View source for Beechcraft Twin Bonanza

{{Short description|Twin-piston-engine utility aircraft built 1951–1961}}
{{Use mdy dates|date=August 2019}}
{{Infobox aircraft
 |name= Model 50 Twin Bonanza
 |image= File:BeechD50lodi (4462819660).jpg
 |caption= Beech D50 Twin Bonanza
 |type=[[Utility aircraft]]
 |manufacturer=[[Beechcraft|Beech Aircraft Corporation]]
 |designer=
 |first_flight=November 15, 1949
 |introduction=1951
 |retired=
 |status= Active 
 |produced=1951–1961
 |primary_user=Private operators
 |more_users=
 |number_built=975 (includes 195 L-23)
 |unit cost=
 |variants= [[Beechcraft L-23 Seminole|Beechcraft L-23/U-8 Seminole]]
 |developed_into= [[Beechcraft Queen Air]]
}}

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 [[Beechcraft Bonanza|Model 35 Bonanza]] and the larger [[Beechcraft Model 18|Model 18]].<ref name="BPp46"/> 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==
[[File:Beechcraft U-8D Seminole US Army in flight.jpg|thumb|The military version of the Twin Bonanza, The [[L-23 Seminole]].]]

The Twin Bonanza was first flown on November 15, 1949 after rapid development, begun only in April of that year.<ref>[http://www.beechcraftheritagemuseum.org/collection/N14VU.php Beechcraft Heritage Museum Twin Bonanza page] {{Webarchive|url=https://web.archive.org/web/20100525113416/http://www.beechcraftheritagemuseum.org/collection/N14VU.php |date=May 25, 2010 }} retrieved December 26, 2007.</ref> The aircraft was first designed to use [[Franklin Engine Company|Franklin]] engines with [[supercharger]]s, but engine company owner [[Preston Tucker]] diverted all of its aviation resources to support his ill-fated [[Tucker 48]] automobile project, and the aircraft was hastily modified to accept the [[Lycoming GO-435]]. However, the engine [[nacelles]] were not redesigned to fit the smaller Lycoming, creating unusually generous internal clearances that facilitate engine maintenance.<ref name=Bedell/> The Model 50's [[type certificate]] was awarded in 1951,<ref name=aerofiles>{{cite web
 |url=http://aerofiles.com/_beech.html
 |title=Beechcraft
 |work=Aerofiles: A Century of American Aviation
 |date=July 14, 2006
 |access-date=October 5, 2006 | archive-url= https://web.archive.org/web/20061018142954/http://aerofiles.com/_beech.html| archive-date= October 18, 2006 | url-status= live}}</ref> and production began the same year. The Twin Bonanza is one of only a few light twin-engined civil aircraft certificated in the [[Federal_Aviation_Regulations#Part_23|utility category]], and was the first production light aircraft to feature [[Seat_belt#Three-point|shoulder belts]].<ref name=eaa12-22>{{cite magazine |last=Caldwell |first=Kris |date=December 2022 |title=Beech D50C Twin Bonanza |url=https://sportaviation.mydigitalpublication.com/publication/?m=53731&i=767519&p=1&ver=html5 |url-access=subscription |magazine=EAA Sport Aviation |location=Oshkosh, Wisconsin |publisher=[[Experimental Aircraft Association]] |access-date=January 20, 2023 |pages=34–36}}</ref>

Despite its name, the Twin Bonanza is a substantially larger and heavier aircraft that is mostly dissimilar to the single-engined [[Beechcraft Bonanza|Bonanza]]; 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 {{convert|12|in|cm|abbr=on}} wider than that of the Bonanza.<ref name=Bedell>{{cite web |url=https://www.aopa.org/news-and-media/all-news/1999/september/pilot/beech-twin-bonanza |title=Beech Twin Bonanza: A Legend Roars On |last=Bedell|first=Peter A.|date=5 September 1999|website=www.aopa.org |publisher=[[Aircraft Owners and Pilots Association]] |access-date=26 February 2021}}</ref>

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]] Claude Palmer crashed while trying to land over a {{convert|50|ft|m|adj=on}} 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.<ref name=aerofiles/> It was also the first twin-engined aircraft in its class to be offered to the business market, but the [[Korean War]] was raging in the early 1950s and the US Army took almost the entire production for 1952 and 1953.<ref name="BPp46">{{harvnb|Phillips|1992|p=46}}</ref> 

The [[Beechcraft Queen Air|Beechcraft Model 65 Queen Air]] and [[Beechcraft King Air|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 [[turboprop|turbine power]] and [[Cabin pressurization|pressurization]]. Twin Bonanza production ended in 1963<ref>[http://www.twinbonanza.com/assets/pdf/stats.pdf Twin Bonanza Model data] {{webarchive|url=https://web.archive.org/web/20061124073324/http://www.twinbonanza.com/assets/pdf/stats.pdf |date=November 24, 2006 }} retrieved December 26, 2007.</ref> while the King Air was under development.

==Design==
The Twin Bonanza is an all-metal [[low-wing monoplane]] with a [[cantilever wing]] and [[retractable landing gear|retractable]] [[tricycle landing gear]], initially powered by two wing-mounted [[reduction drive|geared]] 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.<ref name=eaa12-22/><ref name="ab">{{cite magazine|magazine=Air-Britain Aviation World|publisher=[[Air-Britain]]|date=June 2016|volume=68|issue=2|title=The Beechcraft Twin Bonanza|author=Rod Simpson|pages=62–58|issn=1742-996X}}</ref> The {{convert|260|hp|kW|abbr=on}} GO-435 was replaced by the {{convert|275|hp|kW|abbr=on}} [[Lycoming GO-480]] in 1954; this engine was subsequently upgraded with [[fuel injection]] and then superchargers, increasing power to {{convert|295|hp|kW|abbr=on}} in 1956 and {{convert|340|hp|kW|abbr=on}} in 1957.<ref name=Bedell/>

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]] and allowing the pilot some directional control using [[differential braking]].<ref name=eaa12-22/><ref name="ab"/> 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.<ref name=eaa12-22/> In many Twin Bonanzas, the [[copilot]]'s seat and [[rudder]] 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]] to the center for the copilot to fly. Instead of conventional [[cowl flaps]] 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]] and high engine RPM from the geared engines gives the Twin Bonanza a characteristic sound.<ref name=eaa12-22/>

"Junior [[JATO]]" 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]]s. However, it is unclear whether this feature was ever installed on a production aircraft or used in any instance other than test flights.<ref name=eaa12-22/>

==Operational history==
The Twin Bonanza had trouble competing with the similarly capable but substantially lighter [[Cessna 310]] and [[Piper PA-23]], so Beechcraft used the basic single-engined Bonanza fuselage and many other Bonanza parts to create the Twin Bonanza's effective replacements: the [[Beechcraft Travel Air|Travel Air]] and the closely related [[Beechcraft Baron|Baron]].<ref>{{cite web |url=https://www.aopa.org/news-and-media/all-news/2002/october/pilot/beechcraft-travel-air |title=Beech Travel Air: Baron Lite |last=Bedell|first=Peter A.|date=5 October 2002|website=www.aopa.org |publisher=[[Aircraft Owners and Pilots Association]] |access-date=26 February 2021}}</ref> 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.<ref name=Bedell/>

The Twin Bonanza is popularly known as the "Twin Bo" or the "T-Bone".<ref name=Bedell/>

In January 2012, the Australian [[Civil Aviation Safety Authority]] 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]], the US [[Federal Aviation Administration]]. The FAA instead opted to issue a ''Special Airworthiness Information Bulletin'' (SAIB) requesting that the elevator control cables be inspected during the annual inspection.<ref name="Niles15Jan12">{{Cite news|url = http://www.avweb.com/avwebflash/news/Australia_Grounds_Older_Bonanzas_206024-1.html|title = Australia Grounds Older Bonanzas |access-date = January 16, 2012|last = Niles|first = Russ|date = January 15, 2012| work = AVweb}}</ref><ref name="HeraldSun">{{Cite news|url = http://www.heraldsun.com.au/news/breaking-news/casa-issues-directive-on-light-planes/story-e6frf7jx-1226243962836|title = CASA issues directive on light planes |access-date = January 16, 2012|last = AAP|date = January 16, 2012| work = [[Herald Sun]]}}</ref><ref name="Niles24Jan12">{{Cite news|url = http://www.avweb.com/avwebbiz/news/No_FAA_Bonanza_Cable_AD_206087-1.html|title = No FAA Bonanza Cable AD |access-date = January 26, 2012|last = Niles|first = Russ|date = January 24, 2012| work = AVweb}}</ref>

==Variants==
[[File:Beech Twin Bonanza VH-BRH.jpg|thumb|Beechcraft J50 Twin Bonanza]]
;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 {{convert|275|hp|abbr=on}} Lycoming GO-480-F1A6 engines, 155 built (one to [[United States Air Force]]).
;Model D50: Superseded the C50; fitted with {{convert|295|hp|abbr=on}} 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]] 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 {{convert|295|hp|abbr=on}} Lycoming GO-480-G2F6 engines, 47 built.
;Model E50: Supercharged version of the D50; with increased takeoff weight and {{convert|340|hp|abbr=on}} 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 {{convert|340|hp|abbr=on}} 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 {{convert|340|hp|abbr=on}} 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.<ref>{{Cite book |last=Ward |first=Richard I. |title=Beechcraft Twin Bonanza: Craft of the Masters |publisher=Forward Horizons |year=1996 |isbn=0-9652727-1-0}}</ref>
[[File:N14VU.JPG|thumb|The Excalibur 800 modification]]
;Excalibur 800
:A modification designed originally by [[Sino Swearingen Aircraft Corporation|Swearingen Aircraft]] 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.<ref>{{harvnb|Trammel|1966|p=50}}</ref> Other optional improvements were also available.
;[[Beechcraft L-23 Seminole|L-23 Seminole]]: Military version


==Operators==

===Military operators===
;{{CHI}}:[[Chilean Air Force]] (5 x C50, 4 x D50)<ref name="ab" />
;{{COL}}:[[Colombian Air Force]] (1 x D50)<ref name="ab" />
;{{JOR}}:[[Royal Jordanian Air Force]] (1 x F50)<ref name="ab" />
;{{MAR}}: [[Royal Moroccan Air Force]]<ref>{{harvnb|''Air International'' November 1985|p=229}}</ref>
;{{SUI}}:[[Swiss Air Force]] (3 x E50)<ref name="ab" />
;{{URU}}:[[Uruguayan Air Force]]

==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]], his wife, and two others were killed when the aircraft struck terrain during an apparent [[ditching]] attempt in a lake near their intended destination, [[Lansing Municipal Airport]].<ref>{{cite news |author=<!--Staff writer(s)/no by-line.--> |title=Tony Lema and 3 Die in Air Crash |url=https://timesmachine.nytimes.com/timesmachine/1966/07/25/82847772.html?zoom=15 |work=[[The New York Times]] |location=New York City|agency=[[United Press International]]|date=25 July 1966 |url-access=limited}}</ref>

==Specifications (D50)==
[[File:Beechcraft L-23A Seminole 3-view line drawing.png|frameless|right|3-view line drawing of the Beechcraft L-23A Seminole]]

{{Aircraft specs
|ref=Jane's All The World's Aircraft 1956–57<ref name="jawa56 p231">{{harvnb|Bridgman|1956|p=231}}</ref>
|prime units?=imp 
<!--
        General characteristics
-->
|genhide=

|crew=1
|capacity=5 passengers
|length m=
|length ft=31
|length in=6+1/2
|length sigfig=3
|span ft=45
|span in=3+3/8
|span sigfig=4
|height m=
|height ft=11
|height in=4
|wing area sqm=
|wing area sqft=277
|aspect ratio=7.51:1
|empty weight kg=
|empty weight lb=3981
|gross weight kg=
|gross weight lb=6300
|fuel capacity={{convert|180|USgal|impgal L|abbr=on}}
<!--
        Powerplant
-->
|eng1 number=2
|eng1 name=[[Lycoming O-480|Lycoming GO-480-C206]]
|eng1 type=air-cooled [[flat-six]] 
|eng1 kw=
|eng1 hp=295

|prop blade number=<!-- propeller aircraft -->
|prop name=
|prop dia m=<!-- propeller aircraft -->
|prop dia ft=<!-- propeller aircraft -->
|prop dia in=<!-- propeller aircraft -->

<!--
        Performance
-->
|perfhide=

|max speed kmh=
|max speed mph=214
|max speed kts=
|max speed note=at {{convert|2500|ft|m|abbr=on}}
|cruise speed kmh=<!-- if max speed unknown -->
|cruise speed mph=203<!-- if max speed unknown -->
|cruise speed note=at {{convert|7000|ft|m|abbr=on}} (70% power)
|range km=
|range miles=1650
|range note=at {{convert|10000|ft|m|abbr=on}} and {{convert|160|mph|kn km/h|abbr=on}}
|ceiling m=
|ceiling ft=20000
|climb rate ms=
|climb rate ftmin=1450
|more performance=*'''Take-off run to 50 ft (15 m):''' {{convert|410|yd|ft m|abbr=on}}
*'''Landing run from 50 ft (15 m):''' {{convert|458|yd|ft m|abbr=on}}
|avionics=
}}

==See also==
{{Aircontent
|related=
* [[Beechcraft L-23 Seminole|L-23/U-8 Seminole]] 
* [[Beechcraft Travel Air]] 
* [[Beechcraft Queen Air]]
* [[Beechcraft King Air]]
|similar aircraft=
* [[Aero Commander 500]]
* [[Cessna 310]]
* [[Cessna 402|Cessna 401]]
* [[Piper PA-23]]
* [[Piper PA-31 Navajo]]
* [[Piper Aerostar]]
|lists=
|see also=

}}

==References==
{{Reflist}}

* {{cite book |last=Bridgman |first=Leonard |author-link=Leonard Bridgman |title=Jane's All The World's Aircraft 1956–57 |year=1956 |location=New York |publisher=The McGraw-Hill Book Company, Inc. }}
* {{cite book |author-link=Edward H. Phillips|last=Phillips |first=Edward H. |title=Beechcraft – Pursuit of Perfection, A History of Beechcraft Airplanes |year=1992 |location=Eagan, Minnesota, US |publisher=Flying Books |isbn=0-911139-11-7}}
* {{cite magazine |title=The Royal Moroccan Air Force...A Seasoned Air Arm |magazine=[[Air International]] |date=November 1985 |volume=29 |issue=5 |pages=226–232, 250–252 |issn=0306-5634 |ref={{harvid|''Air International'' November 1985}} }}
* {{cite magazine|last=Trammel|first=Archie|title=The Conversion Game|magazine=[[Flying (magazine)|Flying]]|date=October 1966|volume=79|issue=4|pages=47–50|url=https://books.google.com/books?id=wsVehG-3TggC}}

==Further reading==
* Aviation Media, Inc. ''Wonderful World of Flying.'' New York: Aviation Media, Inc, 1992. {{ OCLC | 704064237}}
* Beech Aircraft Corporstion. ''Beechcraft Bonanza.'' Wichita, Kan. : Beech Aircraft Corp., 1947. {{ OCLC | 797985508}} 
* Beech Aircraft Corporation. ''The Story of Beechcraft.'' Wichita, Kan., 1969. {{ OCLC | 6164869}}
* Beech Aircraft Corporation. ''The World of Beechcraft.'' Wichita, Kan. : Beech Aircraft, 1973. {{ OCLC | 55965444}}
* Christy, Joe. ''Beechcraft Guide: Bonanza, Debonair, Musketeer.'' New York : Modern Aircraft Series, 1962. {{ OCLC | 1544220}}
* McDaniel, William Herbert. ''The History of Beech.'' Wichita, Kan. : McCormick-Armstrong Co. Pub. Division, 1982. {{ISBN|0-911978-00-3}} {{ OCLC | 9093762}}
* Pelletier, Alain J. ''Beech Aircraft and Their Predecessors.'' Annapolis, MD. : Naval Institute Press, 1995. {{ISBN|1-55750-062-2}} {{ OCLC | 33167975}}
* 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. {{ISBN|0-9652727-1-0}}  {{ OCLC |36105983}} 
* Wixey, Kenneth E. ''Beechcraft.'' Stroud: Tempus, 1999. {{ISBN|0-7524-1617-0}}  {{ OCLC | 45308272}}

==External links==
{{commons category-inline|Beechcraft Twin Bonanza}}

{{King Air family}}
{{Beechcraft}}

[[Category:Beechcraft aircraft|Twin Bonanza]]
[[Category:1940s United States civil utility aircraft]]
[[Category:Low-wing aircraft]]
[[Category:Aircraft first flown in 1949]]
[[Category:Twin piston-engined tractor aircraft]]
[[Category:Aircraft with retractable tricycle landing gear]]