Subject: Number Sixty-Nine in the Series--Republic XP-69

From: [email-masked]
Date: 17 May 93 18:45:55 GMT

>From [email-masked]

In 1940, Alexander Kartveli, vice president and technical director of 
the Republic Aircraft Corporation, drew up plans for a new escort 
fighter built around the proposed 2350-hp Wright R-2160 Tornado, an 
experimental 42-cylinder, six-row liquid-cooled radial engine driving 
contrarotating propellers.  Designated Model AP-18 by the company, the 
aircraft was envisaged as a potential replacement for the P-47 
Thunderbolt when that aircraft became obsolescent.  

The Wright Tornado engine was one of the most odd engine products of 
the entire American aircraft industry during the Second World War.  It 
was a oddity in that it was a LIQUID-cooled radial engine.  The 42 
cylinders were arranged in six radial banks.  This configuration was 
chosen so that the Tornado engine would have an extremely small 
overall diameter, enabling aircraft designers to build fuselages with 
small cross section areas.  However, the Tornado required the use of 
rather heavy and complicated systems of cooling radiators, which 
probably would have negated any aerodynamic advantage it might have 
otherwise had.  

In the XP-69, the Tornado engine was to be located immediately behind 
the pilot, and was to drive a set of contrarotating propellers via an 
extension shaft to the nose.  The air intake and the cooling system 
were located under the fuselage.  The pressurized cockpit featured a 
large bubble canopy.  A laminar flow wing was planned.  Proposed 
armament was two 37-mm cannon and four 0.50-inch machine guns, all 
mounted in the wings situated so that they fired outside the radius of 
the propellers.  

Estimated performance included a maximum speed of 450 mph at 35,000 
feet, a service ceiling of 48,900 feet, and a climb to 35,000 feet in 
20 minutes.  Maximum range was to have been 1800 miles.  Estimated 
weights were 15,595 pounds empty, 18,655 pounds gross, 26,164 pounds 
maximum.  Dimensions were wingspan 51 feet 8 inches, length 51 feet 6 
inches, height 17 feet, and wing area 505 square feet.  

In July 1941, the USAAF ordered two prototypes of the AP-18 under the 
designation XP-69.  A P-69 mockup was inspected in June of 1942.  
However, delays in the delivery of the Wright Tornado engine caused 
the XP-69 project to be cancelled on May 11, 1943 in favor of 
Republic's parallel XP-72 project which showed more promise.  In
the event, the Tornado engine project was itself cancelled before 
anything could be built.  

Sources: 

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

  American Combat Planes, Ray Wagner, 3rd Edition, Doubleday, 1982.  

  War Planes of the Second World War, Fighters, William Green, 1964.  

Joe Baugher		AT&T Bell Laboratories   	
2000 North Naperville Road      Naperville, Illinois 60566-7033