The Curtiss XF9C "Sparrowhawk"

The Curtiss F9C Sparrowhawk had originally been designed as a small single-seat shipboard fighter developed in response to a Navy spec laid down on May 10, 1930. It was in competition with the General Aviation (formerly Fokker) XFA-1 and the Berliner-Joyce XFJ-1.

The XF9C-1 (Navy serial number A8731) was ordered from Curtiss on June 30, 1930. It made its first flight in March of 1931. It had a metal monocoque fuselage and tail and fabric-covered metal-frame wings. The upper wing joined the fuselage at the top, giving the pilot an excellent upward view. Power was provided by a 420 hp Wright R-975C (J-6-9) Whirlwind radial engine. The high-pressure tires had no wheel pants or fairings.

XF9C-2 was the unofficial designation given to a second prototype built by Curtiss as a private venture. The engine was the 438 hp R-975E-3 engine, and it had a single-leg wire braced undercarriage and a four-inch-higher location for the upper wing that resulted in a more noticeable gull-wing effect at the fuselage. In addition, a set of wheel spats were fitted.

The Navy's small fighter concept did not ultimately prove successful, and the Sparrowhawk would have been abandoned along with its rivals had it not been for the appearance of an entirely new mission.

Contracts for two airships, the USS Akron and Macon had been issued on October 6, 1928, and it was intended from the start that these airships should be capable of carrying aircraft and launching and retrieving them while in flight. While the airships were under construction, however, plans for a suitable fighter to be carried by them lagged. The F9C, the best of the three competitors, was deemed to be the only high-performance type which was small enough to be carried aboard these airships.

The first airship docking tests were carried out with the prototype XF9C-1. The XF9C-1 was fitted with airship hook-on gear at the Naval Aircraft Factory and was transferred to Lakehurst, New Jersey for trials. It first hooked-on to the airship Los Angeles on October 17, 1931. Based on these tests, the Navy ordered six production versions of the XF9C-2 (designated F9C-2) in October 1931. Navy serial numbers were 9056/9061. The Navy then purchased the second prototype, and the XF9C-2 designation became official. The serial number 9264 was assigned to the XF9C-2. 9264 was later modified to full production standards, and it was redesignated just plain F9C-2.

As first flown on April 14, 1932, the first production F9C-2 (serial number 9056) was fitted with the single-leg XF9C-2 undercarriage. However, this undercarriage was soon changed to the earlier XF9C-1 tripod type, and the other F9C-2s were completed with the same type. After a short period in service, the vertical fin area of the F9C-2s was increased by adding a new rudder post eight inches aft of the original. The original high-pressure tires of the XF9C-1 were replaced by low-pressure types, and the wheels were enclosed in open-sided fairings.

The production F9C-2 was powered by the 438 hp Wright R-975E-3 Whirlwind radial engine, enclosed in an anti-drag ring. Maximum speed was 176.5 mph, and initial climb was 1690 feet per minute. Service ceiling was 19,200 feet. Range was 297 miles. Weights were 2117 pounds empty, 2779 lbs gross. Armament was a pair of 0.30-cal machine guns mounted in the upper fuselage deck, firing through the cylinder banks and synchronized to fire through the propeller arc.

The first F9C-2 made its first hook-on to the Akron on June 29, 1932. All six F9C-2s were delivered to the Navy in September 1932. The XF9C-1 and all six F9C-2s were originally assigned to the Akron, which was based at Lakehurst, New Jersey.

The airship could each carry up to four F9C-2s in an internal hangar, with one more Sparrowhawk suspended from an external station. The airplanes were fitted with a hook-on gear above the fuselage which enabled them to fly up under the airship and engage a trapeze at the bottom. Once firm contact was made, an arm on the trapeze would swing down to steady the rear fuselage. The aircraft would then be pulled up into the belly of the airship and stored in the hangar. Although the F9C-2s were popularly regarded as defensive fighters, their principal mission was to act as scouts to extend the effective operating area of the mother ships, which were themselves used as scouts.

Consolidated N2Y-1 two-seat trainers were used as "skyhook" trainers for pilots assigned to the Akron and the Macon. They were fitted with hook-on gear above the fuselage. These were later replaced by the Waco XJW-1 two-seat trainer, which was a modification of the Waco UBF commercial sport plane. These planes were also used to fly mail and passengers back and forth between the airships and the ground.

The Akron was lost at sea off New Jersey on April 4, 1933, but no airplanes were aboard the airship at that time. The Sparrowhawks were then transferred to the Macon, based at Moffett Field, California. They were later joined by the XF9C-2, which had been redesignated F9C-2.

In addition, the prototype XF9C-1 was assigned to the Macon as a spare. After brief service aboard the Macon, the XF9C-1 was transferred to the Naval Aircraft Factory and was scrapped there in January 1935.

On a few occasions when the Sparrowhawks were operating exclusively from the Macon without using land bases, they were flown without undercarriages. This reduced both weight and drag and allowed the installation of a streamlined auxiliary fuel tank under the fuselage which increased their range still further.

The Macon went down at sea off Point Sur, California on February 12, 1935. She took four F9C-2s with her (9058, 9059, 9060, and 9061) when she was destroyed. The loss of the second mother airship brought an abrupt end to the parasite fighter program.

The three F9C-2s that were not aboard the Macon when she went down were stripped of their hook-on gear and were redesignated XF9C-2. Two of them were scrapped at San Diego in 1936.

The sole surviving Sparrowhawk was reassigned to the Naval Air Station at Anacostia, Maryland. In 1939, it was given to the Smithsonian Institution, fitted with a replacement skyhook built for the purpose at the Naval Aircraft Factory, and put on display with an inaccurate color scheme. There seems to be some question as to which Sparrowhawk this is. Some sources say that it is actually the XF9C-2 (9264), but Dick Smith in his book on the Akron and the Macon claims that it really is 9056. The Museum of Naval Aviation says that the aircraft they have on display is actually a conglomerate of the XF9C-2 and 9056 and 9057.

As a result of their dramatic operations with the Navy's short-lived airships Akron (ZRS-4) and Macon (ZRS-5 ), the Curtiss F9C biplane fighters gained fame all out of proportion to their small number. The type originated with a May 1930 specification for a small aircraft carrier-based fighter. The resulting XF9C-1 (Bureau of Aeronautics serial # 8731) was built under a June 1930 contract and delivered in March 1931. Tested over the next several months, it showed good performance but was not particularly suitable for carrier use. However, the plane did have one significant feature: it was the only available combat airplane small enough to fit through the hangar door of the dirigible Akron, which was then nearing completion. Accordingly, the XF9C-1 was modified with a "skyhook" that would allow launching and recovery from the airship's "trapeze" airplane handling device. The plane first "landed" on the older airship Los Angeles (ZR-3) in October 1931 and subsequently was actively employed in developmental operations with the Akron.

The XF9C-1's successful new role resulted in the construction of seven modified versions, the XF9C-2 (Bureau # 9264) which was a 1931 private Curtiss project that was purchased by the Navy in November 1932, and the production F9C-2s (#s 9056-9061). The latter were built under an October 1931 contract and were the only "Sparrowhawks" that were suitable for operational, as opposed to experimental, use. The first of these was flown in April 1932 and began work with Akron late June. Further modifications resulted and all six F9C-2s were in Navy hands by September 1932. These planes worked with Akron until her loss on 4 April 1933. They were then transferred to the heavier-than-air unit of Macon, which was nearing completion. From late 1933 until early 1935 they were vigorously employed in efforts to demonstrate the dirigible's value as a unit of the United States Fleet. Beginning in mid-1934 they generally had their wheeled landing gear replaced with a "teardrop" fuel tank whenever they were based on board Macon, thus considerably improving their endurance, an important element in extending the strategic scouting reach of the airship-airplane team.

Unfortunately, this aspect of Naval aviation history abruptly ended when Macon crashed at sea on 12 February 1935. Four F9C-2s were lost with her. The two survivors (#s 9056 and 9057) were subsequently used in Fleet utility work. F9C-2 # 9057 was disposed of in 1937, but # 9056 remained in Navy service until 1940, when it was transferred to the Smithsonian Institution for preservation as a museum artifact. The XF9C-1 was surveyed in 1936 and the XF9C-2 was wrecked late in that same year.

Pilots of the USS Akron's Heavier-Than-Air unit pose in front of one of their Curtiss F9C-2 "Sparrowhawk" fighters, at Naval Air Station Lakehurst, New Jersey, in 1933 sometime after Akron's loss. Present are (left to right):
Lieutenant (Junior Grade) Robert W. Lawson,
Lieutenant Harold B. Miller,
Lieutenant Frederick M. Trapnell,
Lieutenant Howard L. Young, and
Lieutenant (Junior Grade) Frederick N. Kivette

The Curtiss F9C-2 Sparrowhawk biplane fighters gained fame all out of proportion to their small number. The type has interested people for 74 years now, ever since the six actual airplanes were first delivered to the U.S. Navy to operate from the dirigibles U.S.S. “Akron” and U.S.S. “Macon,” which had been ordered in October 1928 from the Goodyear Zeppelin Corporation of Akron, Ohio. Originally known to the public as “Akron fighters,” since they all were serving with the “Akron” at Lakehurst, New Jersey, which was close enough to New York City for them to be widely publicized.

Dirigibles to this day seem to exercise some special hold on the aeronautical imagination, despite the manifest failure of the concept when it was first advertised as the “dreadnought of the sky” during the First World War, and the fact that all but two of those built after the war by four different countries were destroyed in major accidents that held the public imagination for years (if you consider the destruction of the “Hindenburg,” the memory has become immortal). Despite losing the U.S.S. “Shenandoah” in 1924, and never finding much operational success with the U.S.S. “Los Angeles” acquired from Germany shortly afterwards, it seemed to many in Naval Aviation that the rigid airship could play an important role since American military policy was defensive in orientation between the world wars. The “Akron” and the “Macon,” were intended to operate as airborne coastal defense scouts, keeping watch over the approaches to the United States with their extended range and endurance. The two airships were 785 feet long with a range of over 9,000 miles and the ability to remain airborne for days at a time. They used non-flammable helium to achieve their lighter-than-air status, unlike the hydrogen that had been turning German Zeppelins into flying explosions since 1915.

Originally, the concept of basing small aircraft aboard the two dirigibles was to provide defense. However, since they were only able to carry five such aircraft - which were really insufficient to be of much use for aerial defense - it was decided instead that airship itself would remain out of harm’s way while launching the smaller aircraft to serve as scouts for the battle fleet.

The XF9C-1 originated with a May 1930 specification for a small aircraft carrier-based fighter. The resulting XF9C-1, BuNo 8731, was built under a June 1930 contract and delivered in March 1931. Tested through that year, it demonstrated good performance but was not particularly suitable for use from an aircraft carrier. However, the plane did have one significant feature: it was the only available combat airplane small enough to fit through the hangar door of the Akron, which was then nearing completion. The XF9C-1 was modified with a "skyhook" that would allow launching and recovery from the airship's "trapeze" airplane handling device, and first "landed" on the U.S.S. :Los Angeles” in October 1931. It was actively employed in developmental operations with the “Akron.”

The success of the XF9C-1 in this new role resulted in the construction of seven modified airplanes: the XF9C-2, BuNo 9264 - which was a 1931 private Curtiss project that was purchased by the Navy in November 1932 - and six production F9C-2s, BuNos 9056-9061), built under an October 1931 contract and the only "Sparrowhawks" suitable for operational use. The production F9C-2 was powered by a 438 h.p. Wright R-975E-3 Whirlwind radial engine, providing a maximum speed of 176.5 mph, with an initial climb rate of 1,690 feet per minute. Service ceiling was 19,200 feet, with a range of 297 miles. Armament was two 30-cal machine guns synchronized to fire through the propeller arc.

The first flew in April 1932 and began work with a hook-up to “Akron” on June 29. Further modifications resulted and all six F9C-2s were delivered by September 1932. They worked with “Akron” from Lakehurst until the airship was lost April 4, 1933. The F9C-2s were then transferred to the heavier-than-air unit of “Macon,” which was nearing completion. Operating on the Pacific Coast at Moffett Field in the San Francisco Bay Area from late 1933 until the “Macon” was lost February 12, 1935, they were used in efforts to demonstrate the dirigible’s value as a unit of the United States Fleet.

When “Macon” crashed at sea on February 12, 1935, four of the F9C-2s were lost with her. The two survivors, BuNos 9056 and 9057, were subsequently used in Fleet utility work, with 9057 disposed of in 1937. BuNo 9056 remained in service until 1940, when it was transferred to the Smithsonian Institution for preservation as a museum artifact. The XF9C-1 had been surveyed in 1936, while the XF9C-2 was wrecked that same year.

BuNo 9056 had been rebuilt from the best parts of the surviving F9C-2s. When it was first set up for exhibit at the Smithsonian, it carried the unit markings of the U.S.S. Akron. In 1970, the Potomac Chapter of the Antique Airplane Association, under the supervision of the National Air and Space Museum, restored the F9C-2 as a group project. With restoration completed in 1974, the Sparrowhawk emerged in the markings of the U.S.S. “Macon” unit to which 9056 had been assigned.

Not only is BuNo 9056 the last surviving Sparrowhawk, it is the only survivor of all the fighters built by Curtiss from 1928-38, that formed the backbone of fighter aviation for the Army Air Corps and the U.S. Navy during the “Golden Wings” era. (An interesting note is that these planes were designed to operate without landing gear, the theory being that it would increase their speed and since their carrier was always airborne, landing gear were not needed. Aside from a test flight or two, I believe they all went through their short lives with the safety of landing gear. Ed)

Sources:

DEPARTMENT OF THE NAVY -- NAVAL HISTORICAL CENTER