Operating the DC-4

Information courtesy of Joe Hennessy

dc-4_11.jpg
Photo from Seaboard Archive

The DC-4 was powered by four 1,450 horsepower Pratt and Whitney R-2000 engines, had eight gas tanks and a maximum fuel capacity of 3,600 U.S. gallons.

The empty weight on the DC-4 in passenger configuration varied from 43,000 to 45,000 lbs. Stripped for cargo operations, it would be 39,000 to 41,000 lbs, In 1952, the maximum takeoff weight was 71,500 lbs. In 1954, this was increased to 73,500 lbs. Maximum landing weight was 63,500 lbs.

The true airspeed was 181 knots, the fuel flow was 208 gallons/hr. in cargo configuration and 211 gallons/hr in pax configuration. (The additional three gallons/hr. was for the heaters when carrying passengers.) Reserve and alternate fuel was computed at 180 gallons/hr. Westbound trips for MATS (the Military Air Transport Service, normally operated Frankfurt - Shannon - Gander - Idlewild. They pax flights for MATS usually carried 72 passengers.

The critical leg was Shannon - Gander, 1,717 miles of water. The westbound wind component would on average be minus twenty knots, resulting in a ground speed of 161 knots with a flight time of approximately 10:30.

Leg Time  (hr:min)
  
Frankfurt - Shannon 4:00
Shannon - Gander10:30
Gander - Idlewild4:30
  
Total Time19:00

There were occasions however, when a DC-4, due to head winds, would be unable to operate non-stop from Shannon to Gander and would have to stop in Keflavik in Iceland. At that time, there was no alternate airport for Keflavik, so the requirement was to take an additional three hours of fuel sufficient to get back to Prestwick, Scotland.

Another route occasionally used was Frankfurt - Santa Maria (in the Azores) - Gander.

The passenger were normally fed on the ground at Shannon where they would also pick up 72 box lunches that were the main meal and the same number of snacks for the west-bound trip across the water. The only thing hot on the aircraft was the coffee. The passengers were fed on the ground at Gander and food would be loaded there for the leg to Idlewild.

A cargo flight plan worked out as

Leg Time  (hr:min) Fuel  (gallons)
   
Shannon - Gander10:302,215
Alternate airport 1:00  180
Reserve 2:00  360
   
Total13:302,755

2,755 gallons x 6 lbs./gallon = 16,530 lbs.

This was all manually calculated on an E6B computer.

Operating (empty) weight = 41,000 lbs + 16,530 lbs. fuel = 57,530 lbs.

Maximum takeoff weight = 73,500 lbs - 57,300 lbs = 15,970 lbs payload.


Productivity Comparison

The last aircraft operated by Seaboard was the Boeing 747-200F. The latest model of the aircraft is the Boeing 747-8F.

The table shows the relative productivity in ton-miles flown per crew member per hour (P). The actual productivity increase was greater due to the ability of B-747 aircraft to cross the Atlantic Ocean non-stop.

TypePayload  (lbs)Speed  (kts)CrewP
     
DC-416,00018171
B-747-200F253,000492*3100
B-747-8F303,700492*2180

*True airspeed at M.84 at 31,000 feet on a standard day.

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