somewhat susceptible to damage in rough field landings. Learn more about Stack Overflow the company, and our products. Tailplane forces: The vertical stabilizer should be made stronger and stiffer in order to support all the forces generated by the tailplane. 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. . The control runs to the elevators are more complex,[1] and the surfaces are more difficult to inspect from the ground. A T-tail is a type of empennage where the tailplane (horizontal stabilizer) is mounted to the top of the fin. The conventional tail Lance (or Six) benefits from having air pushed over it by the prop - which means that it is effective at much lower indicated airspeeds - hence allowing you to rotate the wing into a flying attitude (and fly off) at much lower ias than in the T Tail. Rotate at 75 knots. Page 1 of 3 1 2 3 Next > ror76a Well-Known Member. Rudder authority: T-tail design gives you a better rudder authority when flying at a very high AOA and stalls thus preventing a spin. This is because there is generally less surface area needed for a V-Tail (you have two surfaces cutting through the air, not three). Copyright SKYbrary Aviation Safety, 2021-2023. 4. Pros: 1. The aerodynamic consequences of a T-tail have most to do with stability and control in stall and post-stall behaviour, and can be grave. From my reading, they take a longer take off roll and higher speed on approach. Making statements based on opinion; back them up with references or personal experience. This causes an up and left force from the right tail surface and a down and left force from the left surface. Frequent air travellers would have noticed different aircraft for longer and shorter air routes. Get My thoughts on 159 hours in rented T-tail Turbo Arrows One nice feature on my Sky Arrow is that the position of the CG means that if you lower the tail to the ground it stays there: I think the OP was asking about 'real' planes. There were a LOT of legit proposals out there. Disadvantages: Very messy loading and structural design. 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. 7. T-tails must be stronger, and therefore heavier than conventional tails. [3], The design and structure of a T-tail can be simpler. Save my name, email, and website in this browser for the next time I comment. If they were better, they would be used everywhere, and mostly they are not. Given the option, I preferred the conventional tail. It got them more weight and less authority in the TO roll and flare. Nahhthe 90 and 100 were pretty good lookin' birds. The T-tail design is popular with gliders and essential where high performance is required. A stick-pusher can be fitted to deal with this problem. position if empty. 7. The uninitiated pilot can overcontrol a bit at this point, but one soon gets used to it. 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. The main hazard with this design is the possibility of entering aDeep Stall. The best answers are voted up and rise to the top, Not the answer you're looking for? It ensures clean airflow, at least on gulfstream aircraft. From a structural point of view, when flying transonic (or even supersonic) it is not good to have a T-tail configuration because it usually induces flutter on the tail. somewhat difficult to align.. lots of ground clearance when landing. 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. 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. This ensures no dead air zone above the elevator. Popular in fighter jets: Twin Tail, aka Double Vertical Stabilizer. Note: This is really depending on the details, the. The effect of this is that the tail will be pushed left. The "top view" of the tail represents the equivalent area of a flat horizontal tail, and the "side view" of the tail represents half the equivalent . For a T-tail you have a greater chance of deep stall (or super stall as people over the pond seem to call it!) A T-tail is a form of empennage where the horizontal stabilizer is mounted to the top of the fin. Use MathJax to format equations. Twin tail (also referred to as H-tail) or V-tail are other configuration of interest although much less common. ..The T-tail Lances have the same issue. 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. The bending loads are the same..but when placed at the top of the tail the vertical structure must be capable of transmitting those loads and could require additional material (stiffening). Note that the increased leverage means that the horizontal tail can be smaller as well. The simple answer is that they can be more efficient than a conventional tail. This anti-torque system works by placing a multi-bladed fan within a duct in the tail of the helicopter. BERIEV A-40 Albatross) often have T-tails in order to keep the horizontal surfaces as far from the water as possible. Can archive.org's Wayback Machine ignore some query terms? I am not so sure about your argument for added drag @yankeekilo But you do agree that the wake is wider? Quiz: Do You Know These 6 Common Enroute Chart Symbols? Don't have an account? The Verdict: These machines are most useful for applications where space is confined . As I already explained in this answer, the tail is used to create some lift that is required to fulfil the trim relations. (However, T-tail aircraft may be vulnerable to deep stall, see Disadvantages below. 1. obtain an immediate elevator authority by increasing the aircraft power. 10. an aft CG, T-tail aircraft may be more susceptible to a deep stall. I have no idea how those loads are calculated much less how they are combined in order to estimate total stress. Yes the T tail requires a bit more speed for elevator authority to rotate on takeoff. To learn more, see our tips on writing great answers. What is a 'deep stall' and how can pilots recover from it? As a consequence, the tail can be built lower. 4. The horizontal force generated is "wasted" in essence as it does not contribute to the desired pitch outcome. You can reach Swayne at swayne@boldmethod.com, and follow his flying adventures on his YouTube Channel. A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. 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. This is due to the fact that the stabilator sits up out of the propwash, and so is less effective at low airspeeds. This page titled 2.2.3: Empennage is shared under a CC BY-SA 3.0 license and was authored, remixed, and/or curated by Manuel Soler Arnedo via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. in large a/c deep stalls can get quite stable because of fuselage lift and (especially in case of airliners) sweptback wings that move center of pressure forward when stalling. What airframe design is best for stormy weather? The t-tail is a popular design in aircraft with aft fuselage mounted engines (e.g. 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 wonder if full scale requires additional considerations on those tails. What video game is Charlie playing in Poker Face S01E07? Too many people still have the idea that you can give a V-tail the same projected area as the supposedly equivalent conventional tail, which results in an undersized V-tail. Press question mark to learn the rest of the keyboard shortcuts. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. MathJax reference. Confused by the V-Tail? Though on most aircraft the horizontal stabilizer does indeed produce negative lift, for positive stability it is only required that the rear surface flies at lower angle of attack than the forward surface. Lighter: V-tail-designed aircraft is lighter compared to the conventional tail configuration of other aircraft designs. There can also be some slight negatives in terms of efficiently generating pure pitch or yaw moments without also generating unwanted roll moments. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. The T-tail, depending on airspeed, is either very effective or far less effective than a conventional tail, which isnt as prone to abrupt transitions between different flying regimes. ", "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. Sounds good, but if you examine engine FOD statistics, the MD80 actually has a higher rate of engine FOD events than the 73Classic/NG. 8. Loss of Control). Aerodynamically, the V tail provides the same stabilizing forces in both the pitch and yaw axes that the conventional tail does. Joined: Sep 1, 2008 Messages: A T-tail may have less interference drag, such as on the Tupolev Tu-154. 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. Inadequate maintenance of t-tail may lead to loss of control of the aircraft on air. I really don't care either way except to be ready for the different feel on takeoff and the flare. With a minimized counterweight radius, the excavator. T-tail will give you better rudder authority at very high AOA and stalls so as to prevent a spin. Swayne is an author of articles, quizzes and lists on Boldmethod every week. I'd like to learn as much in this area as possible. The T-tail raises the tailplane out of the fuselage drag-hole which can reduce your tailplane effective aspect ratio by 20% or more. 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. This may result in loss of elevator authority and consequently, inability to recover from the stall (i.e. 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. 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. 6. [2][7], For propeller aircraft, a T-tail configuration may reduce pitch control effectiveness if the elevators are outside the propeller slipstream. This article is for you. Rear mounted engines also require more fuselage structure. 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 is this the case? Log-In The T-tail stays out of ground effect for longer than the main wing. 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. It depends on the airplane. Swayne is an editor at Boldmethod, certified flight instructor, and a First Officer on the Boeing 757/767 for a Major US Carrier. Name as many disadvantages and advantages of each that come to mind. What are the advantages of the Cri-Cri's tail and fuselage design? [5][2] Smaller and lighter T-tails are often used on modern gliders. This was necessary in early jet aircraft with less powerful engines. I have heard a conventional tail has better stall recovery characteristics than a T-tail. There's a lot to this, and I'm no aircraft engineer, so if there are any other answers, I'll happily delete this. Others make/models don't. What do labyrinthulids do? As a consequence of the smaller vertical tail, a T-tail can be lighter. This is a lot lower compared to the Fenestron RPM of roughly 3150 RPM (about 50% higher RPM! Compare this to unstable conventional tailed planes such as the Super Hornet, Raptor, and Lightning which are all 50+ AoA fighters. Incorrect Traffic Pattern Entry Leads To Mid-Air Conflict, How To Correct A High Flare During Landing. Kingdom Chromista (= Stramenopila or Heterokonta): - Hyphochytriomycota, the "tinsel-tailed water moulds" They regulate aquatic populations of freshwater planktonic algae, chytrids and oomycetes. We thank you for your support and hope you'll join the largest aviation community on the web. 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. Passenger cabin shots showing seat arrangements as well as cargo aircraft interior, Cargo Aircraft The reason for this is the reversal of the $C_M$ - $\alpha$ slope of T-tails, as depicted below. In addition to this, there is a horizontal stabilizer. receive periodic yet meaningful email contacts from us and us alone. Seaplanes and amphibian aircraft (e.g. Create An Account Here. Other common tail designs: V-Tail, T-Tail, Cruciform, Dual-Tail, Inverted Y. 6. Let me repeat that, just in case you missed it . 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. (Picture from the linked Wikipedia article). The difference lies in the arrangement of their respective wheels. Tell us in the comments below. As we all know, a standard tail uses the rudder for yaw and the elevator for pitch - so how do V-Tail arrangements achieve these two functions? Why is this sentence from The Great Gatsby grammatical? [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. At the other end, the fuselage does this already, so moving the horizontal tail up does not hurt so much there. Apart from that it was fine. I have about 200 hours in a T tail Lance and do some instructing in it. T-tails keep the stabilizers out of the engine wake, and give better pitch control. Quiz: Can You Answer These 7 IFR Checkride Questions? Thanks. But the only other T I've flown is a Skipper. This article highlights the pros and cons of using a V-tail configuration. There is no prop wash over the elevator. With all these advantages, why at least some of commercials does not consider this solution? a lot of guys want the straight tail for the look of a 180 imo. This shape resembles a capital T, giving birth to the moniker of T-tail. For smaller aircraft though it is very difficult to hold nose high enough to overshadow a T-tail. Discussion in 'Hangar Talk' started by SixPapaCharlie, Oct 4, 2015. The vertical tail fin (with the airline logo on it) is technically called the vertical stabilizer. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. This ensures smooth flow and better pitch control of the aircraft. Legal. Aviation Stack Exchange is a question and answer site for aircraft pilots, mechanics, and enthusiasts. I would be keeping that in mind if I ever had an emergency in the plane. The disturbed airflow over a lower stabilizer can make control more difficult at lower speeds. [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. Both military and civil versions, Blimps / Airships T-tails are also sometimes chosen to provide additional separation from non-sky (as in sea planes). T-tails. 2. [1], During normal flying conditions, the tailplane of a T-tail is out of the disturbed airflow behind the wing and fuselage,[2] which provides for more consistent elevator response. 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 considerations in the roe's answer are entirely correct but there might be other factors to take into account. With heavy attachments or loads the zero swing is likely to pitch more than a conventional machine. Are there other reasons for having a T-tail? If a law is new but its interpretation is vague, can the courts directly ask the drafters the intent and official interpretation of their law? 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. 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. The biggest thing I noticed was that soft field landings were a LOT harder (read almost impossible to keep the nose up) in the T-tail Arrow I flew on my CFI checkride vs. the low tail Arrow. Can airtags be tracked from an iMac desktop, with no iPhone? 1. 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. Most of the entries in the NAME column of the output from lsof +D /tmp do not begin with /tmp. Either way it makes more sense to have a pitch up tendency when appying more thrust. But when you got authority, you got it RIGHT NOW.
