There are a lot of questions that can be answered with facts and reason, but that doesn’t always mean they can be proven beyond a shadow of a doubt. Theories are usually answers to questions that can’t really be proven but should be able to happen due to the laws of physics and gravity.
Can an Airplane stand still in mid-air? Technically, it is possible for an airplane to hover for a few moments, but only in the rarest of circumstances. If weight and lift cancel each other out at the same exact time that thrust and drag cancel each other out, the plane would hover until one of these variables changed.
This occurrence is so rare that most people don’t even believe it can actually happen. This is more of a theory than anything, and it applies to most planes, but not all. Most planes are built the same way, but some are different enough that it changes the way forces act with, or against, the plane.
How Do Planes Stay Up in the Air?
For us to understand how an airplane would be able to hover or fly, we need to understand the meaning behind the forces at work when an airplane is in the air.
- Airspeed – The speed that the air is hitting the wings
- Groundspeed – the speed at which a plane is moving across the ground
- Headwind – a wind blowing from directly in front that opposes the forward motion
- Weight – the weight of the plane due to the force of gravity
- Lift – The force that acts at a right angle to the direction of motion through the air. This is created by air pressure
- Thrust – the force that propels a flying machine in the direction of motion. Engines produce thrust
- Drag – the force that acts opposite of motion. This is caused by friction and air pressure
An airplane relies on the laws of physics and motion. Specifically, Newton’s third law of motion explains how the engine and wings work together to keep the plane in the sky.
Generally, an airplane’s engine is designed to move it at a very high speed. This allows for the airflow over the wings to move rapidly as well, which throws air down towards the ground generating lift. Lift overcomes the plane’s weight and holds it in the sky. The force of the hot exhaust (or gas) that shoots backward from the plane engine is what pushes the plane forward.
However, during take-off, a few more things are at play. When taking off, the plane’s purpose is to climb to a higher elevation in the sky. The only way this can happen is when the thrust from the engine exceeds the drag that pulls the plane back. This process creates a lift force that propels the plane forward and up.
How Do a Plane’s Wings Help It Fly?
So, the wings of a plane are a huge part of why the plane is able to fly. But just how do they work?
Well, most airplane wings are made with a bit of curvature on the upper part, and a flatter surface on the lower part. This build makes a cross-section called an airfoil. This specific build directly affects the air pressure above and below the plane, and how smooth the plane ride will be.
When the plane is flying, the air is split in half when it hits the wing. The air that goes on top of the wing has a lower air pressure, and what air goes under the wing has a higher air pressure. This creates lift and helps the plane go higher or keeps the plane stable when it just needs to fly straight. When the air converges at the end of the wing, it is pushed down from the top curvature, so there you have a second force creating lift as well.
Now, of course, you can fly a plane with wings that do not have airfoil curvature. On December 17, 1903, the Wright brothers proved that you could fly a plane with only a slightly tilted wing. The Wright brothers were brilliant men for their time; however, we have come so far with technology and the ability to widely manufacture machines than upon the discovery of the airfoil method, it far outperformed the former method.
Steering a Plane
Steering a car or bike makes sense because you have tires that are touching the ground and change the direction of movement, depending on which way the wheel is turned. However, when you are in an airplane, you are obviously not in contact with the ground at all. So how do you change direction? Where does the centripetal force come from where you move the steering column?
Centripetal force is any force that acts on a moving object that is moving in a circular path that is directed towards the center of the object. Centripetal force is usually another object that helps change the direction something is moving. When in an airplane, you don’t have any object that will help you create a force that would shift your direction. However, what you do have is air pressure and forces like lift and thrust.
Pilots have to lean into a turn in a plane, much like cyclists have to lean into their turns. Steering a plane involves banking, where the plane tilts to one side, and one wing is lower than the other one. Now the plane overall is at an angle, and the air pressure is different, causing sideways lift instead of just an upward lift. The sideways part of the lift acts as the centripetal force that helps turn the plane towards a different direction.
Now, while the plane is tilted, you have a lesser upward lift, which can cause you to lose altitude. The pilot can use something called elevators, which are surfaces on the back of the plane that help flight control, to keep altitude and raise the lift. Chances are you will still lose a bit of altitude, but not nearly as much, and it doesn’t take as much time or effort to correct the loss.
Conclusion: Plane Hovering is Rare
So, you can see everything that has to happen for a plane just to perform its normal routine of flying. There’s a lot going on just to keep that plane in motion.
Overall, even if a pilot has been flying planes for most of their life, the chance they have ever seen a plane hover is almost nonexistent. Even the most experienced pilots aren’t going to see the perfect conditions that would allow for this to occur. Let’s be thankful for the science that allows for our planes to stay safely in the air as long as we need them to.