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Topic: Induced drag

Related Topics

Parasitic drag

Winglet

Wingtip vortices

Boeing 747

	Lift-induced drag - Wikipedia, the free encyclopedia
		In aerodynamics, lift-induced drag, or induced drag, is a drag force which occurs whenever a lifting body or a wing of finite span generates lift.
		Unlike parasitic drag, induced drag is inversely proportional to the square of the airspeed.
		Since induced drag is inversely proportional to the square of the airspeed whereas parasitic drag is proportional to the square of the airspeed, the combined overall drag curve shows a minimum at some airspeed - the minimum drag speed.
	en.wikipedia.org /wiki/Lift-induced_drag (794 words)

	Gliding Magazine \| Features (Site not responding. Last check: 2007-11-04)
		Drag in pounds divided by the dynamic pressure of flight in pounds per square foot yields the drag area in square feet.
		The induced drag in pounds is proportional to the square of the gross weight and inversely to the square of the wingspan and the dynamic pressure of flight.
		The induced drag coefficient is proportional to the square of the lift coefficient and inversely proportional to the wing aspect ratio.
	www.glidingmagazine.com /FeatureArticle.asp?id=289 (2087 words)

	Textbook
		Drag is the fourth of the major forces of flight.
		To minimize friction drag on an aircraft all the sheets of metal on the wing join smoothly, and even the rivets are rounded over and as flush with the surface as possible.
		Induced drag or drag due to lift is a small amount of excess (lift) force generated in the opposite direction of the lift force along a wing.
	wings.avkids.com /Tennis/Book/drag-01.html (692 words)

	Design and Analysis of Optimally-Loaded Lifting Systems
		The induced drag of the vortex system is related to the distribution of "normal-wash" in the Trefftz plane (the velocity induced by the vortex system far downstream in a direction perpendicular to the bound vortex and the free-stream).
		Drag is plotted vs the ratio of canard (or tail) span to wing span for three values of the parameter: canard (or tail) aspect ratio / wing aspect ratio.
		Since the induced drag of a system of lifting surfaces is independent of their streamwise position (as of course are wing and tail structural weight and parasite drag) it follows that, for minimum drag, the load carried by a canard surface will be equal to that carried by an aft-tail of equal size.
	aero.stanford.edu /Reports/MultOp/multop.html (3864 words)

	HTML document for the World Wide Web
		The induced drag coefficient is a function of the sail coefficient of lift, aspect ratio, rake angle, planform but its also dependent on how well the gap at the bottom of the sail is closed.
		In one model, the sail induced drag coefficient is inversely proportional to an efficiency variable which has a value of 2 for a perfectly closed gap and it degrades to 1 for a completely un-closed gap.
		However, the induced drag effects of the gap are a result of pressures on each side of the sail which affect each other "at the speed of sound and with a wave nature" so the effects of these pressures likely falls off with the square of distance.
	iceflyer.com /experiment/end_plate.html (1060 words)

	Concept to Reality
		The induced drag is produced by the generation of three-dimensional airflow characteristics near the tips of aircraft wings.
		Induced drag also represents a significant decrement in aircraft efficiency for subsonic transports operating at high subsonic speeds and accounts for as much as 50 percent of total drag.
		Thus, although the potential drag-reducing effects of endplates on induced drag had been identified, the net effect of simple endplates was regarded as inconsequential because of the increase in profile drag.
	oea.larc.nasa.gov /PAIS/Concept2Reality/winglets.html (2884 words)

	North Sails One Design
		The result with the least induced drag is that the foils should contribute to sideforce proportionally to the ratio of their spans squared.
		Note that minimum induced drag occurs when the load is distributed proportionally to the ratio of the span of the keel and rudder, squared (for example 64/36 = 8/6 squared, and 88/12 is close to 8/3 squared).
		The increases in induced drag as the proportions are varied away from the optimums are shown and give incentive to set the boat up to achieve loads that generate the lowest possible induced drag.
	www.northsailsod.com /articles/getaccess-19.php (2421 words)

	Cruise Missile Construction Diary: Airframe Design
		Drag is one of the four key forces that act on any aircraft in flight (the others are gravity, lift and thrust).
		Fortunately, induced drag is more of a problem at low speeds, when there's more time for the air beneath the wing to escape around the tip to the top surface, than it is at high speeds, when air flows past the wing far more quickly.
		In fact, while form drag tends to increase at a rate roughly equal to the square of the airspeed, there are portions of the operating envelope where induced drag usually declines as the speed of a craft increases.
	www.interestingprojects.com /cruisemissile/airframe02.shtml (1525 words)

	Pilot's Web The Aviators' Journal - More About Lift and Drag
		To minimize the parasite drag it is desired to design in airfoil shape all aircraft parts such as struts, wheel fairing, etc. The two major contributors to parasite drag are the form drag and the skin-friction drag.
		Induced drag is inversely proportional to the speed (velocity) of the air.
		As shown previously, induced drag is inversely proportional to the velocity of the air.
	www.pilotsweb.com /principle/liftdrag.htm (1511 words)

	Helicopter Aviation (Site not responding. Last check: 2007-11-04)
		Drag is the force that opposes the motion of an aircraft through the air.
		Total drag produced by an aircraft is the sum of the profile drag, induced drag, and parasitedrag.
		The induced drag is the portion of the total aerodynamic force which is oriented in the direction opposing the movement of the airfoil.
	www.copters.com /aero/drag.html (362 words)

	Drag - level 3
		Since drag is a force directly opposed to the motion of the airfoil and, as the work of overcoming it is performed by the engine, it is desirable to have it as small as possible, to afford the engine to be more efficient.
		The induced drag characteristics of a wing are not the same very near the ground as they are at altitude.
		The drag on the downgoing aileron is known as aileron drag and if not corrected for in the design of the aileron, tends to cause a yaw in the opposite direction to which the bank is applied.
	www.allstar.fiu.edu /aero/drag3.htm (1627 words)

	Forces of Flight
		Pressure induced drag is caused when the angle of attack becomes high enough that the airflow across the airfoil is no longer smooth and the airflow becomes turbulent as it breaks away from the wing.
		Turbulence and pressure drag also result from the flow of air around the wig tip as the relatively high pressure air under the wing flows over the wing tip to the low pressure area on top of the wing.
		The second type of drag, parasitic drag, is caused by the friction between the outer surfaces of the aircraft and the air through which it moves.
	www.doalasvegas.com /html/forces_of_flight.html (438 words)

	NOVA Online \| Fast Cars \| Hot Science: Lift and Drag \| Glossary
		Drag is a force which acts on any moving object, resisting the forward motion of that object.
		Friction drag acts on the surface of an object, in the layer of air that immediately surrounds it.
		Induced drag only affects object with lift--that is, objects that have the ability to lift off the ground.
	www.pbs.org /wgbh/nova/hotscience/fastcars/draggloss.html (155 words)

	Induced Drag (Site not responding. Last check: 2007-11-04)
		If there is such a thing as induced drag then it must be the case that the actual force created by the wing is inclined from the relative wind, as shown in the picture.
		The induced angle of attack increases the stalling angle of attack.
		Because the upwash (induced AOA) is greatest near the wingtip the the wing root tends to stall before the tip.
	www.professionalpilot.ca /aerodynamics/drag/induced.htm (1771 words)

	Drag (Site not responding. Last check: 2007-11-04)
		Drag is simply force that opposes the motion of an aircraft through the air.
		Total Drag produced by an aircraft is the sum of the Profile drag, Induced drag, and Parasite drag.
		Parasite Drag is the drag incurred from the nonlifting portions of the aircraft.
	www.dynamicflight.com /aerodynamics/drag (337 words)

	Minimum Induced Drag of Sail Rigs and Hydrofoils
		The induced drag is a minimum because the downwash is constant, and the elliptical loading is, for this particular case, the loading required to generate the constant downwash.
		The induced velocities in the Trefftz plane are twice those induced at the origin of the wake, since the trailing vortices extend to infinity in both directions from the Trefftz plane, but only in one direction from the sail planform.
		Reduced moment, minimum induced drag spanloadings corresponding to the previous cases were computed using triangular downwash distributions which had a maximum value at the foot, and went to zero at the head.
	www.tspeer.com /Planforms/Planar.htm (5756 words)

	Aerospaceweb.org \| Ask Us - Adverse Yaw and Aircraft Turns
		Induced drag is a form of drag that is induced by any surface that generates lift.
		This profile drag increases on both wings when the ailerons are deflected, but the increase is equal when the ailerons are deflected by the same amount.
		However, the induced drag on each side is not equal, and a larger total drag force exists on the wing with the down aileron.
	www.aerospaceweb.org /question/dynamics/q0045.shtml (1044 words)

	Embry-Riddle - Air Resistance Is A Real "Drag" (Site not responding. Last check: 2007-11-04)
		Induced drag is that drag which is attributed to the production of lift.
		The magnitude of induced drag decreases as the airspeed increases.
		Induced drag decreases and parasite drag increases with airspeed.
	www.erau.edu /er/newsmedia/articles/cont2.html (509 words)

	DRAG (Site not responding. Last check: 2007-11-04)
		Drag is the frictional force which acts parallel to the air acting around it.
		It is an attempt to reduce the amount of drag being exerted on the vehicle is to reduce the size of the frontal area.
		Induced Drag is a pressure difference at the tip of a wing produced by a swirling air flow.
	www.mrfizzix.com /indyracing/drag.htm (295 words)

	Induced Drag and the Trefftz Plane
		The total induced drag of a system of lifting surfaces is not changed when the elements are moved in the streamwise direction.
		This implies that the drag of an elliptically-loaded swept wing is the same as that of an unswept wing.
		One of these is the mutual induced drag theorem which states that: The interference drag caused by the downwash of one wing on another is equal to that produced by the second wing on the first, when the surfaces are unstaggered (at the same streamwise location).
	www.desktopaero.com /appliedaero/potential3d/induceddrag.html (831 words)

	Lift-Dependent Drag Items
		The remaining portion of the "induced" drag, the so-called viscous part, is chiefly due to the increase of skin friction and pressure drag with changes in angle of attack.
		The values of this factor are obtained from a solution for the minimum induced drag of a lifting line in combination with a circular fuselage of infinite length and at zero angle of attack.
		Ideally, this drag contribution should be estimated for the individual airplane components, with factors such as the influence of wing leading edge geometry, wing camber, wing thickness ratio, wing sweep, pylon interference, fuselage upsweep, tail induced drag, power effects, etc. taken into account.
	adg.stanford.edu /aa241/drag/induceddrag.html (1422 words)

	Horten IV, Flying wing (Site not responding. Last check: 2007-11-04)
		Hence, it is a general practice to express the span efficiency as the ratio between the slopes of the theoretical induced drag polar and the total drag polar.
		This is, however, not precise, since in practice both the profile and parasite drag are subject to change with the lift coefficient, and the slope of the total drag polar is accordingly different from that of the actual induced drag polar.
		The induced drag increment, which is 25 to 30 per cent, could be reduced to at least 8 to 10 per cent if the excessive twist and large negative control deflection were reduced.
	users.acsol.net /~nmasters/H-IV-report.html (4147 words)

	Ground Effect
		We have learned earlier that induced drag is a result of the wing's work of sustaining the airplane and that the wing lifts the airplane simply by accelerating a mass of air downward.
		At high angles of attack, the amount of induced drag is high and since this corresponds to lower airspeeds in actual flight, it can be said that induced drag predominates at low speed.
		However, when the wing is at a height equal to one-fourth its span, the reduction in induced drag is 23.5 percent and, when the wing is at a height equal to one-tenth its span, the reduction in induced drag is 47.6 percent.
	www.faatest.com /books/FLT/Chapter17/GroundEffect.htm (1066 words)

	Reducing_Induced_Drag
		This figure illustrates the wing-span effect on induced drag for airplanes having same wing area, same lift coefficient, and same dynamic pressure.
		Induced drag is a small component at high speeds (cruising flight) and relatively unimportant since it constitutes only about 5 to 15 percent of the total drag at those speeds.
		To give minimum induced drag, the spanwise efficiency factor e should be as close to 1 as possible.
	www.centennialofflight.gov /essay/Theories_of_Flight/Reducing_Induced_Drag/TH16.htm (908 words)

	Drag
		It is defined as the sum of parasitic drag and induced drag.
		This drag is the drag that you referred to as being proportional to speed.
		Drag force depends on velocity, frontal area, and the drag coefficient.
	www.newton.dep.anl.gov /askasci/phy00/phy00107.htm (601 words)

	Re: how does gound effect flight work
		Induced drag is the result of the wing's work in sustaining the airplane.
		The wing tip vortices that also contribute to Induced drag are substantially reduced; the ground interferes with the formation of a large vortex.
		As altitude is gained, induced drag increases as the effect of the ground effect diminishes.
	www.madsci.org /posts/archives/may2000/958682159.Ph.r.html (741 words)

	Total Drag (Site not responding. Last check: 2007-11-04)
		The red curve in the diagram to the right is the sum of the other two curves which you will recognize as the parasite drag and induced drag curves shown previously.
		It is worth noting that minimum drag occurs at the speed where parasite drag is equal to induced drag.
		Of course the aeronautical engineer is generally interested in minimizing the total drag, which includes both the parasite and induced drags.
	www.freewebtown.com /salil/Drag/Page9.html (680 words)

	What is the best fin shape? (Site not responding. Last check: 2007-11-04)
		Hence, the induced drag on the rocket may be near zero.
		Therefore, it is highly likely that your rocket will have the same induced drag forces no matter what shape fin you use - because typically a model flies straight and true and the induced drag in the rocket is very, very small.
		The profile drag force is determined by a number of factors, including the surface finish on the fin, airfoil used, area of the fin, the length of the fin chord, and the speed at which the rocket travels.
	www.apogeerockets.com /technical_publication_16.asp (1120 words)

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