Aircraft Performance Reassessment - Essay Example

Aircraft performance Reassessment The focus of this paper was analysing the flight mechanics andperformance of typical manoeuvres executed at the National (US) Championship Air Races circuit with a view to propose a representative static stability aircraft model that has a well-defined manoeuvrability parameters based on trusted aerodynamic inputs. Table of Contents Abstract 2 Table of Contents 2 Introduction 4 Response to Question 1 4 Aircraft Set-up 4 Response to Question 2 8 Circuit Design 8 Response to Question 3 10 Static and Stability 10 Response to Task 4 15 Reference 16 Introduction The world has recently experienced the national championship air races in the USA in areas like Reno and Nevada as the last tower racing event for aircrafts. There are about seven class models of aircrafts racing around the unique course (Swatton, 2000). The flight span is anywhere from around 50 to 500 feet above the ground. Aircrafts fly wing-tip to wing-tip at speeds greater than 500 miles per hour. This report describes the aircraft of the model, Cassutt 3m, a formula one racing aircraft. Response to Question 1 Aircraft Set-up The Cassutt 3m is a model of a Formula One racing aircraft that is fit with various specifications that make it suitable for racing on a track. Its engine and aerobatic features are unique and subscribe to the general requirements of track racing (Filippone, 2006). The safety and the loading features enable it to manoeuvre bends without the risk of causing accidents. The aircraft is run by the Continential 0-200 engine that saves on consumption of fuel. This aircraft runs at a terrific speed of 185-200 MPH whilst consuming 6 gallons of fuel hourly (Filippone, 2013). Like other racing aircrafts, Cassutt 3m has high aerobatic features enabling it to attain high climb rates of about 3700 feet per climb. Cassutt 3m prominently features in Formula One World Racing Championships. Its unique features make it adaptable to the Formula One Racing Championship that exhibits a show of acrobatic manouvres in aircrafts (Saarlas & Maido, 2006). Visible features that make this aircraft effective in air racing include structure of winglets that minimizes drag and thus improving lift coefficient. The stretch of pilot’s cockpit is characteristic to Cassutt 3m and differs from other racing aircrafts (Saarlas & Maido, 2006). Steel tubes, fabrics, and composites comprise components making up lower and upper fuselages of this aircraft. The landing gears are made up of spring steel and spring aluminium cantilevers. The overall design of Cassutt 3m is unique and differs from design of normal airplanes. The design of the wing is inimitable and has attracted praises over the years. Cassutt 3m manoeuvres across the lands like any normal small plane reaching destinations. Models for Cassutt 3m show basic features of configuring the aircraft (Swatton, 2000). Construction of the Cassutt 3m is a simple process that utilizes materials like steel tubes, fiberglass, wood and specially made fabrics. The aircraft can be constructed in phases utilizing model kits, design plans and fixable portions of the aircraft that are assorted. The special parameters that make up the Cassutt 3m include: Racing: Formula One Cord/Span: 4’ × 16.5’ Engine: Continential 0-200 Gross weight: 900lb Minimum weight: 500lb Minimum racing weight: 690lb Racing fuel load: 15gal/30lb Maximum speed: 230 knots Range: 450n.m Length: 16ft Wingspan: 15ft Height: 4ft Wing area: 66 sq ft The information about the performance of the Cassutt 3m with regards to take off, racing and landing is presented below: Performance Never-exceed Speed: 300 mph Max Cruising Speed : 190 mph Stalling Speed : 68 mph Climb rate : 1500 ft/min Take off Run: 61 m Take off dist: 600 ft Landing dist :800 ft Range with max fuel: 450 miles Despite exceptional wing features that ease maneuverability, Cassutt 3m needs to undergo alterations to control safety during flight. Modifications on systems of fuel and engine, the spans of wings, and viewing cameras improve performance of Cassutt 3m during flight (Saarlas & Maido, 2006). Invention of oil systems corresponding to the aircraft model enable this aircraft to operate efficiently regardless of any gravitational drifts (Filippone, 2013). Additional improvements are made on the gross capability of the fuel tank to hold fuel with an improved minimum capacity. Increasing wingspan improves air lift on the aircraft besides minimizing the effects of drag on manouevrebility of the aircraft. Manouvrebility of aircrafts can be demonstrated by movements of aircrafts between huge pylons. Instantaneous displacements and accelerations are the measure of manouvrebility of an aircraft. An aircraft manouvring between pylons and back has speed, distance and time related by the equation below. 2d = speed × time Acceleration is achieved by relating final and annual speed of the aircraft manouvring between the pylons. Acceleration = (final speed – annual speed)/ time Distance and acceleration determine the manouvrebility of Cassutt 3m aircraft during racing. Response to Question 2 Circuit Design The track for the National Championship Air races encompasses numerous tracks overlaid on the similar ground. The course has pylons that act as marking guides for racing aircrafts . The pylons are poles conveying telephone wires from one point to another. For visibility to pilots of aircrafts, these pylons are fitted with panels of visible colors (Filippone, 2013). The finish line has a special removable pylon that marks the start and end of the air races. The design of the racing circuit is as discussed in the next section. Total distance of the circuit is 5 129.784 metres The plane enters the circuit at  and as it reaches C in section B, it decelerates to m/s. A velocity of m/s is maintained throughout C and D. After D, the plane accelerates to  all the way to the last pylon. Assumed C+D to be 500 meters. The radius at C+D is 159.24 meters. It was calculated by assuming C+D to be half a circle. Hence: Radius = 159.24 meters Since A+B and E+F are equidistant, the distance can be worked out. 5129.784 - 500 = 2314.892 meters The time taken for the whole circuit to be completed is the following: A+B = = 24.7s C+D =  = 5.9s E+F =  = 24.7 s Overall time taken for the circuit is = 24.7 + 5.9 + 24.7= 55.3 Response to Question 3 Static and Stability The static longitudinal stability of an aircraft determines its travel outline as well as the loading conformation. This parameter affects the management features of an aircraft. For an aircraft to attain full stability and control, it balances lateral, longitudinal and directional motions (Filippone, 2013). In the design of an aircraft, preference to the parameters that affect the balancing motion of an aircraft takes precedence. For aircraft design, aerodynamic center position, neutral point and static margin represent the bases for static longitudinal stability. An aircraft that returns to its original locus when after a disturbance attains a trim condition. The weight of the features of an aircraft, their dimensions and the respective moments determine center of gravity of an aircraft. The laws of equilibrium and static stability apply (Filippone, 2006). The two tables below show the design parameters necessary for computation of the stability specifications of a typical formula one aircraft. Parameters Weight (kg) Pilot 72 Tail landing gear (tlg) 15.1 Front landing gear (flg) 289.5 Main 48 Engine 195 Left landing gear (llg) 295.8 Parameter Dimension (m) Pilot (dpilot) 2.30 Tail landing gear (dtlg) 5.32 Front landing gear (dflg) 0.60 Main (dmain) 0.73 Engine (dengine) 1.32 Center of Gravity (cg) = total moment (Mtot)/ total weight (Wtot) … (i) Wtot = ∑Wi = Wpilot + Wtlg + Wflg + Wmain + Wengine + Wllg Wtot is the total summation of the weights of the components of an aircraft. Mtot = ∑Widi = Wpilotdpilot + Wtlg dtlg + Wflg dflg + Wllg dflg + Wmain dmain + Wengine dengine Mtot is the overall summation of the weights of the components of the aircraft multiplied by the corresponding distances from the reference datum along the fuselage stripe of orientation (Filippone, 2013). There exist two scenarios for the calculation of the center of gravity of an aircraft. The first scenario entails the calculation of center of gravity when the fuel tank (main) is full. The second scenario entails the calculation of center of gravity when the fuel tank (main) is empty. Scenario 1 To calculate the total moments a reference datum is necessary. The reference datum is the front end of the aircraft at the propeller (Saarlas & Maido, 2006). The dimensions given in the table are made with reference to reference datum. The equation one above enables the computation of the center of gravity at a typical locus of aerobatic. Therefore, cg = (76×2.30 + 15.1×5.32 + 289.5×0.60 + 295.8×0.60 + 48×0.78 + 195×1.32) / (76+15.1+289.5+295.8+48+195) = 901.152 / 919.4 = 0.98m Therefore, cg = 0.98m from the datum line. Scenario 2 The computation of the center of gravity when the fuel tank is empty is as shown below. Wtot = ∑Wi = Wpilot + Wtlg + Wflg + Wengine + Wllg Mtot = ∑Widi = Wpilotdpilot + Wtlg dtlg + Wflg dflg + Wllg dflg + Wengine dengine Therefore, cg = (76×2.30 + 15.1×5.32 + 289.5×0.60 + 295.8×0.60 + 195×1.32) / (76+15.1+289.5+295.8+195) = 863.712 / 871.4 = 0.99m Therefore, cg = 0.99m from the datum line. The diagram shown below depicts the interactions of the aerodynamic components of an aircraft (Saarlas & Maido, 2006). The computations thereafter follow the combinations in the diagram. To obtain the aerodynamic center position, the equation below applies. …..(ii) The computation does not take effect of the wind experiment and thus the value of CLW = zero. The equation below aids in the calculation of.  = 2/3 cr () Applying a root chord (cr ) value of 1.53 and a taper ratio value of 0.3, the equation yields,  = 2/3×1.53(1.39/1.3) = 1.09 The mean aerodynamic chord (MAC) of 1m from the datum and a corresponding leading edge of 0.5m (taking the moment datum about the pilot’s seat) for a Cassutt 3M aircraft (Filippone, 2006). Therefore, the distance of the leading edge from the MAC (xac,w) = 1.0-0.5 = 0.5m. Xac,t = 0.5/2+2.5 = 2.75m. Taking St = 9.7m and Sw = 36.3m, the equation (ii) applies to obtain the value of CLt CLt = (-0.04- (0.98-0.841)/1.07)/9.7/36.3((4.22-0.98)/1.07) = -0.21m Calculation of the Neutral Point (Xnp) The computation of the neutral point for an aircraft utilizes the equation, … (iii) The gradient of the lift curve is approximately 2π. The wing and the tail have identical aerofoils and thus the overall slope is 2π. Replacing the differentials in the equation (iii),  = (0.5/1.09+ (2.5/1.09). (9.7/36.3)) 2π/2π+(9.7/36.3). 2π = 0.85 Therefore, Xnp = 0.85 × 1.09 = 0.92m The neutral point is 1.42m away from the leading edge. Calculation of the Static Margin Static margin is given by the equation, Static Margin = Xnp - Xcg … (4) Xnp = 0.92 + 0.5 = 1.42m away from the reference datum, Xcg = 0.98m Therefore, Static margin = 1.41 – 0.98 = 0.44m A low value of the static margin for a formula one aircraft increases the ease by which it manoeuver (Saarlas & Maido, 2006). This is possible through the evasion of factors that drag the trim of the aircraft. The value of the static margin for the Cassutt aircraft is low. Response to Task 4 The analysis of the parameters of the formula one aircraft encompasses numerous assumptions (Filippone, 2013). These assumptions may affect the design considerations and deductions. The culminating design estimates may not be practically applicable. For instance, the calculations neglect the effects of wind to the flight performance (Saarlas & Maido, 2006). The computations in task 2 fail to exploit the bank turn for climb manoeuver. This assignment aids in in the development and adoption of strategies for approximating design parameters. Improvements to reduce the static margin improve the performance of the formula one aircraft (Filippone, 2006). Work packages that provide design information permit the approximation of aircraft mechanic computations. The sources that serve as database for aircraft model design from aircraft manufacturers should be definite rather than rely on approximations. Reference Filippone, A. (2006). Flight performance of fixed and rotary wing aircraft. Amsterdam [u.a.: Elsevier. Filippone, A. (2013). Advanced aircraft flight performance. New York: Cambridge University Press. Saarlas, Maido. 2006. Aircraft performance. Hoboken, NJ: John Wiley. Swatton, P. J. (2000). Aircraft Performance Theory for Pilots. 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