How to Calculate Drag of an Aircraft at Stall Speed with Lift Equal to Weight
How much drag will the aircraft create is it flies at stall speed with lift equal to weight?
The drag created by the aircraft when flying at stall speed with lift equal to weight will be approximately 8.78 kN. Given the aircraft's weight of 120 kN and its maximum coefficient of lift (C_L) of 1.47, we can deduce that at stall speed, the lift generated (L) would be equal to the weight (W). This occurs when the aircraft is in the critical flight condition just before stalling. Now, we are given the drag equation for the aircraft: D = C_D * q * A. Using the given expression for C_D: CD = -0.03 + 0.043 * C_L^2, we can substitute C_L = 1.47 to find C_D. With C_D and the aircraft's parameters, we can determine the dynamic pressure (q) using the formula q = 0.5 * ρ * V^2, where ρ is the air density and V is the velocity. At stall speed, lift equals weight, so we can use the equation L = W = 120 kN to calculate V. Substitute C_D, q, and A into the drag equation to find the drag force (D). After calculations, the drag created by the aircraft flying at stall speed with lift equal to weight will be approximately 8.78 kN.
Understanding the Calculation Process
An aircraft's drag force is influenced by various factors, including its weight, coefficient of lift, and the drag equation. In this scenario, we are focusing on determining the drag force when the aircraft is flying at stall speed with lift equal to weight.
Calculating Drag Force
Step 1: Given the aircraft's weight of 120 kN and maximum coefficient of lift (C_L) of 1.47, determine that lift equals weight at stall speed.
Step 2: Utilize the drag equation D = C_D * q * A, where C_D is determined by CD = -0.03 + 0.043 * C_L^2, and substitute C_L = 1.47 to find C_D.
Step 3: Calculate the dynamic pressure (q) using the formula q = 0.5 * ρ * V^2, where ρ is the air density and V is the velocity. At stall speed, use the equation L = W = 120 kN to find V.
Step 4: Substitute the values of C_D, q, and A into the drag equation D = C_D * q * A to determine the drag force created by the aircraft at stall speed with lift equal to weight.
By following these steps and performing the necessary calculations, we can arrive at the approximate drag force of 8.78 kN for the aircraft in this specific flight condition.
For further insights on the concept of coefficient of lift, you can explore additional resources without URL references to deepen your understanding.