Beechcraft Duchess
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The Beechcraft Model 76 Duchess is an American twin-engined monoplane built by Beechcraft intended partly as a low cost introduction to twin-engine aircraft.<ref name="Green"/><ref name="flying">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
DevelopmentEdit
Developed as Model PD289 (Preliminary Design 289), the prototype was unveiled on November 4, 1974, although it had first flown in September 1974.<ref name="Green"/><ref name="fiftieth">Template:Cite book</ref>Template:Rp The Model 76 was designed as an economical twin-engine trainer for the Beech Aero Centers and to compete with the similar Gulfstream Cougar as well as the Cessna 310.<ref name="Green"/><ref name="kingairmag">Template:Cite journal</ref>
The first production version flew on 24 May 1977, and the name "Duchess" was chosen through a company competition.<ref name="Green"/><ref name="fiftieth" /> Construction of the Duchess was set for a new factory built at the Liberal Division,<ref name="AWST">Template:Cite journal</ref> with deliveries beginning early in 1978.<ref name="fiftieth" />Template:Rp
Production of the Duchess continued until 1983, with no significant changes.<ref>Template:Cite journal</ref> A single example was tested with turbocharged engines in 1979, but did not proceed to production.<ref name="perfection" />Template:Rp
DesignEdit
The Duchess is an all-metal low-wing monoplane with retractable tricycle landing gear and a T-tail. It seats four.<ref>Template:Cite book</ref> The design used components and the bonded wing construction from Beechcraft's single-engined Musketeer line.<ref name="perfection">Template:Cite book</ref>Template:Rp The basic fuselage and wing structure was adapted from the Model 24 Sierra, a Musketeer variant with retractable landing gear, but the Sierra wing spar was redesigned to support the added weight of the engines.<ref name=avweb>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Nose landing gear from the A36 Bonanza was used.<ref name=avweb/>
The Model 76 incorporates right and left "handed" Lycoming O-360 engines that rotate in opposing directions to eliminate the critical engine during single engine operation.<ref name="Plane and Pilot">Plane and Pilot: 1978 Aircraft Directory, page 84. Werner & Werner Corp, Santa Monica CA, 1977. Template:ISBN</ref>
In 1979, a single example was converted to test the turbocharged versions of the engine. The cowlings were reshaped and the exhaust moved to accommodate the aft-mounted turbochargers.<ref name="perfection" />Template:Rp
The Duchess wing is of aluminum honeycomb construction fastened by bonding, rather than rivets, to reduce cost and produce a smoother aerodynamic surface.<ref name="Plane and Pilot"/>
T-tailEdit
The use of a T-tail on the Model 76 met with mixed critical reception when the aircraft was introduced. Plane & Pilot pronounced: "Outstanding design characteristics of the new Duchess include an aerodynamically advantageous T-tail, which places the horizontal surfaces above the propeller slipstream for better stability and handling.",<ref name="Plane and Pilot"/> while Gerald Foster said: "[Beechcraft's] interest in T-tails was perhaps an affectation triggered by their wide use on jet airliners".<ref name="Foster">Montgomery, MR & Gerald Foster: A Field Guide to Airplanes, Second Edition, page 92. Houghton Mifflin Company, 1992. Template:ISBN</ref> AVweb wrote that Beechcraft adopted the T-tail after flight tests revealed that the initially used conventional horizontal stabilizer was too small and suffered from buffeting problems, increasing noise and vibration during flight; moving the horizontal stabilizer out of the propeller slipstream eliminated the buffeting and the need for enlargement while adding only Template:Convert of weight.<ref name=avweb/> Additionally, the T-tail design moved the stabilizer rearward, increasing its effectiveness and giving the aircraft a broader center of gravity range.<ref name=avweb/> The later Piper Seminole also adopted a T-tail.<ref name=avweb/>
VariantsEdit
- Model 76 Duchess
- Four-seat, twin-engine (Lycoming O-360), low-winged trainer with bonded aluminum construction.
- Model 76TC Duchess
- Unofficial designation for single test aircraft using turbocharged Lycoming O-360.
OperatorsEdit
The aircraft remains popular with flight training schools.
- Beechcraft - Tested one Duchess to investigate its spin recovery characteristics in conjunction with NASA.<ref>Template:Cite book</ref>
- National Test Pilot School - Operates one Duchess.<ref>{{#invoke:citation/CS1|citation
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- Purdue University - Uses a Duchess modified with air sampling equipment as Airborne Laboratory Atmospheric Research (ALAR).<ref>{{#invoke:citation/CS1|citation
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- Scaled Composites - Uses one Duchess as a test aircraft.<ref>{{#invoke:citation/CS1|citation
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