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Thursday 7 March 2013

Full power Right rudder

This morning, I told Adam that I was interested
to make my blog to become a website which could provide
more information about aviation and piloting to those aviation enthusiasts.
In fact, I have been doing this since last year if you remember that
I came up with some ideas about this in one of my posts last year.
However, just as I expected, this has never been succeeded since
I'm still considered a newbie in this field and I don't have enough time
to do so after completing my training every day.
I must apologize to my readers out there,
if I have one, for disappointing you.

Today, I'll start it over again.
I'll be sharing some basic theories of aerodynamics with you here.
For your information, a left turning tendency of an aircraft is made up
of four elements which cause or produce a rotating motion around
at least one of the airplane's axes. These four elements are:
1. Torque from engine and propeller.
2. Slipstream effect of the propeller
3. Gyroscopic effect of the propeller
4. Asymmetric loading of the propeller (P-factor)

1. Torque from engine and propeller
  • This involves the Third Law of Newton's which is there's an opposite and equal reaction for every force. To cur it short, for example, if the propeller is rotating in clockwise direction(turning right), there'd be a force, which we call it torque, acting in the opposite direction(turning left) and causing the aircraft to yaw to the left
2. Slipstream effect of the propeller
  • When the propeller is rotating in high speeds, it gives a compact corkscrew or spiraling rotation to the slipstream and exerts a strong sideward force on the aircraft's vertical tail surface.
  • When the slipstream strikes the vertical fin on the left, it causes a left turning moment about the aircraft's vertical axis. Besides, the slipstream also causes a rolling moment around the longitudinal axis.
3. Gyroscopic effect of the propeller
  • The rotating propeller has very good gyroscopic properties. Any time a force is applied to deflect the propeller, the resulting force is 90 degrees ahead of and in the direction of rotation and in the rotation of application, causing a pitching and yawing moment, or a combination of two depending on the point at which the force was applied.
  • When the aircraft takes off, the pitch up attitude will apply a force to the top of the propeller, causing a yawing moment to the left. Just google Gyroscope to know about details about it.
4. P-factor
  • I was asked this question by my flying instructor the other day, thanks god I could answer a bit although it's not perfectly correct.
  • P-factor is an aerodynamic effect experienced by a moving propeller which is responsible for asymmetrical relocation of the thrust line of the propeller at a high angle of attack.
  • Basically, the moving down propeller blades have a higher wind velocity thus higher thrust than the moving up propeller blades. As a result, for a clockwise turning propeller, the aircraft thrust line is more towards to the left of the aircraft and it causes the tendency of yawing to the left. How about anticlockwise turning propeller? Draw it out then you'll know how it actually works.

So the combination of all these forces will actually cause a great left turning force for a PROPELLER aircraft,
that's why we are always told to kick right rudder while taking off so that we could maintain centreline and our flight path. Well, for those who don't know about aircraft, this's actually not scary at all but the design of the aircraft, have faith in the pilots because they are well-trained for handling the aircraft before they get on board. Cheers :) 

Do drop me some comments.

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