×
Military Pay Military Ranks Aircraft Tanks and Vehicles Small Arms Navy Ships
HOME
AVIATION
MODERN AIR FORCES
COUNTRIES
MANUFACTURERS
COMPARE
BY CONFLICT
BY TYPE
BY DECADE
COLD WAR

Martin P4M Mercator


Maritime Patrol Bomber Aircraft


Aviation / Aerospace

Martin developed the P4M Mercator to contend for the USN long-range maritime patrol bomber role - it lost to the Lockheed Neptune design.



Authored By: Staff Writer | Last Edited: 1/16/2019 | Content ©www.MilitaryFactory.com
During the later stages of World War 2 (1939-1945), the United States Navy (USN) began an active search for a new long-ranged maritime patrol bomber to succeed an aging fleet of Consolidated PB4Y "Privateer" aircraft in same role. Two potential candidates emerged from the competing firms of the Glenn L. Martin Company (Martin) and Lockheed and these became the P4M "Mercator" and P2V "Neptune", respectively. In the end, however, the latter was selected for serial production and frontline service while the P4M was taken only into limited service to satisfy a long-ranged electronic reconnaissance role for the USN - this resulted in just nineteen aircraft being built.

The aircraft that would become the "Mercator" was known in-house as the "Model 219" and work began as soon as 1944 on the type (World War 2 ended in 1945). In its prototype form the aircraft recorded a first-flight on October 20th, 1946 and flew with 2 x Pratt & Whitney R-4360-4 "Wasp Major" air-cooled radial piston engines providing necessary power and performance to go along with the range required of maritime types (often operating over swathes of uninhabited, landless terrain).

At this stage during the "age of the jet engine", it proved somewhat common for American warplanes to feature a "combination" propulsion scheme so 2 x Allison J33 series turbojets were added to augment performance for the aircraft - either to reduce the runway take-off length required or escape from pursuing enemy interceptors. The jet systems relied on the same fuel as the prop-driven radials so only a common fuel supply was necessary.

Standard installed armament became 2 x 20mm autocannons in the nose, an additional 2 x 20mm autocannons at the tail, and 2 x 0.50 caliber Heavy Machine Guns (HMGs) in a dorsal turret. In this fashion, the aircraft would defend itself from most any position an enemy was approaching from (save the underside). The optional bomb load could be made up of conventional drop bombs, naval mines, depth charges, or torpedoes up to a 12,000lb total war load.

The aircraft was given a very slim top-down profile, its fuselage glazed at both nose and tail. The cockpit was seated aft and above the nose section as in a typical "stepped" arrangement so this elevated position could improve pilot vision over the aircraft and towards each engine. The engines were underslung at each mainplane, extending noticeably forward from the leading edges. The bomb bay buried within the fuselage was equal in length to the engines. Instead of fitting the main landing gear into the engines, the legs were positioned outboard of the nacelles and recessed into the wings (folding outwards from centerline). The nosewheel was positioned under the mass of the nose section to complete the tricycle arrangement needed for ground-running. The tail unit incorporated an elegantly-shaped single rudder fin with low-mounted, upward-canted horizontal planes. The wing mainplanes were situated directly at midships and were slim in their own right, tapering from centerline to wing tip along both the leading and trailing edges.

Two prototypes were ultimately built to the "XP4M-1" standard and these flew with R-4360-4 engines followed by the production-standard "P4M-1" models of which nineteen were built and these carried 2 x R-4360-20A series engines into service. The "P4M-1Q" designation was used to mark P4M-1 airframes converted as radar countermeasures platforms (SIGnals INTelligence = "SIGINT").


As finalized, the P4M-1 would go one to carry a complete crew of nine and, structurally, it had an overall length of 85.1 feet, a wingspan of 114 feet and a height of 26 feet. Empty weight was 48,535lb with a Maximum Take-Off Weight (MTOW) of 88,380 feet. Power was from 2 x Pratt & Whitney R-4360 "Wasp Major" air-cooled radial piston engines of 3,250 horsepower each and these were aided by 2 x Allison J33-A-23 turbojet engines of 4,600 thrust each. Performance included a maximum speed of 410 miles-per-hour, a range out to 2,850 miles, and a service ceiling up to 35,000 feet. The aircraft was fitted with the AN/APS-33 search radar.

Even as Lockheed's Neptune design went on to win the original USN requirement, the value of the Mercator was not overlooked by authorities as a mine-laying platform so a production order for the design followed in 1947 leading to service entry in 1950. As soon as 1951, the fleet was converted for the SIGINT role and operated under the aforementioned P4M-1Q designation - these flew with additional mission support equipment and more crewmembers for the revised role.

In this guise, Mercators undertook daring, often dangerous, spying missions around communist territories near the likes of the Soviet Union, China, North Korea, and Vietnam. On August 22nd, 1956, a Mercator was shot down by Chinese interceptors, killing all aboard, and another such incident followed with the Soviet Union over Mediterranean waters after the Mercator was caught near Ukraine. Similarly, North Korean interceptors met a Mercator with gunfire though the American warplane managed to survive the encounter and limp home.

Once their useful service lives were over (and pure jet aircraft took over in full), the Mercator line was given up in favor of the Douglas A-3 "Skywarrior" through its "EA-3B" guise. Unlike the Mercator, the Skywarrior was compact enough to be operated from, and be stored below, the decks of American carriers of the period. The last Mercator was retired in 1960 and none of the surviving airframes were spared.


Specifications



Year:
1950
Status
Retired, Out-of-Service
Crew
9
[ 21 Units ] :
Glenn L. Martin Company - USA
National flag of United States United States
- Ground Attack
- Navy / Maritime
- Reconnaissance (RECCE)
Length:
85.30 ft (26 m)
Width:
114.83 ft (35 m)
Height:
26.25 ft (8 m)
(Showcased structural dimension values pertain to the Martin P4M Mercator production model)
Empty Weight:
48,535 lb (22,015 kg)
MTOW:
88,405 lb (40,100 kg)
(Diff: +39,871lb)
(Showcased weight values pertain to the Martin P4M Mercator production model)
2 x Pratt & Whitney R-4360 "Wasp Major" air-cooled radial piston engines developing 3,250 horsepower; 2 x Allison J33-A-23 turbojet engines developing 4,600lb of thrust each.
(Showcased powerplant information pertains to the Martin P4M Mercator production model)
Max Speed:
410 mph (660 kph; 356 kts)
Service Ceiling:
34,449 feet (10,500 m; 6.52 miles)
Max Range:
2,840 miles (4,570 km; 2,468 nm)
(Showcased performance values pertain to the Martin P4M Mercator production model; Compare this aircraft entry against any other in our database)
STANDARD:
2 x 20mm automatic cannons in nose turret.
2 x 20mm automatic cannons in tail turret.
2 x 0.50 caliber (12.7mm) heavy machine guns in dorsal turret.

OPTIONAL:
Up to 12,000lb of conventional drop stores including bombs, torpedoes, depth charges and naval mines.
(Showcased armament details pertain to the Martin P4M Mercator production model)
P4M "Mercator" - Base Series Designation
XP4M-1 - Prototype aircraft with 2 x R-4360-4 series engines fitted; two examples completed.
P4M-1 - Production-quality aircraft; fitted with 2 x R-4360-20A series engines; 19 examples completed.
P4M-1Q - Radar CounterMeasures (CM) conversion model; based on existing P4M-1 framework.
General Assessment
Firepower  
Performance  
Survivability  
Versatility  
Impact  


Values are derrived from a variety of categories related to the design, overall function, and historical influence of this aircraft in aviation history.
Overall Rating
The overall rating takes into account over 60 individual factors related to this aircraft entry. The rating is out of a possible 100.
78
Relative Maximum Speed
Hi: 500mph
Lo: 250mph
This entry's maximum listed speed (410mph).

Graph average of 375 miles-per-hour.
City-to-City Ranges
NYC
 
  LDN
LDN
 
  PAR
PAR
 
  BER
BER
 
  MSK
MSK
 
  TKY
TKY
 
  SYD
SYD
 
  LAX
LAX
 
  NYC
Martin P4M Mercator operational range when compared to distances between major cities.
Aviation Era Span
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Showcasing era cross-over of this aircraft design.
Unit Production (21)
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
21
21

  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.


Max Altitude Visualization
Small airplane graphic
Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for pioneering aircraft
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon representing modern aircraft
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur War
Military lapel ribbon for experimental x-plane aircraft
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.

Disclaimer | Privacy Policy | Cookies
Military Ranks | Military Pay | Aircraft | Tanks & Vehicles | Small Arms | Navy Ships | American War Deaths | 5-Star Generals | Military Alphabet Code | DoD Terms | Convert Knots to Miles-per-Hour



The "Military Factory" name and MilitaryFactory.com logo are registered ® U.S. trademarks protected by all applicable domestic and international intellectual property laws. All written content, illustrations, and photography are unique to this website (unless where indicated) and not for reuse/reproduction in any form. Material presented throughout this website is for historical and entertainment value only and should not to be construed as usable for hardware restoration, maintenance, or general operation. We do not sell any of the items showcased on this site. Please direct all other inquiries to militaryfactory AT gmail.com.

Part of a network of sites that includes GlobalFirepower, a data-driven property used in ranking the top military powers of the world and WDMMA.org, the World Directory of Modern Military Aircraft.


Facebook Logo YouTube Logo

www.MilitaryFactory.com • All Rights Reserved • Content ©2003-