One size fits all, Part I

One of the dreams of countries that have aircraft carriers is an aircraft that can operate equally well from land bases and aircraft carriers without loss of
performance. The benefits of commonality are obvious but, over the years, it has proven an almost insurmountable task. The history of military aviation is littered with unsuccessful attempts to develop such an aircraft; the Spitfire and F-111 are just two of the most famous examples. Aircraft like the F-4 Phantom are very rare exceptions to the rule.

***image1***But despite the challenge, in the mid-1920s, the Curtiss Aeroplane and Motor Company developed the first frontline fighter used success-fully by both the U.S. Army Air Corps and the U.S. Navy – the P-1/F6C biplane. This ground-breaking fighter was developed from the Curtiss PW-8, a racing design that participated in the annual 1920s Pulitzer Trophy Air Races. The P-1 was the first U.S. Army Air Corps aircraft to be assigned the “P” (Pursuit) designation which replaced seven designations for pursuit aircraft, including “PW” (for “Pursuit, Water-cooled engine”), and was dubbed the “Hawk” – a name that was to become a trademark of Curtiss designs.

Perhaps not surprisingly, the P-1 design was not very different from World War I biplane fighters. It had fixed landing gear, mixed construction of wooden wings and steel-tube fuselage with fabric skinning. It was powered by a 435hp Curtiss V-1150-1 12-cylinder water-cooled engine and carried two .30 machine guns. With a flight ceiling of more than 20,000 feet and a speed of 150 miles per hour, the Curtiss aircraft was in many ways inferior to its Boeing competitor, the PW-9, but Assistant Chief of the Air Service Brig. Gen.

Billy Mitchell agreed to purchase 25 P-1s  in return for assistance by Curtiss in making the “Dawn-to-Dusk” transcontinental flight across the United States.
The first production P-1 was delivered Aug. 17, 1925, and 25 became operational with the Air Corps’ 17th Pursuit Squadron. These were followed in successive years by the P-1B and P-1C variants with improved engines.

In mid-1925, the Navy had seen enough of the P-1 to order nine P-1s – designated the F6C – for land operations and four more for carrier operations. These were identical to the P-1 except for arrester hooks and were designated the F6C-2. In 1927, the Navy ordered 35 additional F6C-2s and equipped several Navy squadrons based on the carriers “Langley” and “Lexington” as well as Marine squadrons. Then, in one of the great transitions of U.S. Navy aviation, one of the F6Cs was fitted with a Pratt & Whitney R-1340 radial air-cooled engine and designated the XF6C-3.

The modification was successful and the Navy ordered 31 of a new series of Hawks with air-cooled engines, designated the F6C-4. More importantly, the Navy decided to insist all of its future aircraft be equipped with radial air-cooled engines, which they considered far more reliable and easier to service than liquid-cooled engines. The Navy stayed with air-cooled engines until the beginning of the jet age, while the Army Air Corps and later the Army Air Force split, generally using liquid-cooled engines for fighters and air-cooled radials for larger aircraft.

The engine change sparked Curtiss to install even more powerful engines for the Hawk and both the Air Corps and the Navy produced a tremendous number of Hawk variants – probably more variants than any other airplane in history. The Air Corps went from the P-1 to the P-2 with a turbo supercharger, the radial engined P-3, and finally the very popular and elegant P-6E, which stayed in service until 1937. The Navy built the F-7C and finally the Navy’s first dive bomber, the two seat F-8C dive bomber.

But while the Hawk variants were a major part of the U.S. Air Corps’ and Navy’s military aircraft development history and Curtiss would see the Hawk series as a frontline fighter through most of World War II, the performance of Curtiss fighters was always mediocre. Even in the early, desperate days of World War II, the Curtiss P-40 “Warhawk” – made famous by the Flying Tigers – was nothing more than a stopgap. P-40s were moved to out-of-the-way operations as soon as more advanced aircraft became available.

Questions or comments, contact Dr. Michel at marshall.michel@ramstein.af.mil.