The Beechcraft Model 34 "Twin-Quad" was a prototype
airliner
An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ...
designed and built by
Beechcraft
Beechcraft is an American brand of civil aviation and military aircraft owned by Textron Aviation since 2014, headquartered in Wichita, Kansas. Originally, it was a brand of Beech Aircraft Corporation, an American manufacturer of general aviati ...
in the period between
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
and the
Korean War
, date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks a ...
.
[Phillips 1992] At this time many aircraft manufacturers in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
anticipated a boom in
civil aviation
Civil aviation is one of two major categories of flying, representing all non-military and non-state aviation, both private and commercial. Most of the countries in the world are members of the International Civil Aviation Organization and work ...
and a large number of designs left the drawing board only to ultimately fail. The Model 34 was one of these failures, partly because of its unusual design, and partly because of the thousands of ex-military transport aircraft that were available at the time for a fraction of the price of a new aircraft.
Design and development
The design was a four-engine high-wing
monoplane
A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes.
A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
with
tricycle undercarriage
Tricycle gear is a type of aircraft undercarriage, or ''landing gear'', arranged in a tricycle fashion. The tricycle arrangement has a single nose wheel in the front, and two or more main wheels slightly aft of the center of gravity. Tricycle ge ...
, originally designed for 14 (three abreast seating with six additional seats mounted on the side) and eventually converted to take 20 passengers.
The side "couch seats" were also able to be folded away so that cargo could be carried internally in the cabin. Individual storage space was provided for each passenger seat on the fuselage side above the seat. In order to accommodate a larger cargo load, a cargo hatch was located near the pilot's compartment.
[Neal 1970. p. 15.]
The unusual aspects of the design were the butterfly or V-tail and engine layout that led to its popular nickname, "Twin Quad." The four engines were buried in the wings, with each pair of engines connected to a single propeller via
clutch
A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...
es and a common
gear box
Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differe ...
.
The engines were
horizontally opposed
A flat engine is a piston engine where the cylinders are located on either side of a central crankshaft. Flat engines are also known as horizontally opposed engines, however this is distinct from the less common opposed-piston engine design, wh ...
eight-cylinder air-cooled
Lycoming GSO-580
The Lycoming GSO-580 is a family of eight-cylinder horizontally opposed, supercharged, carburetor-equipped aircraft engines for both airplanes and helicopters, manufactured by Lycoming Engines in the late 1950s and early 1960s.
The family incl ...
s
(GSO denoting "Geared Supercharged and Opposed", with each engine featuring a built-in reduction gear box in addition to the common propeller gear box). The engines were rated at 400
horsepower
Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the ...
at 3,300
rpm
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines.
Standards
ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...
. The tail was unusual because unlike the vertical and two horizontal surfaces found on most aircraft, the Twin-Quad's was a two-surface V-tail similar to the tail fitted to Beechcraft's other new product at the time, the
Model 35 Bonanza.
The V-tail configuration was flight-tested on a twin-engine Beech AT-10.
Another, but more conventional, design aspect was that the belly was made strong enough to sustain minimal damage in the event of a "wheels-up" landing, with built-in integral landing keels or "skids."
[Neal 1970, pp. 16–17.] The wing measured from tip to tip and the fuselage was long. With the top of the V-tail almost above the ground and a design maximum takeoff weight (MTOW) of 20,000 lbs,
the Model 34 is to date the largest and heaviest Beechcraft civil design, with only the smaller
XA-38 Grizzly military aircraft outweighing it.
Operational history
The Model 34 took to the air for the first time on October 1, 1947, with Beech Chief Pilot Vern L. Carstens at the controls. The first flight was uneventful and the initial report from the test pilot was, "We have another outstanding Beechcraft!"
The prototype Model 34 had accumulated more than 200 hours of test flying when the reinforced belly was validated in a wheels-up landing.
[Simpson 1991, p. 42.] On January 17, 1949, in a severe
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. For a full description of these, see article on ' ...
a few miles northwest of the Beech plant shortly after taking off, the sole Beech 34 was damaged beyond repair. An inadvertent cutting off of an emergency master switch when battling an electrical fire had resulted in the shut down of all the powerplants, leading to the crash. The co-pilot was killed and the pilot and two flight observers were injured in the crash.
[Neal 1970, p. 17.]
After the accident, Beech re-evaluated plans to go into series production with the Model 34. At the time, two new prototypes were being manufactured, one for static test and the other to continue the flight test program. One of the main considerations was that the U.S.
Civil Aeronautics Board
The Civil Aeronautics Board (CAB) was an agency of the federal government of the United States, formed in 1938 and abolished in 1985, that regulated aviation services including scheduled passenger airline serviceStringer, David H."Non-Skeds: Th ...
was delaying the licensing of the anticipated "feeder airlines" for which the design was intended.
[Neal 1970, p. 64.] The Beech 34 ultimately could not compete in major and regional airline operations with the thousands of less complex and cheaper war surplus transports, such as the larger
Douglas DC-3
The Douglas DC-3 is a propeller-driven airliner
manufactured by Douglas Aircraft Company, which had a lasting effect on the airline industry in the 1930s to 1940s and World War II.
It was developed as a larger, improved 14-bed sleeper version ...
/
C-47 Skytrain
The Douglas C-47 Skytrain or Dakota (Royal Air Force, RAF, Royal Australian Air Force, RAAF, Royal Canadian Air Force, RCAF, Royal New Zealand Air Force, RNZAF, and South African Air Force, SAAF designation) is a airlift, military transport ai ...
, the similarly sized
C-60 Lodestar
The Lockheed Model 18 Lodestar is a passenger transport aircraft of the World War II era.
Design and development
Sales of the 10–14 passenger Lockheed Model 14 Super Electra, which first flew in 1937, had proved disappointing, despite the air ...
and Beechcraft's own smaller
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 ...
.
Despite its promise, since the "Twin Quad" had attracted no orders, Beech terminated the project, closing down the production line in January 1949.
Specifications (Model 34)
See also
References
;Notes
;Bibliography
* ''
Illustrated Encyclopedia of Aircraft
The ''Illustrated Encyclopedia of Aircraft'' was a weekly partwork magazine by Aerospace Publishing (an imprint of Orbis Publishing) which was published in the United Kingdom (and sold in other countries too) during the early 1980s. The magazine ...
'' (Part Work 1982–1985). London: Orbis Publishing, 1985.
* Neal, Ronald D. "Pioneer Without a Cause." ''Air Classics'', Vol. 6, no. 4, April 1970.
*
Phillips, Edward H., ''Beechcraft - Pursuit of Perfection, A History of Beechcraft Airplanes''. Eagan, Minnesota: Flying Books, 1992. .
* Simpson, R.W. ''Airlife's General Aviation''. Shrewsbury, UK: Airlife Publishing, 1991, .
External links
"Beech Twin-Quad Power Plant"a 1949 ''Flight'' article on the coupled engine installation on the Model 34
{{Beechcraft
0034
Abandoned civil aircraft projects of the United States
1940s United States airliners
V-tail aircraft
Four-engined tractor aircraft
High-wing aircraft
Aircraft first flown in 1947
Four-engined piston aircraft