Martin P4M
| Martin P4M Mercator | |
|---|---|
 US Navy Martin P4M-1 |
|
| Type: | Reconnaissance plane |
| Design country: | |
| Manufacturer: | |
| First flight: |
September 20, 1946 |
| Commissioning: |
June 1950 |
| Number of pieces: |
21st |
The Martin P4M Mercator (trade name Model 219 ) was an American maritime patrol aircraft produced by the Glenn L. Martin Company in Middle River , Maryland .
history
The Martin P4M Mercator was intended to replace the Consolidated PB4Y Privateer when the US Navy announced a competition for a new patrol aircraft in the mid-1940s. To check the performance, the Navy ordered two XP4M-1 prototypes on July 6, 1944. In order to obtain the required flight performance, an unusual concept was used. In addition to the two huge R-4360 Wasp Major radial engines from Pratt & Whitney , each with 28 cylinders arranged in four rows, an Allison J33 jet engine was also housed in the rear part of the engine pod , whereby all engines used the same fuel (no kerosene ) . The jet engines were only switched on when required (for example when starting) and had a separate air inlet on the underside of the engine housing, which could be closed when the jet engine was switched off. In addition, the wings were equipped with two different profiles (the inner part was optimized for high lift , the outer part for high speed). Due to this complicated construction, the Mercator achieved exceptional flight performance. Since mine-laying over enemy territory was also planned as an operational scenario, heavy defensive armament was also planned. This consisted of a weapon stand with 2 × 20-mm cannons in the glazed bow and stern and a turret with two 12.7-mm machine guns on the back of the fuselage.
The rollout of the first of two prototypes (XP4M-1 still with R-4360-4 and J33-10A or -17 engines) took place on June 17, 1946, and the first flight took place on September 20, 1946 Chief test pilot Pat Tibbs at the wheel. During the subsequent testing, some problems emerged. So the pressure of the hydraulic system had to be increased from 2000 to 3000 PSI and the jet engines proved to be unreliable. In addition, since the counter-model P2V Neptune by Lockheed was already nearing series production, a greater range possessed was to produce cheaper and also still less complex structure, it was awarded the contract for the mission of the Navy. Nevertheless, 1947 ordered 19 machines of the series version P4M-1 Mercator, which were delivered between July 1949 and September 1950 after the rollout of the first machine on July 18, 1949. After a few problems with the jet engines, a crash into the sea on March 8, 1951 and the realization that two models were unfavorable for one task (especially since the P4M was only used in two squadrons as an exotic aircraft), the remaining 18 machines became converted for electronic reconnaissance ( ELINT ) tasks and now referred to as P4M-1Q. In February 1951 the first machine flew in this configuration. The machines received four AN / APR-4 and AN / APR-9 receivers and some additional antennas, panels and devices. In addition, operator stations for five electronics specialists and a commander were installed.
commitment
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The machines were used in the Atlantic from Morocco and in the Pacific from the Philippines or Japan . They flew up to nine hours long missions on the border to the Soviet Union , China , North Korea and Vietnam , with one machine being shot down by Chinese fighter planes off Shanghai on August 22, 1956 and another machine by two North Korean MiG-17s on June 16, 1959 was badly damaged and had to make an emergency landing in Japan. Four other machines crashed without any outside interference, so that at the end of 1959, due to a lack of spare parts, most operations were stopped and on July 23, 1960 the last machine was decommissioned and later scrapped. Their duties were taken over by Douglas EA-3 , Lockheed WV-2Q (EC-121M) and Lockheed EP-3B .
Technical specifications
| Parameter | Data |
|---|---|
| Length: | 25.60 m |
| Wingspan: | 34.75 m |
| Wing area: | 121.79 m² |
| Height: | 7.95 m |
| Drive: | 2 × radial engines Pratt & Whitney R-4360-20A with 3,250 HP each (approx. 2,390 kW) and 2 × Allison J33-A-23 with 20.63 kN each |
| Top speed | 660 km / h at 6,125 m altitude |
| Range: | 4,570 km |
| Crew: | nine men (2 pilots, navigator, radio operator, radar operator and operator for electronic countermeasures) |
| Service ceiling: | 10,545 m |
| Empty mass: | 22,016 kg |
| Max. Takeoff mass: | 40,088 kg |
| Armament: | 2,722 kg bombs, torpedoes and four 20 mm cannons and four 12 mm machine guns |
Web links
- Martin Model 219. The Glenn L. Martin Maryland Aviation Museum, 2010, archived from the original on February 5, 2012 ; accessed on June 1, 2019 .
Individual evidence
- ↑ a b FliegerRevue November 2011, pp. 52–55, AM-1 Mauler and P4M Mercator
- ↑ Michael D. Roberts: Dictionary of American Naval Aviation Squadrons. (PDF) P4M-1 Mercator. Naval Historical Center Department of the Navy, 2000, p. 678 , accessed June 1, 2019 .