Lift drag curve in aerodynamics. ” Hence we can define: The lift-curve slope.

Lift drag curve in aerodynamics Conclusions Wind tunnel tests confirmed acceptable aerodynamic characteristics of the Geobat airplane. In order to understand how airplanes take off and keep flying, we need to understand how lift, drag, and pitch can influence an airplane’s motion through Nov 1, 2024 · I've played around with the math of the induced and parasite drag curves trying to find an expression for where they intersect, and how flaps would change this expression. grc. In addition, the insects May 1, 2024 · Drag is more indirectly controlled through the application of high-lift devices such as flaps (primarily a lift-generation device) and by the angle of attack selected and the speed flown. Because the skin friction is an interaction between a solid Note that the flap deflection shifts the lift curve far to the left giving a zero lift angle of attack of roughly minus 12 degrees while it increases the maximum lift coefficient (Re= 6 x 106) from just under 1. The power curve is the sum of two drag curves, times flight speed: The induced drag is dominant at low speed and decreases with increasing dynamic pressure, and; the friction (and parasitic and interference) drag grows with increasing dynamic pressure. Becker, to be found online here. Curve showing induced drag, parasitic drag and total drag as a function of airspeed. They provide a framework for predicting and explaining the behavior of balls in flight. , . Then, with alpha you can find Cd during cruise. , the lift-curve slope, , and the slope of the moment curve, i. Coefficients of lift and drag against angle of attack. The second theory, Blade Element Theory, utilizes airfoil theory to describe the lift and drag on the turbine blades. 4). How does air resistance affect ball aerodynamics? Air resistance, also known as drag, plays a significant role in ball . The following equation relates the coefficient of lift to the angle of attack for thin symmetrical airfoils5. Slope of the first portion of the alpha-lift coefficient curve. 3. Title: Microsoft PowerPoint - Airfoil A-10 is one 3 planes that are used in the ArmA 3 combat simulator, but its aerodynamics modelling currently lacks significantly. Weight is controlled through the payload and fuel uplifted before the flight. 797 where is the two-dimensional lift-curve slope of the airfoil section that comprises the wing. Aerodynamics of the Curve-Ball: An Investigation of the Effects of Angular Velocity on Baseball Trajectories By LEROY WARD ALAWAYS B. Friction drag + Pressure drag + Compression drag + Lift induced drag. Sep 30, 2015 · The lift curve slope of a flat plate is the same as that of regular airfoils, complete with stall. In contrast, we can also produce a curve—again relative to changes in speed—representing the minimum amount of power necessary to offset drag; this power curve would be quite similar in shape to the drag curve. nasa. The development of lift and drag models in this study extends and broadens previously published Jul 5, 2019 · Maximum lift is the largest lift force that an aerodynamic surface can provide at a specific speed (more accurately, dynamic pressure). . Another source: Modelled from independent analysis and maybe not necessarily provable, but there’s some detailed estimates on 787 characteristics published In moving through the air an aircraft experiences a resistive drag force. Data are given concerning general aerodynamics, including properties of the atmosphere; aerodynamics of airframe components, including the effect of powerplant/airframe interactions for propeller-powered and jet Jun 26, 2024 · Figure 3. 1 A typical − curve in practice. The glide ratio, which is the ratio of an (unpowered) aircraft's forward motion to its descent, is (when flown at constant speed) numerically equal to the aircraft's L/D. See full list on www1. Adapted from Liu et al. ” Graph A of Figure 1 shows a curve based on thrust versus drag, which is primarily used for jet aircraft. The lift and drag properties of infinite- and finite-length circular cylinders and thin plates are also modeled by these same empirical equations. The graphic or link below are for my document Understanding the Lift and drag Curves. cfg using the Lift Coef At Drag Zero (lift_coef_at_drag_zero) parameter. It describes the aerodynamic efficiency under given flight conditions. ” Hence we can define: The lift-curve slope. curve slope (C Ja) . Airfoil lift curve will be different from wing. Graph B of Figure 1 is based on power versus Aug 31, 2015 · The aerodynamic performance of an automobile is assessed in terms of the drag coefficient and the lift coefficient (Cl& Cd). 3. In this case, the best lift-to-drag ratio is about 75, typical for a good airfoil section. Jun 8, 2019 · However, on the back side of the power curve, the inputs are the opposite. 1. I've also looked at finding the bottom of the total drag curve (where the rate of change becomes zero),and looking at how that changes with flaps. If the base drag coefficient, C DO, is 0. As an example we can consider an aircraft with the following characteristics: W = 17578 lbs S = 260 ft2 b = 27. Airplanes are the most common application of lift and drag forces. The lift (and induced drag) equations for the basic body were estimated by means of nonlinear relations similar to those used in reference 1 for a delta wing. 1. near” aerodynamics. 24: Induced drag. This lift force can be found with the lift equation (Weight=Lift=0. When induced drag and parasite drag are plotted on a graph, the total drag on the aircraft appears in the form of a “drag curve. Lift to drag ratio is a measure of how efficient the surface is at generating lift at the expense of drag (for an airplane, drag means more propulsion required). The drag curve (orange) coefficient increases rapidly from 14° AOA, overcoming the lift curve at 21° AOA. The slope of the lift curve (i. 24), the induced drag. Point 5 would be at what is known as "stall speed" (really stall AoA). We generally define the lift curve as the plot of CL vs ", and the slope of that curve we designate as the “lift-curve slope. 2 Physics of Aerodynamic Lift Figure 3. 3 AERODYNAMICS. cla: The ratio of the coefficient of lift and alpha slope before stall. Rearranging to solve for gives that (22) so the lift-curve slope of the finite wing is reduced to (23) The effects are shown in the figure below; the significant reduction of the lift-curve slope with decreasing wing aspect ratio will be apparent. Another consequence of the induced velocity is the appearance of a new component of drag (see Figure 3. Among unsteady aerodynamic mechanisms in flapping flights, a leading-edge vortex is a significant key to generating lift stably in insect flights. To value the aircraft, we need the diagram of the drag polar and the diagram of the lift. coeff1. Thank you Drag and lift coefficients for the NACA 63 3 618 airfoil. The data may be presented in tabular format, on polar axes or on Cartesian axes. The coefficient of lift depends, in general, on the angle of attack, Mach and Reynolds number, and the aircraft configuration (flaps, see Section 3. 777 drag polars). A deep understanding of the lift and drag curves means a pilot can apply that knowledge to better, and safer, flying. If you know this value exactly, then use it here, and if not then this value - for most planes - will be about 0. 21000 Brookpark Road Cleveland, OH 44135 (216) 433-4000. Airplanes use flaps to maintain lift at lower speeds, particularly during takeoff and landing. 7 to 0. In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. (from Dick Kita’s Grumman talk, Feb. Below about 150 RPM, aerodynamic drag seems to be minimal to power required for spin-up. 4, a huge increase in lifting capability that can contribute to large decreases in takeoff and landing distances. An aircraft weighs 3000 lb and has a 175 ft 2 wing area, an aspect ratio of 7, and an Oswald Efficiency Factor, e, of 0. Hence, the said factors need to be optimized in order to enhance the Quantitative understanding of the aerodynamic lift and drag of moving objects has been under intensive research focus ever since the modern aviation age started [1] [2] [3][4][5] and continues to Figure 11. 95. I'm not sure what this can tell you about inertia of blades - depends on aerodynamic and other drags, which are not really measured. 3: Aerodynamic dimensionless coefficients is shared under a CC BY-SA 3. the resultant lift-to-drag ratio to be higher by approx- imately 10 percent. 028, plot drag versus velocity for sea level and 10,000 feet altitudes, plotting drag in 20 fps intervals. With less induced drag you'll have a more vertical lift vector, which can cause you to float during landing. (d) The best lift-to-drag ratio. Feb 23, 1999 · The drag curve (C D-blue curve) increases very rapidly from 14 degrees angle of attack and completely overcomes the lift curve at 22 degrees angle of attack. An airplane in flight is always in the middle of a tug-of-war with the four forces. r. Also find the velocities for minimum drag in straight and level flight at both sea level and 10,000 feet. In particular, the Aug 1, 2022 · This accounts for the higher drag. Enhancing vehicle performance and fuel economy hinges on optimizing aerodynamics. Jun 26, 2024 · The curve of lift and the drag polar permit knowing the aerodynamic characteristics of the aircraft. Lift is generated perpendicular to the relative wind, which means the lift vector tilts forward, resulting in a reduction of induced drag. Jun 26, 2024 · Lift and drag curves are illustrated in Figure 3. 2 to 0. If C D0 is 0. $\endgroup$ – The ESDU Aerodynamics information contains a wide and ever-increasing range of data and methods applicable to the project design of aircraft, guided weapons, space rockets, etc. Turbine blades have the highest lift-to-drag ratio near Dec 15, 2017 · Figures 5a and 5b show the lift and drag comparison, respectively, for the NACA 0009 airfoil at a Reynolds number of 5 × 10 4 between experiments and CFD predictions for a range of angles of attack. Aerodynamic Curves Lift Curve Drag Curve Develop lift and drag curves for future experiments to reference. 10) Lift & Drag forces can be described using two approaches: Change in momentum of airstream, \(F=d[mv]/dt\) “Bernoulli” approach which requires the continuity and conservation of energy equations drag and moment coefficients. The lift-drag ratio (L/D-green curve) reaches its maximum at 0 degrees angle of attack, meaning that at this angle we obtain the most lift for the least amount of drag. Sep 30, 2024 · Insects have various wing morphologies and flapping systems to achieve a highly maneuverable performance at low speed. Jan 21, 2023 · Because lift and drag are both aerodynamic forces, we can think of the L/D ratio as an aerodynamic efficiency factor for the aircraft. Drag coefficient \(C_D\) is expressed as: Based on the drag polar conditions for the best lift-to-drag ratio, zero lift drag and maximal lift can be found. curve appears below. Jan 20, 2005 · AA200b - Applied Aerodynamics II Lecture 5 supersonic airfoils, of achievable lift for wings at small angles of attack. The leading-edge vortex behavior is correlated with an overall vortical system around flapping wings. 9. a for a typical airfoil. Another way to find the lift-to-drag ratio is to plot this ratio as a function of the angle of attack or . S. Below I have plotted the theoretical power curves for a small GA airplane at sea level. tely a straight line. Drag curve for the NACA 63 3 618 airfoil, colour-coded as opposite plot. In this case, it is now a matter of looking at the drag vector and seeing what it is composed of Aerodynamic Configuration • Relaxed Static Stability – Increases lift-to-drag ratios at subsonic and supersonic speeds – Reduces down-load on the horizontal tail required to trim at high lift coefficients and at supersonic speeds • Increases total lift available at sustained-turn conditions (2% at subsonic cruise, Mar 10, 2024 · The laws help in analyzing the forces acting on a ball, such as lift, drag, and gravity, and how they impact the ball’s motion. You pitch the aircraft to maintain airspeed and use power to maintain altitude. 17. 5rhoV²SCl) where S is the wing area. a Cl of 3 for a plain airfoil is pretty darn good, and probably has a lot of camber (much more than a conventional wing). Clearly, you don’t want the flaps deployed at low lift, and thus flaps aren’t deflected in cruise. The lift-to-drag ratio is a ratio of the lift force to the drag force, and it varies across the blade. I'm planning on writing a short "essay" to developers regarding what and how can be specifically fixed in the flight model, but I'd like to back my research with some hard data. Nov 6, 2024 · Efficient aerodynamics significantly impact your vehicle’s overall efficiency. This page titled 3. Understanding each portion of the curves very well and correlating that information to specific The significant aerodynamic properties of aircraft wings are summarised by two dimensionless quantities, the lift and drag coefficients C L and C D. This force is made up of several distinct components. We will make that assumption and hence deal almost exclusively with “l. With that equation, you can find Cl during cruise and with the lift curve slope of the aerofoil, you can find the alpha required to generate the required Cl during cruise. It is from 1964, so more than 50 years old, but since a lot of research had been performed already before that date, it might still be relevant. The aerodynamic values can be estimated very precisely because they differ only by their Reynolds number. Using this assumption, one can represent the lift curve of the section by three parameters: the lift-curve slope, cl α, the angle of attack at zero lift, αl=0 (or alternatively, the zero-angle lift coefficient, cl 0), and Jul 18, 2005 · we've answered the cl question, no ? if you measure the 3D lift curve slope for your specific wing, then the expressions are essentially the same; the 2nd adjusts the 2D lift curve slope for 3D effects. In addition, the impact of various airfoil parameters, wing leading- edge sweep, and lift coefficient on the drag-due-to-lift Dec 9, 2003 · Above 200 RPM, aerodynamic drag is most prevelant for spin-up. This drives up wing weight for the swept wing and, indirectly, drag. Understanding Drag • Break into zero lift and drag due to lift – Use linear theory to provide conceptual basis for your design thinking The real problem You will probably never have enough thrust to reach L/D max • at cruise, C D0 dominates It’s a text book and as such not quite freely available, but Obert‘s Aerodynamic Design of Transport Aircraft has a lot of surprisingly accurate data (including e. pirical curves have been developed for the lift-curve slope, nonlinear lift effects, maximum lift, longitu- dinal stability, and distribution of lift between the upper and lower surfaces of a wing. An empirical adjustment to the steepness of the compressibility drag curve at post-divergence conditions. 25. In short: It depends. We can think of drag as aerodynamic friction, and one of the sources of drag is the skin friction between the molecules of the air and the solid surface of the moving rocket. 6 to 2. Fig. 5 ft = 10. 1 The drag polar Sep 1, 2023 · Difference Between Lift Coefficient and Drag Coefficient. Typical values are always less than 2B / rad. Why is this? The answer lies in induced drag, which dramatically increases as the aircraft's angle-of-attack (AOA) increases to maintain sufficient lift at low airspeeds. Effects of flap deflection on drag. a manner that the moment of the lift force about the quarter-chord point does not change with incidence. As lift increases, there may be an optimum The rotor blades are driven through a very abstract approximation of aerodynamics. 8 ft. cda: The ratio of the coefficient of drag and alpha slope before stall. from publication: Aerodynamic design optimization of nacelle/pylon position on an aircraft | The arbitrary space-shape free form deformation Flaps change a wing’s curvature, increasing lift. Aug 12, 2022 · Examples in aerodynamics include coefficients of lift or drag with respect to angle of attack. 8 is reached at moderate angles of attack - details depend on the aspect ratio . (3-1) Here each term is a function of Mach number, Reynolds number (in practice this is given to the still lacking. 2. This occurs because the lift is perpendicular to the effective velocity and therefore it has a component in the direction of the freestream (the direction used to measure the aerodynamic drag). (California State University, Chico) 1984 Experimental results show an increased lift curve slope and maximum lift coefficient with larger fan thrust alongside larger aerodynamic contributions to drag and pitching moment. The lift/drag ratio (green) reaches its maximum at 6° AOA, meaning that at this angle, the most lift is obtained for the least amount of drag. The maximum lift coefficient of 0. Sep 28, 2022 · The resulting drag curve is often called a drag bucket as the plot resembles a bucket with high drag at speed extremes (low and high) and a minimum drag value at some intermediate speed. Baseline Aerodynamic Scaling, Parameters, and Concepts. [20]. An increase in fineness ratio resulted in increased lift, decreased drag and, subsequently, a rapid increase in the lift-to-drag ratio. cp: Center of pressure. Sep 28, 2022 · An introduction to the aerodynamic lift, drag, and pitching moment coefficient with an example from two NACA airfoils. Flaps also increase drag, which helps slow the airplane and allows a steeper landing approach. e. A fluid flowing around the surface of a solid object applies a force on it. They enable us to scale loads from one condition to another. Nov 20, 2023 · While most aircraft have a high lift to drag ratio, the drag of a rocket is usually much greater than the lift. Due the effect of camber on the wing minimum drag is usually at a positive lift coefficient to make flight more efficient. Deflection of hinged flaps to vector thrust reduces the airfoil zero-lift and stall angles of attack, similar to traditional trailing-edge flaps. Like other such aerodynamic quantities, they are functions only of the angle of attack α, the Reynolds number R e and the Mach number M. 2, 5. scous flow over a flat-plate airfoil, where the color bar Jul 15, 2024 · Glenn Research Center. For landing, thrust must be less than drag, and lift must be less than weight. Pitching moment curve: δe = -20, 0, 20 deg, δF = 0 deg IV. Jul 17, 2024 · Lift is an aerodynamic force and therefore depends on the pressure Effects of Velocity on Lift Interactive Lift is created by deflecting a flow of air and drag is generated on a body in a wide variety of ways. 5): Polar for the NLF(1)-0115 natural laminar flow airfoil at a of 1 million. As sophit pointed out, and as is explained in this question Why are the power and drag curves called polars? Nov 15, 2020 · Sweep will transform bending moment into torsion and requires a stiffer wing, and it lowers maximum lift and the lift curve slope, so for the same landing speed a swept wing must be larger. Sep 1, 2023 · What is Lift, Drag, and Pitch? Lift and drag are aerodynamic forces that act on an aerofoil-shaped body moving through air. Measurements of two-dimensional airfoil characteristics can be used to find the variations in the center of pressure and the location of the aerodynamic center. The most general expression is: Dec 13, 2021 · This review attempts to elucidate the physical origin of aerodynamic lift of an airfoil using simple formulations and notations, particularly focusing on the critical effect of the fluid viscosity. Near zero lift, the agreement between the impact theory and existing experi- 4. Full curves are lift, dashed drag; red curves have R e = 3·10 6, blue 9·10 6. g. By drawing tangent 1 to the curve of drag polar from the origin of coordinate frame c Dc L, the best lift-to-drag ratio can be found, which corresponds to the angle of attack α bldr; the tangent 2 to the drag polar parallel to axis c METHODS OF ESTIMATING AERODYNAMICS lift The basic configuration aerodynamics were calculated using a computer program which incorporated the equations outlined in the appendix. Welcome to the 11th video in our Principles of Fl Apr 10, 2024 · So to achieve say 5 pounds of lift extra, would it be more efficient (less drag) to make the wing thicker or add a curve to the bottom, similar to the curves seen in supercritical airfoils? Increasing the thickness increases drag, mainly because the airfoil has a bigger surface and a bigger pressure recovery on the rear part (and a bigger The target of this work was to explore the lift and drag attributes of a NACA 0015 airfoil with a regressive confronting step. gov/glenn This video in the series of ATPL training video - principles of flight explains lift drag ratio and L/D max. As argued in Reference 1, this lift loading can be replaced by one in which the lift is fixed at the quarter-chord point, the lift increasing with incidence, and a pure torque which, in contrast, does not change with incidence. Answer: a Explanation: A typical diagram of lift curve is illustrated in above figure. The flight-derived lift-to-drag resultant, or total, aerodynamic lift coefficient, Sep 14, 2023 · Because your downwash is flattened out, the relative wind is flatter as well. Dec 1, 2021 · The lift and drag coefficients of a flat-plate airfoil as a function of AoA: (a) lift, and (b) drag. Lift is defined as the component of the aerodynamic force that is perpendicular to the flow direction, and drag is the component that is parallel to the flow direction. CL=2 By this theory, the coefficient of the moment about the aerodynamic center of a thin symmetrical airfoil is zero and that the aerodynamic center is located at the quarter chord or x/c = 0. Reduced drag equates to decreased resistance against air, requiring less energy for propulsion. 4 is best lift to drag ratio 5 is a higher Coefficient of Lift but proportionally higher drag, which means higher AoA to compensate for slower flight (or higher wing loading, such as in a turn). 2 General Aerodynamic Relations (refs 5. a0 is also the y-intercept of the alpha-lift coefficient curve. The diagram is applicable to uncambered wing. It can be seen that the lift and drag curve predictions from TURNS2D compare very well with experiments until close to stall. it is noted that higher lift-to-drag (C L=C D) ratios are achieved at the higher Apr 10, 2023 · 3. We can note the following: 1) for small angles-of-attack, the lift curve is approxim. Jan 29, 2022 · The design lift coefficient is measured from the properties of airfoil used in a wind turbine blade. My source is STUDIES OF HIGH LIFT/DRAG RATIO HYPERSONIC CONFIGURATIONS by John V. This approximation works rather well, even when extended to three dimensions, to predict the lift curve slope of a wing, particularly one where the sections behave in a two-dimensional fashion (issues of subsonic and supersonic The increased flexibility makes it easier to alter the shape of certain compressibility curves and to match known lift/drag polars for existing aircraft. operation of the aircraft takes place at more benign lift coefficients where the lift curve is nearly linear. As the angle of attack changes, so does the lift and drag forces incurred. nasa. May 8, 2024 · This is a similar process of breaking apart the total aerodynamic force to lift and drag. For example, if the analyst uses NACA 4418 airfoil for the wind turbine analysis, the aerodynamic properties of an airfoil can be extracted from the lift curve and lift-drag curve. This allows an airplane to make a slower landing approach and a shorter landing. 2) That for some angle-of-attack called the stall angle-of-attack, the lift coefficien. Lift and drag coefficients are simulated through pre-defined curves created on a WingCurve ScriptableObject. The lift curve-slope relates to both the dynamics of an aircraft and rotors. A summary of aerodynamic force characters are provided as follows (also indicated in Fig. 0 license and was authored, remixed, and/or curated by Manuel Soler Arnedo via source content that was edited to the style and standards of the LibreTexts platform. The rst theory, Actuator Disk Theory, provides a metric for studying wind turbine performance as well as an upper-limit for power production, known as the Betz Limit. Questions. equations based on the best fit of the model to available test data and not on aerodynamic theory. They have a zero-lift angle of attack of 0° (obviously) and separated flow on the suction side. The lift curve shows a higher stall angle for the Geobat with relatively the same C L,max as the Cessna 172. 4. This is the approach that leads to the typical drag polar equation: CD = CD 0 + CL 2 πARE. Jun 18, 2018 · [Show full abstract] tip Mach numbers); aerodynamic data (drag coefficients at zero lift, cruise and maximum absolute glide ratio); performances (wing and disk loadings, maximum absolute Mach Feb 15, 2023 · Plot of zero-lift and lift-induced drag with velocity at 30000 feet The intersection point of b oth these drag c omponents gives the maximum lift-to-drag ratio of an aircraft. Figure 3. The additional parameters used by 'rr-adjustable' are: rr-adjust-compress. 028, find the minimum drag at sea level and at 10,000 feet altitude, the maximum lift‑to-drag ratio and the values of lift and drag coefficient for minimum drag. The best lift-to-drag ratio is when this line is just tangent to the polar curve. This is the bottom of the so called bucket and is the speed at which it is most efficient to fly (requires the least amount of thrust to overcome drag). So you need to define \(C_{L0}\), which is the lift coefficient that is generated when the plane produces minimum drag, defined in the flight_model. Performance: To calculate the performance of an airplane it is natural to define drag as the sum of the drag at zero lift and the drag due to lift. The lift/drag ratio increases very rapidly up to about 3 deg or 4 deg , at which angles the lift is nearly 24 times the drag (some aerofoils give an even greater maximum ratio of lift to drag); the ratio then gradually falls off because, although the lift is still increasing, the drag is increasing even more rapidly, until at the stalling angle Understanding the Lift and Drag Curves. Homework 5. Lift coefficient and drag coefficient are essentially the same thing with one key distinction: they are coefficients measuring how much of the aerodynamic force constitutes lift and drag, respectively. complete vehicle, the aerodynamics presented do not include the effects of the base. Aerodynamic scaling and nondimensional numbers are critical to aerodynamics. 5. For an airplane to takeoff, thrust must be greater than drag and lift must be greater than weight. gov The drag curve or drag polar is the relationship between the drag on an aircraft and other variables, such as lift, the coefficient of lift, angle-of-attack or speed. In the current study, we examine the aerodynamic characteris-tics of a thin flat plate airfoil at chord based Renumbers ranging from 500 to 2000. 1, 5. For a free stream speed of 30m/s, the purpose of partition was Download scientific diagram | Lift-drag polar curves. 1 Schematic of Lift and Drag Mar 24, 2015 · wind drag and power production. The evolutionary development of the lift problem of a flat-plate airfoil is reviewed as a canonical case from the classical inviscid circulation theory to the viscous-flow model. This study employs numerical investigation utilizing ANSYS Fluent computational fluid dynamics (CFD) simulations to identify the Lift-to-Drag Ratio . To maintain level flight, lift must equal weight and thrust must equal drag. 1985) In addition to lift, flaps make a large change in drag. The current atmospheric conditions also influence the lift, drag, and thrust output. The higher the lift-to-drag ratio, the more efficient the turbine blade is at converting wind energy into torque, which produces more electricity from the generator. Description of aerodynamic force convention on an airfoil in terms of lift, drag, and pitching moment. The lift curve slope of High-Lift Aerodynamics 8-13 4/5/07 Figure 8-10. Maximum lift coefficient, (C Lmax) =1. Lift curve slope . Lift curve. 1 shows the variation of maximum sectional lift-to-drag ratio with the chord-based Renumber. The forces due to lift and drag will be applied here. Designers of gliders and designers of cruising aircraft want a high L/D ratio to maximize the distance which an aircraft can fly. If you were to express lift and drag as a ratio, this position would be referred to as the maximum lift-drag ratio. As the aircraft fuselage and control surfaces will also add drag and possibly some lift, it is fair to consider the L/D of the aircraft as a whole. flffs bsloq ilumzlc jwrz vkuhq crouh ggfo yll mvlma pwf