7.14 (Reference Figure 7.2) Using Figure 7.2, find the velocity for maximum endurance for the airplane at 8,000 lbs. This process would become even more cumbersome as we added other design objectives such as a minimum turning radius or a minimum stall speed. 2.20 The total pressure of the airstream is the sum of the static pressure and the __________________. The pilot selects the desired RPM with a leaver, and a control governor automatically changes the blade pitch to maintain a constant RPM. Again it is common for aircraft design texts to propose approximate or semi-empirical relationships to describe this and those relationships show landing distance to depend only on the wing loading. The essence of all this is that if we even have only three primary design objectives; a cruise specification, a climb requirement, and a takeoff or landing constraint, we can end up with three different values for wing area and thrust required for a given aircraft weight. A head wind is encountered. Arc Sine ratio of Vv/Airspeed = climb angle Do you think this is a reasonable speed for flight? 12.23 An aircraft in which of the following situations is most likely to create the most intense wake turbulence? 5.5 Laminar flow airfoils (NACA 66-XX series) are designed for the airflow to remain laminar much further back from the leading edge than on the conventional airfoils. 10.17 Which of the following is the speed at which an aircraft must be accelerated at or before reaching 35 ft at the end of the runway? 12.13 The primary way to tell if you are in a spin and not a spiral is, 12.14 An airplane in flight encounters wing icing. Available from https://archive.org/details/9.4_20210805. Effect of Desired Takeoff Characteristics on Aircraft Design Space. CC BY 4.0. 1.18 An aircraft's turbojet engine produces 10,000 lbs of thrust at 200 knots true airspeed. 8 0 obj Figure 9.3: James F. Marchman (2004). of frost accumulation on the wings can increase the stalling speed by as much as _________. As fuel is burned the pilot must. 8.16 A gas turbine engine that uses most of its power to drive a propeller. Steeper approach angle with a touchdown closer to the approach end of the runway, 11.22 A high roundout during landing may result in ______, Slowing of the aircraft well above the runway with increasing angle of attack. Any combination of W/S and T/W within that space will meet our design goals. 13.6 (Reference Figure 5.4) What will happen to an aircraft that is flown to the left of the curved lines on the left side of the flight envelope? This limits your maximum allowable propeller diameter to 72 inches (36" x 2" = 72"). 8.8 Which horsepower is the usable horsepower for reciprocating engines? What is the stall speed? , Does an airfoil drag coefficient takes parasite drag into account? For a propeller-powered airplane, at an airspeed just above stall speed and below L/D MAX. Since your graph already shows the origin (0,0), you are almost done already! What is the arrow notation in the start of some lines in Vim? + (kn2/q)(WTO/S)(Walt/WTO) + (1/V)dh/dt + (1/g)dV/dt} . Each plot of the specific power equation that we add to this gives us a better definition of our design space. First is that the figure from Raymer on the preceding page has two types of plots on it, one for ground run only and the other for ground run plus the distance required to clear a 50 ft obstacle. 10.18 If the ______________ is exceeded, the aircraft cannot be brought to stop in the remaining runway. 10.12 The following items all affect takeoff performance except __________. 11.1 A steep, low-power approach is more dangerous for heavy airplanes than light airplanes because, 11.2 Braking action on a dry concrete runway is ____________ that of a wet runway. 7.24 Increased weight has what effect on rate of climb? Once the value of TOP has been found the relationship above is plotted to give a straight line from the origin of the constraint analysis graph. '!,9rA%-|$ikfZL G1.3}(ihM Either can be used depending on the performance parameter which is most important to meeting the design specifications. Thanks for contributing an answer to Aviation Stack Exchange! 10.14 When taking off from a high-density altitude airport, the ________ will be higher than at sea level. Find the potential energy. 3.13 thru 3.17 Reference Figure 2. 6.25 Endurance is _____________ fuel flow. And both approaches are maximizing the same angle on the right triangle comprised of the vertical speed, horizontal speed, and airspeed vectors. Turboprop aircraft are classified as power producers because: Helicopters have another power requirement over fixed wing propeller airplanes. Best rate of climb, or Vy, maximizes velocity to obtain the greatest gain in altitude over a given period of time Vy is normally used during climb, after all obstacles have been cleared It is the point where the largest power is available Occurs above L/Dmax for a jet Occurs at L/Dmax for a prop Provies more visibility over the cowling 1.17 An airplane weighs 8,000 lbs and is flying at 6,000 ft altitude and an airspeed of 200 fps. 4.17 Laminar flow involves the rapid intermixing of the air levels over a wing. MathJax reference. 11.25 Using Fig. It would not, however tell us if this would result in a good ability to climb or the ability to takeoff and land in a reasonable distance. It usually is restricted to either the takeoff setting or the cruise setting. 5.21 Wingtip vortices are formed by higher-pressure air beneath a wing moving into __________ pressure air above the wing. Find the maximum range and the maximum endurance for both aircraft. 3.18 Critical angle of attack can be defined as: 3.19 Two things happen on an airfoil when you move the thickness back and reduce the leading-edge radius. What two requirements must be met in order to be considered in a state of equilibrium? This is a nice concise answer with a nice graphic. Maximum excess thrust occurs: For a jet-powered airplane, at approximately the maximum lift/drag ratio (L/D MAX). The figure below (Raymer, 1992) is based on a method commonly used in industry. When I started the engines this time I found for left and right: RPM 90% 52% ITT 735 735 N1 63 63 N2 90 52 FF 20 49 PSI 83 77 Aviation Stack Exchange is a question and answer site for aircraft pilots, mechanics, and enthusiasts. This can be determined from the power performance information studied in the last chapter. The question with the design of an airplane as with a car or a tire, is how do we arrive at the best compromise that will result in a good all around design while still being better than average in one or two desired areas? to the wing planform shape? One of these items is ________________. How can I get the velocity-power curve for a particular aircraft? 1.9 An aircraft is traveling west at an airspeed of 120 knots and is experiencing a crosswind of 20 knots from the north (90). Hg and a runway temperature of 20C. In the figure above this will be either where the takeoff and climb curves intersect or where the takeoff and landing curves intersect. Figure 9.7: Effect of R & e Variation on max Range Cessna 182. Naturally, for this calculation you'll need to use the same units for both values-- a conversion may be necessary. Asking for help, clarification, or responding to other answers. These two ratios are tied together in aircraft performance through the same power relationship that we looked at when we first examined climb and glide. You are correct that Vy will give you the max RoC. 7.22 The value of (L/D)max changes when the gear and flaps are lowered. 2.24 Calculate the density altitude for an aircraft at an airport with a pressure altitude of 5,000 feet when the current temperature is 13 degrees C. 2.25 Using Table 2.1, calculate the dynamic pressure, q, at 8,000 feet density altitude and 250 knots TAS. Find the acceleration of the airplane. Finding this value of drag would set the thrust we need for cruise. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Cruising at V Y would be a slow way to fly. 4.21 When analyzing the air moving from the leading edge toward the trailing edge of a wing, until the air reaches the point of minimum pressure it is in a favorable pressure gradient. Under what conditions can the maximum angle of climb be achieved for jet and propeller aircraft? We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. 8.20 As altitude increases, power available from a turboprop engine _____________. Aircraft Design: A Conceptual Approach, AIAA, Washington, DC. A light wave has wavelength 500nm500 \mathrm{~nm}500nm in vacuum. Or in some cases the power-to-weight ratio (P/W) is used instead of T/W. Time to Climb Between Two Altitudes RWY 27L & 27R), and the winds are 360/5, which choice(s) is/are true? 12.3 ______________ wings will stall at the wing tips first and then progress toward the rest of the wing. 8.24 Though a turboprop produces power and thrust, the amount of thrust produced directly by the engine is only about what percentage of the total? The climb curve would probably be plotted at sea level conditions since that is where the target maximum rate of climb is normally specified. 4.10 and the following data: W = 25,000 lb, wing area S = 300 ft2,CL(max), sea level, standard day. Power required is the power needed to maintain straight and level flight, i.e., to overcome drag and to go fast enough to give enough lift to equal the weight. We cant fly straight and level at speeds below the stall speed or above the maximum speed where the drag equals the maximum thrust from the engine. 7.18 Increasing the weight of a thrust-producing aircraft moves all points on the thrust-required curve ____________. 9.1 The power-required curves for an increase in altitude show that the, Pr increases by the same amount as the velocity, 9.2 A propeller aircraft in the dirty condition shows that the Pr moves up and to the left over the clean configuration. (More characteristic of a jet with a high thrust loading -- see diagram on this answer --. The climb angle will be the arcsine of (vertical speed / airspeed). 11.1, what is the minimum landing distance required (50 ft obstacle on final approach) for the given aircraft with the following conditions: 30C OAT, PA 2000 ft, weight 2800 lb., 5-kt tailwind? As an example, most piston engine aircraft will cruise at an engine power setting somewhere between 55% and 75% of maximum engine power. For example, if the hub-to-ground measurement is 45 inches, subtracting 9 inches will leave an effective radius of 36 inches. 6.19 For a turbojet, each pound of drag requires a pound of ____________ to offset it. The standard RoC formula (using FPM and LBS) usually shows the excess HP at sea level at max gross to be around 33% of the rated HP for most GA propeller aircraft. In other words, only when velocity (V) is constant is this relationship strictly equal to the rate of climb. 9.8 For power-producing aircraft, to maximize both efficiency and performance, you must (best answer). The limit is a sailplane with T/W = 0 and at the other extreme we have fighter aircraft where T/W approaches unity. 4.15 A thicker airfoil results in what change to AOA? Figure 9.5: James F. Marchman (2004). Acknowledgment: Thanks to Dustin Grissom for reviewing the above and developing examples to go with it. Figure 9.1: James F. Marchman (2004). 13.23 High bank angles and slower airspeeds produce ________ turn radii. 6.20 Where is (L/D)max located on a Tr curve? Now, to simplify things a little we are going to use a common substitution for the dynamic pressure: We will also define the lift coefficient in terms of lift and weight using the most general form where in a turn or other maneuver lift may be equal to the load factor n times the weight. Raymer proposed the relationship below: Sa = 1000 for an airliner with a 3 degree glideslope, 600 for a general aviation type power off approach. The second is that the takeoff parameter (TOP) defined for propeller aircraft is based on power requirements (specifically, horsepower requirements) rather than thrust. 13.8 (Reference Figure 5.4) An aircraft flying at 200 knots can pull how many G's before stalling the aircraft? 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