# Physics-flight help

by marinepyre
Tags: physicsflight
 P: 6 I need help with understanding bernoulli's principle, how an aerofoil develops lift i have horrible knowledge and understanding on how it works And how the aerofoil produces lift in regards to bernoulli's principle. Diagrams would help alot Thanks
 HW Helper P: 6,931 The simple explanation is that using a wing as a frame of reference, the wing diverts the relative air flow downwards. This corresponds to the wing exerting a downwards force onto the air, and the air exerting an upwards force on the wing. The exertion of a downwards force on the air corresponds to a lower pressure above the wing and/or a higher pressure below the wing. Air accelerates from higher pressure areas towards lower pressure areas, and as the air accelerates, Bernoulli equations notes a relationship between the decreasing pressure and increasing speed, assuming no work is done, and ignoring issues related to turbulence and friction with the wing. A wing performs some work on the air (using the air as a frame of reference, a wing adds energy to the air), and the work related portion of lift violates Bernoulli. Previous threads: http://www.physicsforums.com/showthread.php?t=707155 http://www.physicsforums.com/showthread.php?t=699059 http://www.physicsforums.com/showthread.php?t=618500
 P: 6 How does the air going downwards make air go upwards i don't understand Im sorry
P: 6

## Physics-flight help

I also have another problem in regards to finding the maximum lift to drag ratio
I have been given a graph of airspeed over drag graph where airspeed is x axis and drag is y axis
I have to find out maximum lift to drag ratio at what airspeed and when it occurs