I noticed a manifold pressure gauge with two arms on the copilot's side, next to the electrical panel.. the only thing I ever saw doing it is showing outside air pressure, what is the meaning of this? I couldn't find something about it in the manual so far..

Straight from the aircraft that this model was based on.  I remember part of the story and that was that is is a MP gauge replacing an altimeter.  My first guess would be it is cabin altitude (shown in in HG) but if you say that it tracks outside pressure then ok.  They didn't have a spare altimeter and stuck this in there.

Funny story! Allright, so I can stop searching for any deeper functionality here ;)

Hi,

Another really late answer: On RW DC-6's it is the pressure indicator of the two cabin superchargers. PMDG repeatedly emphasised that they followed strictly the cockpit layout of an exisiting, restored DC-6 (my opinion: in some cases it's pitty!). Obviously, the guys doing the real restoration work were unable to find an original instrument and fitted an engine manifold gauge instead. Interestingly, the values indicated on this instrument are close to the book values produced by the cabin supercharges. In short: good indications on an incorrect gauge.

 

Cheers,

Tamas