In the course of last century and even today, aerodynamics “experts” take pride in revolving around scientific principles of Bernoulli and Newton as they explain how lift is produced by the airfoil. Einstein designed a wing, which failed disastrously, due to a lack of insight into airfoil behavior. Einstein used Bernoulli’s principle so failure was the only possible outcome.
Coming back to our analysis of why the science of these prominent scientists could not unravel the secret of lift, lets see why Bernoulli and Newton failed to lift 🙂 … How could they both be so wrong?
The fault lies not in their respective principle, but in the application of it. Needless to say, both are wrong tools for the job … 🙂
Here’s why …
Bernoulli’s Failure
Take a look at the equation below. Bernoulli says the pressure (p) and speed (v) of a moving or flowing fluid are inversely proportional. If v increases p decreases, and vice versa. The point is whose speed v1 or v2, are we talking about ? Because if we say its the speed of the air in which the aircraft is experiencing lift, then both v1/v2 are zero, since the air in atmosphere is not moving at all. This fact is so easy to observe … just look at a plane flying through clouds … Do you see the clouds move with it ? 🙂 That air in which plane flies has no kinetic energy. Nothing is conserved, so as per the principle of Bernoulli, obviously its application to explain lift is invalid.
Newton’s Failure
It is evident that in order to make an air-frame airborne with just Newton’s forces alone, is an impossibility. The demand on the engines for such a flight i.e. with just reaction force, requires an enormous amount of engine power. In such an aircraft the maximum lift and minimum drag do not coincide since the lift is the result of the reaction drag on the wing.
For a given thrust, as the wing size is increased in a false hope it will increase lift also, the drag builds rapidly and ultimately consumes all engine thrust. What we have here is a situation in which only the lift upwards lift force of collision against the oncoming air mass is available, unlike the force multiplication of an airfoil due to its vacuum generating ability. The airfoil drag is of a completely different nature which results not due to the action-reaction with air, but rather by the suction effect of air above the awing, as stated in the Zone Theory. This suction drag does not increase as rapidly as an angled wing, therefore the lift always overcomes drag.
We can analyze the above reasoning in a more detailed manner to illustrate this inherent ineffectiveness of Newton’s 3rd law of reaction and how much lift is produced by an angled wing having some value of angle of attack (AoA). For this discussion we will use a a nearly flat wing, which has no airfoil shape, as shown in Fig-1 below. This is the stretched-diamond wing cross section used in the notorious Lockheed F-104 Starfighter.
Reaction lift force, on such an angled wing of Fig-1, starts from zero at zero degree angle of attack, to the maximum achievable, at 45-degs. Beyond this value the wing becomes more flat to the oncoming air striking it. and the lift starts to decline and drag increases. Ultimately, at 90-degs AoA, all lift ceases to exist and drag is at maximum value, depending upon the surface area of the wings. Since there is no pressure difference advantage achieved by a flat reaction wing, its mandatory to have a thrust much greater then the MTOW of the aircraft.
But obviously, airplanes with only fractional thrust, fly effortlessly on the airfoil lift action. This forms the basis of all modern aviation, and has nothing to do with any angle of attack. Therefore, unless it is a fighter jet with a thrust-to-weight ratio exceeding unity, Newtonian reaction force can never achieve flight in modern aircraft. A typical airfoil wing is shown in Fig-2 above, which produces lift even at zero angle of attack.
The picture above shows the notorious F-104 Starfighter, based on Newtononian forces to create lift. Pilot stories abound about its moody aerodynamic behaviour often resulting catastrophic consequences for both the flyer and the machine.
See links below for more info:
But now we have a breakthrough zone theory of lift which demystifies lift in toto