The Handley Page aero-concern was established in June of 1909 and quickly went to work producing heavy bombers for the British Royal Navy (RN) when World War 1 (1914-1918) came about. From this exposure, further developments appeared during the Interwar years (1919-1938) and the company remained a player in the World War 2 (1939-1945) period. In the post-World War 2 world, the firm continued work in the aviation field though, not having taken advantage of a major merger to remain viable, it was unable to compete effectively for government contracts during peacetime - as such it faltered and ultimately went defunct in March of 1970.
Back during the World War 2 period, the company remained a primary contributor to the British war effort, particularly in the early-going. Even before the official outbreak of war on September 1st, 1939, the company was drawing up internal plans to develop a tailless "bomber defender", a unique heavy fighter that would provide critical defense to vulnerable large bomber aircraft of the Royal Air Force (RAF). To prove this flying wing design sound, a subscale development was in order and company personnel came to know it as "Manx" (this name became official in 1943). The project designation of "HP.75" was not made official until 1945.
As a tailless aircraft design, the Manx held no traditional tail unit - though a centralized, small-area vertical tailfin was used. The wing mainplanes were composed of two primary sections, an inboard and outboard section. The inboard section acted as the major fuselage mass carrying the two de Havilland "Gypsy Major II" engines in "pusher" fashion. Each of these engines drove a two-bladed propeller unit and they were eventually given spinners by 1945 for better streamlining. This inboard section was given straight leading and trailing edge lines. Conversely, the outboard section was well-swept along both its leading and trailing edges and winglets were affixed to their absolute tips for added control.
The fuselage was of a deep teardrop shape and positioned the pilot forward and a flight observer aft. Both seats were glazed/framed for optimal viewing during test flights. The aft position held a unique quality in which the tail cone could be jettisoned in an emergency and allow the observer to vacate his position in short order.
The undercarriage was of a rather-modern tricycle arrangement involving two single-wheeled main legs and a single-wheeled nose leg. The main legs were eventually upgraded (and reinforced) to twin-wheels after testing and the nose leg was to be faired over for aerodynamic streamlining - it remained fixed in flight whereas the main legs retracted into the inboard wing sections.
Development and Subsequent Flying Career
The Manx was not a pretty aircraft by any measure but it's utilitarian appearance was born from the fact that it was developed exclusively to collect data on tailless flight. Its design was attributed to Gustav Lachmann (1896-1966) who was born in Germany but eventually settled in the United Kingdom - he was interred for the duration of the war which did the Manx project no favors (he became a citizen in 1949). Data on this special aircraft type was being pulled together as early as 1936 and a special research arm of Handley Page was arranged in 1938 with Lachmann as its lead. The project gained steam into 1939 but the original firm tagged with construction of the new aircraft, Dart Aircraft, could not pull together the needed resources so Handley Page regained control - leading to the completed aircraft becoming available in 1940.
By this time, Handley Page was fully-committed to the British war effort and production of its Halifax heavy bombers so the Manx was left to develop along a much slower timeline than originally planned. Taxi trials were had in late-February of 1940 and more intense ground-maneuvers were seen into March of that year. The aircraft then languished until March 1941 but, even at this point, deterioration of the wing members were noted, resulting in a lengthy period of repair and refurbishment.
Trials resumed in September of 1942 though one run resulted in a damaged nose wheel and nose section - adding to the delays; it was not made available again until May of 1943. A first-flight was finally had on June 25th, 1943 as the flying wing completed a ten minute jaunt before landing successfully. Additional test flights followed that summer into the fall but, again, the project languished until making its fourth flight the following in June of 1944 (by this time the fairing over the nose wheel was added). Another fourteen flights were completed heading into December of 1944.
In September of 1945, with the war in Europe now over, the Manx was put on public display for the first time. The last test flights of the now-improved, streamlined aircraft were recorded in early April of 1946 and, in total, the prototype completed thirty-one. The sole flyable example was put into storage thereafter and ultimately burned in 1952.
For its time in the air, the Manx was noted for poor performance blamed on the increased gross weight, low-powered engines, vibration issues, and the generally low operating ceiling required of the early testing phase. On-the-whole, the flying wing concept was more-or-less sound though a steady hand at the controls was still a requirement in a time when Fly-by-Wire technology was a topic of science fiction. Thought was given to adding a foreplane element to the aircraft to add longitudinal stability and additional maneuverability but this initiative fell to naught - the component was, in fact, completed by the woodworkers of Percival Aircraft but never installed on the flyable aircraft.