Consolidated PB2Y Coronado
With the great clarity afforded by 20-20 hindsight, questions are sometimes raised as to whether a particular aircraft should have been developed at all, not necessarily because the aircraft considered as a flying machine was inferior but because of flaws in the operational concepts that engendered its development. Such questions surround the only four-engine patrol boat operated by the United States in World War II, the Consolidated PB2Y Coronado series of aircraft.
A 1936 Navy requirement for a long-range, four-engine patrol boat capable of carrying a greater payload than the PBY was responsible for the Coronado family of aircraft. The prototype first flew in December 1937. In configuration concept, the PB2Y was similar in many respects to the Boeing 314 with the wing positioned on top of the deep, large-volume hull and the four radial air-cooled engines mounted in the wing leading edge, two on either side of the hull. In contrast to the sponsons used for lateral stabilization of the Boeing 314, however, the PB2Y had retractable wingtip floats similar to those on the Catalina. These floats and their supporting struts are clearly visible in figure 8.21, as are details of the bottom of the single transverse step hull. Although wheels are visible in the photograph, these were used only for beaching and ground handling. The aircraft was not an amphibian. The PB2Y was a thoroughly modern aircraft for its day and featured all-metal construction, trailing-edge flaps, controllable-pitch propellers, and engines equipped with two-stage superchargers for high-altitude operation.
The similarity between the configuration of the Boeing 314 and the Consolidated PB2Y highlights the similarities and differences between the two aircraft. The zero-lift drag coefficient and the maximum lift-drag ratio of the two aircraft were about the same. The Boeing, however, was 23 percent heavier, had more wing area and thus more drag area, and more power than the Consolidated boat. Both aircraft first flew with a single vertical fin and shared a common aerodynamic problem. In their initial form, both the 314 and the PB2Y had insufficient lateral-directional stability, no doubt caused by the large side area of the deep hull forward of the center of gravity. Boeing solved the problem by adding two additional fins, one on either side of the original center fin, near the tips of the horizontal stabilizer. The Consolidated solution consisted of eliminating the center fin and placing large vertical surfaces at the tip of each side of the horizontal tail and introducing a small amount of dihedral in the horizontal surfaces. Although great progress had been made during the 1930's in achieving an understanding of the science and art of aerodynamics, the lateral-directional problems of the Boeing and Consolidated boats clearly showed that more was yet to be learned.
Powered by four "twin wasp" engines that generated more than 1400 horsepower, the PB2Y Coronado required a crew of ten. Its range was almost 1500 miles. The letters in its name designated the plane's mission (P = patrol), capability (B = bombing) and manufacturer (Y = Consolidated Aircraft Corp.). Founded in 1923, the Consolidated Aircraft Corp. moved to San Diego in 1935 where it produced propeller-driver "flying boats" that carried cargo long distances in the 1930s. The "twin wasp" engine was the most common one used in the War: Pratt & Whitney produced 173,000 of them for a variety of aircraft, including the B-24 bomber.
As an instrument of war, the PB2Y could carry 12 000 pounds of bombs, had eight machine guns, six of them in pairs of two located in power-operated turrets, and was equipped with self-sealing fuel tanks and a certain amount of armour plate. It had a maximum ferry range of 3120 miles and could carry 8000 pounds of bombs for a distance of 1380 miles.
Although the Coronado seemed to have considerable potential as a patrol bomber, it saw little operational use in this role. The basic problem was one of cost effectiveness. A Coronado cost three times as much as a Catalina. Yet it is doubtful that a single Coronado could effectively patrol as large an ocean area as three Catalinas or whether the one large aircraft could attack a single surface target with as high a probability of success as three of the smaller boats. Questions such as these limited the operational use of the PB2Y as a weapon of war. As a consequence, most Coronados were used in freight or passenger/carrying roles and all were retired from the Navy by the end of 1945. Total production of all versions of the aircraft was only 217. The Coronado is an illustration of how a basically good aircraft was little used because of faulty assumptions in the formulation of the basic requirements for the aircraft.
|
NEWSLETTER
|
| Join the GlobalSecurity.org mailing list |
|
|
|
