Dgca Module 08 Online Test 01

Lift is the force that allows an aircraft to overcome gravity and stay in the air. On a delta wing aircraft, lift increases with an increase in the angle of attack. The angle of attack refers to the angle between the wing's chord line and the oncoming airflow. When the angle of attack is increased, the airflow over the wing is deflected downwards, creating a pressure difference that generates lift. Therefore, as the angle of attack increases, the lift also increases.

The temperature variation near the Earth's surface is greater. This means that there are larger differences in temperature from one location to another. This could be due to various factors such as differences in altitude, proximity to bodies of water, or the presence of urban heat islands. These variations in temperature can have significant impacts on weather patterns, climate, and the distribution of plant and animal species.

Induced drag is a part of lift. When an aircraft generates lift, it also creates a downward force called induced drag. This drag is caused by the production of vortices at the wingtips, which are necessary for lift generation. These vortices result in a horizontal component of force, known as induced drag, which acts opposite to the direction of the aircraft's motion. Therefore, induced drag is directly related to the lift being produced by the wings.

The correct answer is "Ratio of stress velocity to velocity gradient". This is because the coefficient of viscosity is a measure of a fluid's resistance to flow. It is determined by the ratio of the shear stress (force per unit area) exerted on the fluid to the velocity gradient (change in velocity per unit distance) within the fluid. This ratio represents how easily the fluid can deform under an applied force, with higher values indicating higher viscosity and greater resistance to flow.

During a turn, the outer wing of an aircraft offers more lift. This is because the outer wing has a larger radius of curvature compared to the inner wing, resulting in a higher airspeed and lower pressure on the upper surface of the wing. This pressure difference creates more lift on the outer wing, helping to maintain the balance and stability of the aircraft during the turn.

In the case of aircraft nose drop, the thrust line is placed high and the drag line is placed low. This configuration helps to create a downward force on the nose of the aircraft, causing it to drop. Additionally, having the thrust line high and the drag line low helps to minimize drag and improve the overall aerodynamic efficiency of the aircraft.

During equilibrium flight operation, stability depends on both the magnitude of force applied and the length from the C.G (Center of Gravity). The magnitude of force applied affects the balance and stability of the aircraft, while the length from the C.G determines the aircraft's ability to maintain its equilibrium position. Therefore, both factors are crucial in ensuring stability during flight operations.

If the aspect ratio is higher than 40%, it means that the wings of the aircraft are longer and narrower. This type of wing design reduces the induced drag, which is the drag produced by the creation of lift. A higher aspect ratio allows for a more efficient distribution of lift along the wing, resulting in a lower induced drag. Therefore, if the aspect ratio is higher than 40%, the induced drag will be more than 40%.

The stick shaker gives a stall warning to the pilot. When the aircraft approaches a stall condition, the stick shaker vibrates, alerting the pilot to take immediate action to prevent a stall. This warning system helps the pilot maintain control and prevent the loss of lift, which can lead to a dangerous situation. The stick shaker is designed to provide a tactile and noticeable warning to the pilot, ensuring they are aware of the potential stall and can take appropriate corrective measures.

The correct answer is that stability characteristics about all axes are different. This means that the stability of an object or system can vary depending on the axis around which it is being measured. In other words, the stability around the lateral axis may be different from the stability around the roll and yaw axes. This suggests that different factors or forces may be influencing stability in different directions, leading to varying characteristics.

The correct answer states that the longitudinal stability of an aircraft depends on the tail plane, its area, and its distance from the center of gravity (C.G). This is because the tail plane, also known as the horizontal stabilizer, plays a crucial role in balancing the aircraft and maintaining stability. The area of the tail plane affects the amount of lift it generates, which can help counteract any pitching moments caused by changes in the aircraft's center of gravity. Additionally, the distance between the tail plane and the C.G determines the lever arm, which affects the effectiveness of the stabilizing forces.

The ideal airfoil refers to an aerodynamic shape that is designed to have both a high maximum lift coefficient and a good lift/drag ratio. A high maximum lift coefficient indicates that the airfoil can generate a significant amount of lift, allowing an aircraft to take off and land at lower speeds. A good lift/drag ratio means that the airfoil produces a high amount of lift relative to the drag it creates, resulting in efficient flight and better fuel economy. Therefore, the correct answer is "Both a and b" because an ideal airfoil possesses both of these desirable characteristics.

If the pitching moment about the fuselage is disturbed, it would affect the longitudinal stability of the aircraft. The pitching moment refers to the tendency of the aircraft to rotate around its lateral axis, causing changes in its pitch attitude. Longitudinal stability is the stability in the aircraft's pitch motion, ensuring that it maintains a steady and controlled climb or descent. Therefore, any disturbance in the pitching moment about the fuselage would directly impact the longitudinal stability of the aircraft.

An airfoil with a slightly negative angle can still generate lift because lift is primarily generated by the difference in air pressure between the upper and lower surfaces of the airfoil. Even with a negative angle, the shape of the airfoil can still create this pressure difference and generate lift. However, the amount of lift generated may be less compared to an airfoil with a positive angle of attack. Therefore, it is possible that the airfoil may generate lift, but the magnitude of the lift force may be lower.

The correct answer is "The interference between different parts of A/C and airflow." This is because when different parts of an aircraft, such as the wings, fuselage, and tail, interact with the airflow, it can create disturbances and turbulence. These disturbances increase the drag on the aircraft, making it harder to move through the air. Therefore, the interference between different parts of the aircraft and the airflow is a primary factor in determining the amount of drag experienced. The speed of airflow over the wing and other parts can also influence drag, but it is not the primary factor mentioned in the question.

When the pilot releases the control column, it means they are no longer applying any input or force to the elevators. As a result, the elevators are free to move and take up their own positions based on the balance of forces acting on them. This allows the aircraft to maintain a stick-free condition, where the elevators are held in their neutral position relative to the tail plane. Therefore, the correct answer is both a and b.

At high speeds, induced drag is typically reduced compared to total drag. This is because at higher speeds, the lift produced by the wings is more efficient, resulting in a decrease in the angle of attack and therefore a decrease in induced drag. Therefore, the correct answer is that at high speed, induced drag is 10% less than total drag.

The performance capability of a jet engine with a propeller depends on power. Power is a measure of how quickly work is done, and in the case of a jet engine with a propeller, it determines the speed and efficiency at which the engine can generate thrust. A higher power output allows the engine to produce more thrust, enabling the aircraft to fly faster and more efficiently. Therefore, power is a crucial factor in determining the performance capability of a jet engine with a propeller.

The correct answer is "Actual position depends on the relative resistance of different parts of the airplane." This means that the center of drag, which is the point where the aerodynamic forces act on the aircraft, is determined by the distribution of resistance across its various components. The position of the center of drag affects the stability and control of the aircraft during flight.

In gliding flight, the stalling angle refers to the angle at which the aircraft's wings can no longer generate enough lift to sustain flight, causing the aircraft to stall and lose altitude. The stalling speed is the minimum speed at which the aircraft can maintain level flight without stalling. When the weight of the aircraft increases, the stalling angle and stalling speed are both reduced. This means that the aircraft can fly at a lower angle and speed without stalling. Additionally, when the weight increases, the range of the aircraft is also reduced. Therefore, the correct answer is that the stalling angle and range are reduced, while the speed remains unaffected.