Specific fuel consumption at altitude will
- decrease.
- remain constant.
- increase.
Explanation from PART66Online
Climbing into colder, less dense air lowers the engine's specific fuel consumption, so for a given thrust less fuel is burned per unit of output. The improvement in thermal efficiency at altitude is a key reason jet aircraft cruise high; SFC does not stay constant or rise with height.
S
simontay asked · 13 Apr 2012
As I know SFC decreases with altitude.
Community Comments (6)
P
PART66Online
13 Apr 2012
Hey Simon!
Thrust specific fuel consumption, or just TSFC (SFC) increases with altitude. Here is proof link: grc.nasa.gov/WWW/K-12/airplane/ngnsim...
Thrust specific fuel consumption, or just TSFC (SFC) increases with altitude. Here is proof link: grc.nasa.gov/WWW/K-12/airplane/ngnsim...
S
simontay
16 Apr 2012
wiki.answers.com/Q/Is_thrust_specific...
"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."
"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."
P
PART66Online
19 Apr 2012
As I understand, question is about engine, not about aircraft. If I'm right everything is ok. :)
K
kufu
22 Sep 2013
The question says sfc.....not tsfc....!!!!
P
PART66Online
22 Sep 2013
Lets put a point on that.
This question is about SFC and about ENGINE, not about aircraft and flight performance.
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.
This question is about SFC and about ENGINE, not about aircraft and flight performance.
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.
S
Shawez
16 Feb 2015
As per what i know, SFC will increase with altitude since its the amount of thrust per pounds of fuel used per hour, since at high altitude the density of air is less, more fuel must be burnt to compensate this decrease in density to produce that same amount of thrust at sea level,hence resulting in an increase in SFC.
Please Sign In to post a comment.