Curtiss Hawk I

History

 The Curtiss Model 33 was developed in September 1923 from the Curtiss R-6 race plane. The aircraft was purchased by the United States Army as PW-8 after a competition with the Boeing Model 15, which was designated PW-9. The Boeing was purchased as a main fighter.

The Curtiss P-1 Hawk was the first type in the United States Army Air Service receiving the P indicator (P = Pursuit). The P-1 was the production version of the Curtiss XPW-8B, an improved version of the PW-8 and had, at the request of the Air Service, the same type of wing as the Boeing PW-9.

The first P-1, Curtiss designation Model 34A, made its first flight in mid-August 1925 and soon several variants followed that differed primarily in engine equipment.

In March 1925 an order was received for the delivery of five P-1s equipped with the more powerful Curtiss V-1400 engine of 500 hp. These aircraft were designated XP-2. The first example of this series was modified and equipped with a turbocharger, which had been applied at the side of the nose.

However, the V-1400 did not met the expectations and it was replaced in three machines by the standard Curtiss C-1150. These aircraft were then designated as P-1.

The fifth P-2 also received another engine, a Curtiss Conqueror V-1570 and was designated as XP-6.

A total of 93 Hawks was produced in P-1 to P-1C variants. Also, 52 P-1 versions P-1D to P-1F were built. However, these types were conversions of mostly trainers like AT-4 and AT-9.

Also, a number of test aircraft were built. The P-3 was actually a P-1A equipped with a Pratt & Whitney R1340 Wasp radial engine. Initially, the intention was to equip this aircraft with the Curtiss R-1454 engine but this one proved to be to unreliable.

Four examples were built under the designation P-3A, which were mainly designed to test the engine.

Later, two of these aircraft were equipped with a Pratt & Whitney R 985-1 Wasp Junior and designated XP-21.

In 1928 five Curtiss P-5s, similar to the P-1C, but with a turbocharger, were delivered. The performance at higher elevations and the service ceiling were clearly better than that of the P-1C. However, performance at lower altitudes were less.

In total, 202 Curtiss Hawk variants were delivered.

Curtiss P-6

The first aircraft with the designation P-6 was the fourth P-2 (serial number 25-423) which was modified for the National Air Races of 1927 and was equipped with the Curtiss V-1570, later known as Conqueror. This engine was an development of the Curtiss D-12 engine.

The US Army therefore gave it the designation XP-6. This aircraft has been stripped of all military equipment and became second in the air race.

There was ordered to convert a P-1A, (Ser. No 26-295), which received a V 1570-1 Conqueror engine and the wings of the PW-8A, with radiators in the wing.

This version was given as a factory designation Model 34Q and was designated by the Army as XP-6A. This aircraft also took part in the air race of 1927 and reached the first place.

There was an order for 18 Curtiss Model 34P, army designation P-6. The first nine aircraft, serial number 29-260 t / m 29-268 had an engine that was cooled by Prestone, broadly comparable with glycol. This not only saves a lot of weight, but also reduces the radiator.

Due to delivery problems with Prestone-cooled engines, the other aircraft, serial number 29-269 were - 29-273 and 29-2 = 363 till 29-366 delivered water-cooled Curtiss V 1570-17 engines.

The rest of the series was delivered with Prestone-cooled engines, and designated as Curtiss P-6A

The P-6 was largely consistent with the P-1, but differed mainly in the more rounded hull so that it would connect to the Conqueror engine better.

Furthermore, the underside of the hull has been made ​​deeper, so that it corresponds better to the bottom of the radiator. The suspension was adjusted and replaced by Oleo-spring system which is mounted on the front style.

Hawk I

Hawk I (or export Hawk) was the designation of the civilian and the export version of the Curtiss P-6. In 1930 a demonstration aircraft was built and usually flown by the famous aviator James Doolittle. This aircraft was known as the Doolittle Hawk.

See also the article about the Curtiss Hawk I at Avianet.eu

Versions.

Each version became heavier, causing to perform less than the previous version.

• XPW-8: Three prototypes, one was converted to XPW-8A and later to XPW-8B standard; one was converted into CO-X two seat scout.
  • XPW-8A: modified prototype with new cooling system and adapted wings.
  • XPW-8B: Curtiss Model 34 with modified wing as adapted to Curtiss P-1.
• PW-8: 25 examples of the production version
• P-1: Curtiss Model 34A – production version of the XPW-8B with modified rudder and some other smaller modifications and equipped with a Curtiss V-1150-1 rated 435 hp (324 kW); Ten examples built.
• P-1A: Model 34G – P-1  with extended fuselage (3 inch), larger wheels  and revised fuel system; 25 examples built plus three modified P-2’s.
  • XP-1A: One P-1A used for development purposes
• P-1B: Model 34I – 25 examples built in 1928, equipped with a Curtiss V-1150-3 (D-12D) engine.
• P-1C: Model 34O - 33 examples built in 1927 – 1928, equipped with a Curtiss V-1150-5 (D-12E) engine.
  • XP-1C: A P-1C with a revised radiator.
• P-1D: 24 converted AT-4 trainers; equipped with a Curtiss V-1150-3 (D-12D) engine.
• P-1E: 4 converted AT-5 trainers equipped with a 328 kW Curtiss V-1150-3.
• P-1F: 24 converted (in 1929) AT-5A trainers plus one converted XP-21A; equipped with a 328 kW Curtiss V-1150-3.
• P-2: Model 34B – Five P-1s equipped with a Curtiss V-1400 rated 500 hp.
  • Three of these aircraft were later converted to P-1A; another on was equipped with a Curtiss V1570 engine an designated XP-6.
• XP-3: Converted P-1A equipped with a Curtiss R-1454 radial engine rated 390 hp. later modified to XP-3A.
  • XP-3A: XP-3 equipped with a Pratt & Whitney R-1340-1 radial engine rated 410 hp
  • XP-21: XP-3A equipped with a Pratt & Whitney R-985 Wasp Junior radial engine.
• P-3A: Model 34N – Production version of the AT-5A, fice examples built , equipped with an Pratt & Whitney R-1340-7 radial engine rated 410 hp.
• XP-4: Modified P-1A with a turbocharged Packard 1A-1530 engine rated van 510 hp.
• XP-5: P-1A equipped with a Curtiss V-1150-3 engine rated 435 hp.
  • P-5: Model 34L – production version of the XP-5, later equipped with a Curtiss D-12F engine; Four examples built.
• XAT-4: Model 34J -  One P-1A equipped with a Wright-Hispano E rated 180 hp for the advanced training.
  • AT-4: production version of the XAT-4, 40 examples ordered. The first 35 examples were modified in 1929 to P-1Ds with a Curtiss D-12 engine; the remaining five were finished as AT-5s.
• AT-5: Model 34J – Five modified AT-4s with a Wright J-5 rated 220 hp; later modified to P-1E.
• AT-5A: Model 34M – based upon the P-1B with an extended fuselage ; 31 examples built; later modified to P-1Fs.
• XP-6: Model 34P, modified P-1 equipped with a Curtiss V-1570-17 engine.
• XP-6A: Model 34K, as XP-6 but with different wings and wing radiators.
• P-6A 18 examples built for US Army.
• XP-6B: Modified P-1 equipped with a V-1670 engine.
  • XP-6D: XP-6B, equipped with a turbocharged Curtis V-1570-C engine.
• P-6D: Modified P-6As (6 examples) in 1932 equipped with a turbocharged Curtiss V-1570-C.
• XP-6E: Model 35, also referred to as Y1P-22, built in July 1931 as prototype of the P-6E
  • XP-6F: Modified XP-6E with a turbocharger and enclosed cockpit.
• P-6E: 46 examples delivered in 1931-1932
  • XP-6G: A P-6E equipped with a Curtiss  V-1570F engine.
  • XP-6H: A P-6E with four  .30 in (7.62 mm) machine guns in the wings.
• P-6S Hawk I: Three examples sold to Cuba, equipped with a450 hp Pratt & Whitney R-1340 Wasp radial engine plus one sold to Japan as Japan Hawk with a Curtiss V-1570 inverted V-engine.