The Marsden Gemini is a Canadian
mid-wing
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 wings.
A monoplane has inherently the highest efficiency and lowest drag of any wing config ...
,
T-tail
A T-tail is an empennage wikt:configuration, configuration in which the tailplane of an aircraft is mounted to the top of the vertical stabilizer, fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs fr ...
ed, two-seats in
side-by-side configuration
Tandem, or in tandem, is an arrangement in which two or more animals, machines, or people are lined up one behind another, all facing in the same direction. ''Tandem'' can also be used more generally to refer to any group of persons or objects w ...
,
experimental
An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs whe ...
research
glider that was designed and constructed by David Marsden at the
University of Alberta
The University of Alberta (also known as U of A or UAlberta, ) is a public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta, and Henry Marshall Tory, t ...
, first flying in 1973.
Design and development
The Gemini was designed to explore the use of
flaps to create a variable geometry sailplane that would be optimized for both low speed thermalling flight and also high speed gliding between thermals.
The aircraft was predominantly made from
aluminium
Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
, with some
stainless steel
Stainless steel, also known as inox, corrosion-resistant steel (CRES), or rustless steel, is an iron-based alloy that contains chromium, making it resistant to rust and corrosion. Stainless steel's resistance to corrosion comes from its chromi ...
used for the
wing rib
In an aircraft, ribs are forming elements of the airframe structure of a wing, especially in traditional construction.
By analogy with the anatomical definition of "rib", the ribs attach to the main spar, and by being repeated at frequent inter ...
s, controls and fittings. The two-place side-by-side cockpit was made from
fibreglass
Fiberglass (American English) or fibreglass ( Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass c ...
. Its four-piece span high
aspect ratio
The aspect ratio of a geometry, geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side—the ratio of width to height, when the rectangl ...
wing employed a modified Wortmann FX-61-163/35SF
airfoil
An airfoil (American English) or aerofoil (British English) is a streamlined body that is capable of generating significantly more Lift (force), lift than Drag (physics), drag. Wings, sails and propeller blades are examples of airfoils. Foil (fl ...
. The Fowler flaps occupied the entire
trailing edge
The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...
of the wing and accounted for 35% of the wing chord. In cruise the flaps were retracted, reducing the wing area. While climbing, the flaps were extended, producing a high
lift coefficient
In fluid dynamics, the lift coefficient () is a dimensionless quantity that relates the lift generated by a lifting body to the fluid density around the body, the fluid velocity and an associated reference area. A lifting body is a foil or a co ...
of 2.2. For glidepath control when landing the flaps deployed to 80° to create
aerodynamic drag
In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers, two solid surfaces, or b ...
. The outer flaps acted as slotted
aileron
An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement aroun ...
s for roll control.
Operational history
Only one Gemini was built.
The aircraft was still operational in August 2011, owned by William G. Osoba of
Wichita, Kansas
Wichita ( ) is the List of cities in Kansas, most populous city in the U.S. state of Kansas and the county seat of Sedgwick County, Kansas, Sedgwick County. As of the 2020 United States census, 2020 census, the population of the city was 397, ...
,
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
, but was removed from the US register in April 2019 and its fate is unknown.
The aircraft was flown to set seven Canadian multi-place records, including the record for speed over a triangle. It was also used to set the US national record for the of .
On July 2, 2011, Osoba and his wife Christine flew the Gemini on a free distance flight from
Zapata, Texas
Zapata is a census-designated place (CDP) in and the county seat of Zapata County, Texas, United States. The population was 5,383 at the 2020 United States census, 2020 census. As an unincorporated community, Zapata has no municipal government, b ...
to just east of
Amarillo, Texas
Amarillo ( ; Spanish language, Spanish for "yellow") is a city in the U.S. state of Texas and the county seat of Potter County, Texas, Potter County, though most of the southern half of the city extends into Randall County, Texas, Randall County ...
, a flight which won the 2011
Barringer Trophy
The Lewin B. Barringer Memorial Trophy was established by the will of Lewin Barringer in 1948. The original rules specified that the trophy would be awarded for the longest distance soaring flight from any type of launching method other than ai ...
.
Specifications (Gemini)
See also
References
{{reflist
1970s Canadian sailplanes
Canadian experimental aircraft
Aircraft first flown in 1973
Mid-wing aircraft
T-tail aircraft