin piston-engined tractor aircraft Aircraft with retractable tricycle landing gear