A glider has many of the same parts as an airplane:

* fuselage
* wings
* control surfaces
* landing gear

But, there are significant differences in these parts on a glider, so let's take a look at each.

Fuselage
Gliders are as small and light as possible. Since there is no large engine taking up space, gliders are basically sized around the cargo they carry, usually one or two people. The cockpit of a single-seat glider is small, but it is large enough for most people to squeeze into. Instead of sitting upright, pilots recline with their legs stretched out in front of them. The frontal exposure of the pilot is reduced and the cross-sectional area of the cockpit can be substantially smaller.


The glider's fiberglass construction enables a sleek, smooth design.

Gliders, along with most other aircraft, are designed to have skins that are as smooth as possible to allow the plane to slip more easily through the air. Early gliders were constructed from wood covered with canvas. Later versions were constructed from aluminum with structural aluminum skins that were much smoother. However, the rivets and seams required by aluminum skins produce additional drag, which tends to decrease performance. In many modern gliders, composite construction using materials such as fiberglass and carbon fiber are quickly replacing aluminum. Composite materials allow aircraft designers to create seamless and rivet-less structures with shapes that produce less drag.

Wings
If you look at a glider next to a conventional powered plane, you'll notice a significant difference in the wings. While the wings of both are similar in general shape and function, those on gliders are longer and narrower than those on conventional aircraft. The slenderness of a wing is expressed as the aspect ratio, which is calculated by dividing the square of the span of the wing by the area of the wing.

Glider wings have very high aspect ratios -- their span is very long compared to their width. This is because drag created during the production of lift (known as induced drag) can account for a significant portion of the total drag on a glider. One way to increase the efficiency of a wing is to increase its aspect ratio. Glider wings are very long and thin, which makes them efficient. They produce less drag for the amount of lift they generate.

The aspect ratio of a wing is the wingspan squared divided by the area of the wing. The glider has a much larger aspect ratio than a conventional plane.

Why don't all planes have wings with high aspect ratios? There are two reasons for this. The first is that not all aircraft are designed for efficient flight. Military fighters, for example, are designed with speed and maneuverability well ahead of efficiency on the designer's list of priorities. Another reason is that there are limits to how long and skinny a wing can get before it is no longer able to carry the required loads.

Control Surfaces
Gliders use the same control surfaces (movable sections of the wing and tail) that are found on conventional planes to control the direction of flight. The ailerons and elevator are controlled using a single control stick between the pilot's legs. The rudder, as in conventional aircraft, is controlled using foot pedals.


Mouse-over the control names to see where they're located on the glider.

* Ailerons
Ailerons are the movable sections cut into the trailing edges of the wing. These are used as the primary directional control and they accomplish this by controlling the roll of the plane (tilting the wing tips up and down). Ailerons operate in opposite directions on each side of the plane. If the pilot wants to roll the plane to the right, he moves the control stick to the right. This causes the left aileron to deflect down (creating more lift on this side) and the right aileron to deflect up (creating less lift on this side). The difference in lift between the two sides causes the plane to rotate about its long axis.

* Elevator (horizontal stabilizer)
The elevator is the movable horizontal wing-like structure on the tail. It is used to control the pitch of the plane, allowing the pilot to point the nose of the plane up or down as required.

* Rudder (vertical stabilizer)
The rudder is the vertical wing-like structure on the tail. It is used to control the yaw of the aircraft by allowing the pilot to point the nose of the plane left or right.

Landing Gear
Another way to reduce the size of an airplane is to reduce the size of the landing gear. The landing gear on a glider typically consists of a single wheel mounted just below the cockpit.

What happend to the tale unit??? Captain Abbas ben Farnas

see the the control surfaces section and the elevator,rudder section capt!!!u will find what u need.


Best Regards
Abbas Bin Firnas

All parts and air dynamic described at the article

it’s a brief

The elevator is the movable horizontal wing-like structure on the tail
Dear Phantom quoting you the elevator (and the rudder) are on the tail so what does the tail do. the elevator and the rudder are used for directional controle, but what dose the tail do?

The tail unit is important for the aircraft it’s is the stabilizer

It's for Pitching ... and Stabilizer ... is that correct!

Yes, that's right.

the idea is to creat a foce to change the status of the A/C, so if you need to change the pitch of the A/C you'll have to provide a moment force around the CG. That force is formed when you change the the status of the elevator up or down, thus the force on it will change due to the aerodynamic force of lift on the elevator part, thus either to pull the pitch angel to a higher position or to push it down or to hold it still.

so when the tail goes up, the nose goes down, and vice versa

Click here for more details

yours

Thanks alot for the information CFI Ghassan.

while am reading, I couldn't help it to think about the effect of the pitch on the angel of attack ... specially if you add to this formula a low demsity atmospher ... wouldn't we have whay you call a "Stall"?!!! is that right?!! .. and what is the best way to get out of this setuation?!! .. I feel so sure that what ever the pilot well do he still well loss a lot of altitude!!!!! is that true?!!!

Am so soryy if am aking alot .. I have never piloted anything ...

first of all I'm not a CFI. I'm still a P

The state of STALL happens when there's no sufficient lift on the wings because the flow of the air around the wings will not generate a suitable pressure-difference between the upper side of the wing and the lower side. thus the A/C will FALL.

this is called stall. the range of the Angle of Attack (AoA) will affect the coficient of lift (CL) as it's increasing with the increase of AoA till the AoA is around 15 degrees, after that CL will start to decrease rapidly with the increase of AoA, and when there's no sufficeint lift you STALL

the procedure to get out of Stall is to push the nose down and get accl. then to pull the A/C again

but you also will lose alot of altitude so be ware not to hit the ground before you recover the A/C.

So sorry P Ghassan ... well .. inshallah you'll be a CFi oneday soon ...

I see ... here where I brains start to be an unpleasant trip we may take ...
You see .. I do understand that the cause of the stall is the drop in lift ... but isn't it the same .. I mean .. when the the AoA is over 15 degrees on an certain speed (case A) the lift would be greater ... if the speed (case B) drops down to a certain kts where the lift can no longer support the weight .. wich the makes the drag effect the lift ...
ok ... if what I think is correct .. then .. if the density of the air is low then even if the AoA and knt speed in case A which used to generate greater lift now it would not .. and we well have a stall ...

I know .. I ask and talk too much .. but please help ... my brain spins alot in average during the day ...

first of all I'm not a CFI. I'm still a P

The state of STALL happens when there's no sufficient lift on the wings because the flow of the air around the wings will not generate a suitable pressure-difference between the upper side of the wing and the lower side. thus the A/C will FALL.

this is called stall. the range of the Angle of Attack (AoA) will affect the coficient of lift (CL) as it's increasing with the increase of AoA till the AoA is around 15 degrees, after that CL will start to decrease rapidly with the increase of AoA, and when there's no sufficeint lift you STALL

the procedure to get out of Stall is to push the nose down and get accl. then to pull the A/C again

but you also will lose alot of altitude so be ware not to hit the ground before you recover the A/C.

The lift is affected with th denisty of the air surrounding the wing, you can see that espicaily when you get to hogh altitudes, thus you'll need to increase the lift force either by increasing the speed or changing the AoA, or to get to a lower altitude before you get into a stall.

The aerodynamic lift formula does count the density of the air, and there's a universal chart for the density cooficent vs altitude. you can make use of it.

Click here for further details

yours

Thank you very much P Ghassan for your continual support.

It is nice to find supporting information .. supporting in sence of approving or denying the point that you discuse ...

Another powerful resource I advice verybody to read is "THIS ONE" .... it is a study of an all lifting low aspect ratio configuration airoplane feasibility study done by California State Polytechnic University.

thanx alot for the interesting info in the PDF file...

we hope that some day we'll be able to construct a better one ourselfs.

Yeeessssssssss ... this is the talking man ...
why don't we start a topic studying the features of such an airoplane .. and how to construct it .. just like those guyz with the SWIFT ...

we can debate on the compromise that we have to approch in constructing such a plane ....