Saurer YS engines

[Algernon]

Some pages with description for Suisse aircraft engines Saurer YS-2, YS-3 and YS-4. But, unfortunately, only in German language. (PDF files.)

https://www.e-periodica.ch/cntmng?pid=sbz-002:1948:66::10
https://www.e-periodica.ch/cntmng?pid=sbz-002:1948:66::24

 

[Piper106]

Some pages with description for Suisse aircraft engines Saurer YS-2, YS-3 and YS-4. But, unfortunately, only in German language. (PDF files.)

https://www.e-periodica.ch/cntmng?pid=sbz-002:1948:66::10
https://www.e-periodica.ch/cntmng?pid=sbz-002:1948:66::24

Aircraft Engines of the World 1948 edition by Paul H. Wilkinson pages 226 and 227 give a picture and a description for the Saurer YS engines.
All versions were 150 mm (5.90") bore x 170mm (6.69") stroke for 36 L (2197 cubic inches).
The YS-4 had a take off rating of 1600 HP @ 2800 rpm with 1200mm (47.2") manifold pressure.
The variable speed single stage supercharger gave a military rating of 1500 HP / 2800 rpm / 4600 meters (15500 feet).

The YS-3 had a single speed super charger 1500 HP take off 1600 HP military at 4700 meters.
The YS-2 also had a single speed supercharger 1300 HP take off 1410 HP at 4800 meters

They look to be licensed versions of the Hispano Suiza !2Z engines.

Does any know how the reliability was on the Saurer engines??? Internet 'experts' have indicated that the reliability and/or time between overhauls of both the genuine French 12Z engines and the similar Klimov VK-107 / VK-108 engines were between poor and pitiful when pushed to 1500 to 1600 HP.

 

[MiTasol]

I ran giggle translate on the first document which they say is called The acid-injection aircraft engine
Despite the crappy translation I found that document is worth the trouble of reading.
I will giggle mistranslate the other one later

 

[Shortround6]

I believe Wilkinson also lists the weights and the valve arrangements (or at least the number of valves per cylinder)
The VK-106 porked up a bit in weight and the VK-107 was quite a bit heavier.
The Saurer YS-4 went 1555lbs
The YS-2 was listed at 1510lbs in the 1947 edition. Both engines are listed as using 4 valves per cylinder and both use direct fuel injection. A Bosch-Saurer 7190-3 12 plunger injection pump.
I can't find it at the moment but I believe the Saurer engine used a considerably heavier crankshaft than the original Hispano.

 

[rinkol]

Aircraft Engines of the World 1948 edition by Paul H. Wilkinson pages 226 and 227 give a picture and a description for the Saurer YS engines.
All versions were 150 mm (5.90") bore x 170mm (6.69") stroke for 36 L (2197 cubic inches).
The YS-4 had a take off rating of 1600 HP @ 2800 rpm with 1200mm (47.2") manifold pressure.
The variable speed single stage supercharger gave a military rating of 1500 HP / 2800 rpm / 4600 meters (15500 feet).

The YS-3 had a single speed super charger 1500 HP take off 1600 HP military at 4700 meters.
The YS-2 also had a single speed supercharger 1300 HP take off 1410 HP at 4800 meters

They look to be licensed versions of the Hispano Suiza !2Z engines.

Does any know how the reliability was on the Saurer engines??? Internet 'experts' have indicated that the reliability and/or time between overhauls of both the genuine French 12Z engines and the similar Klimov VK-107 / VK-108 engines were between poor and pitiful when pushed to 1500 to 1600 HP.

Kotelnikov's book on Soviet piston engines states that "owing to drawbacks in the design [of the VK107], manufacture was stopped several times". It also mentions that, in 1946, a reduction in the allowed RPM and addition of a second oil pump allowed an increase in service life to 100 hours during tests.

Kotelnikov also lists two further engines, the VK108 and VK 109, but these suffered further development problems and were abandoned with the shift to jet propulsion.

Hispano Suiza developed a follow on engine, the 12B, which is described in the August 11, 1949 edition of Flight magazine. This was more strongly constructed and seems to have the more usual arrangement of intake and exhaust valves. However, it was too late and suffered the same fate as the VK109.

I'm not sure about the Swiss engines - probably these would have been built to higher standards, but suspect that they were not without problems. The Spanish, after starting out with the 12Z series in the license built version of the Bf109, switched to the RR Merlin.

 

[cherry blossom]

...
I can't find it at the moment but I believe the Saurer engine used a considerably heavier crankshaft than the original Hispano.

There is a photograph (figure 5) of the Hispano-Motor crankshaft (47kg) compared to the Saurer (80 kg) on page 7 of the first attachment above.