Subject: Number Forty-Two in the Series--Curtiss XP-42

From: [email-masked]
Date: 12 Jan 93 16:42:37 GMT

>From [email-masked]

The fourth Curtiss P-36A (serial number 38-4) was used by the US Army 
and NACA for aerodynamic research in an attempt to overcome the 
aerodynamic drag penalty inherent in large-diameter air-cooled radial 
engines as compared to narrower liquid-cooled Vee-type engines.  The 
aircraft was given the company designation of Model 75S, and the USAAC 
assigned it the designation of XP-42.  

As initially delivered in March of 1939, the XP-42 had a special 1050 
hp Pratt and Whitney R-1830-31 radial engiine fitted with a long 
extension fitted to the propeller shaft and nose casing which 
permitted the use of a streamlined nose with a large propeller 
spinner.  The intake for cooling air was located under the engine, and 
the intake for carburetor air was located above the engine.  

The initial configuration of the XP-42 suffered from serious 
overheating problems and from vibrations of the propeller shaft.  
Attempts to cure these problems resulted in no less than twelve 
different cowling designs being tested on the XP-42.  Various types of 
cowl flaps were fitted, and short-nose high- and low- inlet velocity 
cowlings were tried with and without fans.  The nose was progressively 
shortened until the airplane gradually once again resembled a P-36A.  

The XP-42 was entered by Curtiss in the 1939 USAAC fighter 
competition.  Although the XP-42 was faster than the P-36A, it was 
slower than the XP-40.  Consequently, the XP-42 lost out to the XP-40 
for production orders.  

The XP-42 was finally scrapped in January 1947.  

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.  

  The American Fighter, Enzo Angelucci and Peter Bowers, Orion Books, 
  1987.  

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