44 votes
Accepted

Can a plane fly without the vertical stabilizer?

The plane will probably crash. The vertical stabilizer provides stability in yaw to conventional aircraft. Aircraft such as the B-2 manage to provide stability through computer control, and aircraft ...
  • 70.1k
30 votes
Accepted

Why do aircraft need a vertical tailfin, but birds don't? (and lots of fish do?)

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 ...
30 votes

Can a plane fly without the vertical stabilizer?

As always, it depends. There are several things which provide directional stability: The stabilizer, obviously, Positive wing sweep, Fins and pusher propellers. They have to work against the ...
20 votes
Accepted

What are the spiky things on the back of the Antonov-225 vertical stabilizers?

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 ...
  • 99k
18 votes
Accepted

Why are there double hinge lines on the rudders of the Grumman C-2?

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 ...
  • 111k
17 votes
Accepted

Why are the leading edges on the Boeing 787 made from aluminum?

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 ...
  • 70.1k
17 votes

Can a plane fly without the vertical stabilizer?

There are several planes that are designed to fly without vertical stabilizers (like the B-2 bomber, for example). But they have very clever split flaps that make up for the lack of stability/control ...
  • 23.7k
15 votes

Can a plane fly without the vertical stabilizer?

Probably not. One sad example is American Airlines Flight 587. If the plane loses just a small part of of the fin, it might be ok, but if it loses the fin completely two major things happen: The ...
  • 1,611
15 votes

Why doesn't the A320 have a dorsal fin like the 737?

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 ...
14 votes
Accepted

What is the difference between a vertical stabilizer and a rudder?

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 ...
  • 26.3k
14 votes

Why are there double hinge lines on the rudders of the Grumman C-2?

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 ...
  • 456
13 votes
Accepted

Why is the DC10/MD11/TriStar vertical stabilizer noticeably smaller than other contemporary aircraft?

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 ...
11 votes

Is a vertical stabiliser needed for straight line flight in a glider?

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 ...
9 votes
Accepted

Is there a formula to calculate how big a ventral fin should be?

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 ...
9 votes

Is a vertical stabiliser needed for straight line flight in a glider?

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 ...
9 votes

What is this mysterious thing on the vertical stabilizer of the Boeing 707?

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 ...
  • 9,769
8 votes
Accepted

Are the panels in this vertical stabilizer part of the flight controls?

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 ...
  • 70.1k
8 votes

Why is a blunt trailing edge a better stabilizer at hypersonic speeds?

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 ...
7 votes

Why is the DC10/MD11/TriStar vertical stabilizer noticeably smaller than other contemporary aircraft?

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 ...
7 votes

What is the correct procedure in case of vertical stabilizer failure?

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, ...
  • 50.9k
7 votes

Is a vertical stabiliser needed for straight line flight in a glider?

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 ...
  • 18.3k
7 votes

Why are Vertical tails generally tapered?

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 ...
  • 59.2k
6 votes

Could the vertical stabilizer be removed on the NASA X-57?

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 ...
  • 50.9k
6 votes

Why aren't there aircraft with forward-mounted vertical stabilizers?

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 ...
  • 17.8k
6 votes

What is the aerodynamic reason that the An-225's vertical stabilizers are not simply vertical?

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 ...
  • 8,745
6 votes
Accepted

How do I choose the vertical tail's airfoil?

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 ...
5 votes
Accepted

Do vertical stabilizers create vortices like wingtips do?

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 ...
  • 99k
5 votes

How can a flying wing style airplane recover from a spin without a vertical stabilizer?

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 ...
  • 2,396

Only top scored, non community-wiki answers of a minimum length are eligible