Aviation Hobby > Flying
Physics of flight?
Gripen:
Question: Whose the rascals
And random thing: dont let the wings fall off otherwise you are sooooo f****d!!!
Webmaster:
--- Quote from: Viggen on October 19, 2006, 10:11:09 PM ---I asked a friend of mine who fly planes about this today. Guess what??? Our dear webmaster was right again, i got the same answer from my friend. The wing will still produce lift if you are upside down, you will just need to adjust the power, give it more throttle and rudder input (dive). It is not just the shape of the wing that makes it possible, it is all combined. :)
No more sleepless nights for me... Thanks to you two rascals! :D
--- End quote ---
Right, and I now see some problem in both answers, of course it's not the rudder (yaw moving), but the stick (pitch) and this controls not the ailerons I have drawn on the wings, but the elevators on the horizontal tail planes or the entire tail planes and/or canards on some aircraft. You might have to use the rudder in propellor driven aircraft though, to compensate for the drift because of the power up.
Goose:
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.
Viggen:
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?
Goose:
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.
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