An airliner has about 8 sets of huge wheels and when the plane takes off the wheels go into the aircraft body. now this action l believe should occupy a very large section of the aircraft right?

l have walked the full lenth of aircrafts because l have traveled alot but never noticed the space the wheels occupy when they go in

why is that?

When u say, ''walked the full length,'' what exactly do u mean?

If u mean, u have walked the full length, inside, that is because the plane is much larger than what u see inside. There r lots of electrical & mechanical spaces/closets, cargo storage (checked baggage & other items). There r large open spaces above ur head & even more below ur feet.

If u mean u have walked outside & have not noticed where the landing gear goes, that may be because the bombay doors that would cover these spaces in flight r probably obstructing ur view. There r large gapping holes where the landing gear & all the mechanics & eletronics to operate them r situated. They r designed to retract/fold up neatly inside & to save space.

The landing gear retract into compartments that are under the cabin floor or in the wings.

Try an internet search on ''retractable landing gear'' for some pictures and diagrams.

walking the full length of the cabin where the passengers stay will not permit u to see the landing gear retracted.

To have a chance at seeing the gears inside the airplane. You need to be under the passenger deck, in the cargo deck. Even then, the wheels retract into the wheel wells ( the cavities built for them inside the airplane) so u usually wo not be able to see them even from the cargo deck.

To get a peek, most of the time, there is a small window in a door or a bulkhead leading to these wheel wells. And that is how u can see them. Passengers will likely never see them retracted inside the airplane.

On many airplanes there is area added to the lower fuselage somewhat like a bubble to accommodate the gear. In any case, there is ample room between the floor of the cabin and the bottom of the fuselage to accommodate the gear when raised.

That is because when you are walking through the cabin, you are walking on the main deck. Below you are the cargo holds. The main landing gear wheel wells sit between the fore and aft cargo holds. The nose gear well sits beneath the cockpit.

On a 747, the nose gear well sits under the first class (usually) section of the aircraft.

So, even though you have ''walked the full length of aircrafts'' you have not walked on the area that the wheels are housed in.

Good engineering. The more you can hide the gear into the fuselage the better. It makes the planes more aerodynamic. Planes like the C-5, C-17, C-130, and MU-2 (longbody) have these bellies that sit around the retracted hear. That is becuase they needed the fuselage space for cargo.

They retract into 'wheel bays'. These are spaces inbuilt in the fuselage, wing fairings or wings. From outside, these are not noticeable with the gear retracted (for aero-dynamic reasons), but those bays which are in the fuselage appear as bulges from the inside. The space they consume inside the fuselage can be termed as a necessary evil, something which we need but also cannot do without. Yes they consume a lot of area.

The main landing gear forms the principal support of the aircraft on land or water & may include any combination of wheels, floats, skis, shock-absorbing equipment, brakes, retracting mechanism with controls & warning devices, cowling, fairing, & structural members necessary to attach any of the foregoing to the primary structure. The auxiliary landing gear consists of tail or nose wheel installations. And yes they r very large on commercial aircraft sitting on the ramp.

However they fold up & r stowed in the wheel wells of aircraft so u will not see them from inside the aircraft.. Most large commercial aircraft such as B-737, B757, B-767. B-777, & B-747 r considered wide bodies with two deck the upper for passengers & the lower deck for cargo & the well wells.

The number & location of wheels on the main gear vary. Some main gears have two wheels. Multiple wheels spread the aircraft is weight over a larger area in addition to providing a safety margin if one tire should fail.

Heavier aircraft may use four or more wheels. When more than two wheels r attached to one strut. the attaching mechanism is referred to as a ''bogie,'' . The number of wheels that r included in the bogie is determined by the gross design weight of the aircraft & the surfaces on which the loaded aircraft may be required to land.

The main landing gear consists of several components that enable it to function. Typical of these r the torque links, trunnion & bracket arrangements, drag strut linkages, electrical & hydraulic gear-retraction devices, & gear indicators.

Devices used in a typical hydraulically operated landing gear retraction system include actuating cylinders, selector valves, uplocks, downlocks, sequence valves, tubing, & other conventional hydraulic components. These units r so interconnected that they permit properly sequenced retraction & extension of the landing gear & the landing gear doors.

Here is how the land gear system works.

The operation of a hydraulic landing gear retraction system is of such importance that is must be covered in some detail. First, consider what happens when the landing gear is retracted. As the selector valve is moved to the ''up'' position, pressurized fluid is directed into the gear up line. The fluid flows to each of eight units; to sequence valves C & D, to the three gear downlocks, to the nose gear cylinder, & to the two main actuating cylinders.

Since the sequence valves r closed, pressurized fluid cannot flow to the door cylinders at this time. Thus, the doors cannot close. But the fluid entering the three downlock cylinders is not delayed; therefore, the gear is unlocked. At the same time, fluid also enters the up side of each gear-actuating cylinder & the gears begin to retract The nose gear completes retraction & engages its uplock first, because of the small size of its actuating cylinder. Also, since the nose gear door is operated solely by linkage from the nose gear, this door closes. Meanwhile, the main landing gear is still retracting, forcing fluid to leave the downside of each main gear cylinder. this fluid flows unrestricted through an orifice check valve, opens the sequence check valve A or B & flows through the landing-gear selector valve into the hydraulic system return line. Then, as the main gear reaches the fully retracted position & engages the spring-loaded uplocks, gear linkage strikes the plungers of sequence valves C & D. This opens the sequence check valves & allows pressurized fluid to flow into the door cylinders, closing the landing gear doors.

The landing gear will retract into the wheel wells, these wheel wells are covered up by the landing gear doors. Before a movement of the landing gear either up or down, the doors will open allowing the gear to enter/leave the wheel well. The gear doors ensure aerodynamics on the underside of the aircraft when the gear is either down or up.

The only way you would be able to clearly see the wheel wells on the ground is if the gear doors have been manually opened.

You can not see the space they occupy unless you walk closer to the wheels and look under the Aircraft, directly where the wheels are sticking out from.

http://b737.org.uk/main_gear_ng_labelled.jpg

If u look up u can see a ''hole'' to the right of the wheel. That is where the gear goes.

Some planes have a door that closes after the gear is locked, 737 is don't.

http://farm3.static.flickr.com/2241/1555697596_2f7c99a6b6.jpg?v=0

When this 777 is gear is retracted & put down, this door closes after its locked in place. (that thing sticking down on the right side of the gear is the door.

Here is the front landing gear of a 757...http://serendipity.li/wot/757ng4ocups.jpg

Retracts right into the body of the plane, where there is a small space for it.
Notice the door.

http://rubenerdshow.com/blog/wp-content/uploads/photo.ansett.737.jpg

Every plane including the 737 has a door in the front landing gear.

Now the space that the landing gear is stored, is just big enough for the landing gear to fit. There may be some space, which is where stowaways find them self is crapmed for hours in the cold dark hellish place.

And u really cant see where the landing gear goes in.

The nose gear folds up beneath the flight deck. The main gear are right behind the wing, under the pressure deck.

You probably do not bump into any baggage either, right? That is because it is in a cargo bin below the cabin floor. So are the wheels, below the floor, l mean.