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There are 2 kinds of thrust, so basically 2 different s... Static thrust is the actual thrust produced, measured in pounds of force. As air density decreases at higher altitudes, the amount of static thrust the engine is able to produce decreases. In order to produce an equivalent amount of thrust at a higher altitude, a higher power setting is required, using more fuel. The other thrust is what we'll call Relative thrust. This would be the power setting itself, such as 65% or 100%. An equivalent power setting across different altitudes will consume similar amounts of fuel. The reason more fuel efficiency is seen at higher altitudes is because drag on the aircraft by air density decreases faster than the power drop-off. Thus, an aircraft needing an 80% power setting to fly at 350 knots at 15,000 feet might only need a power setting of 65% to cruise at the same speed at 28,000 feet. ------
In open propulsion systems, i.e. jets, at high altitude, fuel consumption increases due to a lack of oxygen in the surrounding air, resulting in incomplete combustion. The increase is indirectly proportional to thrust, with the variables being the PO2, air density (temperature), humidity (as water flashes to steam and can improve thrust under certain circumstances), and the overall efficiency of the engine.
The simple is yes, TSFC is "lower" at higher altitudes. The TSFC of a jet engine is generally (there are other factors) a function of temperature and improves up to the altitude of the coldest air temperature. (In the ISA this is the tropopause.) Consequently, assuming lowering temperatures, endurance and range will both increase with altitude. This is why commercial jets are generally flown as high as they can unless adverse winds make it necessary to choose lower altitudes.
Another based on the assumption that the question refers to the engine only, and does not include the efficiencies of the airframe:
Short : HIGH
Long : Thrust Specific Fuel Consumption (TSFC) increases with increasing altitude. This means it is lowest at sea level and increases as you go up.
Therefore ANY turbofan engine will be most efficient at sea level and least efficient at cruising altitude.
If you don't believe me, try it yourself. Go to http://www.grc.NASA.gov/WWW/K-12/airplane/ngnsim.html and select CF-6 engine and see how the TSFC varies with altitude.
CAUTION: Do not confuse TSFC with the efficiency of the engine AND aircraft as a whole. While engines are more efficient at sea level, a jet-powered aircraft as a whole will more efficient (in terms of fuel required to cover a given distance) at an altitude of about 30-35,000 feet.
What else can I help you with?
Where does a gas turbine engine get its best thrust specific fuel consumption?
I think it happens because of the altitude and the fuel burn rate get slower as they clam higher 10,000 fleet
What is thrust specific fuel consumption of turbo shaft?
There is no such thing as thrust specific fuel consumption of a turboshaft engine, as a turboshaft is designed to deliver mechanical power, not thrust. This mechanical power can be converted into electric power by a generator or converted into thrust by a propeller or rotor. Basically, a turboshaft uses jet technology but is an alternative to a piston engine. While thrust specific fuel consumption doesn't exist for a turboshaft, "brake specific fuel consumption" does. It measures the rate of flow of fuel required for a certain amount of power. For example, a specific fuel consumption of 0.2 lbs/h/hp means that for every horsepower the turboshaft produces, it burns 0.2 lbs of fuel each hour.
How do you calculate specific fuel consumption in a plant?
at first we have to know what is specific fuel consumption. From definition we know that- "The amount of fuel required per unit production".
How high up do rockets fly?
A rocket can reach any altitude until it runs out of fuel, provided it has enough thrust
What is specific fuel oil consumption?
consumption of fuel in grams per horse power(kw) one hour
What is the fuel consumption of a fairchild Merlin iiib?
The Fairchild Merlin IIIB typically has a fuel consumption rate of approximately 30 to 35 gallons per hour, depending on the specific operating conditions and flight profile. This twin-engine aircraft is powered by Pratt & Whitney PT6A engines, which are known for their efficiency and reliability. Actual fuel consumption can vary based on factors such as weight, altitude, and speed.
What is the fuel consumption of MD-90?
The McDonnell Douglas MD-90 typically has a fuel consumption rate of around 3,000 to 3,500 pounds of fuel per hour, depending on factors such as passenger load, flight altitude, and specific operating conditions. This translates to approximately 1,350 to 1,600 kilograms per hour. However, fuel efficiency can vary with the aircraft's configuration and operational factors.
What is the difference between a 6cylinder engine and an 8cylinder engine?
Simplistically, 8 cylinder engines have a bigger fuel consumption than 6 cylinder engine because you burn fuel in two more cylinders. But, in the same time, will give you more thrust because you use that extra burned fuel to generate more thrust by moving more pistons. The is very basic. The number of cylinders are not the only factor determining the fuel consumption and thrust of an engine but in general the above statement is true.
What is the fuel consumption of Boeing 787?
There are many variables to figuring fuel consumption such as airspeed, altitude, and throttle settings. The average used for flight planning is 12,500 pounds per hour, or 1840 gallons per hour.
What is the fuel consumption in US gallons of a Boeing 737-800 per nautical mile?
That is dependant on the wind, altitude and speed.
Which term describes the amount of the thrust created per unit of mass of an engine and fuel?
Specific impulse :)
Which term describes the amount of thrust created per unit of mass of an engine and fuel?
Specific impulse :)
