R-1690 Hornet

 
 

By the time production Wasp engines were being delivered, design of a second, more powerful air-cooled engine was well under way. Called the Hornet, it was initially rated at 525 horsepower, with later models developing as much as 875 horsepower. The Hornet was an essential factor in the growth of the commercial air transport industry.

Displacement: 1,690 cubic inches (R-1690); 1,860 (R-1860)
Revolutions per minute: 1,900-2,300
Weight: 840-1,070 pounds
First run: 1926
First flight: 1927
Production years: 1926-1942
Engines produced: 2,944