Does the concept of flying of Quadcopter is the same concept of Fixed wing aircraft?
Bernoulli Equation and Delta P, and if this right, Where is the shape of airfoil in the quadcopter?
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Adel, the concepts for a quadcopter are more akin to a helicopter.
Now, a helicopter, quadcopter and fixed wing aircraft do share the same laws of physics, but engineers design them to use these laws differently.
For example, a quadcopter is generally designed for hovering, not forward motion. Because of this, the fuselage / airframe is designed to minimise drag along the vertical axis, to reduce the disruption to airflow coming from each propeller.
Now, when a quadcopter is moving forward, it gets complicated.
In terms of lift, it is possible to have an airfoil surface on the quadcopter fuselage. However, with a quadcopter, the aircraft needs to tilt into the direction of travel, meaning that such an airfoil must be designed to have a static positive angle of attack. The airfoil would likely need to be very thick too in order to accommodate the required batteries, electronics and structural members that hold the arms of the quadcopter.
Because of these challenges, designers do not design quadcopter frames to generate lift in forward flight. Rather, they first design them to be rigid and not bend. Once they have satisfied that requirement, they then design it to be as light as possible. Once they've also satisfied that, they then try to create the most laminar flow possible across the fuselage, in all directions. Often this is just done by making a rounded shell around the electronics / batteries.
Now, in order to generate lift for normal flight (hovering, etc) a quadcopter uses rotary wings (propellers), which use the same principles as a wing, where the spinning propeller redirects air downwards.
The propeller is designed to have an airfoil. Because quadcopters are required to have their motors / propellers change RPM very rapidly, these propellers are made thin to reduce their weight and reduce the amount of torque required to generate a change in RPM.
When a propeller is creating thrust, it does so through Newtonian physics and pressure differences. The front of a propeller, which hits incoming air and scoops it downwards, is operating mainly through Newtonian physics; it deflects air. Behind the propeller is where pressure differences and Bernoulli have a more significant effect. If a propeller has too much pitch, the pressure difference between the front and back of the airfoil becomes too great, Bernoulli can't keep up and laminar airflow is lost, creating significant cavitation, stalling the airfoil, which leaves a pocket of turbulent air for the other end of the propeller to move through, affecting the thrust / lift generated. This is just like a fixed wing aircraft.
One thing that separates wings from propellers however is the fact that a propeller blade has to be designed to generate efficient lift at different airspeeds across the propeller's diameter.
If a propeller is 30cm long and is spinning at 15,000RPM, then the air at the ends of the propeller is moving at 848km/h relative to the airfoil. near the center of the propeller, at a radius of 3cm, the air is moving at only 170km/h. That means propellers are designed to have a large pitch near the center and a small pitch at the tips. Some propellers even use tiny winglets to reduce the formation of vortices that form at the tips of propellers.
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That's one of the best answers to a question I have seen for months nice one Joshua