Article from 2016-01-05
What usually comes to mind when you mention America in the twenties and early thirties? For some, the wars of the Chicago mafia, for some for the Ford automobile empire, for the majority, images of huge skyscrapers and bright advertising lights will simply pop up. And few will remember the successes of the United States in the aviation field. And how many of them were there? Participation in races for the Schneider Cup and Lindbergh's flight in the "Spirit of St. Louis" across the ocean look much more modest than, say, the grandiose successes of "Stalin's falcons". In addition, in those years, the Americans did not fight anyone, at least not "seriously." For many, American aviation appeared to the world in World War II, literally out of nowhere. One of the pages of "obscurity" turned out to be the Curtiss aircraft, which to one degree or another bore the proud name "Hawk" - a falcon.
Hawks are perhaps the most significant page in the development of American aviation at the turn of the 1920s and 1930s, forming, together with the Boeing aircraft, the backbone of overseas aviation. Moreover, it was the Curtiss aircraft that were honored to become the first air-based combat aircraft.
The Glen Curtiss Hawk fighters were the logical evolution of the Curtiss Airplane & Motor Company series of racing aircraft. The company used an engine of its own design on them - a 12-cylinder, V-shaped, liquid-cooled, having a volume of 7.4 liters and developing 435 hp. The engine bore the brand designation D-12, but in the mid-twenties by the US military service, it was given the designation V-1150 - V-shaped, with a volume of 1150 cc. inches.
The first fighter for the new engine was developed by Curtiss as a personal initiative back in 1922. The aircraft received the brand designation "Model 33". Three prototypes were ordered by the Army Aviation Service on April 27, 1923 under the designation PW-8. In general, they resembled the Boeing RM-9 fighter, also ordered by the army.
The name of the PW-8 fighter stands for "fighter" (Pursuit - literally: hunter, pursuer), water-cooled engine, model 8 ". This fighter designation scheme was adopted by the army in 1920. The fighters were divided into seven categories: RA - "air-cooled fighter"; РG - "fighter-attack aircraft"; РN - "night fighter"; PS - "special fighter"; PW - "liquid-cooled fighter"; R - "racing"; TR - "two-seat fighter". Experienced RM-8s received later, since 1924, the designation XPW-8, where "X" stood for an experimental aircraft.
The first experimental PW-8 was delivered to the army on May 14, 1923. The design of the fighter was mixed - the fuselage was welded from steel pipes and had a fabric skin. The chassis was of an obsolete type with a common axle. The wing is made of solid wood, with a very thin profile, which required making a two-post biplane box. The cooling system included special surface radiators on the wing - a design by Curtiss, first tested on racing aircraft in 1922. Radiators were installed on the upper and lower plane of the upper wing.
During the joint tests of the XPW-8 and the Boeing XPW-9 at McCook Field, the first showed itself to be a faster aircraft, but the XPW-9 was more maneuverable, durable and reliable. The main problem of the PW-8, from the point of view of the army, was the surface radiators. Despite the gain in aerodynamics, they became a real headache for the maintenance personnel and, moreover, constantly flowed. In addition, the army concluded that such radiators were too vulnerable in combat.
The second experimental XPW-8 differed from the first in more aerodynamically clean landing gear. The aerodynamics of the hood were improved, struts connecting the ailerons of the upper and lower wings were installed, and a new elevator was installed. The takeoff weight increased from 1232 to 1403 kg.
Although the Army favored the Boeing design, Curtiss also received an order for 25 production PW-8s. It was a kind of payment for the company's cooperation in the implementation of the idea of General Billy Mitchell, a flight across the United States for one daylight hours.
The experienced XPW-8 received weapons and the necessary equipment, and on it Lieutenant Rossel Mowen, in July 1923, twice unsuccessfully tried to make such a flight. Later, the aircraft was equipped with a second cockpit, and under the slightly misleading designation CO-X ("experimental reconnaissance"), it was entered to race for the 1923 Liberty Engineering Builders prize. However, the plane was withdrawn from the races due to the protest of the fleet, which recognized the deception.
Production aircraft ordered in September 1923 began to enter service in June 1924. These machines were similar to the second copy of the XPW-8 and differed mainly in the landing gear. Most of the production PW-8s entered the 17th Fighter Squadron, and several vehicles were sent for various studies at McCook Field. On June 23, 1924, one of them made the first successful trans American flight within one daylight hours. The aircraft, piloted by Lieutenant Russell Mowan, took off from Mitchell Field and, with stopovers for refueling at Daytona, St. Joseph, Cheyenne and Seldur, reached Long Island.
The third experimental XPW-8 was in the meantime returned to the plant for refitting. He received a new wing with more powerful spars, which made it possible to abandon one of the billon box struts. The new aircraft received the brand designation "Model 34". The fighter was returned to the army in September 1924, already under the designation XPW-8A. The source of constant problems - the surface wing radiators have been replaced by conventional radiators installed in the center section of the upper wing. In addition, the aircraft received a new rudder - without a balancer. The XPW-8A raced for the 1924 Pulitzer Prize. Moreover, before the races, it was equipped with a tunnel radiator installed directly above the engine modeled on the Boeing RM-9 aircraft. At the same time, the car was again renamed XPW-8AA, and it came third.
The new radiator made it possible to reduce the temperature of the coolant compared to the surface radiator of the first two XPW-8s, but even this seemed small for the army. At the same time, the army was completely satisfied with the Boeing XPW-9 fighter, which differed from the XPW-8 primarily in the tunnel radiator and tapering upper wing. As a result, the army asked to use both on the XPW-8A and re-submit the aircraft for testing. Curtiss agreed with this, and in March 1925 a modified aircraft was handed over to the army.
The army was now completely satisfied and on March 7, 1925, the order for mass production was handed over to Curtiss. In the meantime, in May 1924, the army changed the designation of the fighters - instead of seven categories, one designation R. was introduced. It was the XPW-8A that turned out to be the first aircraft ordered by the army under the new designation - 15 machines were named P-1.
The P-1 (brand name "Model 34A") was also the first Curtiss biplane to receive the name "Hawk", which was synonymous with all further fighters of the company up to the P-40, during the Second World War. Externally, the P-1 differed from the XPW-8B only in the additional aerodynamic rudder compensator and some modifications to the wing struts. The aircraft was powered by a Curtiss V-1150-1 (D-12C) 435 HP engine, but the engine mount allowed for a more powerful and heavier 500 HP V-1400. (originally it was planned to supply the V-1400 on the last five aircraft of the series). The wing retained its wooden structure, but with tapering consoles. The fuselage was welded from steel pipes and had a fabric skin. A 250 liter fuel tank was installed under the fuselage.
The first P-1 was delivered to the army in August 1925. Its empty weight was 935 kg, and its takeoff weight was 1293 kg. The maximum flight speed at the ground reached 260 km / h, and the cruising speed was 215 km / h. He gained an altitude of 1500 m in 3, 1 min. The ceiling reached 6860 kg. The flight range was 520 km. The aircraft was armed with one large-caliber and one rifle-caliber machine gun, synchronized to fire through the propeller.
The first copy of the P-1 was used as an experimental one. It was temporarily re-equipped with a Liberty engine and used in the 1926 National Air Races. Later, an experimental Curtiss V-1460 engine was installed on it, and the aircraft was renamed XP-17.
The last five P-1s were planned to be equipped with a larger Curtiss V-1400 engine, and therefore, by the time of delivery to the army, they were renamed P-2. However, the V-1400 engines turned out to be unreliable in operation, as a result of which the last three P2 aircraft were converted to the usual engine a year later.
The P-1 A ("Model 34G") was an improved version of the P-1, and became the first large-scale version of the Hawk. In September 1925, 25 P-1A fighters were ordered, and deliveries began in April 1926. The aircraft was several longer than the previous modification, the hood received new contours, the fuel system was changed, bomb racks and new equipment were installed, due to which the weight increased by 7 kg, and the speed decreased slightly.
If we count the three converted P-2s, then of the planned 25 P-1A, 23 fighters were delivered according to the original version. One of the P-1A was converted into an army racing plane XP-6A No. 1. It was equipped with a wing from the former XPW-8A, as well as a surface radiator with a PW-8 along with its own engine, on which a new V-1570 engine was installed. " Conqueror ". In addition, the aircraft was somewhat improved aerodynamically. The result is a really fast plane. In 1927, at the National Air Races, the XP-6A took first place, showing a speed of 322 km / h. However, shortly before the next races in 1928, the plane was crashed.
The designation XP-1A was given to the machine, which was used for various tests. Despite the "X" prefix, the aircraft was not actually planned as a prototype for a new fighter jet. The R-1V was a new modification of the fighter ordered in August 1926. Deliveries to the Army Air Corps began in October 1926. The radiator has now become more rounded, and the wheels have become slightly larger in diameter. The engine hood has been redesigned and refined. The aircraft also received flares for landing in the dark. Due to the new equipment, the weight has increased and the characteristics have decreased. Army deliveries began in December 1926. The aircraft received the Curtiss V-1150-3 (D-12D) 435 hp engine. Empty weight was 955 kg, takeoff weight - 1330 kg. The maximum speed was at the ground 256 km / h, cruising - 205 km / h. The rate of climb dropped to 7, 8 m / s. The flight range reached 960 km. The armament has not changed. The P-1Bs were used by the same squadrons that had operated the previous Hawk models.
The XP-1B designation was carried by the P-1B pair used at Wright Field for test work. Moreover, the latter received wing-mounted machine guns. In October 1928, the largest order at that time for Hawk fighters followed - for 33 aircraft of the R-1C modification ("model 34O"). The first of these was delivered to the army in April 1929. These cars had larger wheels fitted with brakes. The last two R-1Cs received, instead of rubber, hydraulic shock absorption of the chassis. The aircraft was equipped with a variant of the Curtiss V-1150-5 (D-12E) engine with a capacity of 435 hp. Since the weight of the aircraft increased again - empty to 970 kg, and takeoff - 1350 kg, the characteristics decreased again. The maximum speed at the ground was 247 km / h, the cruising speed was 200 km / h, the ceiling was 6340 m. The R-1S climbed to the altitude of 1500 m in 3, 9 minutes. The initial rate of climb was 7.4 m / s. The normal flight range is 525 km, the maximum is 890 km.
The R-1C was converted into the racing XP-6B, replacing the D-12 with the Conqueror engine. The plane was intended for a high-speed long-distance flight from New York to Alaska, but was crashed, not reaching the final point of the route, and it was returned by ship to the States for recovery.
The designation ХР-1С was worn by the Р-1С used for testing. The aircraft received an experienced Heinrik radiator and a Prestone cooling system.”Despite its designation, the XP-1C, again, was not a prototype of any aircraft.
In 1924, the American army had the idea to use a conventional fighter equipped with a reduced power engine as a training aircraft. Such training fighters were usually not armed. However, this idea was not very successful. Since the training aircraft retained the design of a combat fighter, with a lower engine power, it clearly had excessive structural strength and, as a result, was overweight. Accordingly, the flight data was poor. Pretty soon, all such training aircraft were converted back to fighters. The D-12 engines were re-mounted on them, and they received the designations P-1F and P-10.
The first Curtiss training fighter was the P-1A, equipped with a 180-horsepower liquid-cooled Reut-Hispano engine, the aircraft was delivered to the army in July 1926 under the designation KHAT-4. The serial version was designated AT-4. In October 1926, 40 numbered training vehicles were ordered. All of them were equipped with the Reut-Hispano E (V-720) engine. With it, the maximum speed at the ground reached 212 km / h, cruising speed - 170 km / h. The rate of climb at sea level is 5 m / s. Takeoff weight - 1130 kg. Later, 35 AT-4s were converted back into fighters with the installation of the Curtiss V-1150-3 engine and one 7.62 mm machine gun. These aircraft received the designation P-1D.
The last five AT-4s were completed already as AT-5s powered by a 220-horsepower Wright J5 (R-970-1) "Verlwind" air-cooled engine, instead of a liquid-cooled Wright-Ispono engine. The new engine was lighter than its predecessor, but the thrust-to-weight ratio of the aircraft remained low. The maximum speed at the ground was 200 km / h, cruising speed - 160 km / h. These trainer aircraft were also converted to fighter jets with the 425 hp D-12D engine. and one 7, 62 mm machine gun. At the same time, the fighters received the designation P-1E. These vehicles, along with the P-1D, were in service with the 43rd Training Squadron at Kelly Field.
The AT-5A ("model 34M") was an improved version of the AT-5 with an elongated fuselage and other design differences similar to the P-1A. By July 30, 1927, the army had received 31 such aircraft. In 1929, all AT-5A were also converted into fighters with the installation of D-12D engines and weapons. The aircraft were renamed R-1R.
R-1 Hawk was sold in small numbers abroad. Four cars were sold to Bolivia, eight P-1A-Chile in 1926. One aircraft was sold in 1927 to Japan. In the same year, eight P-1 Bs were delivered to Chile. Later, apparently, several more Hawk fighters were manufactured in Chile on their model.
The P-1 in its original version had rather high flight characteristics, but as this type developed, the weight of the fighter increased and the characteristics fell. The P-1s were in service with the 27th and 94th Fighter Squadrons of the 1st Fighter Group at Selfridge Field in Michigan, and later with the 17th Squadron, where they were used until 1930, when they were replaced by more advanced fighters.
