30

Not all of them need a fin: This is the Horten IV, a flying wing glider that did not need a fin (picture source). Instead, it used spoilers at the wingtips to create yawing moments, and the swept wing helped in improving its weak directional stability. It could afford to do so because it was a glider. The second prototype of a jet-powered flying wing, the ...


20

It appears to be the extension of the aerodynamic fairing between the vertical and horizontal tails (note that the horizontal tail extends outside the vertical one). It can be seen more clearly in the following image. Image from diecastaircraftforum.com. Original image appears to be from airliners.net This type of fairings (usually called bullet fairings) ...


17

There are probably many factors in choosing aluminum vs. composites. A big one is bird strikes. The leading edges are at the highest risk for this. Metal tends to absorb the impact better while retaining its strength, while composites would tend to delaminate and become much weaker. Resistance to in-flight hail must also be considered. (Source Left, Right) ...


17

The double hinged rudder is also a Dehavilland Canada feature on most of its larger designs like the Caribou/Buffalo/Dash 7/Dash 8, where maximum yaw power for a given surface area was a design priority (especially if there are height or other limitations that prevent you from adding more area by going up; in the C-2's case, they also added more surfaces as ...


15

Boeing learned the value of a dorsal strake the hard way: On their civilian version of the B-17, the Boeing 307 Stratoliner, the first Boeing aircraft with a pressurized cabin, the lack of a strake ahead of the fin caused the rudder to lock in the hard-over position when the pilot demonstrated the capability of the aircraft to fly with two dead engines on ...


14

The vertical stabilizer is immobile (if it starts to move, you're in deep shit), and provides stability in yaw (it keeps the aircraft pointed more or less in the direction that it's moving). The rudder is mobile, and typically attached to the aft edge of the vertical stabilizer. It provides controllability in yaw (it allows the aircraft, if necessary, to ...


14

2 hinge lines will give the rudder more authority because it will direct the air more aggressively. We can think of rudders as vertical and two way extending flaps. It's like the difference between a fowler flap and a split flap. fowler will create a curvature with 2 or more components while split flap only hinges down. Fowler flaps increase the Cl of a wing ...


13

Two characteristics drive vertical tail size in airliners: Critical engine out: Here the tail needs to compensate the yawing moment of the live engine on one wing. Yaw damping: This is aided by a yaw damper, but enough damping must remain for the case of a failed damper. Especially the dutch roll eigenmode is driving tail size. On the other hand the tail ...


11

The stabilizer is meant to keep the nose pointing into the wind. Any asymmetry in he wings/fuselage will create a tendency to yaw, you will need to compensate for that. The easiest is a fixed vertical stabilizer at the rear.


9

The underlying function of a VTP (not rudder) is mitigating the lateral-directional eigenmodes of the aircraft (Dutch roll, spiral divergence and roll subsidience). Unless you can guarantee a perfect launch and no crosswind, you will need some kind of yaw damping. For a conventionally-shaped aircraft, Dutch Roll will likely be the worst offender, as roll ...


9

It is the high-frequency shortwave antenna of a 707-321B, specifically Clipper Yankee Ranger N418PA. Also present on the KC-135. You can read about the Antenna Coupler Program from the people involved in its development. You might want to look at What radio frequency bands are associated with the long wire antennas, why do some aircraft have them and ...


8

There is no single formula - the number of factors to consider are too numerous and the load cases are too diverse. Here is an incomplete list: Directional stability: Depending on fuselage size and shape, the tail must be sized to pull the aircraft into the wind direction. The fuselage is destabilising in yaw and the tail is needed to counteract that. ...


8

The C-2 was developed from the E-2 Hawkeye (the one with the big radome). The radome disrupts the airflow behind, hence the need for the inboard fins (source), they help stabilize the airflow and act as fences for the outboard fins. Those inboard fins were not needed for the streamlined radome of the earlier E-1 (shown below). Alternatively they could ...


8

The part I have outlined below is the rudder. That is the only control surface on the vertical stabilizer. The segments on the leading edge are just the leading edge surfaces. One may include an antenna, but they are only segmented for easier manufacturing and assembly. The ones just forward of the rudder are panels that cover the rudder attachment and ...


8

A converging shape at hypersonic speed in a low-pressure medium will produce close to vacuum pressure on its surfaces (hypersonic shielding). A small sideslip angle will only result in a very small pressure difference between both sides. Contrast this with a diverging shape which produces higher than ambient pressure on both sides. In hypersonic flow this ...


7

Doesn't this make it more difficult to control during flight as the surface is way smaller? Design Rudder authority becomes most important (arguably) when one wing-mounted engine fails or is shut down. To combat this on the DC10 The rudder takes up a large proportion of the area of the fin The rudder has dual articulation - there are two vertical hinges....


7

There is no procedure, generally a vertical stabilizer failure makes an airplane uncontrollable, meaning everyone dies. There have been examples where vertical stabilizers failed and people survived, see this question for details. A pilot local to me cut 2/3 of his vertical stabilizer on high tension power wires while scud running and still landed safely. ...


7

It's unlikely that your project will succeed without a vertical fin. Are you aware that there are countless radio-controlled model airplanes and gliders that feature a fixed vertical fin but no rudder? The fin is much more than just a thing to attach the rudder to. The rudder itself is not very necessary if the aspect ratio of the wing is not too high. (...


7

The vertical tail and the horizontal tail are wings, and follow the same construction rules. The span-wise lift distribution is much better if the wing is tapered: more lift at the root, less at the tip. The wing can be built lighter, root area is larger, torsion stiffness is higher. Vortex induced drag is lower. As a reference, from Torenbeek: pages 232 &...


6

From the image you can see that a vertical stabilizer mounted behind the aircraft CG imparts a restoring moment to a yaw disturbance which increases as the yaw movement increases. If the fin were placed on the nose of the aircraft, ahead of the CG, the moment would amplify the yaw disturbance, which is destabilizing. An actively controlled rudder could be ...


6

Differential thrust is not a good way to control the yaw of an airplane. For one thing thrust control has to be extremely quick, if it takes even a second between a control input and the thrust response then you won't have adequate control over the airplane. For another you are entirely dependent on having engine power available for stability, if you lose ...


6

I'm fairly sure (but have no sources to confirm) that the reasons are purely structural. The vertical stabilisers are simply set at a right angle to the horizontal one. This is just the easiest thing to do, and it also provides better clearance with deflected lower rudders. The aerodynamic consequences of this (for such small angles) are pretty minor. Now ...


6

Normally, you would pick a symmetric airfoil. The thickness should be between 9% and 15% to find a good compromise between structural efficiency and maximum side force. Choose a thicker airfoil at the root, a thinner one at the tip and interpolate linearly between them. Of course, for supersonic designs a thinner airfoil should be selected. In some special ...


5

In general, the vertical stabilizer and rudder create a symmetric airfoil. As there is no pressure difference between the two surfaces of the vertical stabilizer, vortices doesn't form, unlike the wing, which is designed to produce lift at normal angles of attack (it is usually cambered, producing lift at zero angle of attack). You're correct that the ...


5

The answer depends on the type of flying wing aircraft. Drag rudders The B2 for example is an example of a flying wing aircraft with rudders. It's just that it doesn't use conventional boat style rudders attached to vertical stabilisers since it doesn't have any vertical stabilisers. Instead it uses drag rudders. There are several different types of drag ...


5

Adding to PK's very informative answer: The 737 Original series did not have this dorsal fin. When the newer series was introduced (737 Classic) with the new 1.6x more powerful engines, the dorsal fin was needed "to cope with greater asymmetric thrust potential." Source: Flight, (1982). The design remained with the 737NG and 737 MAX to keep the cost down: ...


5

Right side slip from left rudder, rudder stalls, what happens? This is comparable to a wing stalling in that it is caused by the rudder/vertical stabilizer exceeding a critical angle of attack. There for, it has passed its maximum deflection potential. The result will be the fuselage slip will reduce until the rudder/vertical stabilizer assembly unstalls....


4

Another very good reason for not changing the tail surface at all is that this is a research aircraft--it is not an ideally optimized aircraft. By basing it on the Tecnam fuselage with no changes, NASA can get a baseline number for the drag reduction allowed by this small high aspect ratio wing vs. the original, much larger wing on the Tecnam twin engine ...


4

There are a few reasons, the first is that the leading edge of the wing will be eroded in service by flying through dust, sand rain, hail etc. Metals are always typically used on such surfaces (termed an 'erosion shield') to reduce this effect, and also because minor damage can be polished out to keep the aircraft looking nice. Aluminum isn't the hardest ...


4

In order to deserve its name, a stabilizer must be located aft of the center of gravity. Once it is shifted ahead, it will become a de-stabilizer. The only way to laterally stabilize an aircraft with a vertical surface ahead of the center of gravity is to make it moveable and actively controlled, either being slaved to a gyro or, even better, continually ...


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