DB603N

[wiking85]

How was the DB603N able to achieve 2800hp for takeoff and over 1900hp for max continuous usage?
https://en.wikipedia.org/wiki/Daimler-Benz_DB_603

DB 603N (prototype with two-stage supercharger, C3 fuel)
Power (max): 2800 PS (2762 hp, 2059 kW) at 3000 rpm at sea level
Continuous: 1930 PS (1904 hp, 1420 kW) at 2700 rpm at sea level

Clearly there was some boosting system for take off power, but did C3 fuel and the supercharging really add that much power to the basic 603A or were there other developments to the engine? How much was attributable to the better fuel and how much to the supercharger?

 

[tomo pauk]

Please note that max RPM was up-rated, from 2700 RPM as, for example, in the well known DB-603A, to 3000. More rpm - more power. The C3 fuel enabled more boost, 2 ata was used on take off and up to 32600 ft (capable for 1930 PS there). The 'Fugmotoren und S.' book has the graph that shows the lines for 603 line, there is a caption 'DB 603N-MW Projekt 1945. The 603N endured a redesign, vs. the 603L for example. The inlet guide vanes were also incorporated, that device can further increase the power under rated altitude.

Two-stage compressor played as much as no role in take off performance, some designs (like P&W ones, for example) were capable to completely disconnect one stage in really low altitudes, so less power was being taken away from prop.

 

[rinkol]

I understand there were changes in construction to the cylinders and/or cylinder heads. Can we confirm whether the cylinder liners are of the wet or dry types?

 

[wiking85]

Please note that max RPM was up-rated, from 2700 RPM as, for example, in the well known DB-603A, to 3000. More rpm - more power. The C3 fuel enabled more boost, 2 ata was used on take off and up to 32600 ft (capable for 1930 PS there). The 'Fugmotoren und S.' book has the graph that shows the lines for 603 line, there is a caption 'DB 603N-MW Projekt 1945. The 603N endured a redesign, vs. the 603L for example. The inlet guide vanes were also incorporated, that device can further increase the power under rated altitude.

Two-stage compressor played as much as no role in take off performance, some designs (like P&W ones, for example) were capable to completely disconnect one stage in really low altitudes, so less power was being taken away from prop.

Thanks for the response. What are inlet guide vanes? I cannot seem to get a clear answer through a search engine. Also how was the RPM increase achieved? Via improved a cooling system or strengthened component or both?

 

[tomo pauk]

For inlet guide vanes, please check out this thread:
www.ww2aircraft.net/forum/engines/superchargers-mikulins-klimovs-jumos-etc-40086.html

The 603N was strengthened to allow for greater RPM. More power always demands more/better cooling.