Why Aircraft Vibrate More During Takeoff: Have you ever experienced the slight shaking of an aircraft during takeoff and wondered why it happens? It may feel like the plane is about to fall apart, with each part breaking away. But fear not, my friend, because this vibration is actually quite normal and can be attributed to a multitude of factors.
Why Aircraft Vibrate More During Takeoff
During flight, aircraft may encounter sudden vibrations for a variety of reasons. These can range from the design of the runways to imbalanced tires or even crosswinds. Sometimes, the wake generated by other planes can also impact the aircraft’s aerodynamic performance when it’s closer to the ground. As a result, during takeoff, the aircraft may experience shaking or vibrating as it adjusts to the different forces in the air.
Factors Causing Vibration In Aircraft
1. Aircrafts can experience vibrations due to runway expansion joints
Major airports witness hundreds of thousands of departures and arrivals annually, involving aircrafts that weigh hundreds of tons. As a result, runways must offer a sturdy, stable surface for safe departures and arrivals.
Airport runways are usually built using a mix of concrete and asphalt. This combination of materials is chosen based on the specific aircraft that will be using the runway and the local weather conditions. Concrete is often the go-to choice for runways at commercial airports because it offers greater durability and a longer lifespan.
Imagine this, when runways are being built, the top layers consist of concrete slabs deliberately separated by gaps. These gaps play a vital role in accommodating the concrete’s expansion or contraction due to temperature fluctuations. To protect against ice damage, a flexible sealant is applied within these gaps. Fascinatingly, the first vibrations and noise experienced during takeoff are often caused by the aircraft’s tires rolling over these expansion gaps.
2. A plane can vibrate due to wake turbulence
Wake turbulence is like a little whirlwind that forms in the air after an aircraft passes by. It’s made up of different things, but the most significant ones are wingtip vortices and jetwash. Out of the two, wingtip vortices are the more steady ones and can linger in the air for about three minutes after the plane has flown past. Interestingly, the size of the aircraft determines the strength of the wake it creates.
Just like crosswinds, unpredictable air pockets can make the pilot adjust to maintain the plane’s stability. These unexpected shifts make the wings of the aircraft flex, leading to vibrations spreading across the plane. Air traffic control sometimes makes a departing plane wait on the runway for a short while to let wake turbulence settle before takeoff, especially if a smaller plane is following an Airbus A380.
3. Vibrations are impacted by crosswinds
Strong crosswinds can change how lift is generated on a plane’s wing during takeoff. Lift is produced when the airflow over the wing is fast enough. If the wind gusts disrupt the airflow over the wings, it can affect the lift being generated.
As the wings are constructed, they are intentionally designed to flex, resulting in vibrations that ripple through the entire aircraft. However, there is no cause for concern as this is a normal occurrence. Additionally, when the plane takes off in strong crosswinds, the pilot may need to make sudden control adjustments, adding extra strain to the aircraft.
4. Vibrations can occur due to the plane’s tires
As planes touch down on the runway, you may notice smoke billowing from the wheels. This happens when the stationary wheel rubs against the fixed surface, causing friction. The skidding tire during acceleration also contributes to the smoke.
A brief skid of the tires can lead to irregular rubber wear, subsequently causing the plane to shudder during takeoff. Moreover, unbalanced wheels can trigger vibrations that resonate throughout the entire aircraft. To better grasp this concept, imagine an old washing machine. When the clothes inside the drum get stuck in one place, the machine starts trembling and shaking uncontrollably due to the imbalance. Similarly, the irregular wear on plane tires can produce a similar unsettling effect.
5. Pulling up the landing gear may result in the aircraft shaking
One more factor that can lead to vibrations in an aircraft is the change in weight on the wheels during takeoff. As the plane lifts off the ground, the pressure on the wheels suddenly shifts from heavy to light, causing the tires to deform and become unbalanced. The greater the number of wheels on the aircraft, the stronger the vibration will be.
As the skilled pilot expertly pulls up the landing gear, the brakes are swiftly engaged to ensure the tires remain stationary within the wheel wells. This deceleration prompts a gentle vibration in the tires, gradually bringing them to a halt. Additionally, the opening and closing of the wheel well doors contribute to the symphony of sounds and vibrations experienced during this process.
Vibrations and noise during takeoff are completely normal, and airplanes are specifically engineered to withstand them. So, when you’re up in the air, just sit back, relax, and enjoy the flight without any worries.
Conclusion on Vibration
- During takeoff, various factors such as runway expansion joints, wake turbulence, crosswind effects, and tire irregularities can contribute to the vibrations experienced by an aircraft.
- The initial vibrations and noise encountered during takeoff can be attributed to the presence of gaps between slabs on concrete runways.
- As the landing gear is retracted after takeoff, the transition of weight from heavy to nothing can induce vibrations in the tires.
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