Rotax 915 is not for new pilots

Greg Vos

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Reading the comments on Terecel and such.....I have hundreds of hours on Xenon type gyro, I often see the in incorrect take off procedure being used.
I prefer to just pre rotate to 150 Rpm, then stick back and gently run down the RW letting the inflow air spin her up, at 200 Rpm the the nose will gently come up ...catch it right there and keep the nose wheel 10 inches off the deck now take power and when you see 60 Mph indicated fly it out.

This saves wear on the pre rotator mechanism and make the take off elegant and smooth ......now the front wheel is off the ground you have the stick in hand and if your not ham fisted the front wheel should not touch the ground so how much right rudder is used is irrelevant
As for power well that is one thing I will never complain about saying a 915 is not for a beginner is not correct I think a big problem is the flight training and making sure a student pilot is familiar with his machine.
 

rdalcanto

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But why should there be more p-factor with one person than with two? Is it because you significantly increase your angle of attack when solo?
I think one vs two is more about how soon the front wheel comes off the ground. With one person, the front wheel comes off when there is less airflow over the rudder, and the main rotor is still going slower.

Since starting this thread, I've done a lot of takeoffs with a lot less power at the start of the takeoff roll. I use twice as much runway, but there is no question that makes it easier. One of my instructors was a very high time pilot in the Tercel, and he would slam to full throttle at the end of pre-rotation. That worked for someone like him, but I think for new pilots, it is too difficult a technique. In fact, a new student wrecked a Tercel when he went off the left side of the runway on take off in Spanish Fork in the last year, and I would not be surprised if he was going to full throttle right away.
 

Tyger

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I think one vs two is more about how soon the front wheel comes off the ground. With one person, the front wheel comes off when there is less airflow over the rudder, and the main rotor is still going slower.

Except that, as Phil and Jean Claude have suggested, I think your left yaw is caused by (twisting) airflow over the vertical surfaces of the low tail. Actual p-factor will yaw you to the right.
 
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WaspAir

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P-factor is a term that airplane people use all the time, but we rotorcraft folk have other words to describe it better. It is really just the old familiar dissymmetry of lift, but as seen at the prop, rather than at the main rotor, with the "advancing" blade being the one that's descending as you move forward with a bit of upward airframe pitch.

Picture tilting a propeller very far back or a rotor very far forward, and it's all the same thing (we just don't bother to hinge or teeter the prop). Sometimes as an instructor I get annoyed that the existence of a different name implies to a student different physics to be learned, when it often doesn't, and it just makes thing unnecessarily hard for the student.
 
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