Helmy Aerogypt
| Helmy Aerogypt | |
|---|---|
|
|
| Type: | Test aircraft |
| Design country: | |
| Manufacturer: |
Saleh Helmy Aircraft, from 1945: Aerogypt High Speed Development Co. Ltd. |
| First flight: |
February 1939 |
| Commissioning: |
- |
| Production time: |
- |
| Number of pieces: |
1 |
The Helmy Aerogypt (for Airplane of Egypt , German about Egypt's airplane) was a three-engine test aircraft that was designed and built by the Egyptian medical student Saleh Helmy. The Aerogypt was probably the smallest three-engine airplane that has ever flown. Similar to the American designer Vincent Burnelli, Helmy developed a concept for increasing the lift share of the fuselage in the total lift of an aircraft, with the main focus being on increased safety during generally critical take-off and landing processes.
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 airplane which, according to his plans, would then be built in his native Egypt. The outstanding thing about his design was the so-called Helmy flap, which he had patented. The flap had a profile shape in the longitudinal section and was attached to the fuselage of an aircraft, practically as a second roof. The flap should be designed to be movable in order to be able to change its angle of incidence and thus to obtain an additional surface that allows the take-off and landing speeds to be reduced. When straightening up, the flap should move backwards on rails on the fuselage in order to leave the flow to the tail unit largely undisturbed. Helmy claimed that the flap even after the stall would deliver on the wings still buoyant.
The National Physical Laboratory in Teddington assessed the Helmy conception positively from the aerodynamic point of view, but pointed out that it did not consider the practical mechanical implementation to be feasible. Helmy then founded his own company in 1937 with the long-term goal of building an 80-person passenger aircraft with a wingspan of 33 m (100 ft) using its patented flap as a structural element. First, however, a 1: 4 model of the planned aircraft should be built in order to prove the feasibility of the concept .
This is how the Aerogypt was created with a wingspan of 7.90 m (26 ft), a relatively wide fuselage and the prototype of the Helmy flap on the roof. On February 17, 1938, the machine received the civil registration G-AFFG. The construction took place in Helmy's house in Maidenhead , after completion the individual parts were brought to Heston for assembly and flight tests . The first flight took place in February 1939.
After a landing accident and the subsequent repair, the machine without the Helmy flap was referred to as the Aerogypt II. After another accident in which the landing gear was damaged, further modifications such as improved engine fairings, enlarged rudder surfaces and additional auxiliary fins on the horizontal stabilizer were implemented. The name was then Aerogypt III, with her the last flight was carried out on September 26, 1940.
After relocation to White Waltham , the three engines were replaced by two more powerful and quieter Continental A65s , each with 65 hp. The tail wheel landing gear was converted into a nose wheel landing gear , which was also designed by Helmy himself. After a first attempt to take off the machine, now called Aerogypt IV, failed on January 12, 1946, a 20-minute flight succeeded on February 17. After a few more successful flights, Helmy planned to transfer the machine to Egypt and initiate series production of 100 machines for private pilots and clubs there. Allegedly, King Farouk and the Egyptian government supported his plans.
During the transfer flight on November 26, 1947, the aircraft was irreparably damaged during the first stopover and the subsequent rescue attempt.
construction
The construction was based on the De Havilland DH.88 Comet with the monocoque construction made of diagonally processed plywood strips . The drive initially consisted of three 22 HP Aero Sprite two-cylinder air-cooled engines. The panels for this ran down into trouser leg panels for the fixed chassis. Similar to the Burnelli constructions, the fuselage had a profile shape in the longitudinal section. The tank volume of 15 gal was divided into two tanks with which a range of 300 miles could be achieved. A 32 gal long-range tank was constructed for the planned transfer flight to Egypt.
Technical specifications
| Parameter | Data |
|---|---|
| crew | 2 (?) |
| length | 5.80 m (19 ft) |
| span | 8.03 m (26 ft 4 in) |
| height | 1.98 m (6 ft 6 in) |
| Wing area | 7.90 m² (85 ft²) |
| Wing extension | 8.02 |
| Rate of climb | 180 m / min (600 ft / min) |
| Max. Takeoff mass | 1090 kg (2400 lb) |
| Cruising speed | 230 km / h (145 mph) |
| Top speed | 256 km / h (160 mph) |
| Service ceiling | 5200 m (17,000 ft) |
| Range | 770 km (480 ml) |
| Engines | 3 × two-cylinder Aero Sprite engines with 22 HP each, later 2 × Continental A-65 with 65 HP each |
See also
literature
- Richard Riding: The Maidenhead Baby , Airplane Monthly, April 1990, pp. 213ff.