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| General Electric CF6 | |
|---|---|
.jpg) General Electric CF6 during testing at NASA'sGlenn Research Center in 1979 | |
| General information | |
| Type | Turbofan |
| National origin | United States |
| Manufacturer | GE Aviation |
| Major applications | |
| Number built | 8,300 (2018)[1] |
| History | |
| First run | 1971 |
| Developed from | General Electric TF39 |
| Developed into | General Electric LM2500 General Electric LM6000 |
TheGeneral Electric CF6, US military designationsF103 andF138, is a family ofhigh-bypass turbofan engines produced byGE Aviation. The CF6, based on theTF39, the first high-thrust, high-bypass jet engine, has been used in a wide variety of airliners, but has been superseded by theGEnx in newer airliners.[1]
The CF6 core has been used for theLM2500, LM5000, andLM6000 industrial and marine gas turbines.
After developing theTF39 for theC-5 Galaxy in the late 1960s, GE offered a higher thrust variant for civilian use, the CF6.[2] GE proposed the CF6 toEastern Airlines, for theLockheed L-1011 and theMcDonnell Douglas DC-10. Lockheed used theRolls-Royce RB211 as its exclusive engine, but the CF6 was chosen for the DC-10, and entered service in 1971. It was also selected for versions of theBoeing 747, and then for theAirbus A300,A310 andA330,Boeing 767,Lockheed C-5M Galaxy, andMcDonnell Douglas MD-11.
By 2018, GE had delivered more than 8,300 CF6s: 480 -6s, 2,200 -50s, 4,400 -80C2s, more than 730 -80E; and 3,000LM6000 industrial and marine derivatives.The in-service fleet included 3,400 engines, generating over 600shop visits per year.
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The CF6-6 was first used on theMcDonnell DouglasDC-10-10.
It has a single-stage fan with one core booster stage driven by a 5-stage LP (low pressure) turbine, and a 16-stage HP (high pressure)axial compressor driven by a 2-stage HP turbine; thecombustor is annular; separate exhaust nozzles are used for the fan and core airflows. The 86.4-in (2.19-m) diameter fan generates an airflow of 1,300 lb/s (590 kg/s), resulting in a bypass ratio of 5.72. Theoverall pressure ratio is 24.3. The engine develops a maximum static take-off thrust of 41,500 lb (185.05 kN).
The CF6-32 was to be a lower-thrust derivative of the CF6-6 for the Boeing 757. In 1981, GE stopped work on this engine so no longer competed with Pratt & Whitney and Rolls-Royce on this aircraft.[3]
The CF6-50 series are rated between 51,000 and 54,000 lb (227.41 to 240.79 kN, or '25 tons') of thrust. It was launched in1969 to power the long range McDonnell DouglasDC-10-30, and was derived from the earlier CF6-6.
Not long after the -6 entered service, an increase in thrust was required. It was obtained by increasing the airflow through the core. Two booster stages were added to the LP (low pressure) compressor and the last two stages of the HP compressor were removed[4] which increased the overall pressure ratio to 29.3. Although the 86.4 in (2.19 m) diameter fan was retained, the airflow was raised to 1,450 lb/s (660 kg/s), giving a static thrust of 51,000 lb (227 kN). The increase in core flow decreased the bypass ratio to 4.26.
In late 1969, the CF6-50 was selected to power the then newAirbus A300.Air France became the launch customer for the A300 by ordering six aircraft in1971. In1975,KLM became the first airline to order theBoeing 747 powered by the CF6-50. This led to more variants, such as the CF6-80. The CF6-50 also powered theBoeing YC-14 USAF AMST transport prototype.
The CF6-50 was also offered with 10% less thrust, and known as CF6-45, for the 747SR, a short-range version used by All Nippon Airways for domestic Japanese operations.
The engine, known by its military designation F103, is used on theKC-10 Extenders andBoeing E-4.
Starting in 1977, a derivative known as the LM5000 was offered as an industrial gas turbine. The first unit was sold in 1978, with 30 orders by October 1, 1988.[5]
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The CF6-80 series has a thrust range of 48,000 to 75,000 lb (214 to 334 kN).
There are 4 variants.
The CF6-80A3, with thrusts from 48,000 to 50,000 lb (214 to 222 kN), powered two twinjets, theBoeing 767 andAirbus A310. The GE-powered 767 entered airline service in1982, and the GE powered A310 in early1983. It is approved forETOPS operations.
For the CF6-80A/A1, the fan diameter remains at 86.4 in (2.19 m), with an airflow of 1435 lb/s (651 kg/s). Overall pressure ratio is 28.0, with a bypass ratio of 4.66. Static thrust is 48,000 lb (214 kN). The basic mechanical configuration is the same as the -50 series.
For the CF6-80C2-A1, the fan diameter is increased to 93 in (2.36 m), with an airflow of 1750 lb/s (790 kg/s). Overall pressure ratio is 30.4, with a bypass ratio of 5.15. Static thrust is 59,000 lb (263 kN). An extra stage is added to the LP compressor, and a 5th to the LP turbine.[6]
The CF6-80C2 is used on fifteen commercial and militarywidebody aircraft including theBoeing 747-400, andMcDonnell Douglas MD-11. The CF6-80C2 is also approved forETOPS-180 for theAirbus A300,Airbus A310,Boeing 767,KC-767A/J,E-767J,Kawasaki C-2, and (as the F138) theLockheed C-5M Super Galaxy andVC-25A.
The F138-GE-100 is a military designation given to the modified version of the CF6-80C2, to produce 50,400–51,600 lb, with Strict Noise Regulations and Green Emissions, for theLockheed Martin C-5M Super Galaxy. The F138 replaced the TF-39 when the Galaxy was upgraded to the Super Galaxy.
The CF6-80E1 has the highest thrust of the CF6-80 Series, with the fan tip diameters increased to 96.2 in (2.443m), and an overall pressure ratio of 32.6 and bypass ratio of 5.3.[7] The 68,000 to 72,000 lbf (300 to 320 kN) variant competes with theRolls-Royce Trent 700 and thePratt & Whitney PW4000 to power theAirbus A330.[8]
The industrial and marine development of the CF6-80C2, theLM6000 Series, has found wide use including fast ferry and high speed cargo ship applications, as well as in power generation. The LM6000 gas turbine family provides power in the 40 to 56 MW range for utility, industrial, and oil & gas applications.[9] Dozens of refurbished aircraft CF6-80C2 engines (and similar) have been modified with natural gas and generators etc. to power the rapid increase indata centers.[10]
In1973, a CF6-6 fan assembly disintegrated, resulting in the loss ofcabin pressurization ofNational Airlines Flight 27 overNew Mexico, United States.[11]
In1979 a CF6-6 engine detached from the left wing ofAmerican Airlines Flight 191 due to faulty pylon maintenance, severing hydraulic lines and causing the aircraft to crash.
In1989, a CF6-6 fan disk separated from the engine and damaged all three hydraulic systems. The flight,United Airlines Flight 232, continued with no hydraulic power until it crash-landed at the airport inSioux City, Iowa.
In 2000, theNational Transportation Safety Board (NTSB) warned that the high-pressure compressor could crack.[12]
Following a series of high-pressure turbine failures on September 6, 1997,[13] June 7, 2000[14] and December 8, 2002,[15] and resulting in 767s being written off on September 22, 2000,[16] on June 2, 2006,[17] andon October 28, 2016,[18] theFederal Aviation Administration issued an airworthiness directive mandating inspections for over 600 engines and theNTSB believed that this number should be increased to include all -80 series engines with more than 3000 cycles since new or since last inspection.[19]
In May 2010, The NTSB warned that the low-pressure turbine rotor disks could fail.[20] Fouruncontained failures of CF6-45/50 engines in the preceding two years prompted it to issue an "urgent" recommendation to increase inspections of the engines on U.S. aircraft : none of the four incidents of rotor disk unbalance and subsequent failure resulted in an accident, but parts of the engine did come through the engine casing each time.[21]
In November 2025,UPS Airlines Flight 2976, aMcDonnell Douglas MD-11 powered by three CF6-80C2D1F engines, crashed shortly after takeoff following an in-flight separation[22] of the number one engine pylon, causing a subsequent fire and crash into a building, killing three on board and eleven on the ground. The preliminary report states the engine pylon fractured due to metal fatigue cracks. All MD-11s and DC-10s are currently grounded.
| Variant | CF6-6[24] | CF6-50[24] | CF6-80A[25] | CF6-80C[25] | CF6-80E[26] |
|---|---|---|---|---|---|
| Type | Dual rotor,axial flow, high bypass ratioturbofan, annular combustor | ||||
| Compressor | Fan & 1 LP + 16 HP | Fan & 3 LP + 14 HP | Fan & 4 LP + 14 HP | ||
| Turbine | 2 HP + 5 LP | 2 HP + 4 LP | 2 HP + 5 LP | ||
| Length | 188 in (478 cm) | 183 in (465 cm) | 167 in (424 cm) | 168 in (427 cm) | |
| Overall diameter | 105 in (267 cm)[27][28][29] | 106–111 in (269–282 cm)[6] | 114 in (290 cm)[6] | ||
| Fan diameter | 86.4 in (219 cm)[30] | 93 in (236 cm)[31] | 96.2 in (244 cm)[7] | ||
| Takeoffthrust | 41,500 lbf (185 kN) | 51,500–54,000 lbf (229–240 kN) | 48,000–50,000 lbf (210–220 kN) | 52,200–61,960 lbf (232.2–275.6 kN) | 65,800–69,800 lbf (293–310 kN) |
| Pressure ratio | 25–25.2 | 29.2–31.1 | 27.3–28.4 | 27.1–31.8 | 32.4–34.8 |
| Bypass ratio | 5.76–5.92[27] | 4.24–4.4[28] | 4.59–4.66[29] | 5–5.31[6] | 5–5.1[32] |
| Thrust-specific fuel consumption | 0.35 lb/lbf/h (9.9 g/kN/s)[27] | 0.368–0.385 lb/lbf/h (10.4–10.9 g/kN/s)[28] | 0.355–0.357 lb/lbf/h (10.1–10.1 g/kN/s)[29] | 0.307–0.344 lb/lbf/h (8.7–9.7 g/kN/s)[6] | 0.332–0.345 lb/lbf/h (9.4–9.8 g/kN/s)[6] |
| Application[33] | DC‑10‑10 | 747,A300,DC-10-15/30,KC‑10 | 767,A310 | 747-400,767,A300,A310,C‑2,C‑5M,E‑767,KC‑767,MD‑11 | A330,A330 MRTT |
| Weight[a] | 8,176 lb (3,709 kg) | 8,825–9,047 lb (4,003–4,104 kg) | 8,760–8,776 lb (3,973–3,981 kg) | 9,480–9,860 lb (4,300–4,470 kg) | 11,225 lb (5,092 kg) |
| Maximum fanrpm | 3,810 | 4,102 | 4,016 | 3,854 | 3,835 |
| Maximum compressor rpm | 9,925 | 10,761 | 10,859 | 11,055 | 11,105 |
| Thrust-to-weight ratio | 5.08 | 5.84–5.97 | 5.48–5.7 | 5.51–6.28 | 5.86–6.22 |
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