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Author Topic: Physics of flight?  (Read 15323 times)

Offline Goose

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Re: Physics of flight?
« Reply #12 on: October 21, 2006, 08:19:07 PM »
Ok I am a pilot and an engineer and the answer is semi correct. The wing will produce lift no matter what aspect it is in as long as there is laminar airflow over it. Now this is due to Bernouli's principle which states that the rates of flow must be equal. For it to be equal the flow traveling over the curved (upper) surface of a wing has to travel faster to cover the longer distance. Due to the higher speed the pressure is less. This is what lift is the 'Pressure Differential' between the two surfaces.

An inverted wing still produces this force but it no longer cancels the weight of the aircraft or generates an upward force. It is combined with weight now to pull the aircraft down. Normally you can counter a downward pull by increasing power and/or pitching up. In this case you cannot counter by increasing power since that will increase the pressure differential and increase the downward pull. Ergo you must pitch the nose upward. What this means is inverted a pilot must push the stick forward to deflect the Horizontal tail planes downward. This will force the tail down and the nose up. That is how you maintain your altitude when inverted. Additionally from vectors since the force is now at an angle to counter the vectors you will need to increase your forward thrust by increasing the power output of your engine.

Hope I was helpful. 

Offline Viggen

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Re: Physics of flight?
« Reply #13 on: October 21, 2006, 09:56:17 PM »
Of course you were helpful and i thank you for that explicit answer.  :)

He also mentioned alfa-angel (but in swedish) or is that the same as angel of attack?
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Patrik S.

Offline Goose

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Re: Physics of flight?
« Reply #14 on: October 22, 2006, 07:07:06 PM »
He is talking about the 'Angle of Attack' of a wing. That is the angle of the wing to the relative airflow. A wing stops flying, 'Stalls,' at an angle not a speed. When the wing reaches this angle the point of pressure is to far forward along the wing and the flow breaks down from laminar to turbulent. When this happens the pressure differential no longer exist and there is no lift.

Offline Viggen

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Re: Physics of flight?
« Reply #15 on: October 23, 2006, 12:37:27 AM »
Thanks again,  it was really helpful.  :) :) :)
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Patrik S.

Offline Raptor

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Re: Physics of flight?
« Reply #16 on: March 01, 2007, 06:26:47 AM »
Ok. I finally figured it out. Thanks to my Aerospace Engineer Uncle who lent me that book. But this helped some. Thanks.
-JCLim

 



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