Lorraine Pétrel

Source: Wikipedia, the free encyclopedia.
12H Pétrel
Type Upright water-cooled V-12, supercharged and geared
aeroengine
National origin France
Manufacturer Société Lorraine, Argenteuil
First run 1932[1]
Major applications
Potez 542

The Lorraine 12H Pétrel was a French V-12

aeroengine
initially rated at 370 kW (500 hp), but later developed to give 640 kW (860 hp). It powered a variety of mostly French aircraft in the mid-1930s, several on an experimental basis.

Design and development

During the 1930s

Société Nationale de Construction de Moteurs (SNCM), continued its tradition of building large water-cooled aeroengines. These later engines were named after birds: Eider, Courlis (en:curlew), Pétrel and Sterna. The last two remained in production in 1938.[2]

The Pétrel was an upright V-12 engine with two banks of six cylinders, arranged at 60° to each other, driving a common

Roller bearings were used at the crankshaft ends; the remaining five were plain. The upper crankcase section also had integrally cast water channels as part of the cooling system.[2]

Steel cylinder liners were screwed into the heads, with their lower parts projecting into the crankcase. Steel seats for valves and sparking plugs were shrunk into the heads. The pistons were forged from

big ends with white metal bearings; the auxiliary rod ends ran between the forks on bronze bushes.[2]

The Pétrel had four overhead valves per cylinder, two exhaust and two inlet, in bronze valve guides. Each bank had its own

planet gearset, with six satellite gears, provided an 11:17 reduction of propeller shaft speed.[2]

Engine lubrication was by forcing pressurized oil through the crankshaft, with sump scavenging. The supercharger had its own lubrication system.[2]

First run in 1932, the early Pétrels produced only 370 kW (500 hp) but by 1938 the engine had been developed into the 12Hars model which gave 640 kW (860 hp). This variant was used by the Koolhoven F.K.55 fighter, where it drove a pair of counter-rotating, twin-bladed propellers.[1]

Operational history

Like the Koolhoven F.K.55, many of the aircraft types to use the Pétrel were one-offs, testing the Lorraine against better known engines from Hispano-Suiza and Rolls-Royce but the

Potez 542 version of the Potez 540
family were built in numbers, with 74 of these twin-engined, multi-role (bomber, reconnaissance and transport) aircraft supplied to the French and Spanish air forces.

Variants

12H Pétrel
Initial power 370 kW (500 hp).[1]
12Ha
370 kW (500 hp)
12Hars
477 kW (640 hp).[1]
12Hdr
370 kW (500 hp) at 2300 rpm
12Hdrs
536 kW (719 hp) at 2300 rpm
12Hfrs Normale
536 kW (719 hp).[2]
12Hfrs Chasse
Designed for fighter aircraft produced higher powers, 567 kW (760 hp) at 2,800 rpm and 4,000 m (13,000 ft).[2]
12Hgrs
608 kW (815 hp) at 2800 rpm

Applications

Engines on display

  • A Pétrel is on display in the aircraft section of the
    Musée Royal de l'Armée, Brussels
    .

Specifications (12Hfrs, Normale)

Data from Jane's all the World's aircraft 1938 [2]

General characteristics

  • Type: Supercharged upright water-cooled 60° V-12 piston engine
  • Bore: 145 mm (5.71 in)
  • Stroke: 145 mm (5.71 in)
  • Displacement: 28.73 L (1,753 cu in)
  • Length: 1,858 mm (73.15 in)
  • Width: 707 mm (27.83 in)
  • Height: 795 mm (31.30 in)
  • Dry weight
    :     with accessories 475 kg (1,047 lb)

Components

  • Valvetrain: 4 spring-loaded valves per cylinder, driven in pairs via T-shaped tappets by cams on overhead camshafts, one per block
  • epicyclic gears
    ; independent lubrication with dedicated pressure and scavenge pumps
  • Fuel system: single or double barrelled Lorraine carburettor at supercharger inlet, supplied by 2 A.M. fuel pumps
  • Ignition system: 2 plugs per cylinder; 2 magnetos
  • Fuel type: petrol
  • Oil system: 1 pressure pump supplies oil via crankshaft, removed from sump by 2 scavenge pumps. Operating pressure 0.49 Mpa (71 psi)
  • Cooling system: water
  • Reduction gear: 17:11

Performance

  • Power output: 536 kW (720 hp) rated at 2,650 rpm and 4,000 m (13,000 ft)
  • Compression ratio: 6:1
  • Specific fuel consumption
    :     315 g/(kW.h) (8.0 oz/(hp.h))
  • Oil consumption: cruise 12±1 g/(kW.h) (0.33± 0.05 oz/(hp.h))

References

Wikimedia Commons has media related to Lorraine 12H Pétrel.
  1. ^
    ISBN 1-85260-163-9
    .
  2. ^
    ISBN 0-7153-5734-4
    .
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