The LADA Class, The Russian Diesel Submarine the Russian Navy Would Not Accept
By Bruce Rule - Feb 9, 2014
The following article is written primarily for use by active-duty System analysts but, hopefully, will be of interest to those now retired. References available upon request; specify area of interest.
Starting in 1986, the Soviet Union, and since 1992 the Russian Federation (RF), did and now continue to export KILO Class diesel submarines. Countries receiving either Project 877 KILOs or later, improved Project 636 KILOs, include Poland, Romania, Algeria and Iran with the largest numbers bought by China and India. These sales provided important foreign currency for use by RF shipyards: Komsomolsk in the Far-East and Admiralty in St. Petersburg.
Project 636 KILOs have a single, skewed, 7-bladed propeller that operates at a maximum speed of 250 rpm which provided (quote) a substantial reduction in the acoustic signature of the submarine (end quote) over Project 877 KILOs which used a flat-faced, 6-bladed propeller with a maximum speed of 500 rpm. (See article archived this site as “KILO Class SS Design Characteristics Recovered from Open Sources.”)
When other countries began to cut into foreign sales of KILO Class submarines with technologically more advanced designs – such as the German Type 212 with an Air-Independent (Fuel Cell) propulsion capability, the RF Rubin Design Bureau began production of a competing design, the Project 677 LADA Class to be exported as the Amur 1650.
Construction of the lead LADA unit, the St Petersburg, started in December 1997; she was launched in October 2004 and, although commissioned in May 2010, the Russian Navy did not, after eight years of trials, accept the unit because the boat's propulsion and sonar systems were inadequate. Navy support of the program was terminated. ((FYI: the LADA used two constant speed (1,000 rpm) D49 diesel engines (V8 design) that operated as diesel-generators: a diesel-electric propulsion system.)) A candidate engine for the LADA/Amur 1650 was the V8 configured ED-2, a D49 (ChN26/26) engine (bore of 260mm and a stroke of 260mm). The ED-2 operates at a constant speed of 1,000 rpm to drive a six-pole generator to produce 50 Hz power which then is converted to dc power for propulsion. For use in a submarine, this engine would have to be modified to start pneumatically rather than electrically. In terms of the engine's "footprint," space occupied for horsepower delivered, the ED-2 is an attractive power plant for submarine use, and we may see it again in the future.
Although efforts were underway to correct the observed deficiencies in the LADA design, construction, without Navy support, appears to have been halted on the two units that were to follow the St. Petersburg. Instead, the Rubin Design Bureau, in an effort to capitalize on the earlier success of the KILO Class is producing - with Navy support - a third-generation KILO, Project 636.3, which will be significantly quieter, have new combat systems and possibly (in follow-on design improvements) an air-independent propulsion capability.
The writer extends his previous open-source estimate about Project 636 KILOs with an assessment that Project 636.3 units will still use the 500 rpm, 5,500 hp PG-141M main electric motor but will increase the reduction ratio of the single-stage gear system between the motor and the propeller shaft line from 2:1 in 636 units to about 2.5:1 to lower the maximum shaft rpm for the 636.3 from 250 to about 200 with the same maximum speed capability of about 20 knots. If the KILO 636.3 uses the 3:1 ratio gear system known to have been installed on the single BELUGA Class experimental Soviet diesel submarine, the maximum KILO 636.3 propeller shaft rpm will be about 170 rpm. (See the writer's commentary on the BELUGA also archived on this site.) When used as an ASW platform in littoral waters, the 636.3 could conduct passive search and destroy missions at 3-4 knots while operating submerged at no more than about 45 rpm, a speed unlikely to produce detectable cavitation.
Additionally, it is probable the rating of the two six-cylinder Kolomna 30/38 (300mm bore, 380mm stroke) diesel-generators will be further increased for the KILO 636.3, perhaps to as much as 2000 kW (2680 hp) each at or near 850 rpm, with the use of charge-air-cooling (intercoolers) at various positions in the air-intake path to reduce air temperature and increase density, and by the use of a two-stage, exhaust-driven turbo-charging (the outlet of the first stage would feed the inlet of the second stage with air-flow cooling between). This rating (2000 kW) would compare with the rating of 1000 kW (1340 hp) at 715 rpm for each engine on the first Project 877 KILO units. (Note that, as first designed and built in 1935, the basic six-cylinder Kolomna 30/38 engine, designated the 38K6, developed only 300 kW (400 hp) at 600 rpm, and, as installed first in 1963 in JULIETT Class submarines as a twin-six engine. 4012 hp at 750 rpm.)
(Technical Note: Traditional turbo-charged diesels have Mean Effective Pressures (MEP) of about 1.7 MPa (17bars/245 psi). A twin-turbo system developed for commercial use in Western Europe has an MEP of 2.6 MPa (26 bars/380 psi). Single-stage turbo-charging with air-cooling can be used with D42 (30/38) diesel engines with MEPs below 2.0. The charge air-pressure delivered by the single-stage turbo-charger of a Kolomna 30/38 series engine operating at 750 rpm is 1.96 bars (28.4 psi). The temperature of the discharged exhaust from a single-stage turbo-charger should be no higher than 530C/986F. The engine gas outlets of Kolomna 30/38 engines are made of a titanium alloy to better withstand these high temperatures. MEPs above 2.0 require two-stage turbo-chargers with air-cooling after each stage. It is probable that if installed on KILO 636.3 units, such high performance diesels will require maintenance/overhaul cycles that cannot be performed by consumer countries thus requiring their return to Russia for such work.)
Meanwhile, it is highly likely Germany and other countries will have continued to make advances in the area of submarine technology thus providing continuing competition for Russian diesel submarine sales.
The above information has been derived only from Internet sources.