Step 3: Wing Area DeterminationStep 4: Other Relevant ParametersHomework Set #5Due on Monday, April 7, 2008This homework covers the third and fourth steps in your design. In this assignment, you only need to do the transport aircraft part if you are designing the transport aircraft, and vice versa.In the first step of your design, you surveyed existing aircraft to have an idea about the weight of your aircraft, and the engine that it will use. In the second step of your design, you determined the gross weight, the empty weight and the weight of the fuel. The third step in your design is to estimate the wing area S. This depends on the lift coefficient needed at take-off CLmax, the lift coefficient needed at landing, and the take-off thrust. In the fourth step, you will determine the tail surface areas, and their placement.When the fourth step is done, you are ready to hit the drawing board (or a CAD package) and creating a three-view drawing of your aircraft.Step 3: Wing Area DeterminationThe wing area is chosen from several considerations: (Take-off performance, landing performance, stall speed, cruise speed, climb rate, time to climb to a specified altitude, maneuvering, etc.). Our design requires only that the wing area should be large enough of meet the take-off and landing performance.From a survey of existing transport and final aircraft, the following values for the lift coefficient may be found:Fighter aircraft:CLmax with the flaps up: 1.2 - 1.8CLmax during take-off with the flaps down: 1.4 - 2.0CLmax during landing with the flaps down: 1.6 -2.6Transport aircraft: CLmax with the flaps up : 1.2 - 1.8CLmax during take-off with the flaps down: 1.6 - 2.2CLmax during landing with the flaps down: 1.8 -2.8Take-off and Landing for Commercial Transport Aircraft (FAR 25 regulations): The federal aviation regulations (FAR) state that the take-off length be computed using the following curve fit:Take-off length = 37.5 (W/S)Take-off { 1/} {1/ CLmax at take-off } {W/T} Take-off We already know the gross weight at take-off from step 2. We know from step 1 what engines wewant to use, and the maximum thrust T available at take-off. The design project specifications give the take-off length as 5,000 feet. The quantity  ("sigma") is air density ratio and equals 0.8616 at 5,000 feet. From this, find the wing area S.Take-off and Landing for Military Aircraft:DGLoffTa keCWTkCSWkceDisoffTake72.0tan_2max1Here: k1 = 0.0447k2 = 0.75 ( 5+)/(4+) where  is the by-pass ratio of the engine. Use a value of 3.CD = Drag coefficient of the aircraft during take-off, assume 0.013.G = Friction coefficient. For concrete surfaces, use 0.025. (Soft ground will have a valuebetween 0.1 and 0.3)You know the take-off distance (2000 feet), the air density during take-off , the gross-weight W,the by-pass ratio  of the engine you have selected, and the maximum thrust available T for take-off. Compute the wing area S.Landing Distance Performance:Landing distance depends on landing weight, approach speed, deceleration method used, and pilot techniques. We will assume that the landing weight is equal to the take-off weight, in case the aircraft has to make an emergency landing shortly after take-off. In practice, fuel is either dumped, or consumed before landing is attempted.FAR-25 regulations state that the filed length equals 23.0AV. Here VA is the approach speed in knots. For transport aircraft, VA is 1.3 times the stall velocity. For military aircraft, VA is 1.2 times the stall velocity.In your design project, you are given the landing distance. Since you already know the landing weight (equal to take-off weight), and the maximum lift coefficients for landing, you may easily compute the wing area needed for landing as:knots. into feet/s converts 1.688design,fighter for 1.2 ort,for transp 1.3k,688.11213.0Distance Landing2max,whereSCWkLStep 4: Other Relevant Parameters In an industry setting, at this point, three teams (Red, White, Blue..) will be formed, who will come up with three (or more) independent designs. Some of them will be conventional, while others may be unconventional (canard configuration, flying wing, etc.). These teams will compete with each other. The winning entry will be chosen by an independent design review board within the company. Your team has neither the resources nor the time to look at several configurations in detail. Choose a configuration that you are most comfortable with. Look at the pictures on the web of aircraft that have design specs similar to yours.We need to select for the wing: Aspect Ratio, taper Ratio. (Other parameters may include wing thickness, airfoil shapes, twist distribution etc. We will not choose these at this point in our preliminary design). We need to select the tail surface areas and their locations. We will turn again to historical data to look at appropriate values. Use public sources (e.g. from Jan Roskam, Aircraft design, Volume II available in the AE library or my office) to choose representative values. In the class, we will discuss some of the rationale behind the