Szekely SR-3

SR-3
	SR-3 Model L - Flathead version of the Szekely SR-3 aircraft engine, Pima Air & Space Museum
Type	Radial engine
Manufacturer	Szekely

Szekely aircraft engines were three-cylinder radial engines built in Holland, Michigan in the 1920s and 30s. They were used to power small aircraft such as the Rearwin Junior, Taylor H-2 and American Eagle Eaglet. Often criticized for reliability issues and design flaws, many were replaced with better engines in their original airframes. Few examples still exist but a museum quality example is on display in the Holland Museum in Holland, Michigan.

Variants

Data from:Jane's all the World's Aircraft 1931^[1]

SR-3 O: Overhead valve combustion chamber, compression ratio 4.6:1, 45 hp (34 kW) at 1,750 rpm.
SR-3 L: Side-valve combustion chamber, compression ratio 5:1, 30 hp (22 kW) at 1,750 rpm.

Applications

Specifications (SR-3 Model O)

Data from American Engine Specifications,^[2] Jane's all the World's Aircraft 1938,^[3] Jane's all the World's Aircraft 1931^[1]

General characteristics

Type: Three-cylinder radial engine
Bore: 4+1⁄8 in (105 mm)
Stroke: 4+3⁄4 in (121 mm)
Displacement: 191 cu in (3.13 L)
Length: 25 in (635 mm) overall
Diameter: 36 in (914 mm) (Model L 30 in (760 mm))
Dry weight: 147 lb (67 kg)

Components

Valvetrain: one camshaft per cylinder: pushrod-operated overhead inlet outlet valves, one each per cylinder; (Model L valves directly operated by tappets.)
Fuel system: Stromberg NA-S3 Carburetor or Zenith equivalent
Cooling system: Air-cooled
Bosch FU6/3 or Scintilla magnetoes

Performance

Power output: 45 hp (34 kW) at 1,750 rpm
Specific fuel consumption: 0.60 lb/(hp·h) [0.365 kg/(kW·h)]
Oil consumption: 0.16 lb/(hp·h)

References

^ ^a ^b Grey, C.G., ed. (1931). Jane's all the World's Aircraft 1931. London: Sampson Low, Marston & company, ltd. p. 86d.
^ "Table 4: American Engine Specifications". Aviation. Vol. 30, no. 7. July 1931. p. 43.
^ Grey, C.G.; Bridgman, Leonard, eds. (1938). Jane's all the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. p. 102d.

External links

"Szekely SR-3 L" Old Rhinebeck Aerodrome, retrieved October 30, 2007

[JAWA1931-1] Grey, C.G., ed. (1931). Jane's all the World's Aircraft 1931. London: Sampson Low, Marston & company, ltd. p. 86d.

[Aviation-2] "Table 4: American Engine Specifications". Aviation. Vol. 30, no. 7. July 1931. p. 43.

[JAWA1938-3] Grey, C.G.; Bridgman, Leonard, eds. (1938). Jane's all the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. p. 102d.

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