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The General Aircraft Monospar
was a 1930s British family of touring and utility aircraft built
by General Aircraft Ltd (GAL).
In 1929, the Monospar Company
Ltd was formed to pursue new techniques of designing cantilever
wings, based on the work of Swiss engineer Helmuth J. Stieger,
who headed the company. Helmuth John Stieger was born in Zurich
in 1902 and educated at the Swiss Federal Polytechnic then the
Imperial College of Science in London. While working as a designer
for William Beardmore and Company, he formed his own ideas about
wing design and evolved an improved method of building and stressing
wings for which he was later granted a British Patent in December
1927. The principle behind this Patent No. 306,220 was that the
wing needed only one spar with torsion loads resisted by an efficient
system of strong compression struts with triangulated bracing
in the form of thin wires. The design was revolutionary and very
light for its strength. Based on this design, The Monospar Company
designed a twin-engined low-wing aircraft designated the Monospar
ST-3, that was built and flown in 1931 by the Gloster Aircraft
Company at Brockworth, Gloucestershire. After successful testing
of the Monospar ST-3, a new company General Aircraft Ltd was
formed to produce aircraft that used the new Monospar wing designs.
The first production design was the Monospar ST-4, a twin-engined
low-wing monoplane with a fixed tailwheel landing gear and folding
wings for ground storage. Powered by two Pobjoy R radial engines,
the first aircraft (G-ABUZ) first flew in May 1932, and was followed
by five production aircraft. The Monospar ST-4 Mk.II, an improved
variant with minor differences, followed with a production run
of 30. In 1933, the Monospar ST-6 appeared, a similar aircraft
to the ST-4 with manually retractable landing gear and room for
an extra passenger. The Monospar ST-6 was only the second British
aircraft to fly with retractable landing gear (the first, the
Airspeed Courier, was flown a few weeks earlier). Another Monospar
ST-6 was built, and two ST-4 Mk.IIs were converted. GAL then
produced a developed version, the Monospar ST-10, externally
the same but powered by two Pobjoy Niagara engines, an improved
fuel system, and aerodynamic refinements. The Croydon factory
closed down in 1934, and a larger factory was opened in 1935
at London Air Park, Hanworth. |
