Helmy Aerogypt
The Helmy Aerogypt ( for Aeroplane of Egypt, Egypt about German aircraft ) was a three -engined experimental aircraft, designed and built by the Egyptian medical students Helmy Saleh. The Aerogypt was probably the smallest three-engined aircraft that has ever flown. Helmy developed, similar to the American designer Vincent Burnelli a concept to increase the buoyancy of the hull portion of the total lift of an aircraft, especially an increased safety in the general critical takeoff and landing operations were the focus.
History
Born on February 17, 1905 Helmy was a student at St. Mary's Hospital in Paddington (London), in addition to his studies, he was very interested in the constructive aspects of aviation. He began to design an aircraft which should then be built in his native Egypt to his plans. The most prominent of his design was the so -called Helmy - flap, which he had patented. The flap had a profile shape in longitudinal section and is mounted on the fuselage of an aircraft, as a kind of second roof. The flap should be designed to move in order to change its setting angle can thus obtain an additional lifting surface, which allows to reduce the take-off and landing speeds. As you raise the flap should move on rails on the fuselage to the rear to allow the flow to the tail largely undisturbed. Helmy claimed that the flap even after the flow separation on the wing would provide more lift.
The National Physical Laboratory in Teddington assessed the Helmy conception quite positive from the aerodynamic point of view, but pointed out that it regards the practical mechanical conversion as not feasible. Helmy then founded his own company in 1937 with the ultimate aim of a 80 -person passenger aircraft with a wingspan of 33 m building ( 100 m), which uses its patented flap as a design element. First, however, a proposed 1:4 model of the aircraft to be built to demonstrate the feasibility of the concept.
So the Aerogypt originated with a wingspan of 7.90 m (26 ft), a relatively wide trunk and the prototype of the Helmy flap on the roof. On February 17, 1938, the aircraft received the civil registration G- AFFG. The construction took place in the House of Helmy in Maidenhead, after the completion of the items were taken to the assembly and flight testing by Heston. The first flight took place in February 1939.
After a landing accident and the subsequent repair the machine was called without the - flap Helmy as Aerogypt II. After another accident in which the chassis was damaged, were further modifications, such as improved engine cowlings, enlarged control surfaces and additional auxiliary fins on the tailplane, implemented. The term was then Aerogypt III, with it, the last flight on September 26, 1940 was performed.
After a transfer to White Waltham the three engines were replaced by two more powerful and quieter Continental A65, each with 65 hp. The spur wheel chassis was converted into a tricycle landing gear, which was also designed by Helmy itself. After a first attempt to start the machine now Aerogypt IV mentioned had failed on January 12, 1946, succeeded on February 17, a 20-minute flight. Helmy planned after a few more successful flights to convert the machine to Egypt and to conduct there a series production of 100 machines for private plane and clubs in the way. Supposedly, his plans have supported King Farouk and the Egyptian government.
During ferry flight on 26 November 1947, the aircraft was damaged beyond repair during the first landing and the subsequent rescue attempt.
Construction
The design was oriented with the monocoque construction of diagonally processed plywood strips at the De Havilland Comet. The drive consisted initially of three each 22 hp Aero Sprite payable two-cylinder air-cooled engines. The panels for ran down into leg fairings for the fixed landing gear. Similar to the Burnelli constructions of the hull pointed in longitudinal section on a profile form. The tank volume of 15 gal was divided into two tanks which has a range of 300 miles could be achieved. For the planned ferry flight to Egypt a 32 gal long distance tank was constructed.