Where's the torque?

[Yo-Yo]

1 hour ago, Bremspropeller said:

 

You always have considerable net flow through the prop disc - even when standing still. Hence you also have P-factor at zero airspeed.

The only question is the angle of the flow-field, which may be tilted in line with the engine's waterline. Then there'd be no P-factor, but not because there's no air-speed, but because there's no difference in blade AoA.

 

But the difference in AoA is a result of tilted inbound airstream exclusively due to non-zero  airspeed...

[Bremspropeller]

25 minutes ago, Yo-Yo said:

But the difference in AoA is a result of tilted inbound airstream exclusively due to non-zero  airspeed...

 

Let's make sure we're not mixing up coordinate systems here, when talking to each other

 

When standing still, the induced flow-field will go normal to the prop-disc area (hence no AoA difference).

When going forward, there'll be a superposition of that flow-field normal to the disc area and the resultant airflow from the movement of the airplane - with a resultant net vector.

[Yo-Yo]

15 minutes ago, Bremspropeller said:

 

Let's make sure we're not mixing up coordinate systems here, when talking to each other

 

When standing still, the induced flow-field will go normal to the prop-disc area (hence no AoA difference).

When going forward, there'll be a superposition of that flow-field normal to the disc area and the resultant airflow from the movement of the airplane - with a resultant net vector.

Absolutely right. 

 

[Bozon]

3 hours ago, Bremspropeller said:

 

You always have considerable net flow through the prop disc - even when standing still. Hence you also have P-factor at zero airspeed.

The only question is the angle of the flow-field, which may be tilted in line with the engine's waterline. Then there'd be no P-factor, but not because there's no air-speed, but because there's no difference in blade AoA.

 

Good point about air speed due to propeller “suckage”. By “air speed” I meant for the whole plane. When standing still, the airflow due to prop sucking air into it is perpendicular to the prop disc (barring ground and airframe interference effects on the flow), hence the blades experience the same local AoA regardless of rotation position and there is no P-factor.

[grafspee]

Unless you take off with strong head wind, then P-factor should be noticeably stronger, but at the same time rudder would be more efficient then nothing drastic should happen.

Edited September 23, 2021 by grafspee

[Wrcknbckr]

On 9/23/2021 at 10:12 AM, Wrcknbckr said:

I'm curious to know how engine torque is counteracted in cruise flight; differential aileron as base? structural asymmetry? tabs? continuous roll trim?

 

 

Just found out that the Mosquito has one-sided aileron trim; left only!

[grafspee]

7 minutes ago, Wrcknbckr said:

 

Just found out that the Mosquito has one-sided aileron trim; left only!

Pretty ordinary thing in airplanes.

[Wrcknbckr]

3 minutes ago, grafspee said:

Pretty ordinary thing in airplanes.

One sided? I'd expect tabs on both sides, or none at all...

Edited September 24, 2021 by Wrcknbckr

[grafspee]

3 minutes ago, Wrcknbckr said:

One sided? I'd expect tabs on both sides, or none at all...

 

One tab for simplification and weight reduction, one tab or 2, job done is the same, it affects both ailerons.

Edited September 24, 2021 by grafspee