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Comparisonbetween Conventional Flaps and the ACTE Flaps

Comparisonbetween Conventional Flaps and the ACTE Flaps


Theneed for pilots to control and effectively make necessary adjustmentsto an aircraft’s altitude movement prompted the development of theairplane flaps. The flaps help provide control to aircrafts in theirtake-off, cruising and landing, hence, a vital component ofairplanes. In the aircraft industry, there are at least four flaptypes the plain flaps, the split flaps, the slotted flaps and thefowler flaps. All these types of flaps play a very important role inaiding the pilots to efficiently control the planes at various flightinstances as they are fixed to the plane wings. The extension orretraction of the airplane flaps helps guide the plane in specificfight phases during landing or takeoff, the flap extension helpsreduce speed and increase lift to facilitate the phase whereas theretraction of the flaps aids reduce drag, enabling the planes tocruise at high speeds.

Asnoted by Kota et al (2003), the flaps are attached to all plane wingsdue to the benefits hey accord the planes and pilots such as theflaps can enhance a plane’s lift by reducing the landing andtakeoff speeds, hence, making it pretty easier for the pilots toexecute such flight phases. The flaps also play a major role inaiding with steeper descent angles from high altitudes withoutnecessarily incurring increases in plane speeds. This happens whenthe extension of the flaps produces increased drag that supports thetight angle descent. Additionally, the flaps help in reducing thelengths of landing or takeoff distances, ensuring the planes don’ttake much time on such flight phases in addition to reducing thedistances of the required runways.

Plainflaps fitted on various airplanes are the simplest types of flapsused on plane wings. They are attached at the back of plane wings andcan provide a downward inclination once extended (Tilmann et al,2003). Due to their location at the back of the plane wings, theyprovide little influence on an aircraft because, the air thatbasically reaches the back of a plane’s wings has already split andlost energy which therefore means that the lift they can produce islimited. The plain flap extension thus results in increased airseparations at the back of the plane wings with little lift as alarge wake is produced. The huge wake created can however be used toa pilot’s benefit as it results in a drag that can aid a pilot seta plane on steep descent with no increase in plane speed. Thus, thismeans that the pilots can efficiently extend their plane flaps tocreate drag that aids facilitate acute descents without altering theplane airspeeds.

Splitflaps are located beneath the plane wings and are a little bitadvanced than the plain flaps. Just like the plain flaps, the splitflaps produce a huge amount of drag though they additionally aid inthe provision of lift to the aircrafts to some limited degree. Theslotted flaps on the other hand are very common in a variety ofairplanes in the modern world on both the large and small aircrafts.They seem exceptionally special due to their huge level of demand onthe wide variety of aircrafts to which they are fitted. The slottedflaps are hugely in demand due to their desirable features likeincreasing the wing cambers in addition to opening of slots betweenwings and flaps upon extension. The creation of slots is veryimportant because it is through it that high pressure air at thebottom of the wings flows onto the upper wing surface resulting inincreased energy to the boundary layers of the wings. The slotsdelays the rate of airflow separation thus resulting in reducedamounts of drag created in the process. It therefore leads tocreation of a huge amount of lift and hugely reduced levels of drag.

Fowlerflaps are the other very essential type of flaps used in airplanewings. The fowler flaps are widely accredited for their massiveability to create huge amounts of lifts as sufficiently required byvarious aircrafts. They are serious flaps that help increase the wingareas through their extensions on rails. The fowler flaps are attimes referred to as slotted-Fowler flaps due to the availability ofslots on them boost the amount of airflow energy. The large increasein lift with little production of drag on the fowler flaps aids aplane in its takeoff phase when extended, hence, enabling the planesto takeoff faster.

TheJunkers flap is a type of flap that is plain and slotted and isusually fixed under the trailing edge of a wing. The flap forms aninboard hinged section as it makes rotations around the forward edge.When the Junkers flaps are not in use, they create more drag than theother types of flaps but still help provide lift that is greater thanwhat other flaps like the plain flap and the split flap produce. Agouge flap on the other hand is a sort of a spit flap that slidesthrough the curved tracks that force down the plane trailing edge.The gouge flap slides through the curves increasing the camber withno requirement of any extra mechanism. The Blown flaps help blow theexhausts of an aircraft engine over the other flaps with theintention of lowering the air pressure on top of the wings, hence,creating lift. The lift comes about due to the lightness of hot airwhich results in high pressure beneath which forces the aircraftupwards. Such lift is in addition to the lift created mechanically byother plane flaps on the wings.

AdaptiveCompliant Trailing Edge (ACTE)

TheAdaptive Compliant Trailing Edge (ACTE) is an experiment intended totest the ability of advanced flexible trailing wing flaps inenhancing an aircraft’s aerodynamic efficiency in addition toreducing the airport noises generated when planes take off. The ACTEis an experiment propelled by the US Air Force in conjunction withNASA to help improve the state of the conventional flaps, hence,increasing the levels of aircraft efficiency. The move for ACTE hasbeen prompted by the need to ensure Environmentally Friendly Aviationto help reduce adverse environmental effects caused by aircraftsmost notably the excessive noise productions during takeoff. The ACTEflaps are designed in such a way that they are gapless, ensuringsmooth transition of air on the wings with the wings still firmlyattached to the sides and the forward edges.

TheACTE flaps ensure closure of the gaps that exist in the conventionalflaps by use of very flexible materials which results in the creationof bendable surfaces. Thus, this results in more efficient wings thatproduce minimal noise pollution in addition to saving the amounts offuel in use. The ACTE program is strategically efficient and is boundto close up all inefficiencies related to the conventional flaps asit has the ability to alter its shape in various flight phases, hencemaking it more efficient and less noisy. The bendable surfaces arebound to replace the traditional aluminum flaps. The ACTE technologyis still under testing at the Armstrong laboratory and it isanticipated that the “variable geometry foil” commonly referredto as FlexFoil can be readily fitted n already existing aircrafts toimprove efficiency. It therefore means that the ACTE is not designedfor new aircrafts only but can be efficiently fitted to aircraftsoperating on the old conventional flaps. The program to develop theACTE has been funded by an innovative program of the US Air Force forSmall Businesses.

TheACTE program has already been put to test and worked so efficiently.Several main elements of the trailing edges have been put to test andproved excellent. The program is primarily targeting to make theaircrafts lighter and quieter in addition to increasing theirefficiency in various aspects such as flap twisting in response tovarious flight conditions. However, the major efficiency anticipatedis the fuel use efficiency which is bound to go up by up to 12%. TheACTE case study is proving the vital need for technology in theaircraft industry to help boost various airplane services (Reed,2006). The figure below is a representation of the Adaptive CompliantTrailing Edge, illustrating the twisted edges.


Theadaptive compliant trailing edge wings are bound to help conservehuge amounts of fuel that gets consumed when the planes operate onthe traditional conventional flaps. The fuel burn on the conventionalflaps is high because they are hinged and rigid, requiring the inputof energy generated by fuel to either retract or extend the flaps inresponse to a given condition (Carter &amp Osborn, 2007). Theprocess of either retracting or extending the flaps with the demandsof various flight phases is thus expensive in terms of the amount ofenergy required to facilitate the actions resulting in high fuel use.Thus, the mechanical flaps end up consuming a lot of fuel energy. TheAdaptive Compliant Trailing Edge flaps on the other hand are verysmooth and aid in the seamless air transition on the wings, hencereducing the amount of fuel energy required in cruising.Additionally, this modern wing flaps are hinge less and their leadingand hind edges morph flexibly with the demand of various flightphases (Kota &amp Hetrick, 2006). The lead and hind trailing edgesare best suited to the Modern Adaptive Compliant Wings which helpenhance the efficient movement of the plane through various flightphases, changing automatically with the ensuing flight conditions(Schlichting &amp Gersten, 2000). The Adaptive Technology isseemingly very powerful as it enables the plane to have more powerand increased ability to carry extra loads than the conventionalflaps with little fuel consumption (Lu &amp Kota, 2003).Aerodynamics

Theaerodynamic performance of both flaps is done with the help ofcomputational fluid dynamics. Pressure based procedures used inaerodynamic experiments aid in the determination of the requiredstoke equations with the help of the study of viscosity. Thecomparison of the aerodynamic performance of the two flap designsbased on lengths, angles and ground clearances does indicate theAdaptive technology flaps are much better and more enhanced than theconventional flaps. The lift-drag ratio is extremely high for theadaptive flap, hence proving that they have superior aerodynamic(Trease &amp Kota, n.d).

Advantagesof Adaptive Compliant Trailing Edge

  • The Adaptive Compliant Trailing Edge flap is superior to the conventional flap because of the use of low amounts of fuel, hence resulting in reduced cost of energy spent of aircraft fueling.

  • The adaptive technology will save the aircraft industry millions of dollars per annum as a result of the adoption of the new technology. The money can be appropriated to other programs like research.

  • The technology helps reduce the amount of noise generated by planes during takeoff, hence reducing noise pollution at the airports.

  • The Adaptive technology can also help in the enhancement of environmental conservation as less fuel gets used in addition to reduced noise pollution at the airports.

  • The Adaptive technology provides the planes with additional power and increased load carriage ability with no significant increases in energy demands.

  • The Adaptive compliant trailing edge flaps indicate a lift increase co efficiency of about 25% whereas the coefficient of the created lifts to drag is estimated at about 51%. This shows that there is increased lift to drag ratio in the Adaptive technology flaps as compared to the ordinary conventional flaps.

  • Additionally, the adaptive compliant technology flaps are flexible and provide seamless air transitions across the flaps unlike the conventional flaps that are rough surfaced preventing smooth air flow from the lead edge to the hind one.

  • The Adaptive technology additionally creates more lift and less drag unlike the conventional flaps that create huge amounts of drag, at times with less lift.

  • Can be easily fitted to already existing plane wings to enhance their performance in addition to being used on new aircrafts. Thus, this means that the filling material required in this process is very flexible for use and multipurpose on various aircrafts (Kota, n.d).

Disadvantageof ACTE

  • Uses fossil fuel energy whose combustions leads to increased threats of global warming.

Advantagesof Conventional flaps

  • Have strong aerodynamic power.

  • Can provide the required lifts and drags needed by the aircrafts at various flight phases.

  • Can be extended to facilitate landing or takeoff in addition to being retracted to facilitate the cruising at high altitudes.

Disadvantagesof Conventional flaps

  • Make a lot of noise when planes are taking off, hence, causing noise pollution.

  • They do not provide for seamless transition of air from the lead edges to the hind edges.

  • They use a lot of fuel energy in their mechanical extension and retraction processes. Hence are expensive.

  • They contribute a lot to environmental pollution as they are responsible for the loud noises created by aircrafts in their takeoff processes. The use of excessive fuel also results in environmental pollution that consequently leads to global warming.

  • Can’t respond to the changes in cruising environment condition on their own, must always be facilitated by the pilots.

  • Increases in plane load capacity and power is accompanied by increased use of fuel energy which thus makes them expensive.

Theadaptive compliant trailing flap by far seems to be much efficientthan the conventional flaps. It complements several inefficiencies ofthe conventional flaps, hence boosting the performance of variousaircrafts in addition to increasing their aerodynamic power. The fuelconsumption rate of the ACTE is notably efficient, helping savemillions of dollars that could otherwise be spent on fuel. All theseare in addition the ACTE flap’s ability to reduce aircraft noiseand increase its lift-drag ratio. Thus, the ACTE flaps undisputedlyrepresent the future of aircrafts in the modern world.


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