t tail vs conventional tail

1Cause deep stall: T-Tail surface may cause deep stall where the elevator/stabilizer becomes stalled making the nose impossible to push over due to the stalled condition. MCDONNELL DOUGLAS MD-82) because it removes the tail from the exhaust blast. Obviously MD-80s aren't shedding their tails in flight but. Every type from fighters to helicopters from air forces around the globe, Classic Airliners Rotate at 75 knots. In addition to this, there is a horizontal stabilizer. If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user. an aft CG, T-tail aircraft may be more susceptible to a deep stall. It ensures clean airflow, at least on gulfstream aircraft. Reduces stick lightening: The greater height of T-tail can help reduce stick lightning caused by the conventional tail after entering the wake while maneuvering. Frequent air travellers would have noticed different aircraft for longer and shorter air routes. Due to the aft C.G. Elevator operation in undisturbed air allows control movements that are consistent throughout most flight regimes. Joined: Sep 1, 2008 Messages: Tail and Winglet closeups with beautiful airline logos. Most of the (small aircraft) T-tails I have flown it takes a bit of extra effort to stall the aircraft hard because gently the disruption just lets the nose back down and then you aren't stalled anymore. Others have given you aerodynamic reasons (which are all very good), but a reason why most military cargo planes have t-tails is also because it allows for larger loading ramps at the tail. For smaller aircraft though it is very difficult to hold nose high enough to overshadow a T-tail. 72V Well-Known Member . Disadvantages: Very messy loading and structural design. Source: I study aeronautical engineering and we had to do an exercise involving finding the correct posistion for the HTP to minimize downdraft. Notify me of follow-up comments by email. 9. T-tail will give you better rudder authority at very high AOA and stalls so as to prevent a spin. 2. Ground handling is pretty easy as well. The main hazard with this design is the possibility of entering aDeep Stall. From my reading, they take a longer take off roll and higher speed on approach. (apart some minor commercial airplanes, I saw it above all in military ones like C5 and C-17), @LucaDetomi: Airliners with their sweptback wings run the risk of. Seaplanes and amphibian aircraft (e.g. You use your radio for every flight, but did you know this? TMetzinger, Aug 5, 2012 #10 wabower Touchdown! The control runs to the elevators are more complex,[1] and the surfaces are more difficult to inspect from the ground. The Fokker 28 and F100 had stick pushers that acted upon detecting a high angle of attack, making it pretty much impossible to keep the columns at aft position. Have you ever flown a T-tail airplane? Regarding the "vertical" force equilibrium equation, there is no real difference between the two configurations but there is a big one for the moment equilibrium. All of the Boeings except the 717 have conventional tails. Copyright SKYbrary Aviation Safety, 2021-2023. The C2 has a conventional tail rotor: The RPM of the tail rotor on the C2 is roughly 2150 RPM. Anyway, from what I've been told: The T-tail sticks the elevators out of the disturbed air of the wings, prop, and (usually most of) the fuselage which gives you better elevator authority, and makes a tail stall less likely. Lets take a look at the pros and cons of this arrangement. Provides smooth flow: A T-tail ensures the tailplane surfaces behind the wings are out of the airflow. The non-turbo d Arrows consume nine to 12 gallons per hour, with the blown versions using around 14 GPH when pushed. As a consequence, the tail can be built lower. High performance: It results in high performance of aerodynamics and also ensure there is an excellent glide ratio since the empennage is not affected by the wing slip steam. If You Go-Around On A Visual Approach Under IFR, Do You Need To Contact ATC Immediately? Our large helicopter section. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. A smaller elevator and stabilizer results in less drag. [6][2] The American McDonnell F-101 Voodoo jet fighter suffered from this problem,[citation needed] as did the British Gloster Javelin, Hawker Siddeley Trident and BAC One-Eleven. 9 Things You Didn't Know About Your Airplane's VHF Radio, 3 Ways To Identify Mountain Waves From Forecasts, 10 Skills VFR Pilots Can Learn From IFR Pilots. Most aircraft feature empennage incorporating vertical and horizontal stabilizing surfaces which stabilize the flight dynamics of pitch and yaw as well as housing control surfaces. Incorrect Traffic Pattern Entry Leads To Mid-Air Conflict, How To Correct A High Flare During Landing. - I would guess that a T-tail necessitates a stronger, and thus heavier fin. The loss of Alaska Airlines Flight 261 was attributed to improper maintenance of the T-tail. He graduated as an aviation major from the University of North Dakota in 2018, holds a PIC Type Rating for Cessna Citation Jets (CE-525), is a former pilot for Mokulele Airlines, and flew Embraer 145s at the beginning of his airline career. Aside from the aforementioned lack of propwash, because a T-tail is usually further aft and has more lever arm, it can be made smaller, with less overall drag. Control: T-tail design ensures the elevator and the aircraft stabilizer are out of the way of FOD kicked up by the engines and gears. Tailplane more difficult to clear snow off and access for maintenance and checking. Why Aircraft Weight Affects Climb Performance, How To Correct A Late Or Rapid Flare During Landing, How Pitot-Static Failures Affect Your Indicated Airspeed And Altitude, Why Landing With A Tailwind Increases Your Risk Of An Accident, Ice-Covered Pitot Tube Results In Low-Altitude Alert From ATC, How To Calculate Your Own VDP When An Instrument Approach Doesn't Have One, Quiz: 6 Questions To See How Much You Know About Aerodynamics. Save my name, email, and website in this browser for the next time I comment. with the high t-tail of the lance it makes that a bit more difficult. For the most part this is correct, although if airflow is disrupted over the tail the nose should actually come down because the horizontal stabilizer is what holds the nose up in the first place. A stick-pusher can be fitted to deal with this problem. Maintenance issues: It will be difficult to climb up there and work on the T-tail if it has some problems. How do elevator servo and anti-servo (geared) tabs differ? When flying at a very high AOA with a low airspeed and Not so noticeable on landing as power is reduced, but still a consideration. In this condition, the wake of the wing blankets the tail surface and can render it almost ineffective. One advantage to a T-tail is that the engines can be put on the tail, making them less susceptible to FOD ingestion, except for ice from the wings. Quiz: Do You Know What These 5 ATC Phrases Mean? Tail t/c values are often lower than that of the wing since t/c of the tail has a less significant effect on weight. The duct is integrated into the tail boom and is usually made of a fiberglass skin. Quiz: Can You Answer These 5 Aircraft Systems Questions? The fuselage must be made stiffer to counteract this. Has 90% of ice around Antarctica disappeared in less than a decade? A T-tail has structural and aerodynamic design consequences. A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. Airport overviews from the air or ground, Tails and Winglets In an aircraft with wing mounted engines you get a pitch up moment when you apply thrust (but most of the time if you have to increase thrust its because you are on speed and below profil or on speed but below profil). The reason for this is the reversal of the $C_M$ - $\alpha$ slope of T-tails, as depicted below. Mostly, there is little or no difference in how they perform, certainly not at the level we would notice on our little models. The Pilot Handbook of Aeronautical Knowledge has a whole section talking about T-tails. To learn more, see our tips on writing great answers. Another major difference between these two configurations concerns the stability. A stalled wing at high angles of attack may lead to blanking of the airflow over tailplane and the elevators may lead to loss of pitch control. obtain an immediate elevator authority by increasing the aircraft power. Confused by the V-Tail? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Press question mark to learn the rest of the keyboard shortcuts. As a consequence of the smaller vertical tail, a T-tail can be lighter. While this can occur on other aircraft as well, the risk is greater with T-tails as a highAOAwould likely place the wing separated airflow into the path of the horizontal surface of the tail. This shape resembles a capital T, giving birth to the moniker of T-tail. Why do trijets (3 rear engines) usually have a T-tail instead of a normal tail? I suppose it is possible to disrupt the flow enough to where the controls are ineffective but not enough that it can still hold the nose pitched up to a stall although it seems like long shot and/or a poor design. Tail sweep may be necessary at high Mach numbers. Swayne is an editor at Boldmethod, certified flight instructor, and a First Officer on the Boeing 757/767 for a Major US Carrier. ). Twin tail (also referred to as H-tail) or V-tail are other configuration of interest although much less common. Why are the Antonov An-124 horizontal stabilisers directly behind the wings? MathJax reference. This is a good description of the tail section, as like the feathers on an . This article highlights the pros and cons of using a V-tail configuration. The horizontal stabilizer acts like a winglet, reducing induced drag of the rudder. A stabilizer in undisturbed airflow will produce better L/D than in turbulent flow, as well. However, T-tails are more likely to enter a deep stall, and is more difficult to recover from a spin. uhmmm very interesting but now I can't understand why commercial airliner strictly prefer conventional tail instead of T-Tail. MCDONNELL DOUGLAS MD-82) because it removes the tail from the exhaust blast. Create An Account Here. I suppose depending on the aircraft and the weight and balance situation though maybe it is possible. On takeoff the nose can "pop" up in a different manner than a more conventional tail. Note that the increased leverage means that the horizontal tail can be smaller as well. Name as many disadvantages and advantages of each that come to mind. Moreover, the T tail is the most advantageous on straightening from spin, as the stabilizer will act as an endplate for the rudder. receive periodic yet meaningful email contacts from us and us alone. The AC isn't prescriptive. Boeing could reduce the empty weight of the 733-100 by 700 pounds, We've added a "Necessary cookies only" option to the cookie consent popup. It is structurally more compact and aerodynamically more efficient. The simple answer is that they can be more efficient than a conventional tail. Seaplanes and amphibian aircraft (e.g. Takeoff: The airplane has none of that "ready to fly" feeling as you accelerate. However both halves typically have to be larger in surface area to make up for only having two stabilizing surfaces, so the drag reduction is rendered null. The T-tail avoids this, but it places a large mass (the stabilizer) at the end of a long moment arm (the fin). easiest to do. The empennage, also referred to as tail or tail assembly, gives stability to the aircraft. (However, T-tail aircraft may be vulnerable to deep stall, see Disadvantages below. Before CFD, mounting the engines on the wing created lots of problems, prompting the engineers to move to tail-mounted engines in their next design (DC-8 -> DC-9, B707 -> B727), The mass of the horizontal tail on a long lever arm (= the vertical tail) means that the torsional eigenfrequency of the fuselage will go down. A T-tail produces a strong nose-down pitching moment in sideslip. But, they handle turbulence much better and are very smooth fliers. PoA Supporter Joined: Oct 22, 2008 Messages: 15,568 Location: mass fla Display name: What are the aerodynamic consequences a pilot needs to be aware of with a T-tail (e.g. A conventional aircraft tail consists of two lifting surfaces oriented at right angles to one-another: a horizontal stabilizer and a vertical stabilizer. The Boeing 737 was initially planned with rear-mounted engines, like the Sud-Aviation Caravelle, which it was meant to replace. YouTube Channel: www.youtube.com/projectairaviation, - Find this article & others like it at www.FliteTest.com -, By joining our mailing list via the home page or during checkout, you agree to The aeroplane is aerodynamically stable when the $C_M$ - $\alpha$ slope is negative, such as in cases B and C. For configuration A, the slope becomes positive after the stall point, meaning that the nose wants to increase upwards after reaching the stall - not a good situation. The conventional cross tail is the easiest to design, modify during the development process and adjust during set up of a new model. Why is there a voltage on my HDMI and coaxial cables? Copyright 2023 Flite Test. Making statements based on opinion; back them up with references or personal experience. A T-tail may have less interference drag, such as on the Tupolev Tu-154. In the 1960s, several passenger jets with rear-fuselage-mounted engines featured T-tails, such as the BAC One-Eleven, the Vickers VC10, the McDonnell Douglas DC-9, the Boeing 727, the Fokker F28 Fellowship, and the Russian Ilyushin Il-62 and Tupolev Tu-154. position if empty. The T-tail can be found often found on military transport aircraft, such as the Airbus A400M and the Boeing C-17 Globemaster III. ..The T-tail Lances have the same issue. 10. The airplane lands in typical crosswind with no issues. Props and jets from the good old days, Flight Decks (Picture from the linked Wikipedia article). Learn more about Stack Overflow the company, and our products. Passenger cabin shots showing seat arrangements as well as cargo aircraft interior, Cargo Aircraft T-tails keep the stabilizers out of the engine wake, and give better pitch control. Apart from that it was fine. The arrangement looks like the capital letter T, hence the name. T-tails were common in early jet aircraft. T-tails have a good glide ratio, and are more efficient on low speed aircraft. Press J to jump to the feed. The forces required to raise the nose of a T-tail aircraft are greater than the forces required to raise the nose of a conventional-tail aircraft. 1. There can also be some slight negatives in terms of efficiently generating pure pitch or yaw moments without also generating unwanted roll moments. Together they are referred to as the empennage, which has French origins and translates to "feather an arrow". Depending on the lift characteristics and generall geometric shape of the wing, this vortex results in updraft and downdraft zones. Not only that, but on aircraft where the engines are mounted on the tail section, it puts the tail out of the way of the exhaust. { "2.2.01:_Fuselage" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.2.02:_Wing" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.2.03:_Empennage" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.2.04:_Main_control_surfaces" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.2.05:_Propulsion_plant" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, { "2.01:_Classification_of_aerospace_vehicles" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.02:_Parts_of_the_aircraft" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.03:_Standard_atmosphere" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.04:_System_references" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.05:_Problems" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "2.06:_References" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, [ "article:topic", "license:ccbysa", "showtoc:no", "licenseversion:30", "authorname:msarnedo", "source@http://www.aerospaceengineering.es" ], https://eng.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Feng.libretexts.org%2FBookshelves%2FAerospace_Engineering%2FFundamentals_of_Aerospace_Engineering_(Arnedo)%2F02%253A_Generalities%2F2.02%253A_Parts_of_the_aircraft%2F2.2.03%253A_Empennage, $ \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}$ $ \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} $$\newcommand{\id}{\mathrm{id}}$ $ \newcommand{\Span}{\mathrm{span}}$ $ \newcommand{\kernel}{\mathrm{null}\,}$ $ \newcommand{\range}{\mathrm{range}\,}$ $ \newcommand{\RealPart}{\mathrm{Re}}$ $ \newcommand{\ImaginaryPart}{\mathrm{Im}}$ $ \newcommand{\Argument}{\mathrm{Arg}}$ $ \newcommand{\norm}[1]{\| #1 \|}$ $ \newcommand{\inner}[2]{\langle #1, #2 \rangle}$ $ \newcommand{\Span}{\mathrm{span}}$ $\newcommand{\id}{\mathrm{id}}$ $ \newcommand{\Span}{\mathrm{span}}$ $ \newcommand{\kernel}{\mathrm{null}\,}$ $ \newcommand{\range}{\mathrm{range}\,}$ $ \newcommand{\RealPart}{\mathrm{Re}}$ $ \newcommand{\ImaginaryPart}{\mathrm{Im}}$ $ \newcommand{\Argument}{\mathrm{Arg}}$ $ \newcommand{\norm}[1]{\| #1 \|}$ $ \newcommand{\inner}[2]{\langle #1, #2 \rangle}$ $ \newcommand{\Span}{\mathrm{span}}$$\newcommand{\AA}{\unicode[.8,0]{x212B}}$, source@http://www.aerospaceengineering.es, status page at https://status.libretexts.org.

t tail vs conventional tail 2023