Detlef Faber wrote ... snip ... > > There is also some difference in Boost handling. Some Aircraft switch > the blower by hand, so the switch works like on/off. Other engines (like > the two staged supercharged merlin) switch the gears automatic and the > "user" button just disables this Automatism.
Just to correct a minor misinterpretation here. "Two stage" refers to the construction of the supercharger: 1 compressor delivers (usually via an intercooler) into another compressor which in turn delivers (possibly via an aftercooler) to the engine. In the case of the 2 stage Merlin supercharger, both compressors were mounted on the same shaft, and were not selectable or adjustable. In other designs the first stage was turbo driven while the second was mechanically driven. Superchargers of any number of stages may also be 1 or 2 speed (I know of 1 case of 3 speed - a late model Griffon - there may be more). During its development, various marks of the Merlin had 1 or 2 stage superchargers which were 1- or 2-speed. The speed may be automatically or manually changed. In addition there may be control over the output pressure of the supercharger - in the Merlin this was called a "Boost Controller" which acted by adjusting the throttle. This controller could be overridden (or cut out) in combat or emergency situations. All these combinations are modeled in FG in the Hurricane/Spitfire/Seafire. In all these "Ctrl B" toggles the Boost Controller Cutout. In the Hurricane there is also a panel control, while in the Spitfire/Seafire this is triggered by the throttle opening fully. In the Hurricane the supercharger gear is changed automatically, but can be overridden by a panel control, while the particular variant of the Spitfire/Seafire modeled had a single speed supercharger. As an aside, I know of no case where the supercharger could be switched off, but I cannot exclude the possibility. In most high performance aero engines the carburetor was placed upstream of the supercharger so that the evaporation of the fuel could assist in charge cooling and the supercharger could assist in fuel/air mixing. To disconnect the supercharger would seem illogical, if not impossible in these circumstances. I hope this all helps rather than hinders ... Vivian ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Flightgear-users mailing list Flightgear-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-users
