Shvetsov ASh-73

The Shvetsov ASh-73 started life in 1938 from a specification for a 18-cylinder, twin-row, air-cooled, radial engine. Contrary to popular belief the ASh-73 wasn't a reverse engineered copy of the Wright R-3350, rather the ASh-73 was the product of a similar specification. Since the earlier Shvetsov M-25 engines were a licensed copy of the Wright R-1820, there were similarities and some parts were interchangeable between the R-3350 and the ASh-73. The two engines evolved from a common ancestor and from a similar requirement.

The original project designation for the ASh-73 was the M-70. The M-70 was tested in late 1938 and was a failure. The M-71 of 1940, was the successor to the M-70 and it too was a failure. The M-71 was in turn succeeded by the M-72 of early 1945, which although moderately successful wasn't placed in production. The first prototypes of the ASh-73 were built in 1945 and by the end of 1946 testing had completed successfully and the first models to enter production in 1947 lacked turbo-superchargers. Later turbo-superchargers were fitted and these were direct copies of the units used on the R-3350. The ASh-73 was produced until 1957 and 14,310 were built.

pecifications (Shvetsov ASh-73TK)

]
type=18-cylinder two-row radial engine.
bore=155.5mm (6.122in)
stroke=170mm (6.693in)
displacement=58.113 Liters (3,546.3 cu in)
length=2.29m (7ft 6in)
diameter=1.37m (4ft 6in)
width=
height=
weight=1,339 kg (2,951 Ib)
valvetrain=Pushrod, two valves per cylinder with sodium-cooled exhaust valve.
supercharger=Two-stage supercharging system with intercooler. First stage consisted of two TK-19 exhaust-driven turbochargers (toorbokompressor) operating in parallel (automatically controlled by an electronic governor). Second stage consisted of a PTsN single-speed engine-driven centrifugal blower (privodnoytsentrobezhnw nagnetahtel)
turbocharger=
fuelsystem=Carburettors (last version with direct fuel injection).
fueltype=92/93 octane fuel or 100 octane.
oilsystem=
coolingsystem=Air-cooled
power=
*With direct fuel injection:
*2,720 hp (2,030 kW) for take-off (Dry), 2,360 hp (1,760 kW) maximum continuous
*With Carburettors and 92/93 octane fuel:
*2,400 hp (1,790 kW) at 2,600 RPM for take-off (Dry), boost rated at 1.5 Atm.
*2,200 hp (1,640 kW) at 2,400 RPM at critical altitude of 28,543 ft (8,700 m)
*2,000 hp (1,490 kW) at 2,400 RPM at 30,512 ft (9,300 m)
specpower=0.676 hp/in³ (30.8 kW/l)
compression=6.9:1
fuelcon=
specfuelcon=350 g/hp•h (0.77 Ib/hp•hr) for take-off, 315-335 g/hp•hr (0.69-0.74 Ib/hp•hr) at nominal power (carburettor version).
oilcon=
power/weight=
reduction_gear= 0.375:1

Applications

* Beriev Be-6
* Tupolev Tu-4

References

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