N636X, The Last Flight of the Only Airworthy Martin 4-0-4 Propliner

Copyright 2008, Doug Robertson, posted on 2008-03-02


N636X, a 1952 Martin 4-0-4  pressurized airliner reputed to be the last airworthy example of its kind, made perhaps its last flight recently from Camarillo Airport CMA, California to  The Air Museum "Planes of Fame" in Arizona.  The aircraft had been stationed at CMA for 11 years  before its departure, recently chocked near the Commemorative Air Force hangars.

The genesis of the design manufactured by the Glenn L. Martin Company was the  Martin 2-0-2, a twin engine 36 passenger fast airliner billed as replacement for the Douglas DC-3,  that first flew in prototype form in November 1946. The 2-0-2 cruised at 225 miles per hour, easily besting the 180 mile per hour DC-3 cruise speed. Martin had been building large flying boats such as the Clippers, the Martin Mars and others, and wanted in on the commercial airline passenger business following World War II. Six customers initially ordered the Martin 2-0-2, but the design was soon  found  plagued with mechanical and structural  difficulties.  Cracks in the wing revealed major design flaws.  LAN Chile took first 2-0-2 deliveries in October 1947, and Northwest Airlines in November 1947. Northwest Airlines was the first domestic fleet user. Their 2-0-2 NC93044 lost its outer wing in turbulence  near Winona, Minnesota, grounding Northwest's 2-0-2 fleet until near the end of 1948.  A Minneapolis night crash of a Northwest 2-0-2 in a howling, blinding snowstorm in March 1950 with loss of all aboard and two on the ground, with additional ground injuries was memorable to me as I lived then near the Minneapolis airport, called Wold-Chamberlain Field at the time. That 2-0-2 flight had missed an instrument approach to landing at MSP, and in the go-around attempt the left wing struck a tall steel flagpole in the Veteran's Cemetery south of the field, then crashing into occupied houses with resultant fire. In 1951, after four more lost Martin 2-0-2s in crashes, Northwest Airlines sold off their fleet of 2-0-2s, having taken delivery of just 25 of the 40 on order-the rest were cancelled. Martin brought out an improved 2-0-2A model, but other orders were cancelled and only 47 2-0-2s were manufactured. Howard Hughes's TransWorld Airlines (TWA) subsequently leased a dozen Martin 2-0-2s, later built of surplus parts (with strengthened wings to the 2-0-2A standard). A Venezuelan airline also operated Martin 2-0-2s for a time on Latin American routes.

In March 1950 the Martin 4-0-4 variation of the design looked similar to the 2-0-2 but was a pressurized  twin engine  somewhat larger aircraft  more comfortable for passengers and crew. The Martin 4-0-4 was popular and successful, with TWA and Eastern Airlines acquiring them. The 4-0-4 design shared few components with its ill-fated predecessor. Very similar in appearance to the contemporary Convair CV- 240, CV-340 and CV-440 Convairliner twins, the  Martin  2-0-2s and 4-0-4s were easily diifferentiated  by their much increased wing dihedral outboard of the engines. This dihedral is well shown in the photographs of N636X. The 4-0-4  was considered a success at the time, with 103 built mainly for TWA and for Eastern Airlines.  Please note that the war ace Eddie Rickenbacker who ran Eastern at the time, 1952,  instructed his employees to refer to the 4-0-4s as "Eastern's Silver Falcon", never mentioning "Martin" because of the bad press about the 2-0-2s.  Eastern operated 60  4-0-4s, TWA had 40 and two were used by the US Coast Guard.  The first Eastern 4-0-4 was N440A.  Eastern's 4-0-4 fleet subsequently went to Mohawk, later to Ozark Airlines. In Mohawk's usage, the availability of the Martin 4-0-4 quickly replaced their Convair CV-240s. N636X in the photographs shows the livery of Pacific Air Lines; another secondary operator of the 4-0-4 was Piedmont. Only oldtimers may remember these US airlines. Southeast Airlines operated the ex-TWA 2-0-2As and some 4-0-4s for 16 years to 1978. The Martin 4-0-4 had a good safety record, especially with original operators.

The Martin 4-0-4  with 52 passengers (which was considered a large airliner at the time)  flew about 100 miles per hour faster than the smaller 21 passenger Douglas DC-3 at the time with excellent range near 900 miles fully loaded. (The DC-3 had a 1,500 mile range, however, flying across the United States with only one intermediate fuel stop).  The 4-0-4 carried a flight crew of three, pilot, copilot and navigator, sometimes crew of four, in addition to stewardesses. Compared  with modern jetliners, the 4-0-4 cockpit workload was difficult and excessive, with many gauges, switches and and in-flight procedures to be monitored and followed, requiring much crew coordination and care of operation of the super-turbocharged  Double Wasp  radial engines. The 4-0-4 stood  high off the deck on spindly-appearing fully retractible tri-gear to afford ground clearance for the large diameter three-blade  controllable pitch props needed to absorb torque of the two 2,400 horsepower engines. Integral, retractible steps at the aircraft rear fuselage belly (like the later, more modern Boeing 727 jet airliner) enabled loading and unloading of passengers anywhere on the ramp without need  of a rolling set of ramp steps.  There was a conventional forward door on the fuselage left side behind the cockpit. A standout flight feature was the easy landing characteristics of the design because of the exaggerated nose low attitude during approach and landing- "just aim the nose for the end of the runway and they land almost by themselves".


N636X, the subject of this article, has an interesting history. It was initially used in passenger service from 1952 with TransWorld Airlines. In 1960 it was sold to the E. F. McDonald Company in Ohio. The passenger seats were removed and replaced by custom luxurious red velvet seats and divans interior in its corporate conversion. In 1969 the aircraft was purchased by William Whitesell who trained his son Jeff to be an airline pilot, starting a charter flying service with the 4-0-4. Many famous sports notables-champion boxer Muhammad Ali and sports announcers Howard Cosell, Don Meredith and Frank Gifford were among passengers in this 4-0-4. In the 1970s business downturn the aircraft was sold. Jeff Whitesell then flew for commercial airlines and in 1993 he founded Airliners of America, a foundation to preserve and show classic prop airliners. Looking for a flagship airliner, he found a Martin 4-0-4 in poor shape, the very same aircraft his father had owned years earlier. A lot of time and money was spent returning the aircraft to flight status. Jeff found maintaining the aircraft chocked outdoors over the years was an even more expensive proposition, and finally decided to donate N636X to The Air Museum "Planes of Fame". On Friday, 29 February 2008 Jeff Whitesell flew the aircraft for the last time, delivering it to the Valle, Arizona museum off Highway 64 south of the Grand Canyon. Locally, this aircraft will be missed. Camarillo lost their "Camarillo Connie" Constellation propliner some years ago to a lease in Switzerland by the owner, and now another Camarillo revered aircraft icon is gone.

Per 2-17-2016 email contact from Gene Quinn-"For what it's worth, this plane was used in the 2003 movie 'View From The Top' starring Gwyneth Paltrow".  Thank you, Gene for your welcome aircraft history input.


Please click on the top photo to see the N636X Aircraft Profile page with more photos, including those of Dean Heald. Thank you, Dean! 




52 pass., 3-4 crew + stewardesses short/medium range pressurized transport 

Powerplant: two Pratt & Whitney 2,400 Hp R-2800-CB16 Double Wasp super-turbocharged engines

Wingspan: 93 ft. 3 in.

Wing area: 864 sq. ft.

Length: 74 ft. 7 in.

Height: 28 ft. 5 in.

Weight empty: 29,064 lbs. Max takeoff: 44,805 lbs.

Wing loading: 51.86 lbs./sq. ft.

Power loading: 9.33 lbs./Hp



Max speed: 311 mph

Cruise speed: 277 mph

Initial rate of climb: 1,900 ft./min.

Range: 892 miles with max payload

Service celiing: 29,000 ft.



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