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The particular take-off distance required may be shorter than the available runway length. In this case a lower thrust may be used. Lower thrust settings increase engine life and reduce maintenance costs. The take-off thrust available from a civil engine is a constant value up to a particular ambient temperature.
is the initial value of the state vector; is the final value of the state vector; Sometimes, it is also useful to subject the system to control constraints because in case of continuous low-thrust transfer, there are always bounds on the availability of thrust.
The delta-v required to return from Near-Earth objects is usually quite small, sometimes as low as 60 m/s (200 ft/s), with aerocapture using Earth's atmosphere. [10] However, heat shields are required for this, which add mass and constrain spacecraft geometry. The orbital phasing can be problematic; once rendezvous has been achieved, low delta ...
The thrust-to-weight ratio is usually calculated from initial gross weight at sea level on earth [6] and is sometimes called thrust-to-Earth-weight ratio. [7] The thrust-to-Earth-weight ratio of a rocket or rocket-propelled vehicle is an indicator of its acceleration expressed in multiples of earth's gravitational acceleration, g 0 .
A rocket's required mass ratio as a function of effective exhaust velocity ratio. The classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity and can thereby move due to the ...
The calculation is somewhat different for reciprocating and turboprop engines which rely on a propeller for propulsion since their output is typically expressed in terms of power rather than thrust. The equation for heat added per unit time, Q , can be adopted as follows:
Absolute value – In mathematics, the absolute value or modulus |x| of a real number x is the non-negative value of x without regard to its sign. Namely, |x| = x for a positive x, |x| = −x for a negative x (in which case −x is positive), and |0| = 0. For example, the absolute value of 3 is 3, and the absolute value of −3 is also 3.
TSFC or SFC for thrust engines (e.g. turbojets, turbofans, ramjets, rockets, etc.) is the mass of fuel needed to provide the net thrust for a given period e.g. lb/(h·lbf) (pounds of fuel per hour-pound of thrust) or g/(s·kN) (grams of fuel per second-kilonewton). Mass of fuel is used, rather than volume (gallons or litres) for the fuel ...