Simviation Forums

I've noticed that when crusing at high altitudes 10,000ft. and above and adjusting the RPM's back to conserve fuel that the airplane drops in airspeed and I believe this is incorrect.  I've asked my Dad about this, who is a pilot, and his response to this is that as you climb in alt. the air thins and so does the resistance.  This is why when you reach your alt. you cut back the RPM's and this also changes the prop pitch, taking a bigger bite of the air and the prop doesn't have to turn as fast and because of the less resistance in the atmosphere the plane (in real life) should increase in airspeed and this does'nt occur in cfs2.  Does anyone else agree and how do we fix it.  Step by Step.  Thanks for your input.

I don't know much about props & others might well correct me on this. I believe that after a certain date  most, if not all, WWII fighters were fitted with automatic "constant-speed" airscrews. This could be manually overridden for take-off & landing (& possibly during combat) but otherwise I think the pitch would be automatically controlled. I'm not sure how the prop pitch controls are set up in CFS2 but by reducing the revs you're possibly using the throttle, not the prop. This would obviously affect the airspeed.

To increase the range you'll need to thin the mixture, otherwise at altitude your engine will be getting far more fuel than oxygen and it'll flood, stop working and then allow you to turn into a dollop of strawberry jam
You should also set the pitch of the props to coarse

Most of the CFS aircraft's AIR files give a good model of hi altitude performance especially the 1% type. I agree with all the other comments, obviously if you reduce the boost ( throttle) the RPM will reduce and the aircraft will slow down. Try the same thing at say 18K feet, if the aircraft has a supercharger ( I'm thinking about WWII aircraft) it may be designed not to kick in until above a critical height. Max speed is also related to height. Try one of the YAS spitfires ( search on YAS at Avsim) and you'll see what I mean. You'll see the difference in performance between the original MkI and the later MkXVI.

Basicly, pull the mixture and propeller (aka RPM) levers back until you get the required performance.