12.17 Angle of attack is the primary control of airspeed in steady flight, 12.18 When Trexceeds Ta, the only way to go is __________. 5.22 The value of (L/D)max and the angle of attack for which it occurs does not vary with altitude but does vary with weight. How is the "active partition" determined when using GPT? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. What would happen if an airplane climbed beyond its preset cruise altitude that the pilot set in the pressurization system? Excess power is power available minus power required. Suppose that a 1.0-mm-thick layer of water is inserted into one arm of a Michelson interferometer. 13.20 An aircraft in a level, coordinated turn with a bank angle of 60 is maintaining _____ G's. >ZWCWkW This relationship proves to be a little messy with both ratios buried in a natural log term and the wing loading in a separate term. The groundspeed must be increased over the no-wind groundspeed by the amount of the tailwind. Match the type of engine and the type of propeller where the advantages of each are utilized and nothing is wasted. 5.21 Wingtip vortices are formed by higher-pressure air beneath a wing moving into __________ pressure air above the wing. The figure below (Raymer, 1992) is based on a method commonly used in industry. We might start with cruise since a certain minimum range is often a design objective. Calculate (or find in Table 2.1) the Pressure Ratio: 2.9 An airplane is operating from an airfield that has a barometric pressure of 28.86 in. 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. 3. 10.24 When taking off in a multi-engine aircraft, VRis usually less than V1. For example you can choose a point where the straight line crosses one of the airspeed or vertical speed indices, or where it crosses an intersection of both airspeed and vertical speed indices. 11.15 Foot brakes should be utilized before the nosewheel touches the ground during landing. For example, lets look at stall. As an example, most piston engine aircraft will cruise at an engine power setting somewhere between 55% and 75% of maximum engine power. 8.9 Which horsepower is measured at the propeller shaft and experiences gearing losses in reducing engine rpm to propeller rpm? 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. There are many good textbooks available on aircraft design and the Raymer text referenced earlier is one of the best. 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. 13.8 (Reference Figure 5.4) An aircraft flying at 200 knots can pull how many G's before stalling the aircraft? 2.5 Bernoulli's equation for subsonic flow states that: If the velocity of an airstream within a tube is increased, the static pressure of the air decreases. 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. If T/W = 1.0 or greater we need no wing. Is a condition where the tire is lifted completely above the surface of the runway, Can occur at slower speeds and rather than the water lifting the tire from the pavement, the tire slips on a thin film, 11.7 If a pilot experiences an engine failure and attempts to "stretch the glide" (i.e., increases the angle of attack) the result will be, A decrease in horizontal distance traveled, 11.8 Airline aircraft primarily use _________ to slow the aircraft after landing. , Does an airfoil drag coefficient takes parasite drag into account? Find the Drift Angle. 4.10 in your textbook, what is your AOA if the CL is .6 for a symmetrical airfoil? 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 12.15 Which wing planform is considered to be the most aerodynamically efficient? 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. The relationship above, since it does not depend on the thrust, will plot on our constraint analysis chart as a vertical line in much the same way the stall case did, but it will be just to the left of the stall line. The desire for minimum thrust is obvious, based on the need to minimize fuel consumption and engine cost. 11.20 The power-off stalling speed in a specified configuration is called: 11.21 During a stabilized approach, if an aircraft maintains constant airspeed and constant power but adds flaps, the pilot can expect a _________. These are then plotted to find optimum values of wing loading and thrust-to-weight ratio. 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. 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. In cruise where lift = weight and thrust = drag, T/W = 1 / [L/D], meaning that the high value of L/D that is needed for a large range goes hand in hand with a low thrust-to-weight ratio. 11.12 Which of the following aircraft derive more lift due to high power settings? x\Er0`b.awB7
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H $YAr2j{v{`ssf)w>y~|&KG=|x7j9;87w|upkA`y We could return to the reorganized excess power relationship, and look at steady state climb. I frequently, but not always, have a severe imbalance between the two engines. We could get a different curve for different cruise speeds and altitudes but at any given combination of these this will tell us all the combinations of thrust-to-weight values and wing loadings that will allow straight and level flight at that altitude and speed. Climb Curves - Turbojet. 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? It usually is restricted to either the takeoff setting or the cruise setting. 8.14 A propeller where the pitch setting can only be adjusted on the ground and requires that the engine be stopped is known as: 8.15 An engine where the fuel-air mixture is forced into the cylinders by natural atmospheric pressure upon opening of the inlet valves. Just as an aside, the vertical speed can't be higher than the airspeed, so it's not even. For low angles of climb (non high performance aircraft) airspeed may be directly compared to vertical velocity, as the cosine of lower angles is very close to 1. 3.20 The component of the aerodynamic force that is perpendicular to the relative wind is ________________. 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. 5.23 For a given aircraft wing, if the wing span increases and the average chord remains the same, the aspect ratio will __________. So your graph of vertical speed versus airspeed will work just fine for finding the maximum climb angle. a. 10.4 What effect does a headwind have on takeoff performance? 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. And both approaches are maximizing the same angle on the right triangle comprised of the vertical speed, horizontal speed, and airspeed vectors. It is called: AERO 1020 Final Review: All Past Test Q's/A's, Materials Science and Engineering: An Introduction, CT Basics 2.0 | Module 1: CT Fundamentals Test, MKT201 700 FULL CHAP-Key 700 Trung sa. High thrust will minimize the takeoff ground run but once thrust becomes as high as the weight of the plane we might as well take off vertically! How does the Angle of attack vary from the root to the tip of a propeller for a fixed pitch prop? 3.25 The rudder controls movement around the ________________ axis. Calculate (or find in Table 2.1) the Density Ratio: 2.12 An airplane is operating from an airfield that has a barometric pressure of 28.86 in. 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. 4.18 Using Fig. But, in a jet, you'll often fly close to your best range speed. 9.9 For a power-producing aircraft, an increase in weight results in a decrease of Vmax. Continue searching. 7.24 Increased weight has what effect on rate of climb? 3.22 The example of the pressure distribution on a rotating cylinder that explains why a golf ball slices is best described by ______________. 8.21 For a power-producing aircraft, maximum climb angle is found. Acknowledgment: Thanks to Dustin Grissom for reviewing the above and developing examples to go with it. The climb curve would probably be plotted at sea level conditions since that is where the target maximum rate of climb is normally specified. For the prop aircraft Raymer defines TOP as follows: It should be noted here that it is often common when conducting a constraint analysis for a propeller type aircraft to plot the power-to-weight ratio versus wing loading rather than using the thrust-to-weight ratio. 8.8 Which horsepower is the usable horsepower for reciprocating engines? The other parameter, W/S, or wing loading, is also generally low for sailplanes and high for fighters. 1.15 An airplane is climbing at a constant airspeed in no-wind conditions. These included takeoff and landing, turns, straight and level flight in cruise, and climb. 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)? 6.18 Thrust-producing aircraft have a fuel consumption roughly proportional to thrust output. These relationships also involve thrust, weight, and wing area. | Privacy Policy | Terms of Service | Sitemap | Patreon | Contact, https://www.aopa.org/news-and-media/all-news/2013/november/pilot/proficiency-behind-the-power-curve, Federal Aviation Administration - Pilot/Controller Glossary, Climb performance is a measure of excess thrust which generally increases lift to overcome other forces such as weight and drag, This is true for most aircraft although some high performance aircraft can function like rockets for a limited time, utilizing thrust to lift away from the earth vertically, with no lift required, Excess power or thrust, terms that are incorrectly used interchangeably, allow for an aircraft to climb, Power and thrust are not the same, despite their use as such, Power is a measure of output from the engine while thrust is the force that actually moves the aircraft, In a piston aircraft, power is converted to thrust through the propeller, In a jet aircraft, the engine produces thrust directly from the engine, When you are moving the throttle controls inside of the aircraft, you're controlling the engine and that is why they are referred to as power levers, Therefore the best angle of climb (produces the best climb performance with relation to distance, occurs where the maximum thrust is available, The best rate occurs where the maximum power is available), The relationship between propulsion and drag is such that it takes a certain amount of power/thrust to overcome drag both on the high end (the faster you go) and also the low-end (the slower you go), This is noticeable during slow flight where you find yourself adding extra power to overcome all the increases in drag that are necessary to sustain lift, If you fall "behind the power curve" however, you're in a position where you cannot generate immediate performance by simply increasing power, The increase in power must first overcome the increased drag and then the expected performance will occur, Ultimately, it is because of excess power (or thrust) that an aircraft climbs, For the purpose of initial climb however, we are concerned with our aircraft's performance in order to get away from the ground, Certain conditions will call for a specific climb profile, generally best rate (V, Max excess thrust results in the best angle of climb, Reduced distance to climb to the same altitude as V, 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, Increases airflow over the engine while at high power, Provides additinoal buffer from stall speeds, Takes more distance to reach the same altitude as V. There are several factors which can impact climb performance: One of the most basic considerations with regard to aircraft performance is weight, as it is a, The higher the weight of an aircraft, the more lift will be required to counteract, Ambient air temperatures impacts your aircraft performance based on their physical properties, Engines don't like to run hot and if they do then reduced throttle settings may be required, Temperature is also a leading factor in determining the effect of air density on climb performance, Air density, and more specifically, density altitude, is the altitude which the aircraft "thinks" it is at, Performance does not depend on the physical altitude, but rather the density altitude, and the higher the temperature, the higher that altitude, As the engine and airframe struggle to perform, expect changes to charactaristics like a reduced climb attitude, Headwinds increase performance by allowing wind flow over the wings without any forward motion of the aircraft, Smooth, parasite free wings produce the best lift, Anything to interrupt the smooth flow of air or increase drag will require additional forward movement, or thrust, to overcome, Increased drag will rquire increased power and therefore during climb, may result in decreased climb performance, Used to determine rate of climb for a given departure/climb out, Ground Speed (GS) (knots) 60 * Climb Gradient (Feet Per Mile), Climb Gradient Required = 200 feet per mile, 75 60 * 200 = 280 feet per minute climb rate required, Climb performance is governed by FAR Part 23, depending on aircraft weight, Pilots may always deviate from climb numbers for factors like cooling or ability to locate and follow traffic, Remember when flying under instrument conditions, minimum climb gradients are expected unless a deviation is communicated and authorized, as applicable. 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maximum rate of climb for a propeller airplane occurs