The Siemens-Halske Sh 12 was a nine-cylinder, air-cooled, radial engine for aircraft built in Germany in the 1920s. First run in 1925, it was rated at 80 kW (110 hp).

The Sh 12 is low pressure due to the engine being completely ball bearing. Cylinders are of steel barrel with aluminium alloy heads screwed and shrunk on, and also locked by special nut and counter ring. The intake and exhaust ports are on side.

The crankshaft assembly is composed of two major castings and front and rear cover plates all of aluminium alloy. The crankshaft is two piece single throw.

All connecting rods are tubular. The master rod is on two ball bearings. Aluminium alloy pistons have two compression rings and two oil rings on each pistion. The exhaust and intake valves are tulip shaped.

Accessories available at extra ost were exhaust manifold and Bosch electric starter.

Applications:
Albatros L 68
Albatros L 79
Arado S I
Arado W 2
BFW M.21
BFW M.27
Bücker Bü 133
Udet U-8
Udet U 11 Kondor
Udet U-12

Type: 9 cylinder air cooled radial
Dept Commerce Approved Certificate
Military Rating: 128 hp at 1736 rpm
Commercial Rating: 128 hp at 1736 rpm
Displacement: 517 cu.in
Compression ratio: 5.3-1
Bore: 3.937 in
Stroke: 4.724 in
Length: 32 in
Diameter: 40 1/2 in
Weight: 382 lb dry
Fuel consumption: not more than .53 lb/hp/hr
Oil consumption: not more than .027 lb/hp/hr
Lubrication: Dry sump, forced feed, low pressure
Ignition: 2 Siemens Magnetos
Carburation: 2 Sum carburetters
Spark plugs: 2 per cylinder

The Sh 13 is low pressure due to the engine being completely ball bearings. Cylinders are all of steel barrel with aluminium alloy ribs being cast on by special process, with aluminium alloy heads held down by six studs and are removable.

Intake ports are at the rear and exhaust ports on the side. The crankshaft assembly is composed of two major castings and front and rear cover plates all of aluminium alloy.

The crankshaft is a two piee single throw and all connecting rods are tubular. The master rod is on two ball bearings. The aluminium alloy pistons have two compression ringa and two oil rings in each. Both the exhaust and intake valves are tulip shaped.

Type: 5 cylinder air cooled radial
Approved Dept of Commerce
Military Rating: 83 hp at 1710 rpm
Commercial Rating: 83 hp at 1710 rpm
Displacement: 317 cu.in
Compression ratio: 5.3
Bore: 4.133 in
Stroke: 4.724 in
Length: 33.8 in
Diameter: 39.25 in
Weight: 247 lb
Fuel consumption: not more than .52 lb/hp/hr
Oil consumption: not more than .027 lb/hp/hr
Lubrication: Dry sump, force feed, low pressure
Ignition: 2 Siemens or Scintilla magnetos
Carburation: 1 Sum Carburetor
Spark plugs: 2 per cylinder Siemens
Price: $2100

Siemens-Halske’s Sh.III was an 11-cylinder, air-cooled rotary engine developed in Germany during World War I, similar to the Sh.I. It shared with its predecessor the unusual design feature of having its internal workings (crankshaft, connecting-rods, etc.) rotating in a clockwise direction as seen from “nose-on”, within the engine, and the crankcase and propeller (still fastened to the crankcase, as is usual for rotary engines) rotating in the “accepted” anti-clockwise direction. Also unusual for a rotary engine was the inclusion of a true throttle control. Power was rated at 120 kW (160 hp).

The advantages of the engine were increased propeller efficiency through the reduction gearing effect of having the engine effectively running at 1,800 rpm for only 900 rpm of the airscrew, and excellent high-altitude performance due to the high compression ratio achieved. A bonus was the counter-rotating masses tended to cancel out the gyroscopic forces of the engine. This was achieved by using bevel-gears housed in the rear of the crankcase.

Production problems at the Siemens works, and poor quality lubricating oil, gave the Sh.III engines a life expectancy of only seven to ten hours before pistons began to seize. The license-built Rhemag versions of the Sh.III did not have such problems, so the Siemens-made engines were gradually withdrawn from service.

Applications:
Albatros H.1
Albatros D.XI
Pfalz D.VII
Pfalz D.VIII
LFG Roland D.IX
LFG Roland D.XVI
Siemens-Schuckert D.II
Siemens-Schuckert D.III
Siemens-Schuckert D.IV
Siemens-Schuckert D.VI

Specifications:
Type: 11-cylinder rotary engine
Bore: 124 mm (4.88 in)
Stroke: 140 mm (5.51 in)
Displacement: 18.6 L (1,135 cu in)
Dry weight: 195 kg (430 lb)
Cooling system: Air-cooled
Power output: 120 kW (160 hp) (Later variants produced 200-240 hp)

The Siemens-Halske Sh 11 was a seven-cylinder, air-cooled, radial engine for aircraft built in Germany in the 1920s. First run in 1925, it was rated at 75 kW (100 hp).

Applications:
Albatros L 68
BFW M.26
Messerschmitt M 21
LFG V 40
Udet U 12