What does the RPM reduce/increase buttons makes and means ?

[clouds]

When you press the +/- keys on the Numeric Pad you can see the manyfold boost increasing or decreasing.

Since today I've always thought those keys were used to change the propeller pitch but.....at high altitude when you increase the prop pitch, the plane have to go faster while the rpm have to reduce because of the drag increasing.

Otherwise the NP +/- have to be used to rich/lean the mixture air/fuel and that could explain why when you press the + key (enrich mixture) the rps increases.

But at this point I think (like in the reality) when you increase the altitude of flyght Oxygen % reduces so the mixture could be leaned to maintain a correct ratio oxy/fuel and in any case leaning the mixture at high altitude produces a faster flyght because the engine turns better.

Is it correct or I've lost something ?

Now the question is......why when you press the NP - key rpm decreases and speed too ?

Thanks.

[Ghosth]

# 1   it is prop pitch that you are changing.

#2 when you reduce prop pitch from default, you are feathering the blade, so it takes a smaller slice.

We have constant speed props, so when you lower rpm, prop wants to spin faster, so it lowers manifold to compensate.

There are guys that do nothing but debate this stuff all day long.  Go search for threads about props. You'll find tons to read.

It is the way it is, and its as close as we are going to get for the time being to reality. Pull up your E6B in flight, and see the results of the different settings.

[clouds]

Ok, understood (reducing prop pitch is like reducing the alpha angle [angle of attack]   in a wing because a prop is a turning wing) but.......

if all is like you said, then the rpm reduction could be used only to reduce consumption while in the reality the prop pitch adjustments were more linked to the speed of flyght and the altitude (keeping away problems linked to the atmospherical  pressure, air density and so on..... too complicated for this kind of simulation) like normally actual prop aircrafts do.

And more, usually we have by default all the pitch to max in AH, that means we takeoff, cruise, dive and land always at the same prop pitch.

Do you think this can simulate the reality ?

What about ?

[J_A_B]

"And more, usually we have by default all the pitch to max in AH, that means we takeoff, cruise, dive and land always at the same prop pitch. "

You are setting the RPM.  The actual prop pitch will change depending on flight conditions.   Not everybody leaves their RPM at max all the time  

J_A_B