Why do planes need tail wings?

Question

Why do planes need tail wings? Explain why. Helps is appreciated. :]

Answer 1

Odd, Cofeebuzz's answer is the opposite of the way I learned it, and I think I'm right. The stabilizer prevents the plane for nosing up too much. It provides upward lift that pushes the nose down.

I believe that I'm right and Cofeebuzz is wrong for two reasons:

1) Velocity stability. Imagine if something makes the plane go a bit faster, maybe favorable wind increases. Lift will increase on the main wings. In Coffeebuzz's scenario, the tail will produce more downward force, increasing the angle of attack, leading to more lift on the main wing. This would be unstable. In my scenario, the tail produces more upward force, causing a nose down effect, reduction in angle of attack, reduction in lift, and therefore stability.

2) Pitch stability. Imagine if some turbulence causes an increase in the angle of attack by rotating the plane a bit. Both lift in the main wing and the stabilizer will increase. In my scenario, this means, again, a nose down force, combating the instability. In Coffeebuzz's scenario, this means a nose up force, worsening the instability.

I've tried to look this up from an authoritative source, and I may be missing something. But, again, I believe I am correct. The stabilizer creates additional lift, and a nose down force that improves stability. Most importantly, it allows the plane to not require huge amounts of nose down control inputs as it speeds up or huge amounts of nose up control inputs as it slows down, improving controllability.

Answer 2

the tail section on an aircraft is to direct a flight up or down (pitching, the nose up or down). thats why a tail section in an aircraft is very important, without it, no aircraft in the world could even take-off the ground. another thing that the tail section do on an aircraft is "yawing", to direct the aircraft left or right in the vertical axis of an airplane.

Answer 3

The front wings does the heavy lifting.

It is the tail wing that gives the airplane direction.  Also without tail wings, the plane would nose dive in a second.

Good Luck...

Answer 4

1.  Allows the plane to travel at slower speeds.

2. So elevators can be fitted (these allow the plane to pitch up or  

down).

3.  Makes the plane more balanced.

Answer 5

tail wings? they havn't used those since the civil war!!!

Answer 6

They don't unless it's part of the design ------------------------ B2 bomber.

Answer 7

They dont always need tailplanes. Most pure delta winged aircrafts are designed without them.

The tailplanes are there mainly for holding the surface that provides the pitch control. The aerodynamic forces generated by the deflection of the elevators (the control surface associated with the tailplanes) provides the pitching moment that raises or lowers the nose of the aircraft.

Answer 8

In the classic configuration (wing in the middle, tail in the rear) the horizontal tail provides static stability, as any pitching up (and thus increase in lift) would be imply a reduction in the effective angle of (negative) attack of the tail and a reduction of the downforce there, making the plane less prone to keep pitching up, and actually having a tendency to reduce its pitch up (and conversely if the airplane was to pitch down). This implies stability.

With advanced computer control, it is possible to make plane "artificially" stable, meaning that the tail is not always required in all cases anymore. But of course, the certification authorities have to be convinced that the computers are foolproof and redundant enough to handle likely failures; this requirement does not exist in military planes.

Answer 9

They don't necessarily. Have you ever seen the stealth bomber? It's just a flying wing.

Answer 10

So they can back up.

Answer 11

in short

they're there to provide stability, and vertical control (pitch)

it makes the nose go up or down)

not always needed, most aircraft have them for the reasons mentioned above.

tail wings, or horizontal stabilizer, is there to stabilize. it does not provide any significant amount of lift.

Answer 12

Once again, Coffeebuzz has put into few words (correctly)

to explain a complex question that could take pages of text to explain.  For further information, research airplane stability.

Bravo Zulo Coffee....

For you Joel...From the FAA's handbook of aeronautical knowledge

Most airplanes are designed so that the wing’s center

of lift (CL) is to the rear of the center of gravity. This

makes the airplane “nose heavy” and requires that

there be a slight downward force on the horizontal

stabilizer in order to balance the airplane and keep

the nose from continually pitching downward.

Compensation for this nose heaviness is provided

by setting the horizontal stabilizer at a slight negative

angle of attack. The downward force thus

produced, holds the tail down, counterbalancing

the “heavy” nose. It is as if the line CG-CL-T was

a lever with an upward force at CL and two downward

forces balancing each other, one a strong

force at the CG point and the other, a much lesser

force, at point T (downward air pressure on the

stabilizer). Applying simple physics principles, it

can be seen that if an iron bar were suspended at

point CL with a heavy weight hanging on it at the

CG, it would take some downward pressure at

point T to keep the “lever” in balance.

Even though the horizontal stabilizer may be level

when the airplane is in level flight, there is a

downwash of air from the wings. This downwash

strikes the top of the stabilizer and produces a

downward pressure, which at a certain speed will

be just enough to balance the “lever.” The faster

the airplane is flying, the greater this downwash

and the greater the downward force on the horizontal

stabilizer (except “T” tails).  In airplanes

with fixed position horizontal stabilizers, the

airplane manufacturer sets the stabilizer at an angle

that will provide the best stability (or balance)

during flight at the design cruising speed and

power setting.

If the airplane’s speed decreases, the speed of the airflow

over the wing is decreased. As a result of this

decreased flow of air over the wing, the downwash

is reduced, causing a lesser downward force on the

horizontal stabilizer. In turn, the characteristic nose

heaviness is accentuated, causing the airplane’s nose

to pitch down more. This places the airplane in a

nose-low attitude, lessening the wing’s angle of

attack and drag and allowing the airspeed to

increase. As the airplane continues in the nose-low

attitude and its speed increases, the downward force

on the horizontal stabilizer is once again increased.

Consequently, the tail is again pushed downward and

the nose rises into a climbing attitude.

As this climb continues, the airspeed again decreases,

causing the downward force on the tail to decrease

until the nose lowers once more. However, because

the airplane is dynamically stable, the nose does not

lower as far this time as it did before. The airplane

will acquire enough speed in this more gradual dive

to start it into another climb, but the climb is not so

steep as the preceding one.

After several of these diminishing oscillations, in

which the nose alternately rises and lowers, the airplane

will finally settle down to a speed at which

the downward force on the tail exactly counteracts

the tendency of the airplane to dive. When this

condition is attained, the airplane will once again

be in balanced flight and will continue in stabilized

flight as long as this attitude and airspeed are

not changed.

A similar effect will be noted upon closing the

throttle. The downwash of the wings is reduced

and the force at T is not enough to

hold the horizontal stabilizer down. It is as if the

force at T on the lever were allowing the force of

gravity to pull the nose down. This, of course, is a

desirable characteristic because the airplane is

inherently trying to regain airspeed and reestablish

the proper balance.

Power or thrust can also have a destabilizing effect

in that an increase of power may tend to make the

nose rise. The airplane designer can offset this by

establishing a “high thrustline” wherein the line of

thrust passes above the center of gravity.  In this case, as power or thrust is

increased a moment is produced to counteract the

down load on the tail. On the other hand, a very

“low thrust line” would tend to add to the nose-up

effect of the horizontal tail surface.

Thrust line affects longitudinal stability.

It can be concluded, then, that with the center of gravity

forward of the center of lift, and with an aerodynamic

tail-down force, the result is that the airplane always

tries to return to a safe flying attitude.

Answer 13

By tail wings, I presume you mean the 'tail empennage'. These provide the aircraft with horizontal and linear stability. The elevators control the pitching, while the rudder controls the direction/yaw.

Answer 14

to steer and go up and down

Answer 15

The "tail wing" is technically called the horizontal stabilizer.  It's actually an upside-down wing, meaning it provides lift in the downward direction instead of upward.

I'll try not to get too deep into aerodynamic theory... But the basics - the wings support the weight of the plane by providing lift.  The center of gravity of the airplane - the "pivot point" where all of the axes of movement center on, is not directly below where lift is acting - it's actually in front of the center of lift.  This means the upward lift of the wings would pitch the airplane nose down about the center of gravity.  The horizontal stabilizer balances the nose-down tendency by providing a small tail-down force.