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 planes.
A monoplane has inherently the highest efficiency and lowest drag of any wing con ...
,
T-tail
A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs from the standard configuration in which the tailplane ...
ed, two-seats in
side-by-side configuration
Tandem, or in tandem, is an arrangement in which a team of machines, animals or people are lined up one behind another, all facing in the same direction.
The original use of the term in English was in ''tandem harness'', which is used for two ...
,
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 when a ...
research
glider
Glider may refer to:
Aircraft and transport Aircraft
* Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight
** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...
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 university, public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford,"A Gentleman of Strathcona – Alexande ...
, 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 (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...
, with some
stainless steel used for the
wing rib
In an aircraft, ribs are forming elements of the 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 intervals, form ...
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 clo ...
. Its four-piece span high
aspect ratio wing employed a modified Wortmann FX-61-163/35SF
airfoil. 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, 199 ...
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 com ...
of 2.2. For glidepath control when landing the flaps deployed to 80° to create
aerodynamic drag. The outer flaps acted as slotted
ailerons 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 largest city in the U.S. state of Kansas and the county seat of Sedgwick County. As of the 2020 census, the population of the city was 397,532. The Wichita metro area had a population of 647,610 in 2020. It is located in ...
,
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 territori ...
, 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, Zapata County, Texas, United States. The population was 14,018 at the 2010 United States Census, 2010 census. As an unincorporated community, Zapata has no mu ...
to just east of
Amarillo, Texas
Amarillo ( ; Spanish for "yellow") is a city in the U.S. state of Texas and the seat of Potter County. It is the 14th-most populous city in Texas and the largest city in the Texas Panhandle. A portion of the city extends into 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 a ...
.
Specifications (Gemini)
See also
References
{{reflist
1970s Canadian sailplanes
Canadian experimental aircraft
Aircraft first flown in 1973
Mid-wing aircraft
T-tail aircraft