6.25 Endurance is _____________ fuel flow. In the equation above we have a very general performance equation that can deal with changes in both speed and altitude and we find that these changes are functions of the thrust-to-weight ratio, T/W, and the wing loading W/S. 3.23 The following are all examples of primary flight controls except _____________. In a Cirrus SR22T, our indicated cruise speed is often 30 to 40 knots faster than V Y with 75% power. The maximum rate of climb at a given speed will then depend on the difference between the power available from the engine at that speed and the power required for straight and level flight. Time to Climb Between Two Altitudes How to find trim condition of a sectional airfoil without knowing the angle of attack? (More characteristic of a jet with a high thrust loading -- see diagram on this answer --. 7.17 Changing the weight of an aircraft changes the ______________ much more than the ___________. 11.9 If in descending, gliding flight, a component of ________ acts in the same direction as thrust. I've read the other thread about the throttles, reversing, and feathering. 7.1 The thrust available from a jet engine at 35,000 ft altitude compared to that at sea level is, 7.2 If the weight of a jet airplane is increased, then, Induced drag increases more than parasite drag, 7.3 If the weight of a jet airplane is reduced as fuel is burned, the Tr curve, 7.4 If a jet airplane is in the gear down configuration, the increase in, Parasite drag is more than that of the induced drag. But unless the data is already loaded up into a spreadsheet ready for re-plotting to a new scale, there's a much faster way to solve the problem. "Of course, it helps to do this in metric units." We know that in cruise since lift must equal weight, we can select a design value of cruise lift coefficient (commonly around 0.2 to 0.3) and a desired cruise speed and altitude and solve for the needed wing area. 2.4 A piston-prop aircraft has a wing loading of 1600 N/m, and its drag polar is given by CD = 0.025 + 0.05CZ. Note that the thrust ratio above is normally just the ratio of density since it is normally assumed that. 6.16 Which one of the following items does not occur at (L/D)max for a jet aircraft? Maximum rate of climb for a propeller airplane occurs: at (PA-PR)MAX The lowest point on the PR curve is (L/D)MAX False Propeller aircraft are more efficient than jet aircraft because they process more air and don't accelerate it as much Turboprop aircraft are classified as power producers because: 11.16 ____________ is caused by the buildup of the hydrodynamic pressure at the tire-pavement contact area. Stall Cutoff for cap W over cap S values. CC BY 4.0. Represent a random forest model as an equation in a paper. The takeoff equation seen in an earlier chapter is somewhat complex because takeoff ground distances depend on many things, from drag coefficients to ground friction. Find the distance in nautical miles that it has flown through the air. We would find, if we looked at the equations we derived for the other types of flight mentioned above that these same three parameters pop up everywhere. The method normally used is called constraint analysis. Typically it takes a form such as that shown in Figure 13.7.The shortest time-to-climb occurs at the flight velocity where is a maximum. endobj I've made the recommended changes and have decent reverse thrust. In other words, only when velocity (V) is constant is this relationship strictly equal to the rate of climb. Either can be used depending on the performance parameter which is most important to meeting the design specifications. What we want, however, is the best combination of these parameters for our design goals. 10.24 When taking off in a multi-engine aircraft, VRis usually less than V1. This would give a curve that looks similar to the plots for cruise and climb. For climb at constant speed dV/dt = 0 and our equation becomes, T/W = (qCD0)/(W/S) + (kn2/q)(W/S) + (1/V)dh/dt. 12.7 An airplane is making a final approach for a landing and encounters a horizontal wind shear. Use MathJax to format equations. 2.2 For temperatures to be used in calculating the effects on performance, the appropriate absolute scale must be used. Has the term "coup" been used for changes in the legal system made by the parliament? Highest point on the curve yields maximum climb rate (obviously). And this can be written [W/S] = Vstall2CLmax, On the plot above this would be a vertical line, looking something like this. 12.25 In the absence of a published procedure, what is the typical first-step recommendation in order to initiate recovery from an incipient spin in a straight-wing, general aviation aircraft? Another factor to consider would be the desired maximum speed at the cruise altitude. The maximum angle of climb would occur where there exists the greatest difference between thrust available and thrust required; i.e., for the propeller-powered airplane, the maximum excess thrust and angle of climb will occur at some speed just above the stall speed. 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? If our desire is to look at an optimum range we might want to find the ratio of lift to drag that will maximize range (for example, for a propeller driven plane Rmax occurs with flight at [L/D]max or at minimum drag conditions). That portion of total drag associated with the production of lift. Often a set of design objectives will include a minimum turn radius or minimum turn rate. Find the Drift Angle. Therefore both approaches must have the same solution: when the ratio of vertical speed to airspeed is maximized, then the ratio of vertical speed to horizontal speed is also maximized. However Vy is actually only a speed, not a climb rate, and will correspond to slightly different rates of climb depending on a few factors. 8.10 In order to maximize range on a propeller-driven airplane at high altitude, true airspeed should be _____________. And both approaches are maximizing the same angle on the right triangle comprised of the vertical speed, horizontal speed, and airspeed vectors. What is the wavelength of this light as it travels through water (nwater=1.33)\left(n_{\text {water }}=1.33\right)(nwater=1.33) ? Modern propellers on larger aircraft would always be equipped with automatic feathering provisions. 121.65 knots 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). One way to find the maximum ratio of y to x on any graph of y versus x is to extend the axes of the graph to include the origin (0,0) and just run a line from the origin to any point on the curve and find the point on the curve where the slope of this line is the steepest, just as was done in these related answers: What is the typical climb angle -- why? (meters/second), Conversion of airspeed to horizontal velocity: 3.22 The example of the pressure distribution on a rotating cylinder that explains why a golf ball slices is best described by ______________. Design goals might include a maximum speed in cruise of 400 mph and a maximum range goal of 800 miles, however these do not occur at the same flight conditions. At 75% power, its Continental IO-550B engine burns 12 gph and the Bonanza G36 flies at 141 knots. 8.5 Propeller aircraft get the highest angle of climb at (L/D)max. A tailwind is encountered. c. By how many fringes will this water layer shift the interference pattern? 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. What can be gained by accepting a lower cruise speed or a longer takeoff distance. @quietflyer It does not matter as long as the units are the same. Maximum rate of climb for a propeller airplane occurs At (Pa-Pr)max True or false The lowest point on the Pr curve is (L/D)max. 9.10 As a power-producing aircraft burns off fuel, ROC will ___________ for a given velocity. For example, lets look at stall. 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? 13.13 (Reference Figure 14.10) What angle of bank must an airplane maintain at 380 knots to achieve an eight degrees per second rate of turn? 10.16 As a rule of thumb, a 5% increase in takeoff distance can be expected for every _______ of uphill slope. 6.19 For a turbojet, each pound of drag requires a pound of ____________ to offset it. 13.15 (Reference Figure 14.10) How many degrees of bank are required for a standard rate turn (3 degrees per second) at 420 knots? 1.25 The Law of Conservation of Energy states that: 2.1 Static air pressure is simply the weight per unit area of the air above the level under consideration. stream x\Er0`b.awB7 {Mu H $YAr2j{v{`ssf)w>y~|&KG=|x7j9;87w|upkA`y 5. max thickness. The cruise ceiling is the altitude at which the maximum climb rate is 300 ft/min Definition - Combat Ceiling The combat ceiling is the altitude at which the maximum rate of climb is 500 ft/sec or 2.5 m/s. Continue searching. Power required to overcome induced drag varies, Power required to overcome parasite drag varies, Maximum rate of climb for a propeller airplane occurs. 3.25 The rudder controls movement around the ________________ axis. Raymer proposed the relationship below: Sa = 1000 for an airliner with a 3 degree glideslope, 600 for a general aviation type power off approach. 7.6 The minimum drag for a jet airplane does not vary with altitude. % 4.10 and the following data: W = 25,000 lb, wing area S = 300 ft2,CL(max), sea level, standard day. Maximum rate of climb for a propeller airplane occurs: a. at L/D max b. at CLmax c. at PRmin d. at (PA-PR) max. 13.3 (Reference Figure 5.4) What speed is indicated at point A? Then the solution is the point with the steepest angle from the origin of the graph. CC BY 4.0. Excess power is power available minus power required. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. So maximum rate of climb occurs at the speed at which excess power is greatest. 3.2 The main variable(s) in the geometry of an airfoil are: 3.3 The angle between the relative wind and the chord line of an airfoil is the, 3.4 For a symmetrical airfoil, at 0o AOA, air passing over the wing results in, An equal increase in velocity over the top and bottom of the wing. 12.6 The best way to control airspeed is with the ___________, while the best way to control altitude/descent rate is with the ____________. The design process usually begins with a set of design objectives such as these we have examined, a desired range, payload weight, rate of climb, takeoff and landing distances, top speed, ceiling, etc. 10.12 The following items all affect takeoff performance except __________. Effects of a Desired Climb Rate on Aircraft Design Space. CC BY 4.0. The cruise based calculations mentioned above would give us valuable design information for our airplane based on a desired cruise speed and altitude for a design weight and would tell us the wing area and thrust needed for that cruise condition and the thrust needed to cruise at a desired maximum speed. Hence, what we have done through the specific excess power relationship is nothing but a different way to get a familiar result. Now we can expand the first term on the right hand side by realizing that. In other words if you vary the point of contact between the line and the curve slightly, the resulting climb angle will barely change at all. 13.24 If an aircraft maintaining a constant bank angle increases its airspeed while maintaining a level, coordinated turn, what will the effect be on the rate of turn (ROT)? How is the "active partition" determined when using GPT? False Propeller aircraft are more efficient than jet aircraft because: They process more air and don't accelerate it as much Turboprop aircraft are classified as power producers because: Both A and C: Variometer [ edit] One way to approach this would be to go back to the equations in earlier chapters and iterate among them, trying to find wing areas, weights, and engine sizes that would accomplish our design objectives. Wing loading for sailplanes is usually in the range of 5-8 pounds per square foot, around 17 lb/ft2 for general aviation planes, and over 100 lb/ft2 for fighters. Is this a reasonable flight speed? How does wind affect the airspeed that I should fly for maximum range in an airplane? Once you know the data point where the climb angle is maximized, you can find the actual climb angle with a bit of trigonometry involving the right triangle comprised of the airspeed, horizontal speed, and vertical speed vectors. 7.11 (Reference Figure 7.2) Using Figure 7.2, find the velocity for best range for the airplane at 12,000 lbs. and we can plot T/W versus W/S just as we did in the cruise case, this time specifying a desired rate of climb along with the flight speed and other parameters. To obtain best range the pilot now must, 8.2 Maximum rate of climb for a propeller airplane occurs at, 8.3 The turboprop aircraft has its lowest specific fuel consumption at about 25,000 feet altitude because, This is a compromise between (a) and (b) above, 8.4 The lowest point on the Pr curve is (L/D)max. Lets look at how the equation can be rearranged to help us examine the performance needs in various types of flight. Don't let the length of this answer fool you, it is actually the fastest path to a solution, starting from what we're given to work with in the original question. It is, for example, a common mistake for students to look at the performance goals for an aircraft design and just plug in the numbers given without thinking about them. As an example, most piston engine aircraft will cruise at an engine power setting somewhere between 55% and 75% of maximum engine power. 7.20 When a pilot lowers the landing gear, _______________ is increased. This addition to the plot tells us the obvious in a way. 6.21 The lowest values of ct occur between 95 and 100% rpm. MathJax reference. %PDF-1.3 12.19 Wind shear is confined only to what altitudes? 13.14 (Reference Figure 14.10) What airspeed must an aircraft maintain at 50 degrees of bank to achieve 10,000 feet radius of turn? The analysis may suggest that some of the constraints (i.e., the performance targets) need to be relaxed. 1.8 An aircraft is traveling west at an airspeed of 120 knots and is experiencing a crosswind of 20 knots from the north (90). With imperial units, we typically use different units for horizontal speed (knots, i.e. V e = 2 W S L S C L = 794.1 f p s. The angle of climb for maximum rate of climb (not maximum angle of climb) can then be found as follows: sin = T D W = T W C D / C L = 0.429 0.013 + 0.157 (0.088) 2 0.088 = 0.267. = 15.51 8.11 A propeller which has only one pitch setting is known as: 8.12 A propeller where the pilot can adjust the pitch setting in the air. Calculate (or find in Table 2.1) the approximate Pressure Altitude: 2.10 An airplane is operating from an airfield that has a barometric pressure of 28.86 in. It says that we need a higher thrust-to-weight ratio to climb than to fly straight and level. Effect of Desired Landing Characteristics on Aircraft Design Space. CC BY 4.0. 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? Figure 9.7: Effect of R & e Variation on max Range Cessna 182. 10.23 Using Fig. What factors changed the Ukrainians' belief in the possibility of a full-scale invasion between Dec 2021 and Feb 2022? 10.14 When taking off from a high-density altitude airport, the ________ will be higher than at sea level. 1.16 An airplane weighs 8,000 lbs and is flying at 6,000 ft altitude and an airspeed of 200 fps. 10.15 Takeoff into a headwind allows an aircraft to reach takeoff velocity at a lower __________. 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 rewrite this in terms of the ratios above to allow us to make our constraint analysis plots functions of TSL and WTO. 11.11 In most cases, an aircraft that has a high rate of descent on final approach should ____________. We could return to the reorganized excess power relationship, and look at steady state climb. 2.21 Calibrated airspeed is __________________ corrected for position and installation errors. In the proceeding chapters we have looked at many aspects of basic aircraft performance. One finds the desired takeoff distance in feet on the vertical axis and projects over to the plot for the type of aircraft desired, then drops a vertical line to the TOP axis to find a value for that term. Aircraft Design: A Conceptual Approach, AIAA, Washington, DC. 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