Despite their vulnerability demonstrated in World War I, zeppelins still offered seductive attractions to the world’s navies, notably long range and long endurance.
In 1928, the U.S. Navy succumbed to these attractions and ordered two virtually-identical, 785-foot-long airships, the ZRS-4 “Akron” and the ZRS-5 “Macon,” from the Goodyear Zeppelin Corporation. These airships carried 6.5 million cubic feet of non-combustible helium and had a range of more than 9,000 miles, a speed of 80 mph, and were the most expensive “aircraft” built by the United States until after World War II.
They were about $4 million each.
For protection and additional scouting capability, the Navy required the airships have the capability to hanger four aircraft and launch and recover them with a retractable scaffolding extending below the airship, and thus the airships became the world’s first (and only) fully functioning aerial aircraft carriers.
The aircraft chosen for the airships was the Curtiss F9C Sparrowhawk, a small biplane with a length of only 20 feet and a wingspan of 25 feet. It was very light – 2,700 pounds fully loaded – and powered by a 415 horsepower radial engine.
The first F9C was flown in April 1932 and a total of seven were ordered.
They were soon actively employed in developmental operations with the Akron.
Operationally, the Sparrowhawks launched and recovered using a hook/anchor system know as “the flying trapeze.”
To “land,” the F9C would fly underneath its airship and hook the trapeze cross-bar. Once positively attached, the hook locked automatically.
The Sparrowhawk then shut down its engine and was hoisted aboard, then placed in the hangar. For launching, the hook was engaged to the trapeze inside the hangar, the pilot stepped in and trapeze/aircraft combination was lowered clear of the hull.
The Sparrowhawk would then start its engine, disengage its hook and fall away from the airship.
The system proved so reliable that many of the Sparrowhawks had their high drag, fixed landing gear removed, which gave them much longer range as well as speed and maneuverability that was superior to most normal biplane fighters of the day.
The landing gear was reinstalled if the F9Cs were to return to a land base.
The launch and recovery operations were spectacular and well documented by the Navy, and the diminutive Curtiss fighters gained fame all out of proportion to their small number.
These planes worked with Akron until April 1933 when, on April 3, the airship was caught in a storm over the Atlantic, lost control of its fins in the high winds and crashed into the water.
Amazingly, it carried no life vests and 72 of her 76-man crew drowned, including Rear Adm. William Moffett, considered the “father of U. S. Navy aviation” and a strong supporter of the dirigible.
There were no Sparrowhawks on the Akron at the time, and the fighters then moved to the Macon, where they were widely used in an effort to demonstrate the airship’s value.
But the Macon suffered a similar fate to the Akron when it crashed in another violent wind storm Feb. 12, 1935.
In this case, however, the navy had learned from the Akron disaster and the Macon carried a full load of life vests and rafts; all but two of the 83-man crew survived, though four F9C-2s were lost.
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