Weight distribution is the apportioning of
weight
In science and engineering, the weight of an object is the force acting on the object due to gravity.
Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar qua ...
within a
vehicle
A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), ...
, especially
cars
A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, people in ...
,
airplanes
An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectr ...
, and
trains
In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and transport people or freight. Trains are typically pulled or pushed by locomotives (often know ...
. Typically, it is written in the form ''x''/''y'', where ''x'' is the percentage of weight in the front, and ''y'' is the percentage in the back.
In a vehicle which relies on gravity in some way, weight distribution directly affects a variety of vehicle characteristics, including
handling,
acceleration
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by t ...
,
traction, and component life. For this reason weight distribution varies with the vehicle's intended usage. For example, a
drag car maximizes traction at the rear axle while countering the reactionary pitch-up torque. It generates this counter-torque by placing a small amount of counterweight at a great distance forward of the rear axle.
In the
airline industry, load balancing is used to evenly distribute the weight of passengers, cargo, and fuel throughout an aircraft, so as to keep the aircraft's
center of gravity
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force ma ...
close to its
center of pressure to avoid losing pitch control. In military transport aircraft, it is common to have a
loadmaster as a part of the crew; their responsibilities include calculating accurate load information for center of gravity calculations, and ensuring cargo is properly secured to prevent its shifting.
In large aircraft and ships, multiple fuel tanks and pumps are often used, so that as fuel is consumed, the remaining fuel can be positioned to keep the vehicle balanced, and to reduce stability problems associated with the
free surface effect
The free surface effect is a mechanism which can cause a watercraft to become unstable and capsize.
It refers to the tendency of liquids — and of unbound aggregates of small solid objects, like seeds, gravel, or crushed ore, whose behavior app ...
.
In the
trucking industry, individual axle weight limits require balancing the cargo when the gross vehicle weight nears the legal limit.
See also
*
Center of mass
*
Center of percussion
*
Load transfer
Weight transfer and load transfer are two expressions used somewhat confusingly to describe two distinct effects:
*the change in load borne by different wheels of even perfectly rigid vehicles during acceleration
*the change in center of mas ...
*
Mass distribution
*
Roll center
*
Tilt test
*
Weight transfer
Weight transfer and load transfer are two expressions used somewhat confusingly to describe two distinct effects:
*the change in load borne by different wheels of even perfectly rigid vehicles during acceleration
*the change in center of mas ...
References
External links
Weight Distribution Calculator
{{DEFAULTSORT:Distribution
Aerospace engineering
Mass
Vehicle technology