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How to Design a Aircraft Landing Gear System and How does it Work?

I'm in Final Year of Aerospace Engineering Degree course, and as part of my Final year project I have been asked to design a Tricycle Landing Gear system for a Medium Size Private Jet aircraft.
So far I have got very limited resources and I havn't found good source to tell me how to design the layout including all the calculations for weight, roll, angle of turn and also which system to use for the retraction and extension of Landing Gear.

I Would very much appreciate it if anyone out there could give me some information as I need them ASAP.

Many Thanks for you kindness.

Reza

Look at books on rigid body dynamics and design of machinery. More specifically, look up four-bar linkages. These linkages are ideal for landing gear due to their mechanical advantage and the ability to 'lock' in a specific configuration.

The turn radius (which is what I believe you want) will depend upon the separation distance (D) between the rear two (non-swiveling) wheels of the 'tricycle' gear. The minimum possible turn radius (Rmin) will be half the separation distance (D).

Rmin = 0.5 *D

So to enable 'tight' turns you might want to put the rear wheels close together (small D). However, when you do that, the plane will be more likely to tip over during tight turns at high velocity. The designer's challenge is to balance a tight turn radius will adequate roll support.

To find the minimum separation between the two rear wheels consider the following force diagram. You want the plane to be able to execute a turn at radius R with forward velocity Vmax. The centripetal acceleration vector has magnitude (Vmax)^2/R and is oriented towards the hypothetical center of the circle that descibes the turn's radius. If you imagine looking at the rear of a plane turning right, the centripetal acceleration vector orginiates from the center of mass and points horizontally towards the right The acceleration of gravity pulls the plane downward towards the tarmac and has a magnitude of g=9.81 m/s^2. So the net acceleration on a turning airplane is a vector sum of these two accelerations. The 'sum' vector should point mostly downward. If you extend this vector, it should intersect the tarmac somewhere between the two rear wheels. If it doesn't, the plane will flip over during the turn.

You can use the above visualization to come up with a crieria for minimum distance between the rear wheels:

theta = arctan(g/(Vmax^2/R))

This equation states that the angle theta is the angle between the sum vector and the tarmac.

theta = arctan (L/ (.5*Dmin))

Theta is also the angle between the center of mass and the point where a rear wheel is touching the tarmac. The landing gear length (L) is the vertical distance between the tarmac and the plane's center of mass.

Equating the above two equations, we have

Dmin = 2*L * (Vmax^2)/(R*g)

Now as the designer you have to play around with D (separation distance between the two rear wheels) and L (landing gear length) to acheive an acceptable Rmin and Vmax.

Considering both turning radius and roll resistance, you want rear landing gear that are short (small L) and reasonably close together but not less than Dmin.

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what, generally, are the parts of the landing gear of an airplane?

For commercial aircrafts. Names of parts appreciated. Also the ways it works. Maintenance and upkeep optional.

The undercarriage or landing gear is the structure (usually wheels) that supports an aircraft when it is taxiing or stationary. The assembly usually has wheels and some sort of shock absorber apparatus, but sometimes skis for snow or floats for water, and skids or pontoons (helicopters). To decrease drag in flight the undercarriages on many aircraft, particularly large modern ones, retract behind doors which close flush with the fuselage.

A design for retractable landing gear was first seen in 1876 in plans for an amphibious monoplane designed by Frenchmen Alphonse Pénaud and Paul Gauchot . Aircraft with at least partially retractable landing gear did not appear until 1917, and it was not until the late 1920s and early 1930s when such aircraft became common. By then, aircraft performance was improved to the point where the aerodynamic advantage of a retractable undercarriage justified the added complexity and weight.

Wheeled undercarriages come in two types: either taildragger, where there are two main wheels towards the front of the aircraft and a single, much smaller, wheel or skid at the rear; or tricycle undercarriage where there are two main wheels (or wheel assemblies) under the wings and a third smaller wheel in the nose. Most modern aircraft have tricycle undercarriages or variants thereof. Taildraggers are considered harder to land and take off, and usually require special training. Sometimes a small tail wheel or skid is added to aircraft with tricycle undercarriage, in case the tail strikes the ground during take-off. The Concorde, for instance, had a retractable tail "bumper" wheel.

As aircraft grow larger, they employ more wheels to cope with the increasing weights. The Airbus A340-500/-600 has an additional four-wheel undercarriage bogie on the fuselage centreline. The Boeing 747 has five sets of wheels, a nose-wheel assembly and four sets of four-wheel bogies. A set is located under each wing, and two inner sets are located in the fuselage, a little rearward of the outer bogies. Tricycle undercarriage aircraft are usually steered by the leading wheel(s) when taxiing. On the Boeing 747 the two inner bogies, and on the Boeing 777 the last two wheels on each leg, are also steerable with the nose wheels in order to reduce the lateral stresses on the undercarriage.

Some planes use wheels only for take off and drop them afterwards to gain the improved streamlining without the complexity, weight and space requirements of a retraction mechanism. In this case, landing is achieved on skids or similar simple devices. Historical examples include the Messerschmitt Me 163 and the Messerschmitt Me 321.

Other examples of unusual undercarriage configuration include the Hawker-Siddeley Harrier, which has two mainwheels in line astern under the fuselage (called a bicycle or tandem layout) and a smaller wheel near the tip of each wing (on second generation Harriers, the wing is extended past the outrigger wheels to allow greater warloads to be carried). A multiple tandem layout was used on some military jet aircraft during the 1950s such as the Lockheed U-2, Myasishchev M-4, Yakovlev Yak-25, Yak-28 and the Boeing B-47 because it allows room for a large internal bay between the main wheels. A variation of the multi tandem layout is also used on the B-52 Stratofortress which has four main wheel bogies underneath the fuselage and a small outrigger wheel supporting each wing-tip. The B-52's landing gear is also unique in that all four pairs of main wheels can be steered. This allows the landing gear to line up with the runway and thus makes crosswind landings easier (using a technique called crab landing).

A landing gear which is economical to produce is a simple wooden arch, laminated from ash, as used on some homebuilt aircraft. A recent addition to this type of gear is the fixed-gear RJ.03 IBIS canard homebuilt aircraft.

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