Curtiss PW-8

Curtiss PW-8

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Curtiss PW-8

The Curtiss PW-8 was the first in a long series of Curtiss biplane fighters to be produced for the US Army and Navy between the two World Wars.

The PW-8 was based on a series of earlier Curtiss racers. Its immediate predecessor was the Navy's R3C racing plane, which took first and second place in the 1925 Pulitzer race. This was a small aircraft, with a wingspan of 22ft, a length of 20ft and a height of only 6ft 9.5in. The R3C has a gross weight of 2,150lb, was powered by a 565hp Curtiss V-1400 engine and had thin wings with a Curtiss C-80 aerofoil. The upper wing was on the same level as the top of the fuselage.

The PW-8 was a bigger aircraft, with a wing span of 32ft, a length of 22ft 6in and a gross weight of 3,151lb. It used the Curtiss C-62 aerofoil, a thin wing also used on the R2C racer, and one that required two sets of struts. The upper wing was raised above the fuselage. The PW-8 used a 440hp Curtiss D-12 engine, and the combination of an increase in weight and decrease in power meant that the top speed of the PW-8 was only 168mph, nearly 100mph slower than the R3C.

The PW-8 had a fabric covered welded steel tube fuselage and tail and a wooden wing. The wings had a thin cross-section, forcing the use of a second set of struts, making the PW-8 the only twin-bay single seat fighter used by the US Army after the First World War. The radiators were built onto the skin of the upper wing inboard of the ailerons. This system was used on the 1920s racers, and was efficient and produced less drag than other methods, but it was soon clear that it was too vulnerable to battle damage and the PW-8 was the only American production fighter to use this system. The PW-8 also introduced a divided-axle undercarriage, replacing the single axle system used on the racers.

The PW-8 began live as a private venture, developed by Curtiss in the belief that it would be a big enough improvement on the First World War era fighters then in use to force the US Army to take an interest. The first prototype made its maiden flight in January 1923, and in April the gamble paid off. On 27 April the Army bought the original prototype and ordered two more. These aircraft were delivered with the PW-8 designation and only became the XPW-8 on 14 May 1924 after the introduction of the X for experimental prefix.

On 25 September 1923 the army ordered twenty-five production aircraft based on the second prototype, which featured a number of aerodynamic improvements. These aircraft were delivered between June and August 1924 and entered service over the next year (although some were held back for tests and experiments).

The third prototype was eventually developed into the XPW-8B, with tapered wings based on the wings of the Boeing PW-9. In this form it became the prototype for the Curtiss P-1 Hawk and the entire family of Army and Navy Hawk biplanes that followed.

XPW-8 No.1

The first prototype made its maiden flight in January 1923 and was bought by the US Army on 27 April. On 9 July it was used on an unsuccessful attempt to cross the United States from east to west between dawn and dusk. Later in the year a second cockpit was added by Air Service engineers at McCook Field. The modified aircraft was given the designation Corps Observation Experimental (CO-X) and was entered for the 1923 Liberty Engine Builders Trophy for military two seaters. The aircraft was withdrawn after other entrants complained that it wasn't a genuine two-seat aircraft.

XPW-8 No.2

The second prototype had a revised undercarriage and aerodynamic improvemenets and became the basis for the production aircraft.


Twenty-five production PW-8s were ordered on 25 September 1923 and delivered from June 1924.


The third Army prototype became the basis for the P-1 Hawk. It was completed with revised wings that attempted to solve two of the problems with the PW-8. The wings were made thicker, eliminating one set of struts and thus reducing drag. The surface radiators were replaced with a radiator built into the centre section of the upper wing. This aircraft was delivered in September 1924, and underwent tests at McCook Field. The XPW-8A was delivered on 4 September 1924 and later that year took third place in the 1924 Pulitzer Trophy Race. It was then further modified to become the XPW-8B.


After competing in the air races the XPW-8A was returned to Curtiss to get another set of new wings, this time tapered wings with a Clark Y aerofoil. The new wing was based on the wings of the Boeing PW-9 and had been developed by George Page, a Curtiss engineer, after examining photographs of the Boeing aircraft. The modified aircraft was delivered in March 1925 and was a significant improvement on the standard PW-8. The new design was ordered into production as the Curtiss P-1.


The PW-8 replaced the Boeing MB-3A in the 17th, 27th, 94th and 95th Pursuit Squadrons in 1924, all part of the 1st Pursuit Group based at Selfridge Field, and remained in use until 1926. All for squadrons then moved on to the P-1 and most later used the P-6, although often not for long.

The PW-8 really came to the public's attention on 23 June 1924 when Lt Russell L. Maughan successfully completed the dawn-to-dusk crossing of the United States in PW-8 24-204. He achieved this with one minute to spare, having averaged 160mph on the 2,670 mile journey. Because he was travelling from east to west he was moving with the sun, and had 16.7 hours to make the flight.

The PW-8 was also used for an attempt to fly from Selfridge Field to Miami in a single day during 1925, a distance of 1,300 miles. The attempt failed but it did prove that the idea was practical.

The PW-8 also had a racing career. The XPW-8A came third in the 1924 Pulitzer Air Race where it came third behind a Curtiss R-6 and a Verville-Sperry R-3. The wings of the XPW-8A were later matched with the fuselage of a P-1 to make the XP-6A racer which took part in the 1927 pursuit ship race at the National Air Races.

Engine: Curtiss D-12 inline engine
Power: 440hp
Crew: 1
Span: 32ft 0in
Length: 23ft 1in
Height: 9ft 1in
Empty weight: 2191lb
Gross weight: 3,151lb
Max speed: 171mph
Cruising speed: 160mph at 10,000ft
Climb Rate: 9 minutes to 10,000ft
Service ceiling: 20,350ft
Range: 544 miles in part work
Armament: Two .3in fixed forward firing machine guns

Curtiss PW-8 - History

The Hawk series of fighter aircraft was developed directly from a line of specialized racing planes that the Curtiss Aeroplane and Motor Company of Buffalo and Garden City had built for the Army and Navy between the years 1921 and 1925. The powerplant for the racers was a 435hp Curtiss-developed compact, water-cooled, direct-drive V-12 design. The engine bore the manufacturer's designation of D-12, but in the middle '20s the US military adopted a system in which type and displacement were used as the basis for engine designations. D-12 became the V-1150—V- for the basic Vee design and 1150 for its displacement as measured in cubic inches.

The first fighter based on the new 435hp Curtiss D-12 originated in 1922 as a private venture by Curtiss. The design was given the company designation of Model 33. Three prototypes were ordered by the USAAS on Apr 27, 1923 as PW-8s [23-1201/1203]. Examples of a basically similar competing Boeing design were also ordered by the Army and given the designation PW-9.

The designation PW-8 stood for "Pursuit, Water-cooled, Model 8." This Army designation scheme had been introduced in 1920. There were seven separate Pursuit categories, chosen according to the role of the aircraft and the type of engine which powered it—PA (Pursuit, Air-cooled), PG (Pursuit, Ground Attack), PN (Pursuit, Night), PS (Pursuit, Special Alert), PW (Pursuit, Water-cooled), R (Racer), and TP (Two-seat, Pursuit). PW-8 prototypes were redesignated XPW-8 in 1924 when the X-for-experimental prefix was adopted.

The first XPW-8 prototype was delivered to the Army on May 14, 1923. The fuselage was of welded steel tube construction with fabric covering. The undercarriage was a divided-axle design. Wings were all-wood and of a very thin section that required two bays of interplane struts for stiffening. The cooling system for the D-12 consisted of a set of wing-surface radiators that had been pioneered on Curtiss racers in 1922. The radiators were mounted flush with the upper and lower surfaces of the top wing, resulting in an extremely well-streamlined wing surface.

In the flyoff between XPW-8 and the competing Boeing XPW-9 at McCook Field, the PW-8 proved faster, but the PW-9 was found to be more maneuverable, tougher, and more reliable. The primary problem that the Army found with the PW-8 was in its unique surface radiator cooling system. Although these radiators improved streamlining, they turned out to be a maintenance headache and were prone to constant leaks. In addition, the Army concluded that such a cooling system would probably be extremely vulnerable to damage by gunfire were the Hawk used in combat.

The second XPW-8 prototype [23-1202] differed from the first in having a divided type of landing gear with reduced drag. The streamlining of the cowling was improved, and strut-connected ailerons and unbalanced elevators were provided. Gross weight increased from 2768# to 3151#.

Although the Army favored the Boeing design, the Curtiss company nevertheless did get an order from the Army for 25 production PW-8 fighters. The order was given to Curtiss in return for the company's agreement to collaborate on a pet scheme of General Billy Mitchell of attempting a coast-to-coast flight across the USA to be completed between dawn and dusk of the same day.

Prototype XPW-8 [23-1201] was stripped of all military equipment and used in two unsuccessful attempts in July 1923 to cross the USA in a dawn-to-dusk flight, piloted by Lt Russell Maughan. This aircraft was later fitted with a second cockpit, temporarily given a spurious designation of CO-X (Corps Observation, Experimental) and entered in the 1923 Liberty Engine Builders Trophy race for military two-seaters. It was withdrawn before the race because of objections from the Navy.

The 25 production PW-8s [24-201/225] that were ordered in Sep 1923 began to be delivered to the Army in June 1924. These aircraft were in the configuration of the second XPW-8 [23-1202], which differed from [23-1201] by having a different undercarriage. Most production PW-8s served with the 17th Pursuit Squadron, although several production PW-8s went to McCook Field for experimental work.

PW-8 maximum speed was 171mph at sea level, cruising 136mph. Initial climb rate was 1830 ft/min. Service ceiling was 20,350'. Range was 544 miles. Armament consisted of a pair of .30 machine guns mounted above the engine, synchronized to fire through the propeller arc. Weights were 2185# empty, 3155# gross.

On June 23, 1924 [24-204] was finally able to complete the first successful dawn-to-dusk crossing of the USA. The aircraft, piloted by Lt Maughan, took-off from Mitchell Field on Long Island, with refueling stops at Dayton, St Joseph, Missouri, Cheyenne, and Saldura.

The third prototype XPW-8 [23-1203] from the original order had been held back at the factory for installation of a set of single-bay wings. These new wings had heavier spars that produced a stiffer structure, permitting the installation of only a single bay of struts. The new aircraft was assigned the company designation of Model 34. It was delivered in this form to the Army in Sep 1924, and was later redesignated XPW-8A. The troublesome surface radiators of the first two prototypes were replaced by a core-type radiator built flat into the center section of the upper wing panel.

A modified rudder without balance area was fitted. XPW-8A [23-1203] was entered into the 1924 Pulitzer Trophy race. When modified for the race, the radiator was installed in a "tunnel" underneath the engine, similar to the installation on the Boeing PW-9. In this guise, it was known as XPW-8AA—it came in third.

The new core-type radiator of XPW-8A proved to be somewhat less temperamental than the surface radiators of the first two XPW-8s, but it was still considered inadequate by the Army. In the meantime, the USAAS had been impressed by the performance at McCook Field of the competing Boeing XPW-9, which was basically similar to the XPW-8, but had tapered wings, and a tunnel radiator underneath the engine. Consequently, the Army asked Curtiss to fit tapered wings and a tunnel radiator to its XPW-8A and resubmit the aircraft for consideration. Curtiss agreed to the changes, and the modified [23-1203] was delivered to the Army in Mar 1925. The changes resulted in a change of designation to XPW-8B.

The Army was satisfied with the improved XPW-8B and decided on Mar 7, 1925 to give Curtiss a contract for a production series based on this design. In the meantime, in May 1924 the Army had combined its seven separate pursuit category designations into one single category—"P" for pursuit. The first pursuit aircraft ordered by the Army under this new designation scheme were the production versions of XPW-8B, 15 of which were ordered as serial numbers [25-410/424]. These were given the designation P-1, the first entry in the new series.

P-1 (Model 34A) was the first of the Curtiss biplane fighters to carry the name "Hawk", a name which stuck to Curtiss-designed fighters up to and including the P-40 of WW2. The only external difference between the XPW-8B and the P-1 was the addition of an aerodynamic balance to the rudder of the P-1, plus some minor changes to the single-bay struts. These airframes were fitted with the 435hp Curtiss V-1150-1 (D-12C), but were provided with engine mounts that would permit the installation of the larger 500hp Curtiss V-1400. Original plans were for the last five aircraft of the P-1 order to have the V-1400 installed at the factory. Wings were again of wooden construction, but were tapered. Fuselage was of metal tube construction with fabric covering. A 55-gal auxiliary fuel tank could be fitted underneath the belly.

The first P-1s were delivered to the Army in Aug 1925. Weights were 2058# empty, 2846# gross. Maximum speed was 163mph at sea level, cruising speed was 136mph. The P-1 could climb to 5000' in 3.1 minutes. Service ceiling was 22,500 feet. Range was 325 miles. P-1 was armed with one .50 and one 30 machine gun mounted in the upper fuselage deck and firing through the propeller arc.

The first P-1 [25-410] was used primarily for test work. It was briefly fitted with an inverted air-cooled Liberty engine and was entered in the 1926 National Air Races. Later it was fitted with an experimental inline, inverted, air-cooled Wright V-1460-3 Tornado and redesignated XP-17.

The last 5 P-1s that were destined for the larger Curtiss V-1400 were considered sufficiently different that they were redesignated P-2 when they were delivered to the Army. However, the V-1400 proved to be completely unsatisfactory in service, and three of these P-2s [25-421, -422, -424] were converted back to P-1A standards after less than a year of service.

P-1A (Model 34G) was an improved P-1 with the improved D-12C. It was the first of the Hawks to serve in quantity with the USAAC. 25 were ordered in Sep 1925, with deliveries beginning in Apr 1926 [26-276/300]. The fuselage was 3" longer than the P-1, cowling lines were revised, fuel system was changed, and the bomb-release system was improved. In addition, some additional service equipment was provided which increased the weight by some 20 pounds and decreased the top speed slightly. Weights were 204# empty, 2866# gross. Maximum speed was 160mph at sea level, cruising speed was 128mph. P-1A could climb to 5000' in 2.6 minutes. Initial climb rate was 2170 ft/min. Service ceiling was 21,000' and range was 342 miles. P-1A had the same armament as P-1. Three additional P-1As resulted from installation of D-12s in P-2 airframes as described earlier. Only 23 out of the 25 P-1As originally ordered were delivered as such. [26-296] was later modified as the prototype for the XAT-4 trainer, and [26-300] was transformed first into XP-3, then to XP-21 and -21A.

P-1A [26-295] was modified into an Army racer known as XP-6A #1. The old XPW-8A wings were installed, along with the PW-8-type surface radiators. The new V-1570 Conqueror was installed in a PW-8-type nose cowling and various other minor refinements were made. A really fast aircraft was the result—it won the 1927 National Air Race at a speed of 201mph however, it was destroyed shortly before the 1928 NARs. XP-1A was applied to a stock P-1A [26-280] diverted to test work. Despite the X-prefix, it was not a prototype.

P-1B was an improved model ordered in Aug 1926 [27-63/87]. Deliveries to USAAC began Oct 28, 1926. The radiator was slightly more rounded and the wheels slightly larger in diameter. The cowling was redesigned. Flares were added for night landings and controls were improved. Equipment changes increased the weight still further, reducing the performance still more. First deliveries to the Army began in Dec 1926. Engine was the 435 hp Curtiss V-1150-3 (D-12D). Weights were 2105#, empty, 2932# gross. Maximum speed was 160mph at sea level, cruising speed was 127mph. Initial climb rate was 1540 ft/min, service ceiling was 21,400', and maximum range was 600 miles. Armament was identical to P-1 and P-1A. The P-1Bs served with squadrons already flying earlier Hawks.

XP-1B was applied to a couple of stock P-1Bs [27-71, -73], which were used for test work at Wright Field. The latter had machine guns mounted in the wings.

33 improved versions known as P-1C (Model 34O) were ordered in Oct 1928 [29-227/259]. This was the largest Army Hawk order to date. First deliveries to the Army began in Apr 1929. P-1C had larger wheels fitted with brakes. The last 2 P-1Cs were fitted with hydraulic instead of rubber-block shock absorbers. Once again, weight increased and performance decreased. Engine was the 435hp Curtiss V-1150-5 (D-12E). Maximum speed was 154mph at sea level, cruising speed was 124mph. Service ceiling was 20,800'. Empty weight was 2136#, gross weight was 2973#. The P-1C could climb to 5000' in 3.9 minutes. Initial climb rate was 1460 ft/min. Service ceiling was 20,800'. The normal range was 328 miles, with a maximum range of 554 miles.

P-1C [29-259] was completed as the XP-6B, with a Conqueror engine in place of the D-12, intended for a long-range flight from New York to Alaska. However, the XP-6B crashed short of its goal, and was shipped back to the USA for repair and subsequent test work.

XP-1C was the designation applied to P-1C [29-238] diverted to test work, fitted with an experimental Heinrich radiator and Prestone cooling system. Despite the X-prefix, it was not a prototype.

In 1924 the Army decided it would be a good idea to equip some of its up-to-date pursuit designs with lower-powered engines and use them as advanced trainers. These advanced trainers were all unarmed. However, the concept was not very successful. Since the trainers used the same airframes as did the fighters, the lower-powered trainers were vastly overstressed for their missions, and were overweight for their power and had very poor performances. After a short service, these advanced trainers were converted to full fighter configuration, provided with armament, and were retrofitted with D-12 engines. These converted trainers were then given pursuit designations P-1D through -1F.

The first Curtiss advanced trainer prototype had been created by fitting P-1A [26-296] with the liquid-cooled 180hp Wright-Hispano E. It was delivered to the Army in July 1926 under the designation XAT-4—"AT" stood for "Advanced Trainer."

AT-4 was the production version of XAT-4. 40 were ordered in Oct 1926 [27-88/97, -213/242]. All were powered by the Wright-Hispano E (V-720). Maximum speed was 133mph at sea level, cruising speed was 107mph. Initial climb was 950 ft/min. Range was 535 miles. Weights were 1847# empty, 2484# gross. 35 AT-4s were eventually converted back to fighter configuration by the fitting of the Curtiss V-1150-3 (D-12D) and the a single .30 machine gun. These converted aircraft were assigned the designation P-1D.

The last 5 airframes of the AT-4 order [27-238/242] were completed as AT-5s, with the 220hp Wright J-5 (R-970-1) Whirlwind radial in place of the Wright-Hispano liquid-cooled engine. This engine was considerably lighter than the Wright-Hispano, but the disadvantage of lower power was still there. Maximum speed was 125mph at sea level, cruising speed was 100mph. Initial climb was 1096 ft/min. Range was 488 miles. Weights were 1802# empty, 2445# gross. The AT-5s were later redesignated P-1E when they were repowered with 435hp D-12Ds and fitted with a single .30 machine gun. Both the P-1D and the -1E served with the 43rd School Squadron at Kelly Field.

AT-5A (Model 34M) was an improved AT-5, with the longer fuselage and other structural improvements of the P-1A. 31 examples were ordered by the Army on July 30, 1927 [28-42/72]. In 1929 all AT-5As were converted to fighter configuration with the switch to a 435hp D-12D and the addition of armament, and redesignated P-1F. One other P-1F [28-189] was obtained by converting an XP-21, which in turn had earlier been converted from a P-3A.

There were only a few export sales of the P-1 Hawk. Four P-1s were sold to Bolivia. Eight export models of the P-1A were sold to Chile in 1926. One example was sold to Japan in 1927. Eight P-1Bs were exported to Chile in 1927, and some units are believed to have been built there.

With each successive variant, the weight of the P-1 fighter increased, leading to a gradual falloff in the top speed and in the climbing performance. P-1s were flown by 27th and 94th Pursuit Squadrons of the 1st Pursuit Group based at Selfridge Field in Michigan and later by the 17th Squadron, who kept them in service until 1930 until they were replaced by later types. I don't think they ever fired a shot in the defense of American territory.

23 June 1924

23 June 1924: Lieutenant Russell Lowell Maughan, Air Service, United States Army, took off from Mitchel Field, Long Island, New York, at 3:58 a.m., Eastern Time, and flew across the country to land at Crissy Field, at the Presidio of San Francisco, California at 9:46 p.m., Pacific Time. He covered a distance of 2,670 miles (4,297 kilometers) in 21 hours, 47 minutes. Maughan’s actual flight time was 20 hours, 48 minutes. He averaged 128.37 miles per hour (206.59 kilometers per hour).

His Dawn-To-Dusk transcontinental flight took place on a mid-summer day in order to take advantage of the longer hours of daylight, and he flew from East to West, to follow the advancing Sun across the sky.

Major General Mason Matthews Patrick, Chief of the Air Service, with Lieutenant Russell L. Maughan, 8 July 1924. (Library of Congress)

Lieutenant Maughan made stops at McCook Field, Dayton, Ohio St. Joseph, Missouri North Platte, Nebraska Cheyenne, Wyoming and Salduro Siding, Utah. The stop at Dayton took 1 hour, 20 minutes when a mechanic over-tightened a fuel line fitting and damaged it. When he arrived at “Saint Joe,” the grass field was wet from rains, restricting his takeoff weight. Unable to carry a full load of fuel, he took off with a reduced load and then made a previously unplanned stop at North Platte, Nebraska, where he topped off his fuel tank.

Planned route of Maughan’s Dawn-to-Dusk transcontinental flight. (U.S. Air Force)

Russell Maughan was an experienced combat pilot and test pilot. He had been awarded the Distinguished Service Cross for his actions during World War I, and he had competed in numerous air races and had set several speed records.

The airplane flown by Lieutenant Maughan was the fourth production Curtiss PW-8 Hawk, a single-place, single-engine biplane fighter, serial number A.S. 24-204. It was modified by the Curtiss Aeroplane and Motor Company at its Long Island, New York, factory. Curtiss removed the fighters’s two .30-caliber machine guns and added 100 gallons (378.5 liters) to the airplane’s standard fuel capacity of 77 gallons (291.5 liters).

The Curtiss PW-8 Hawk was powered by a water-cooled, normally-aspirated 1,145.111-cubic-inch-displacement (18.765 liter) Curtiss D-12 dual overhead cam (DOHC) 60° V-12 engine, which was developed by Arthur Nutt, based on the earlier Curtiss K-12 which had been designed by Charles B. Kirkham. The D-12 had four valves per cylinder and a compression ratio of 5.7:1. It was rated at 415 horsepower at 2,000 r.p.m., and 460 horsepower at 2,300 r.p.m. During testing, it produced a 475 horsepower at 2,320 r.p.m. using a 50/50 mixture of 95-octane gasoline and benzol. The D-12 was a right-hand tractor direct-drive engine. It turned a two-bladed, fixed-pitch, forged aluminum propeller designed by Dr. Sylvanus A. Reed. The Curtiss D-12 was 56¾ inches (1.441 meters) long, 28¼ inches (0.718 meters) wide and 34¾ inches (0.882 meters) high. It weighed 678.25 pounds (307.65 kilograms).

The PW-8 had a cruise speed of 136 miles per hour (219 kilometers per hour) and maximum speed of 171 miles per hour (275 kilometers per hour) at Sea Level. The airplane’s service ceiling was 20,350 feet (6,203 meters) and its range was 544 miles (875 kilometers).

In the early years of military aviation, pilots undertook various dramatic flights to create public awareness of the capabilities military aircraft. Of this transcontinental flight, Maughan said, “The real reason for my flight across the United States in the sunlight hours of one day was that the chief of the Air Service wanted to show Congress just how unprotected are the people of the Pacific Coast.”

Lieutenant Russell L. Maughan with Curtiss PW-8 Hawk A.S. 24-204, 10 June 1924. (National Air and Space Museum)

Design and development

The Curtiss P-1 Hawk was the first US Army Air Service aircraft to be assigned the "P" (Pursuit) designation which replaced seven designations for pursuit aircraft, including "PW" (for "Pursuit, Water-cooled engine"). The P-1 was the production version of the Curtiss XPW-8B , an improved variant of the PW-8 , 25 of which were operational with the Air Service's 17th Pursuit Squadron

In September 1923, the Army ordered production of the PW-8 . The PW-8 (Curtiss Model 33) had been developed from the R-6 racer and was acquired by the Air Service after a competition with the Boeing Model 15, designated the PW-9, to replace the existing Army fighter, the Boeing MB-3A. Although the PW-8 was faster than the PW-9 (both having top speeds in excess of 165&nbspmph), it was otherwise outperformed by the Boeing plane, and its surface radiator cooling system, mounted on the upper and lower surfaces of the top wing for streamlining, was more difficult to maintain and vulnerable in combat. However, Assistant Chief of the Air Service Brig. Gen. Billy Mitchell agreed to purchase 25 PW-8s in return for assistance by Curtiss in making the Dawn-to-dusk transcontinental flight across the United States.

The prototype of the P-1, the XPW-8B , came about when the Air Service, which had selected the Boeing PW-9 over the PW-8 as its main production fighter, asked Curtiss to modify the last of its three original XPW-8 prototypes with wings resembling those of the PW-9. Curtiss designated the modified aircraft its Model 34A and returned it to the Air Service for evaluation, from which the service ordered it into production as the P-1 . The first production P-1, serial number 25-410, was delivered on August 17, 1925, and was followed in successive years by the P-1B and P-1C variants with improved engines. The newest P-1 variants remained in operational service until 1930.

The March 7, 1925 order for the P-1 also requested five aircraft with the more powerful 500&nbsphp (373&nbspkW) Curtiss V-1400 engine installed. These were completed in January 1926. The first (SN 25-420) was then modified with a supercharger mounted on the right side of the fuselage nose, and whose turbine was driven by engine exhaust the craft was designated XP-2 .

However, the Curtiss V-1400 engine did not perform up to expectations, with or without the supercharger, and so after a year in service, three of the standard P-2 Hawks had their engines replaced with the Curtiss D-12 and were consequently redesignated as P-1s. The fifth machine (25-243) received a Curtiss V-1570 Conqueror engine and became the XP-6.

93 production P-1s were brought into service in the P-1, P-1A, P-1B, and P-1C variants. 52 other P-1s, variants P-1D, P-1E, and P-1F, were made by conversion of other Hawk variants, primarily AT-4 and AT-5 trainers.

"My final year in high school, I convinced myself that, above all else, I wanted to become an artist, and started a vigorous inquiry into every school of art within a thousand miles of my hometown Pittsburgh," Biederman wrote in his autobiography, published in the November-December 1970 issue of Horseless Carriage Gazette. He attended the American Academy of Art in Chicago. "The only entrance requirement consisted of artistic proof of one's ability, so I prepared a complete catalog featuring an imaginary automobile. Each page portrayed a separate model, each laboriously rendered in profile, all in full and glorious color. When this massive document was finally lashed together, it possessed all the weight and characteristics of a suitcase loaded with bricks. Thus, for better or worse, my artistic career was launched."

Biederman graduated from the Academy in October 1932, and like many of his contemporaries, the rigors of the Depression meant that it took him three years to find a job in his field. "My introduction to the advertising world was a revelation akin to the opening of 1,000 doors," he wrote. "Such mysteries as art direction, layout, production, type, reproduction-all unfolded in rapid succession. I survived this routine for years, but slowly and inevitably had begun the realization that the artist must at some time look to specialization and away from generalization in order that he might achieve recognition, prominence, and even fame. In 1940, I departed the advertising affair for the calmer atmosphere of a studio.

"I turned my full attention and energies to transportation vehicles. on/in the water, air and land," he continued. "Movement in its various forms has dominated my time, my thinking, and my life these past thirty years. In the years that followed, I did become known and my particular specialty recognized, but many detours were necessary, including art directorships, freelance artist, etc. As my exhibits became more numerous and my sells more regular, exposure of my efforts began to enter into commercial channels. calendars, prints, premiums, novelties, magazines, as well as other channels."

As Biederman's expanding body of work was gaining him prominence, he began a relationship with the McCleery-Cumming Corporation in 1956 this calendar company retained the artist to create six paintings for each of their 1958 automobile calendars. He painted for the calendar company for 36 years, and in the first 31 of those years, 186 automobile paintings were printed without interruption. A total of 444 Biederman transportation paintings were published in McCleery-Cumming calendars by 1993. In addition to the calendars, Mr. Biederman's automotive paintings were featured prominently in Playboy magazine, Automobile Quarterly and Horseless Carriage Gazette. He retired at the age of 75, in 1988, and died in 1996.

According to his widow, most of Biederman's paintings were done in tempera on heavyweight 20 x 30-inch illustration board. Calendar art averaged roughly 10 x 15 inches, depending on the subject. A substantial portion of Biederman's body of work remains intact, and most originals are available for purchase at $1,200 apiece.

"It seems to me that despite the untold millions of devotees adherent to this, that and the other. the fundamental 'love affair' lies in and with the internal combustion engine, the good, bad or indifferent that surrounds it," Biederman wrote. "The combination of motor, wheels and body, has known, knows, and will experience moments of greatness, be they in performance, styling, concept, even flights of fancy."

Curtiss Hawk I

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


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.
    • XP-1A: One P-1A used for development purposes
    • XP-1C: A P-1C with a revised radiator.
    • Three of these aircraft were later converted to P-1A another on was equipped with a Curtiss V1570 engine an designated XP-6.
    • 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-5: Model 34L – production version of the XP-5, later equipped with a Curtiss D-12F engine Four examples built.
    • 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.
    • XP-6D: XP-6B, equipped with a turbocharged Curtis V-1570-C engine.
    • XP-6F: Modified XP-6E with a turbocharger and enclosed cockpit.
    • 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.
    Technical information Curtiss Hawk I
    Length: 6,71 m Wing span: 9,60 m
    height: 2,78 m Wing surface: 23,40 m 2
    Empty weight: 1154 kg Full Weight: 1662 kg with a filled belly tank, a total amount of 378 l fuel.
    Max. speed: 278 km/u Climbing speed: 8,3 min to 4000 m
    Range: 690 km with 378 l fuel Service ceiling: 6750 m
    Engine: One Curtiss Conqueror V1570, 640 pk (471 kW) at 2400 rpm
    Crew: One
    Armament: One .50 Colt-Browning machine gun, plus one .30 Colt-Browning machine gun

    Information about Dutch aircraft..

    Serial Construction nr. Date in service Date out of service Notes
    Ordered 1929. Built and delivered by Curtiss
    C-308 27-02-1936 Collided against C-3??
    C-309 15-02-1935 Crashed near Tangkoebanprahoe
    C-312 18-11-1930 Crashed near Andir and written off.
    Ordering date 1929, Build under license by Aviolanda, Papendrecht, The Netherlands

    1/72nd Scale

    Of the Curtiss Hawk I thus far no model has been released. Below an overview of related Curtiss types.

    The Hawk of the NEIAF was an export version of the Curtiss Hawk (certainly it wasn't a Curtiss P.6E, which was released later!!) with a conversion of the engine cowling. The nose section was quite similar to that of the Curtiss P.1C.

    • ArdPol
      • Kit 72-042 : Curtiss A-3B Falcon
      • Kit 72065 : Curtiss P-1C
      • Kit 6794-0108 : Curtiss P-6E Hawk
      • Kit R72-023 : A resin model of a Curtiss P-2 Hawk
      • Kit R72-021 : A resin model of a Curtiss P-1B Hawk
      • Kit R72-001 : A resin model of a Curtiss P-1 Hawk
      • Kit R72-004 : A resin model of a Curtiss P-1A hawk

      Modelling add-on


      1/48th Scale

      Modelling add-on


      Check for an extensive conversion table with lots of colour and paint systems.


      Militaire Luchtvaart in Nederlandsch-Indië in beeld. Deel 1 Hugo Hooftman Pag. 90 - 103 1978 Uitgever Europese Bibliotheek, Zaltbommel
      Air Enthusiast 26: The famed Curtiss Hawks Peter M. Bower Pag. 54 - 71 1984 Uitgever Pilot Press Ltd., Bromley, Kent
      Nederlandse vliegtuigen naar buitenlands ontwerp Theo Wesselink & Thijs Postma pag. 41 1984 Uitgever Romen Luchtvaart, Haarlem
      40 Jaar luchtvaart in Indië Gerard Casius & Thijs Postma pag. 34, 49 1986 Uitgeverij De Alk, Alkmaar
      Van Aviolanda tot Fokker P. van Wijngaarden pag. 37 - 39 1987 Uitgever De Klaroen, Alblasserdam
      Camouflage en Kentekens J.Greuter e.a. 1997 Bonneville – Bergen (NH)


      Special thanks to G. Casius for the very useful information and drawings regarding the Curtiss Hawk I he was so kind to sent me.
      H. Berfelo for providing me with some additional information.

      The Man

      This is a question many followers of the Curtiss brand have asked. Perhaps they wonder why a prominent name in American aviation would be applied to a motorcycle, presuming it’s a mere nod to a famous name to garner some recognition for a new brand.

      A few might be aware of Curtiss’ involvement in early-American motorcycling and his daring records that stood for decades, but they might fail to understand how this relates to the electric revolution Curtiss promises to offer.

      The truth is that Curtiss draws upon a long legacy of innovation, skill, risk-taking, and American ingenuity from a Golden Era of American exceptionalism that is perfectly summarized by the life and work of Glenn H. Curtiss.

      The Curtiss of today seeks to push the boundaries of design, engineering and performance while offering an heirloom quality machine designed from first principles that are unlike anything offered by their competition. These are the very same principles espoused by Curtiss in the earliest days of American motorcycling, so it is fitting that the Curtiss of today seeks to pick up where the Curtiss Motor Company left off more than 100 years ago.

      ‍Curtiss seeks to continue a legacy of innovation that was driven by the vision of one remarkable man whom they have proudly designated their namesake: Glenn Hammond Curtiss.

      “(Glenn Curtiss was) typically American. As typical as the cartooned ‘Uncle Sam’ with his high forehead, light blue eyes, long, thin nose only the chin whiskers and star-spangled plug hat lacking. Large, competent hands the long fingers of the artist, the capable thumbs of the born mechanic.” – Popular Science, March 1927

      ‍He gained notoriety by building his own cameras, and at least one telegraph machine of his own devising, and was fond of using tin tomato cans to construct devices like acetylene gas generators. He was an early adopter of electric power, taking side jobs as an electrician wiring local houses to use this novel, new technology. But he remained a quiet, modest man. He relished challenges and enjoyed his work, free of hubris or pride for his accomplishments.

      Perhaps the most transformative experience during his childhood was the discovery of the safety bicycle, a newfangled device of unparalleled mobility and speed in the small communities of New York that Glenn frequented. Quiet though he was, young Curtiss had a budding fascination with speed and the freedom two wheels could offer. He diligently saved his Eastman wages to purchase a bicycle of his own, and put his acquisition to good use as a Western Union messenger.

      The family moved to Rock Stream, New York where Glenn continued to build and repair bicycles while working as a professional photographer, when he wasn’t working in his step father’s vineyard. He joined a bicycle shop in Hammondsport run by James Smellie his skills as a mechanic led to his appointment as head of the shop by 1899. A budding career in bicycles soon sparked a desire for competition starting in 1896, Glenn made his mark as an accomplished and fearless bicycle racer. Curtiss appeared to excel at everything he put his mind to, and competition was simply the latest challenge he sought to conquer. And conquer he did, earning the American National Championship.

      After marrying Lena Pearl Neff, the daughter of a local sawmill superintendent and future partner in Glenn’s enterprises, in 1898, Glenn struck out on his own in the bicycle business. In 1899 he took over Smellie’s shop, carrying a variety of brands. By 1900 he had opened his second location in Bath and operated a bicycle rental business, with a third shop following in Corning. The natural progression of Curtiss’ business was to produce his own machines, and in 1901 he introduced the Hercules Bicycle Company. Most men would likely have been content to settle into a stable niche, with success in business and competition under their belt, but for Curtiss his Hercules brand would merely be the beginning of his renowned career.

      How Fast Was the Fastest Air Racer in 1925?

      Cyrus K. Bettis was a leading US Army Air Service pilot in the 1920s that became the world’s fastest air racer in 1925. In July 2018, members of his family visited the Museum to donate artifacts and archival materials documenting his life near the airplane that he flew (the Curtiss R3C-2 Racer) and the prizes that he won (the Pulitzer and Mackay trophies). All three are on display in the Barron Hilton Pioneers of Flight Gallery.

      Close-up view of Cyrus Bettis in the cockpit of the Curtiss R3C-1 Racer after winning the Pulitzer Trophy at the 1925 National Air Races at Mitchel Field, Long Island, New York. Credit: National Air and Space Museum, NASM 9A06271.

      Born in Carsonville, Michigan, in January 1893, Bettis grew up on a farm near Port Huron, Michigan. He entered the Army as a flying cadet in February 1918. He earned his pilot’s wings and was commissioned as a Second Lieutenant in the US Army Air Service the following September. By July 1920, he was a First Lieutenant flying along the US-Mexican border and in the Philippines.

      Trained to be a professional military aviator, Lieutenant Bettis used his skills as a fighter pilot (then called a pursuit pilot) to become an accomplished air racer. At the 1924 National Air Races in Dayton, Ohio, he won the John L. Mitchell Trophy Race in his Curtiss PW-8 pursuit plane. The Assistant Chief of the Air Service, Brig. Gen. William “Billy” Mitchell, created the competition for the pilots and pursuit planes of the Air Service’s First Pursuit Group in honor of his brother, who was killed in World War I.

      At the following year’s National Air Races at Mitchel Field in Long Island, New York, Bettis won the October 12, 1925, Pulitzer Trophy Race. Bettis and the R3C-1 flew at an average speed of 248.975 miles per hour, making them the world’s fastest pilot and airplane that year. He said, “My plane was not traveling like the wind it was traveling faster than any wind in history.”

      Cyrus Bettis standing in front of the streamline Curtiss R3C-1 Racer, equipped with a Reed propeller, at the National Air Races, Mitchel Field, Long Island, New York, 1925.

      The first, second, and third place Pulitzer winners received individual medals for their victories. The donation to the Museum in July 2018 included Bettis’ first place medal for 1925. Credit: Shuart family.

      The first, second, and third place Pulitzer winners received individual medals for their victories. The donation to the Museum in July 2018 included Bettis’ first place medal for 1925. Credit: Shuart family.

      After an appearance at the 1926 Sesqui-Centennial International Exposition in Philadelphia, Bettis led a formation of pursuit planes back to Selfridge Field in Michigan. Flying in a heavy fog, he crashed into a mountainside near Bellefonte, Pennsylvania, on August 23. Despite his serious injuries, he crawled over two miles to a nearby highway so he could be found. After being flown to Walter Reed General Hospital in Washington, DC, it appeared Bettis would make a full recovery, but he developed spinal meningitis and died on September 1, 1926.

      “My plane was not traveling like the wind it was traveling faster than any wind in history.”

      After his Pulitzer win in 1925, Bettis gave his first place medal to his sister, Ithrene. Years later, Ithrene gave it and the other memorabilia to her daughter, Helen McGregor Shuart. She safeguarded the items for decades before succumbing to cancer in May 2017. Shuart’s husband, Stanley, and their children dedicated their donation in her honor since both she and Bettis displayed courage, grace, and strength in facing adversity.

      The family of Cyrus Bettis visited the Barron Hilton Pioneers of Flight gallery, at the National Air and Space Museum, in Washington, D.C., July 23, 2018. They donated a number of Bettis' artifacts, including a Pulitzer Race medal, related to his 1920s Army Air Service and air racing achievements. Credit: National Air and Space Museum, NASM2018-01726

      The new Bettis donation will help the Smithsonian and researchers interpret more fully the story of American military aviation and air racing in the 1920s through the story of an Army Air Service pursuit pilot. They will add to the Cyrus Bettis Collection held by the Museum’s Archives. Most importantly, they will contribute to the new Barron Hilton Pioneers of Flight exhibition that will open as part of the Museum’s transformation in 2023.