Warner Scarab / R-420 / SS-50
First run in November 1927, 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.
Amongst the many uses for the Scarab, the engine was fitted to the Cessna Airmaster and the Fairchild 24 (UC61 or Argus). Notably, in 1942, it was put into use powering the Sikorsky R-4, the first helicopter to be put into production.
The Warner 145 and 165 HP engines are the most commonly seen of the small radials for US-built pre-WWII era aircraft, in large part because of good parts availability due to the engines having been used on WWII Fairchild UC61s 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.
An air or hand-electric starter were available at extra cost.
A 7-cyl. air-cooled radial engine introduced in 1928, the Scarab developed 125 hp (93 kW) at 2,050rpm from 422 cu in (7 l) with a dry weight of 285 lb (129 kg).
A 5-cyl. version introduced in 1930 developing 90 hp (67 kW).
Super Scarab 165
Increased capacity 7-cyl engine developing 165 hp (123 kW) at 2,100rpm from 499 cu in (8 l) with a dry weight of 332 lb (151 kg).
Super Scarab SS-50
Alternative company designation for the Super Scarab.
Super Scarab SS-50A
A 145 hp (108 kW) de-rated Super Scarab.
Super Scarab 185
With the capacity increased further, developing 185 hp (138 kW) - 200 hp (149 kW) from 555 cu in (9 l).
Military designation of the Scarab
Military designation of the Super Scarab 165
Military designation of the Super Scarab 185
Alternative designation for the Warner Super Scarab SS-50A
Alternative designation for the Warner Super Scarab 165
Alternative designation for the Warner Super Scarab 185 (Primarily a helicopter application).
Type: 7 cylinder, fxed radial, air cooled 4 stroke
Approved Type Certificate No.2
Military Rating: 110 hp at 1850 rpm
Commercial Rating: 110 hp at 1850 rpm
Displacement: 422 cu.in
Compression ratio: 5.2-1
Bore: 4 1/4 in
Stroke: 5 1/4 in
Length: 29 in
Diameter: 35 1/2 in
Weight: 270 lb
Fuel consumption: not more than .55 lb/hp/hr
Oil consumption: not more than .025 lb/hp/hr
Lubrication: Force feed
Ignition: Dual Scintilla Magneto
Carburation: 1 Stromberg
Spark plugs: 2 per cylinder A.C.