L1: Landing Gear Systems

Landing Gear

supports the aircraft during landing and while it is on the ground

Landing Gear

is the principal support of the airplane when parked, taxing, taking off, or landing

Hard Surfaces

•Most landing gear have wheels to facilitate operation to and from _____ such as airport runways

Skids

____ are found on helicopters, baloon gondolas, and in the tail area of some tail dragger aircraft

Fixed Gear

Simple aircraft that fly at low speeds generally have a ___

Stationary

Fixed gear means that the gear is ____ and does not retract for flight

Retractable

More complex aircraft have ____ landing gear

1. Skids

2. Skis

3. Floats or pontoons

Basic landing gear types including those with wheels

Amphibious aircraft

____ are designed with gear that allow landings to be made on water or dry land. They used Pontoons for water

Skis

A similar system is used to allow the ____ and wheels on aircraft that operate on both slippery, frozen surfaces and dry runways. It is retractable to allow the use of wheels when needed

• Tail-wheel type landing gear (conventional gear)

• Tandem landing gear

• Tricycle-type landing gear

Three basic arrangements of landing gear:

Tail wheel-type landing gear

also known as conventional gear because many early aircraft use this type of arrangement.

Forward

The main gear are located ___ of the center of gravity, causing the tail to require support from a third wheel assembly

Tandem Landing Gear

this type of landing gear has the main gear and tail gear aligned on the longitudinal axis of the aircraft. (Only few are designed with this)

Sailplanes

commonly use tandem gear, although many only have one actual gear forward on the fuselage with a skid under the tail. A few military bombers, such as the B-47 and B-52, have tandem gear.

Tricycle-Type Landing Gear

The most commonly used landing gear arrangement is the _____ landing gear. It is comprised of main gear and nose gear.

1. Forceful application of the brakes

2. Better visibility from the flight deck

3. Prevents ground-looping of the aircraft

Benefits of Tricycle-type landing gear on large and small aircrafts:

Rudder Pedals

On light aircraft, the nose gear is directed through mechanical linkage to the ____

Tiller

Heavy aircraft typically utilize hydraulic power to steer the nose gear. Control is achieved through an independent ____ in the flight deck .

Fixed and Retractable

Further classification of aircraft landing gear can be made into two categories:

Fixed landing gear

Many small, single engine light aircraft have _____, as do a few light twins. This means the gear is attached to the airframe and remains exposed to the slipstream as the aircraft is flown.

Retractable landing gear

_____ stow in fuselage or wing compartments while in flight. Once in these wheel wells, gear are out of the slipstream and do not cause parasite drag.

Converting energy into heat energy

Shock absorbing - the shock is absorbed by?

Weight Force

It cushions the aircraft ____ on the ground in addition to supporting the aircraft for taxi, the forces of impact on an aircraft during landing must be controlled by the landing gearshock absorbers.

Non-shock absorbing

the shock energy is altered and transferred throughout the airframe at a different rate and time than the single strong pulse of impact.

Leaf-Type Spring gear

Many aircraft utilize flexible spring steel, aluminum, or composite struts that receive the impact of landing and return it to the airframe to dissipate at a rate that is not harmful.

Leaf-Type Spring Gear

The gear flexes initially and forces are transferred as it returns to its original position.

Rigid

Shock load transfer to the airframe is direct to this design. Before the development of curved spring steel landing struts, many early aircraft were designed with ___, welded steel landing gear struts.

Bungee Cord

Commonly used in non-shock absorbing landing gear. The geometry of the gear allows the strut assembly to flex upon landing impact. It is positioned between the rigid airframe structure and the flexing gear assembly to take up the loads and return them to the airframe at a non-damaging rate.

Piper Cub Bungee Cord Landing Gear

_____ transfers landing loads to the airframe

Mooney

Rubber, donut-type shock transfer is used on some ____ aircraft