Nose Rises

[SpitfireMelodeon]

Hello Knowledgeable Aviators

Not with my A2A aircraft but -
I have noticed that sometimes (especially with vintage 'twins' i.e. the Dakota) when I slowly reduce power the nose initially rises rather than the expected fall.
In all cases I have the aircraft trimmed for straight and level flight and do not have any autopilot engaged.

Is this a real aerodynamic phenomenon or a shortcoming with add-on developers aircraft or indeed FSX and these models?

Just curious

Cheers n Beers
Bill

[ft]

When designing aircraft, you strive to have a positive pitch moment (nose up) with added power. Generally, when you apply power you are more interested in going up than down. The real driver behind this is the go-around. Cockpit workload will be high anyway, so it is desirable to have the aircraft climb rather than descend if the pilots become task saturated and forget to fly the aircraft.

However, many factors affect the pitching moment with added power. You have the position of the center of drag and center of mass relative to the engine thrust line, you have prop wash interference with aerodynamic surfaces etc. There is historically no shortage of aircraft with flaws in their handling properties, such as pitch-down with thrust increase.

In short, you're right in your assumption that this is not what you would normally want an aircraft to do, but you'd have to look at the specific aircraft to determine whether this is a modelling flaw or correct modelling of a less desirable trait of the real aircraft.

Cheers,
/Fred

[SpitfireMelodeon]

Interesting thoughts Fred.

It seems to happen only with vintage, medium twin prop aircraft that have relatively large wing area for their size such as the HP Hampden which exhibits this behaviour quite markedly when power is reduced. Or at least, mine does

I had assumed that a lessening in prop wash over the wings would have curtailed lift rather than seeming to give it more. Of course it only lasts for a few seconds and then the nose will drop and descent commence as expected.
I just wondered what might be happening aerodynamically in those few seconds but as you point out there are so many variables to put into the equation.

Many Thanks

Bill