Maintenance issues: It will be difficult to climb up there and work on the T-tail if it has some problems. All of the Boeings except the 717 have conventional tails. ", "Summary of spin technology as related to light general-aviation airplanes", https://en.wikipedia.org/w/index.php?title=T-tail&oldid=1142624641, This page was last edited on 3 March 2023, at 13:31. The best answers are voted up and rise to the top, Not the answer you're looking for? ), An aircraft with a T-tail may be easier to recover from a spin, as the elevator is not in a position to block airflow over the rudder, which would make it ineffective, as can happen if the horizontal tail is directly below the fin and rudder.[4]. A T-tail produces a strong nose-down pitching moment in sideslip. Cons: Due to their shorter tail radius, zero swings are likely to have lower rated operating capacities than reduced tail or conventional tail swings designs. And on the landing roll the tail can seem to lose authority all at once with the nose coming down. List price for the PT is a little cheaper than conventional, but you have to buy a plug tail separately. [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. This is because the V tail has projected area in both directions. T-tails must be stronger, and therefore heavier than conventional tails. Copyright SKYbrary Aviation Safety, 2021-2023. This arrangement is different from the normal design where the tailplane is mounted on the fuselage at the base of the fin. basically the best visual inspection I can do and I'll also hop on the wing and move the yoke back and forth so I can see on top of the elevators, basically looking for bird sht and whatnot. 9. 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. Confused by the V-Tail? Don't have an account? T-tails can cause flutter, such as with the Lockheed C-141 Starlifter. The loss of Alaska Airlines Flight 261 was attributed to improper maintenance of the T-tail. 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. What leaves me questioning is that almost all large commercial aircraft feature a conventional tail (B747, B777, A340, A380) while most military aircraft of a similar or larger size have a t-tail (C-17, C-5), and then if you get even larger (AN124, AN225) you're back to having a conventional tail again. Mostly, there is little or no difference in how they perform, certainly not at the level we would notice on our little models. This edition of theFlite Test Aerodynamics Simplified series is all about that weird arrangement of tail feathers you see on some unusual looking airplanes. Observed form behind, this looks like the capital letter T. Sometimes the term is used to refer to an aircraft with such empennage. Different configurations for the empennage can be identified (See Figure 2.13): The conventional tail (also referred to as low tail) configuration, in which the horizontal stabilizers are placed in the fuselage. I have about 200 hours in a T tail Lance and do some instructing in it. Pilots must be aware that the required control forces are greater at slow speeds during takeoffs, landings, or stalls than for similar size aircraft equipped with conventional tails. Quiz: 6 Questions To See How Much You Know About ILS Approaches, Final Video: Your Questions About Mountain Flying, Coffin Corner And Mach Tuck, Explained: Boldmethod Live, Why Fast Jets Have Swept Wings: Boldmethod Live, 6 Aerodynamic Facts About Ailerons Every Pilot Should Know, 5 Things You Learn In Your First 50 Hours Of Instructing, How Airline Pilots Manage Maximum Landing Weight, 8 Tips For Keeping Your Logbooks Clean, Professional, And Interview-Ready, 6 Questions You Should Be Prepared To Answer During Your CFI Interview. Boldmethod 4) Control Forces There were a LOT of legit proposals out there. T-tails keep the stabilizers out of the engine wake, and give better pitch control. And on the landing roll the tail can seem to lose authority all at once with the nose coming down. 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. Learn how and when to remove this template message, "T-time? A T-Tail design is an aircraft configuration in which the tail control surfaces with the horizontal surface are mounted on top of the aircraft fin forming a T look when viewed from the front. - I would guess that a T-tail necessitates a stronger, and thus heavier fin. T-tail of aircraft ( Tu-154) A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. Do I need a thermal expansion tank if I already have a pressure tank? The considerations in the roe's answer are entirely correct but there might be other factors to take into account. Less drag: In a T-tail design, the arm of the CG is made smaller. The fan consists of between 8-18 blades, depending on the aircraft model, and is of a much smaller diameter than a conventional tail rotor system. Why do trijets (3 rear engines) usually have a T-tail instead of a normal tail? Aircraft flying government officials, Helicopters The main hazard with this design is the possibility of entering aDeep Stall. It depends on the airplane. Can airtags be tracked from an iMac desktop, with no iPhone? (https://www.airliners.net/discussions/tech_ops/read.main/138372/). I am not so sure about your argument for added drag @yankeekilo But you do agree that the wake is wider? The vertical tail fin (with the airline logo on it) is technically called the vertical stabilizer. Why was the skid landing gear located so far aft on the X-15? The T-tail configuration, in which the horizontal stabilizer is mounted on top of the fin, creating a "T" shape when viewed from the front. T-tails. Thanks for contributing an answer to Aviation Stack Exchange! document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. As far as I am aware the T-tails I have flown have T-tails for avoiding propwash (PA-44) or aft engine placement (EMB-145). 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. 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 AC isn't prescriptive. 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. Save my name, email, and website in this browser for the next time I comment. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. PoA Supporter Joined: Oct 22, 2008 Messages: 15,568 Location: mass fla Display name: Labyrinthulomycota, the "net slimes" - Labyrinthulida. A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. Designers were worried that an engine failure would otherwise damage the horizontal tail. 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. Is the compressive load from the stabilator that much more than the bending load of the rudder. It has been used by the Learjet family since their first aircraft, the Learjet 23. The arrangement looks like the capital letter T, hence the name. [2][7], For propeller aircraft, a T-tail configuration may reduce pitch control effectiveness if the elevators are outside the propeller slipstream. The control runs to the elevators are more complex,[1] and the surfaces are more difficult to inspect from the ground. Functionally the horizontal stabilizer/stabilator are the same in both cases, providing negative lift, the elevator control and a method for pitch trim. First, it is true that using conventional tail leads to the fact that the airflow over the tail might be disturbed by the main wing and/or the engines and/or the fuselage. [2], T-tail aircraft can have better short-field performance,[2] such as on the Avro RJ-85. Greaser! What is (theoretically) the most efficient shape for an aircraft, assuming you don't have to carry any cargo? Airliners.net is the leading community for discovering and sharing high-quality aviation photography. 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. Already at the earliest time point (i.e., 0.75 hpf) and much more prominently later (i.e., 5.5 hpf), we detected a . The T-tail is very common on aircraft with engines mounted in nacelles on a high-winged aircraft or on aircraft with the engines mounted on the rear of the fuselage, as it keeps the tail clear of the jet exhaust. I think to have the engines underneath the wing and a conventional tail is the better concept (hence why most of the new airliners are like that). With all these advantages, why at least some of commercials does not consider this solution? Tailplane more difficult to clear snow off and access for maintenance and checking. However, T-tails are more likely to enter a deep stall, and is more difficult to recover from a spin. 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. Why is this sentence from The Great Gatsby grammatical? Seaplanes and amphibian aircraft (e.g. Easy to recover from spin: It is easy to recover from a spin with this type of design because the elevator is located above the rudder. Pretty much mirrors my experience with T-Tailed Pipers. The horizontal force generated is "wasted" in essence as it does not contribute to the desired pitch outcome. Source: I study aeronautical engineering and we had to do an exercise involving finding the correct posistion for the HTP to minimize downdraft. This is one reason you'll find T-tail aircraft equipped with elevator down-springs or stick pushers for stall recovery. What airframe design is best for stormy weather? Very interesting, Starlionblue. Tail and Winglet closeups with beautiful airline logos. Disadvantages: Very messy loading and structural design. There are several things to consider in a T-tail design. The conclusion of this study cannot be drawn without a specific example but I hope it is clear for you that stability is really impacted by the choice of the tail. Prevalence over the years While T-tails are a rarity in modern aviation, they were well spotted in the past. [1], The aircraft may be prone to deep stall at high angles of attack, when airflow over the tailplane and elevators is blanked by the wings. Copyright 2023 Flite Test. (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. T-tail is especially popular on modern gliders because of the high performance, the safety it provides from accidental spins, and the safety it provides the stabilizer and elevator from foreign object damage on take-off and landing. Many of the regional jets have T tails. This article highlights the pros and cons of using a V-tail configuration. If they were better, they would be used everywhere, and mostly they are not. 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. Aerodynamically, the V tail provides the same stabilizing forces in both the pitch and yaw axes that the conventional tail does. What, if any, would be the most correct term for the aerodynamic flight control surfaces of SpaceX's Starship? 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. Modern nuclear weapons, such as the United States' B83 bombs, use a similar fission process to . A T-tail is a type of empennage where the tailplane (horizontal stabilizer) is mounted to the top of the fin. Loss of Control). Like many T-tail airplanes, the Arrow IV flies differently than Arrows with conventional tail feathers. It can help to increase the effectiveness of the vertical tail by keeping the air on both sides of it separated. T tail is aerodynamically the most efficient tail type, as the empennage is located above the fuselage and the turbulence created by engines and wing. The simple answer is that they can be more efficient than a conventional tail. avoiding hard de-rotation on touchdown, issues at high AOA, etc)? All rights reserved. The T-tail differs from the standard configuration in which the tailplane is mounted to the fuselage at the base of the fin. The duct is integrated into the tail boom and is usually made of a fiberglass skin. Quiz: Can You Identify These 6 Uncommon Airport Lighting Systems? However, the downwash induced by the main wing on the flow is taken into account (for the cruise conditions) in the design of the tail in order to reduce some negative aspects of the interaction between the main wing and the tail. Yeah, V-tails look cool, and in some modeling instances are easier to run control lines for. Discussion in 'Flight Following' started by kontiki, Aug 5, 2012. Making statements based on opinion; back them up with references or personal experience. With heavy attachments or loads the zero swing is likely to pitch more than a conventional machine. Frequent air travellers would have noticed different aircraft for longer and shorter air routes. What you get is the horizontal stab up out of the prop wash, which reduces inflight vibration -- the reason, I believe, which Piper did it. @p1l0t; you are correct; I was however under the impression that the condition is more or less stable, pushing the tail back into the vortex when it tries to leave (such as when the nose tips over due lack of rear downward pressure). The reason for this is the reversal of the $C_M$ - $\alpha$ slope of T-tails, as depicted below. The structural considerations are of course the increased weight of the vertical tail due to now having to support the forces and moments on the horizontal tail, including strengthening for flutter. The horizontal stabilizer acts like a winglet, reducing induced drag of the rudder. Given the option, I preferred the conventional tail. The 200 and 300 not so much. Yes the T tail requires a bit more speed for elevator authority to rotate on takeoff. Quiz: Can You Answer These 5 Aircraft Systems Questions? I've never met a T-tail that I thought was attractive. Combining both the elevator and the rudder will, as with a conventional empennage, cause the plane to rotate around the yaw and pitch axes. 1. For the elevator, when the stick is pulled back, both ruddervators deflect upwards much like on a normal elevator (just think of this one as having an upward bend in the middle of it). The T-tail lifts the horizontal tail clear of the wing wake (downwash) and propwash, which make it more efficient and hence allow reducing its size and also allows high performance aerodynamics and excellent glide ratio as the horizontal tail empennage is less affected by wing slipstream. Not sure that's a T tail thing, you can hold the nose wheel off for ever in the PC12. an aft CG, T-tail aircraft may be more susceptible to a deep stall. T-tail designs have become popular on many light and large aircraft, especially those with aft fuselage-mounted engines because the T-tail configuration removes the tail from the exhaust blast of the engines. For smaller aircraft though it is very difficult to hold nose high enough to overshadow a T-tail. The fuselage must be made stiffer to counteract this. Beautiful shots taken while the sun is below the horizon, Accidents Use MathJax to format equations. Tailplane more difficult to clear snow off and access for maintenance and checking. The disadvantages ot the T-tail concept are the mentioned deep stalls, maybe a elevator stall during flare, unfavourable C.G. normally I really get into the tail and look at every nut, bolt, rivet, piano hinge and control connection I can see. We thank you for your support and hope you'll join the largest aviation community on the web. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Lighter: V-tail-designed aircraft is lighter compared to the conventional tail configuration of other aircraft designs. Props and jets from the good old days, Flight Decks [1] Rear-mounting the engines keeps the wings clean and improves short-field performance.
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