From: Joseph F Baugher <jfb@ihlpl.att.com>
Subject: Number Thirty Six in the Series -- the Curtiss P-36 Hawk (Part 6 of 6)
Keywords: 6 of 6     The "simplified" Hawk
Organization: AT&T Bell Laboratories -  Naperville, Illinois
Date: Sun, 8 Nov 1992 19:08:14 GMT


From Joseph F Baugher <jfb@ihlpl.att.com>

Early in 1937, Curtiss began the development of a simplified version 
of the Y1P-36 intended specifically for export.  Curtiss was aware 
that some potential customers whose air arms operated under relatively 
primitive conditions would look askance at sophisticated features such 
as a retractable undercarriage which promised to afford difficult 
maintenance problems.  The "simplified Hawk" project was given the 
company designation of Model 75H.  

The construction of the Model 75H was similar to the Y1P-36, but a 
lower-powered engine was provided and a fixed, single-strut 
undercarriage with streamlined fairings was fitted.  These 
modifications were first applied to a demonstrator aircraft which was 
reengined with a Wright Cyclone GR-1820-GE rated at 875 hp for 
takeoff.  This airplane was given the civil registration of NR1276, 
and publicized in Curtiss sales brochures as "Hawk 75".  Emphasis was 
placed on ease of maintenance, rough field performance, and the 
amenability of the aircraft to accommodate different brands of engines 
and different types of armament in order to suit the customer's 
individual requirements.  

A second and more definitive demonstrator aircraft was built which 
differed from its predecessor in some respects, including the adoption 
of the more deeply-scalloped decking immediately aft of the cockpit 
and revised windshield arch and canopy framing.  Armament was 
supplemented by an additional pair of 0.30-cal machine guns in the 
wings, firing outside the propeller arc.  Provision was made for the 
attachment of underwing bomb racks capable of carrying ten 30-lb or 
six 50-lb bombs, plus a centerline rack for a single 500-lb bomb.  
This aircraft was given the civil registration of N1277.  

The first 75H carried the US civil registration of NR-1276.  It was 
sold to China.  The Chinese government presented this airplane to 
General Claire L.  Chennault for his own personal use.  The second one 
was registered as NR-1277 and was sold to Argentina.  

Hawk 75M for China 

The first overseas customer for the Hawk 75 was the Chinese 
Nationalist government, which ordered a total of 112 Hawk 75 
non-retractable undercarriage models with R-1820 Cyclone engines and 
four 0.30-in guns (two in the fuselage and two in the wings).  These 
planes were to be built by Curtiss and delivered as major components 
to the Central Aircraft Manufacturing Company at Loi-Wing, where they 
would be assembled and delivered to Chinese units.  These airplanes 
were retroactively assigned the designation Hawk 75M by the Curtiss 
company.  Aside from the additional wing guns and some minor revisions 
to the undercarriage fairings, these planes were identical to the 
second "simplified Hawk" demonstrator.  

The Hawk 75M was powered by an export-approved 875 hp Wright 
GR-1820-G3 Cyclone radial.  Wingspan was 37 feet 0 inches, length was 
28 feet 7 inches, and wing area was 236 square feet.  Empty weight was 
3975 lbs, and gross weight was 5305 lbs.  Maximum speed was 280 mph at 
10,000 feet, service ceiling was 31,800 feet, and range was 1210 miles 
with fuel overload.  Armament was four 0.30-in machine guns--two in 
the nose and two in the wings.  

It is uncertain just how many Hawk 75Ms actually ended up in Chinese 
service.  Only 30 Hawk 75Ms are accounted for in Curtiss records, with 
deliveries beginning in May of 1938.  Tooling and kits for an 
unspecified number were delivered to the Central Aircraft 
Manufacturing Company Wing for assembly in China, and an unspecified 
number were built there.  Three full squadrons of Model 75Ms are known 
to have been operational.  These fighters achieved few successes 
against the Japanese forces, largely owing to poor serviceability and 
the inadequate training of both pilots and ground crews.  

Hawk 75N for Thailand 

The government of Siam (Thailand) also exhibited interest in the Hawk 
75, and ordered somewhere between 12 and 25 examples (the exact number 
is uncertain, and depends on which source you pick).  These were given 
the designation Hawk 75N by Curtiss, and were generally similar to the 
Chinese Hawk 75Ms except for some minor revisions to the undercarriage 
mainwheel fairings and some differences in the armament.  Sources also 
differ in the armament fitted--one claims that the armament was two 
nose guns (one 0.30-in and one 0.50-in nose guns and four 0.30-in guns 
in the wings, another claims that that there were two 23-mm Danish 
Madsen cannon housed in detachable underwing fairings.  

Twelve Hawk 75Ns were delivered to Siam (Thailand) starting in 
November, 1938.  They These Hawk 75N fighters were involved in the 
Thai invasion of Indo- China in January 1941, the first recorded 
combat taking place on January 11 when four 75Ns escorted nine Martin 
139-Ws in an attack on the French airfield at Nakorn Wat.  The 
formation was intercepted by four French Morane-Saulnier M.S.406s.  In 
the resulting air battle, the Thai Hawks claimed two Morane fighters 
shot down (although the claim was later refuted by the French).  On 
December 7, 1941, the Thai Hawks were in action once again, this time 
against invading Japanese forces.  In the brief battle, one third of 
the serviceable Hawks were destroyed.  Those not destroyed were taken 
over by the Japanese.  One example is now in the Royal Thai Air Museum 
in Bangkok.  

Hawk 75O for Argentina 

After purchasing the NR1277 demonstrator, the Argentine government 
ordered twenty-nine production examples of the non-retractable 
undercarriage Hawk 75 with 875 hp Cyclone engines.  Designated Hawk 
75O by the Curtiss company, these planes had a similar undercarriage 
to the Thai Hawk 75N and featured a redesigned engine exhaust system 
with a semi-circle of electrically-operated gills at the rear of the 
cowling.  Armament consisted of four 7.62-mm Madsen machine guns.  The 
first Hawk 75O was completed by Curtiss in late November, 1938.  
Maximum speed was 239 mph at sea level and 280 mph at 10,700 feet.  
Initial climb rate was 2340 ft/min.  An altitude of 23,000 feet could 
be attained in 12.52 minutes.  Service ceiling was 31,800 feet.  Empty 
and loaded weights were 3975 lbs and 5172 lbs.  

At the same time, Argentina acquired a license to manufacture the Hawk 
75O at the Fabrica Militar de Aviones.  The first FMA-built Hawk was 
delivered on September 16, 1940.  A total of 20 was built.  Some of 
these actually remained in service until the 1960s.  

Model 75Q for China 

Model 75Q was the designation assigned to two additional 
non-retractable undercarriage demonstrators with R-1820 engines.  One 
was converted to retractable undercarriage configuration and was 
presented to Madame Chiang Kai-Shek.  She gave the plane to General 
Claire Chennault who was then reorganizing the Chinese Air Force.  The 
other was flown as a demonstrator in China by American pilots but 
crashed after takeoff on May 5, 1939.  


Sources: 

  Curtiss Aircraft, 1907-1947, Peter M Bowers, Naval Institute Press, 
  1979 

  The Curtiss Hawk 75, Aircraft in Profile No.  80, Profile 
  Publications, Ltd.  1966 

  War Planes of the Second World War, Fighters, Volume Four, William 
  Green, Doubleday, 1961.  

  Air Enthusiast, Volume 1, William Green et al, Doubleday, 1971.  

Joe Baugher       AT&T Bell Laboratories    2000 North Naperville Road 
		  Naperville, Illinois 60566-7033.   (708) 713-4548

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