Do you have problems taking off flying a Prop ?

[Wayne Pierce]

From the training office;
To all AAV pilots,

If any of you, like myself, fly GA aircraft in our off hours from AAV, taking off can be a handful on the runway. A pull to the left upon applied power and then not able to maintain the runway ruins a nice start to a smooth flight. This question and answer was posted on another forum and I have re-posted it here for your general flight knowledge.

Problem Question; Any suggestions fighting gyro drift during takeoff? I know I can turn it off but where's the fun in that right? I struggle battling the pedals all the way down the runway and often end up of it. Any help or suggestions greatly appreciated.

Answer;
First things first... I think you're mixing up gyro drift and p-factor/torque...

Gyro drift is the way your gyroscopic instruments process away from a true setting over time (needing to be reset to the compass) (edit;FSX/P3D keyboard "d" resets compass.)

The reason your plane needs right pedal on takeoff, especially a high power aircraft and even more so a tail dragger with a high power output (ie most warbirds), is a combination of torque and p-factor... Both induce a left turning tendency which can only be countered with steering or rudder control during the takeoff roll.

The problem is, the rudder is only effective once sufficient airspeed is flowing over it... Once it is effective, it should be more than sufficient to counter the left turn tendency. But how to overcome the initial effect when your rudder isn't as effective? Well, that's thankfully easy to fix with some simple technique adjustments...

The left turning tendency is worst at high power settings, and will easily steer you off into the grass if you simply apply full power at the beginning of the takeoff roll. So, keep it manageable... Increase your power to full gradually as you roll... In this case, the turning tendency is less to begin with so the rudder can counter it even at lower airspeed. As your airspeed increases, your rudder becomes more effective, so you can add more power.

In other words, start rolling with low power and use whatever rudder input you need to keep straight, and gradually add power, whilst all the time also using whatever rudder you need to keep straight.

You'll need to maintain that right rudder through takeoff, rotation and climbout and the eventual reduction of power...

Thank You,

[Panagiotis Zervoulias]

Very useful information Wayne! In fact there is also the slipstream effect in combination with the propeller torque, the gyroscopic and the p-factor (assymetric blade thrust) effects but there is no reason to go further with that here...
The only thing I'd like to add is that the gyroscpic effect and the p-factor are more noticeable in the taildraggers because the thrust axis is inclined to the relative airflow. In addition the left turning tendency is for the clockwise propellers (right handed). If the propeller is counter-clockwise (left handed - seen from the cockpit) then you have a right turning tendency (which is not something common today). In fact the only aeroplane that had a left-handed propeller was the spitfire (and again I'm not quite sure about that, so correct me if I'm wrong).
As for the correction I can remember my first days at PPL when I was flying an AERO AT3 light aircraft (MTOW was 582 kgs - something like 1282 lbs). The fin was small enough to make the airplane to turn left enough to make you scirt on takeoff. The second time I went for a solo flight I almost crashed it..... Anyway that time I removed the power, came back to the center line and took off normally. After that time I used a little bit of the right brake for the first 50 meters to counteract the turning tendency until the plane gained enough speed to control it solely by the rudder, but still I had to use almost the whole rudder deflection!!! Of course the other trick was the gradual increase of power - as you correctly stated! After that I've done my CPL in a Diamond DA40NG which had a more effective rudder and I didn't need any differential brake at all. In fact only a small amount of rudder was enough. Now for the multi engine it was even more less than the DA40 and sometimes I didn't use it at all.

Regards

Panos Zervoulias