What is the horsepower in a Jet engine on a 767?
The Boeing 767-300ER is powered by two (2) General Electric
CF6-80C2B2 Gas Turbofan Jet Engines.
The Boeing 767-300ER may also be powered by two (2) Pratt &
Whitney PW4000 Turbofan Jet Engine Powerplants as well.
But this answer will ONLY focus on the General Electric
CF6-80C2B2 Gas Turbofan Jet Engine applicable to the Boeing
767-300ER airliner.
Here are the technical specifications per GE CF6-80C2B2 Gas
Turbofan Jet Engine:
Maximum Static Thrust (Fg) = 51,590 Lbs
Maximum Mass Airflow (Ms) = 1,650 Lbs/Sec
Fan Bypass Ratio (FBR) = 5.31:1
Compressor Pressure Ratio (PR): 23:1
Compressor Efficiency (CE) = 75%
There are two (2) different types of horsepower involved in Gas
Turbine Jet Engines.
1.) Compressor Shaft Horsepower. This is the horsepower required
to keep the
compressor running on a gas turbine engine. The compressor sucks
in air,
compresses it to extremely high pressure, sends it to a
combustion chamber(s)
where it is mixed with kerosene jet fuel and ignited. The high
velocity hot gases
which exit the combustion chamber power a turbine(s) which
is/are connected to
the compressor by a shaft and in turn drive the compressor to
keep the engine
running.
2.) Thrust Horsepower. This is the overall horsepower of the
aircraft while in
flight consolidated with the net thrust rating of the turbine
jet engines. Maximum
static thrust is maximum thrust output while the aircraft and
engine are held at rest
and not permitted to move. Net thrust is the actual thrust used
to move the
aircraft which is the difference in exhaust jet velocity and
forward aircraft speed
times the mass airflow ingested into the engine, divided by
gravitational
acceleration. Net thrust is much lower than the static thrust
rating of the engine.
Total thrust horsepower is the aircraft flight speed divided
into 375 then multiplied
times total net thrust. Thrust horsepower does not exist if the
engine and aircraft
are not moving regardless to the power output or throttle
setting of the engine(s).
I will answer your question with two individual scenarios:
Scenario #1:
The first one will involve one CF6 Gas Turbofan Jet Engine held
at rest on a jet engine stand in 60 degree F outside air
temperature, not permitted to move while operated at Maximum Static
Thrust power setting. In this scenario only Compressor Shaft
Horsepower can be calculated. The Thrust Horsepower is ZERO since
the engine is not moving in forward motion.
Scenario #2:
The second one will involve two (2) CF6 Turbofan Jet Engines
while flying at 240 MPH on the Boeing 767-200ER airliner at maximum
power right after the airliner goes airborne and gets off the
ground, while flying in 45 degree F outside air temperature. In
this scenario, both the Compressor Shaft Horsepower and Thrust
Horsepower can be calculated.
This Wiki Answer is going to be many pages long if I explain
every little detail from here on, so I will just work out the
calculations and produce the correct answers to these two
individual scenarios:
For Scenario #1:
CDT (F) = [((((23^0.263) + (-1)) x (460 + 60))] / (0.75)) + (460
+60)] - [460] = 948.2 F
Tr = 948.2 F - 60 F = 888.2 F
Comp Ms = [(1) / (5.31)] x [1,650] = 310.73
Comp HP = [(888.2 x 0.24 x 310.73 x 778) / (550)] = 93,696.23
HP
The engine will develop 93,696.23 Compressor Shaft
Horsepower.
For Scenario #2:
CDT (F) = [((((23^0.263) + (-1)) x (460 + 45))] / (0.75)) + (460
+45)] - [460] = 907.57 F
Tr = 907.57 F - 45 F = 862.57 F
Comp Ms = [(1) / (5.31)] x [1,650] = 310.73
Comp HP = [(862.57 x 0.24 x 310.73 x 778) / (550)] = 90,992.52
HP
V1 = [(240) x (22 / 15)] = 352 fps
V2 = [(51,590 x 32.2) / (1,650)] = 1,006.8 fps Avg. Core &
Fan Exhaust Nozzles
NT = [((1,650) x (1,006.8 - 352)) / (32.2)] = 33,553.42 Lbt
TNT = [(33,553.42 x 2)] = 67,106.84 Lbt
THP = [(67,106.84) x (240 / 375)] = 42,948.38 HP
90,992.52 Compressor Shaft Horsepower will develop per
engine.
42,948.38 Total Thrust Horsepower will develop amongst both
engines.
---------------------End Wiki Answer----------------------
