The high-torque maneuver also overwhelmed the R-4B’s tail rotor, and the “torque caused the tail to swing almost 90 degrees to the left.” The helicopter was then in an awkward position to depart the tight clearing, but Carle made the best of it. As his helicopter moved sideways, the rotor began to enter what is now known as “effective translational lift,” in which a forward influx of airflow increases rotor efficiency, providing just enough improvement in performance to keep the helicopter from settling onto the ground. Carle then noted that “as the ship picked up speed, the action of the wind swung the tail partially behind me…[but], as I started it soon became apparent that the 210 pounds of my passenger, plus the altitude of 1,500 feet were going to make it impossible to clear the high trees. The rpm was dropping rapidly, and the airspeed was near zero. I was at the limit of my climb and still the tops of the trees were above me. I couldn’t turn back without dropping straight in, probably killing the passenger and myself, so I jerked the pitch control as high as it would go and luckily we cleared the trees by inches, but the effort had cost [rotor rpm] and all of my airspeed.
“As soon as I realized that we were clear of the trees, I dropped the pitch to 4 degrees and held full throttle, at the same time pushing forward on the stick. As the rpm came back within the green, I increased the pitch and fortunately missed dropping into the jungle. Again, the rpm dropped, and again I lowered the pitch enough to bring it back. The airspeed was building slowly and we began to climb to safety. What had actually been a few seconds seemed an eternity. My clothes were drenched with sweat, and I was so weak that I could hardly move the controls.”
Carle’s experiences presaged those of countless combat helicopter pilots in the Korean and Vietnam wars, who were forced to master flying overloaded aircraft into tight landing zones; his recollections vividly illustrate just how risky these early operations were. On June 21, Carle and Cowgill both ran out of luck. Carle’s rotor tip hit a tree, and almost simultaneously, Cowgill, flying an equally treacherous approach in the R-6A, clipped a tree with the tail rotor. Fortunately, the troops at his landing zone were well positioned, and were able to post a guard to watch the aircraft (recovered a week later). Cowgill marched out of the jungle with an escort on a harrowing four-day journey in which he too encountered determined Japanese opposition.
The two crashes ended the Fifth Aircraft Repair Unit’s participation in the operation, as their ship was preparing to support the newly captured airfields on Okinawa. After Carle deployed with his vessel to Okinawa, the war ended. He went back to Luzon to fly R-6As with the Second Emergency Rescue Squadron, which was adding helicopters to an extensive stable of fixed-wing rescue aircraft. After returning to the United States, he suffered persistent pain from the rotor fragment in his skull and never flew helicopters again.
Carle was officially credited with a dozen evacuations (though he may have flown more), and Cowgill with 14.
On June 25, the Sixth Aircraft Repair Unit arrived in Manila Bay, and began rescue operations with their own R-4B and R-6A. In the span of only four days, pilots First Lieutenant James Brown, Second Lieutenant John Noll, and Flight Officer Edward Ciccolella rescued around 40 wounded. In the process, they introduced a significant innovation to the battlefield. Though Sikorsky engineers had designed slots running through the R-6’s frame to mount two encased litter pods, none of the R-6s deployed with the equipment. The helicopter mechanics assigned to the Sixth Aircraft Repair Unit improvised external litters using Stokes baskets (steel-tube and wire-mesh baskets used to transport the injured) welded to steel frames. In this way, prone casualties could be carried without risk to the helicopter.
A small number of additional evacuations took place in July. Of the helicopter evacuations of wounded soldiers and airmen in the Pacific and Far East during the war, more than 60 percent were rescued during the operation on Luzon. Helicopter rescue was in no way decisive to World War II—125 to 150 wounded were evacuated, compared with approximately 40,000 in Korea and well over a million in Vietnam—but it was a huge step in convincing the military that rotary wing flight was a useful battlefield technology.
Roger Connor is the curator of the National Air and Space Museum's vertical-flight collection.