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For this reason, the useful load fraction calculates a similar number, but it is based on the combined weight of the payload and fuel together in relation to the total weight. Propeller-driven airliners had useful load fractions on the order of 25–35%. Modern jet airliners have considerably higher useful load fractions, on the order of 45–55%.
When the weight of the payload and fuel are considered together, it is known as the "useful load fraction". In spacecraft, "mass fraction" is normally used, which is the ratio of payload to everything else, including the rocket structure. [3]
With a fuel fraction of nearly 85%, the GlobalFlyer could carry 5 times its weight in fuel.. In aerospace engineering, an aircraft's fuel fraction, fuel weight fraction, [1] or a spacecraft's propellant fraction, is the weight of the fuel or propellant divided by the gross take-off weight of the craft (including propellant): [2]
As a result of the maximum power theorem, devices transfer maximum power to a load when running at 50% electrical efficiency. This occurs when the load resistance (of the device in question) is equal to the internal Thevenin equivalent resistance of the power source. This is valid only for non-reactive source and load impedances.
The ideal mechanical advantage is the ratio of the force out of the machine (load) to the force into the machine (effort), or =. Applying the constant power relationship yields a formula for this ideal mechanical advantage in terms of the speed ratio:
Feasibility calculations may be affected by seasonality. For example in Finland, capacity factor during the cold winter months is more than double compared to July. [6] While the annual average in Finland is 29.5%, [6] the high demand for heating energy correlates with the higher capacity factor during the winter.
The red curve shows the power in the load, normalized relative to its maximum possible. The dark blue curve shows the efficiency η. The efficiency η is the ratio of the power dissipated by the load resistance R L to the total power dissipated by the circuit (which includes the voltage source's resistance of R S as well as R L):
In engineering, the ultimate load [1] is a statistical figure used in calculations, and should (hopefully) never actually occur.. Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and ultimate loads (limit loads multiplied by prescribed factors of safety).