How does a propfan work?
These fans are driven by a turbine engine through a reduction gear or a low-speed free turbine. High rpm is used to reach higher speeds and altitudes than conventional propellers. The contra-rotating fan arrangement is used to remove torque effect, and to enhance efficiency (note: some early versions had just one fan).
How much does a MD-80 cost?
$750,000 to $800,000
A 737-400 typically costs between $3.25 million and $4 million, while MD-80s sell for $750,000 to $800,000. A 737-400 conversion, which AEI also offers, itself costs $2.7 million to $2.8 million, compared with $2.35 million for the MD-82 it just finished.
Are any MD 80s still flying?
The largest operator. According to data from ch-aviation.com, there are still nearly 100 active examples of the MD-80 family left in the world today. As is common with aging aircraft, some of these have been converted for use as freighters.
What happened to the unducted fan engine?
But what sparked the interest in developing a fuel efficient engine and aircraft became the demise of the UDF and the 7J7. The end of the oil embargo led to cheaper fuel prices. The 737 continued to be a workhorse for short to mid-range flights and the Airbus 320 offered even better performance.
Why are Propfans more efficient?
The propulsive efficiency of a propfan engine is increased by the high bypass ratio achieved using external fan blades. The efficiency boost is maintained even at high speeds because the fan blades are curved like scimitars to prevent shockwave formation on the outer tips of the blades.
Why are turbofans more efficient than turboprops?
Because the fuel flow rate for the core is changed only a small amount by the addition of the fan, a turbofan generates more thrust for nearly the same amount of fuel used by the core. This means that a turbofan is very fuel efficient. In fact, high bypass ratio turbofans are nearly as fuel efficient as turboprops.
Who still uses MD-80?
McDonnell Douglas MD-80
| MD-80 series | |
|---|---|
| First flight | October 18, 1979 |
| Introduction | October 10, 1980 with Swissair |
| Status | In service; mostly for cargo transport |
| Primary users | Aeronaves TSM World Atlantic Airlines LASER Airlines European Air Charter |
Can you buy an MD-80?
American Airlines retired its final MD-80 in September last year. The aircraft’s final flight was celebrated with massive fanfare as it marked the end of an era for the US carrier.
Is the MD-80 a safe plane?
The MD-80 and its variants are the workhorses of airline fleets around the world, and are also regarded as among the safest planes. The mid-range, two-engine, one aisle jet, built by McDonnell Douglas of Long Beach, California, was introduced in 1980.
What is the difference between DC-9 and MD-80?
The DC-9 series features a “pointed” tail cone, while the MD-80 series aircraft have what appears to be a “flat” tail cone. The MD-90 has larger engines than the MD-80 Series. The Boeing 717 has engines which are longer in length than the MD-90.
Which is better turboprop or turbofan?
Overall, a turboprop engine is typically going to be more efficient at subsonic speeds than a turbofan flying in the same conditions. But a turbofan engine is able to continue operating at far higher speeds than a turbofan and is necessary for planes that fly at supersonic speeds.
What are the disadvantages of a turboprop engine?
Planes with turboprop engines are typically limited to a lower cruising altitude than jet engines, capping at around 25,000-30,000 feet. Because of this, turboprops are also more susceptible to turbulence, noise, and inclement weather.
Why can’t turboprop fly at high altitudes?
A turboprop is a constant pressure engine, so as you climb, you kinda need to go faster and faster, but basically you still burn the same amount of air/fuel. You will lose power as you climb in a turboprop, but that’s mostly cause the propeller loses efficiency at the higher speeds you fly higher up.
Can turbofans go supersonic?
Turbofans can tolerate supersonic speeds because the intake creates constant flow conditions irrespective of flight speed. Efficiency for propellers and fan blades is highest at subsonic flow conditions.
What replaced the MD-80?
MD-90
The MD-80 series competed with the Boeing 737 Classic and the Airbus A320ceo family. Its successor, introduced in 1995, the MD-90, was a further stretch powered by IAE V2500 high-bypass turbofans, while the shorter MD-95, later known as the Boeing 717, was powered by Rolls-Royce BR715 engines.
Is the Boeing 717 the same as MD-80?
The Boeing 717 uses two Rolls-Royce BR700 engines 18,920 lbf (84.2 kN) of thrust. The MD-80 uses Pratt & Whitney JT8D-200 series with 18,500 to 21,000 lb (82-93 kN) of thrust. The 717 has a cruising speed of 822 km/h, while the MD-80 with its more powerful engines comes in slightly higher at 873 km/h.
Which is the safest plane in the world?
According to experts, the model (737-800) is considered to be the safest aircraft ever made. The 737-800 belongs to the aviation giant’s next-generation aircraft which also includes 600, 700, and 900.
Is Boeing 717 the same as MD-80?
What are the disadvantages of a turboprop?
What is the most efficient turboprop engine?
P&WC Launches the PT6A-140A Turboprop: The Most Powerful and Fuel Efficient Engine for the General Aviation Market. It has launched the new PT6A-140A turboprop engine and the PT6A-140AG variant – bringing the world’s most popular turboprop family to more than 70 engine models strong.
Why do airlines still use turboprops?
The aircraft is able to take off, land on shorter and non-concrete runways. For travel plans of destinations with shorter, less highly improved runways, a turboprop has a clear advantage over a jet. Turboprops can land on runways as short as 3,200 feet compared to an average jet minimum of 5,000 feet.
Which is safer turboprop or jet?
Myth Busted: Turboprops are equally as safe as jet engines. In fact, turboprops and jets both have turbine engines and are virtually the same thing.
Are turboprops safer than piston?
Turboprops are different from planes with piston engines, which also have propellers. Turbine engines are safer and more reliable than piston engines, which are typically found in smaller aircrafts.
Can a civilian own a supersonic jet?
The answer is a surprising ‘yes! ‘. As soon as an airplane is demilitarized it can be bought by members of the general public.
Do fighter jets use turbofans?
Many modern fighter planes actually use low bypass ratio turbofans equipped with afterburners. They can then cruise efficiently but still have high thrust when dogfighting.