Warner Scarab

The Warner Scarab is an American seven-cylinder radial aircraft engine, that was manufactured by the Warner Aircraft Corporation of Detroit, Michigan in 1928 through to the early 1940s. In military service the engine was designated R-420.

Variants

 * Scarab S-50: A 7-cyl. air-cooled radial engine introduced in 1928. With a bore and stroke of 4.25 inches and a compression ratio of 5.2:1, the Scarab developed 125 hp at 2,050 rpm from 422 cuin with a dry weight of 285 lb.
 * Scarab Junior:A 5-cyl. version introduced in 1930 developing 90 hp at 2,125 rpm from 301 cuin with a dry weight of 230 lb.
 * Super Scarab SS-50/50A: Increased cylinder bore to 4.625 inches to develop 145 hp at 2,050 rpm from 499 cuin with a dry weight of 303 lb.
 * Super Scarab SS-165: Increased compression ratio from 5.2:1 to 6.4:1 to develop 165 hp at 2,100 rpm with a dry weight of 341 lb.
 * Super Scarab SS-185: Increased cylinder bore to 4.875 inches, developing 185 hp at 2175 rpm from 555 cuin, with a dry weight of 344 lb.
 * R-420:Military designation of the Scarab.
 * R-500:Military designation of the Super Scarab 165.
 * R-550:Military designation of the Super Scarab 185.
 * 145: Alternative designation for the Warner Super Scarab SS-50/50A.
 * 165: Alternative designation for the Warner Super Scarab 165.
 * 185: Alternative designation for the Warner Super Scarab 185 (Primarily a helicopter application).

Applications
Among the many uses for the Scarab, the engine was fitted to the Cessna Airmaster and the Fairchild 24 (UC-61 or Argus). Notably, in 1942, it was put into use powering the Sikorsky R-4, the first helicopter to be put into production.

Many of these reliable engines soldier on today, still powering the aircraft to which they were originally mounted. The Warner 145 and 165 hp engines are the most commonly seen of the small radials for US-built pre-World War II era aircraft, in large part because of good parts availability due to the engines having been used on World War II Fairchild UC-61s and Meyers OTWs.

Warner engines are also in demand as realistically sized, though far more powerful, replacement powerplants for many replica or restored World War I era airplanes which were originally fitted with rotary engines.

Application list
• CAC Wackett

• Cessna Airmaster

• Cessna Model AW

• Curtiss XC-10

• Davis D-1

• Fairchild 22 C7E, C7F

• Fairchild 24 C8B

• Fleet Model 1

• FMA Ae.C.3

• General Aristocrat

• Gee Bee Sportster Model E

• Harlow PJC-2

• L-class blimp

• Meyers OTW

• Monocoupe 110

• Pasped Skylark

• Redfern Nieuport 17/24

• Ryan S-C

• Ryan ST-W

• Sands Fokker Dr.1 Triplane

• Sikorsky R-4

• Stinson SM-2

• Waco RSO

• Waco RBA

• Waco BNF and RNF