[Physics] Forces on an aircraft – thrust, lift, drag, weight

aerodynamicsdragliftweight

I'm extremely sceptical about the wikipedia page on aircraft flight mechanics. When describing 'straight climbing flight', it says:

lift is unable to alter the aircraft's potential energy or kinetic energy

This seems like nonsense to me, given that 'lift acts perpendicular to the vector representing the velocity of the aircraft relative to the atmosphere'. In other words, I think there is always a vertical component of lift (except for the conditions where angle of attack for non-cambered aerofoil is 0 or 180 degrees). The reason I want to know this, is it also claims that

in straight climbing flight, lift is less than weight

I also can't believe that this is always the case, since an aerofoil can generate lift when it has a zero angle of attack if it is cambered. So if the aeroplane is going fast enough, not only can the lift can exceed the weight, but just the vertical component of lift can exceed the weight.

I'd appreciate criticisms of my understanding as well as the wikipedia page. (I wonder if it's an incorrect interpretation of the source, 'Aerodynamics' by Clancy).

Thanks

Best Answer

Rather than try to debug a Wikipedia page, I suggest two things:

  1. Take your time and read this delightful on-line book. Also, why not get a copy of Stick and Rudder? It's been a classic for 70 years.

  2. Take an introductory flight lesson. It's a lot of fun and totally safe. They let you take off and fly around, and then you will understand all the basics. Don't worry about landing - they will do it for you.

How airplanes work is not a mystery. They've been around almost as long as automobiles, and they are just as well understood.

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