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jet-planes-vs-propeller-planes-github Jet engines are more fuel efficient at high altitudes and speeds. Propellers are more fuel efficient at lower altitudes and speeds. Giant transport aircraft aren't generally going to be flying at high altitude, nor are they designed for supersonic flight. The high power-to-weight ratio of turboprop engines at low speed allows these planes to take off from land on runways that are much shorter than if they used turbojets, as when you're bring supplies or troops to the front line you probably won't have a long paved runway. Pocket Plane Group has 24 repositories available. Follow their code on GitHub. Propellor planes tend to be much more fuel efficient at low speeds. A propellor equiped engine will typically provide much more low speed thrust for a certain fuel flow. Piston engines also tend to be most efficient at low power settings vs jets that are generally most efficient at high power settjjngs and high true air speed. However, as the bypass ratio of jet engines increases the efficiency at lower airspeed also tends to be better so the gap in efficiency at lower airspeed is closing. Packages 0 No packages published. Most of the time when you see a helicopter flying overhead, they are usually not that high up in the sky. A turbine engine is extremely light and produces tremendous power-to-weight as opposed to a comparable piston engine. Careers Contact us News Blog Testimonials. It is worth noting that jet planes vs propeller planes github aspect of comparison between pusher and puller designs is a generalized consideration. Most turbojets are bigger, fly more people and therefore cost more. The faster the speed of the incoming air, the more the pressure that can be generated by the compressor.

Pusher propeller designs have been adopted where specific design requirements mandate their use. Safety considerations between the two designs are largely operational in nature. These tradeoffs can be summarized by examining the performance, efficiency and safety effects of each layout. Because of their unusual-ness in the broader aviation world, many pusher designs are relatively famous. Fundamentally the performance of pusher aircraft is like that of puller aircraft with similar power outputs and weights.

The difference is how efficiently the propulsion layout and the basic aerodynamic design achieves this performance. Runway performance can be affected by the pusher configuration and is also worth considering. First, propulsive efficiency should be considered.

Propulsion system efficiency is a function a range of factors, but intake losses, fuselage and propeller aerodynamic interactions and cooling are primary installation factors for efficient operation.

Consider first the pusher layout, where the propeller is located behind the wing or fuselage. As air moves across the aircraft toward the propeller, it becomes turbulent, and develops inconsistent small-scale flow patterns. As the flow becomes turbulent, its overall speed tends to decrease as energy in the airflow is reduced by interaction with the airframe.

Pusher aircraft with propellers mounted behind the wing generally see fewer blanking effects than those with propellers installed behind a bulky fuselage such as the Cessna Propellers are most efficient when they ingest smooth, constant velocity airflow at an appropriate airspeed.

The turbulent interactions of pusher propellers result in reduced efficiency and thus performance. It also typically increases propeller noise for both passengers and outside observers. The Beechcraft Starship is well known for its distinct howling noise as it flies. Thus, all things being equal, puller propeller layouts are more efficient for a given engine and propeller combination.

This means that air enters the engine at the back, and flows forward toward the propeller, this results in intake losses as the air travels the length of the engine and reverses direction in the intake duct. PT-6A powered pusher aircraft can avoid these intake losses by eliminating the flow reversal in the inlet.

The overall efficiency improvements are minor in absolute terms but can add up over the life of the aircraft. Pusher configurations allow for more efficient turboprop engine installations due to improved engine intake design. Particularly for air cooled piston engines, engine cooling in the pusher configuration can be difficult to achieve. The same turbulent air disrupting flow to the propeller also disrupts flow to cooling intakes.

Aft mounted piston engines tend to require higher Jet Planes Fly In Which Layer Github climb airspeeds, particularly during warm weather simply to maintain cooling performance. Puller layout aircraft have the advantage of unobstructed cooling intakes and even some propulsive thrust to maintain engine temperatures, resulting in potentially lower climb speeds for the same ambient conditions. Puller engine layouts provide superior cooling flow to piston engines thanks to unobstructed cooling intakes.

This effect can, however, lead to substantial thrust effects due to changes in power output, which will be discussed later.

Pusher aircraft can benefit from reduced induced drag on horizontal tail surfaces. Rear mounted engines tend to locate the CG more rearward reducing the need for the tail to balance the pitching moment of the wing.

This reduction in tail loading appears in puller aircraft as well but requires intentional weight and balance planning to achieve. Note that pusher aircraft still operate within a range of normal weight and balance conditions, but the relative normal envelope tends to be more rearward. Assuming for a moment that all other design aspects are equal, pusher aircraft tend to suffer reduced takeoff performance relative to puller aircraft as a result of prop clearance concerns.

The ability to rotate the aircraft to a sufficiently nose high pitch attitude plays a substantial role in achieving short field takeoff distances. This is as much a safety concern as it is a performance factor, therefore designers generally take care to account for this issue.

It is worth noting that this aspect of comparison between pusher and puller designs is a generalized consideration. In summary of comparing efficiency and performance for pusher and puller configurations, there are distinct advantages to the use of the puller configuration. As a result, puller aircraft are the dominate design choice for Jet2 New Planes Github modern aircraft.

There are specific areas of improvement, but in general these improvements are offset by the general impact of decreased aerodynamic and propulsive efficiency. Aircraft designers consider safety effects of design choices, and engine position is no different. Examining several examples of pusher configured aircraft, a theme emerges: canards and flying wings.

The pusher engine location on these aircraft preserves weight and balance considerations and avoids propeller positions near passenger compartments.

Again, consider the Piaggio with its Jet Planes Vs Propeller Planes 2020 canard design. The pusher configuration simplifies cabin entry and avoids placing propellers near the normal and emergency exits. The pusher configuration also helps to reduce cabin noise as the propeller plane does not intersect the pressure vessel.

King Airs similarly avoid placing propellers near cabin entrances, but in exchange a substantial climb is required to enter the cabin at the rear. Flying wings such as the experimental Northrop bombers needed the rearwardly mounted engines to manage weight and balance considerations. It also allowed bomb loading crews to access the underside of the aircraft from the front where there was more ground clearance and better visibility with the cockpit.

The designers of these aircraft sought to use specific aerodynamic techniques or tools to improve efficiency or achieve an operational goal, in doing so the pusher configuration was required to remain within the specific constraints and still have a safely operable aircraft.

Several safety considerations are worth examining: propeller strikes, visibility, and handling characteristics. As discussed above, rear mounted propellers on pusher aircraft are subject to increased prop strike risks both during takeoff and landing.

While pistons in their various forms rotary, air-cooled, etc. These limitations and the need for high-performance aircraft gave birth to what we now know as jet engines. In very practical terms, the major difference between the turbojet engine and the turboprop engine is that a turboprop adds a propeller in the front right before the inlet into the engine.

Put simply, the turboprop is simply a modified variation of the turbojet which is the original type of jet engine that was designed by Sir Frank Whittle in This design modification directly impacts how each engine type works.

Because turboprops and turbojets are built for different working conditions, it is quite impossible to say which of them is better than the other. While the turbojet is more efficient at higher altitudes, the turboprop is designed for flights at lower altitudes.

In other words, these two gas turbine types have different advantages and disadvantages and these will be considered in detail in this article. Turbojets are the simplest type of gas turbine engines. A turbojet operates based on the principle of compressing, expanding, and releasing air at a high velocity. The basic components of the turbojet engine include the inlet, compressor, combustion chamber, turbine, and exhaust nozzle.

The inlet and compressor are generally referred to as the cold section. These are the components where the temperature of the air is relatively low. The other 3 components make up the hot section. The inlet is the first part right in front of the turbojet engine.

Here, air is sucked from the atmosphere into the engine and driven at a certain angle toward the compressor blades. The inlet regulates the speed of airflow into the engine which is necessary to ensure the engine works optimally.

This compression is needed to increase the pressure of the air which is later sent to the combustion chamber. The combustion chamber is the section where the air from the compressor is burned. The fuel in this part of the engine burns the high-pressure air and energy is released in the process.

The high pressure of the air at the entrance is converted to high velocity at the exit by means of fuel combustion. The turbine performs a reverse of the process that goes on in the compressor. Also using its rotor and stator blades, the turbine expands the air that passes through it. The high-velocity air it produces finally escapes through the exhaust nozzle. As a result, sufficient thrust is generated to power the engine and the plane as a whole.

As earlier mentioned, turboprops contain the same components as turbojets but with Do Jet Planes Have Propellers Year a large fan called a propeller attached in front. Both the propeller and gearbox are connected to the rest of the engine gas generator using a long connecting shaft.

A large portion of the energy generated by the turbine is transmitted to the propeller to induce its rotation. In other words, the propeller is attached in a way in which its speed is independent of the speed of the turbine.

This regulation is achieved by connecting the gear with the lowest speed directly to the propeller. As a result, the rotational movement of the propeller generates thrust to power the whole airplane. In a nutshell, turbojets are perfectly suited for flights at higher altitudes and high supersonic speeds.

They become less efficient when used for other mission requirements. Turboprops, on the other hand, work more efficiently at lower altitudes and subsonic speeds. The application of turbojet and turboprop engines can be compared based on the following factors:. Turbojets are built to be more fuel-efficient at higher altitudes. Altitudes from 41, feet to 45, feet are considered ideal.

Turbojets are more efficient at higher altitudes because the air at these altitudes is cooler. Cool air expands better and therefore is more efficient than the warm air that is characteristic of lower altitudes. Another factor to consider is the density of the air.

The air at higher altitudes is much thinner and of lesser density. This type of air, therefore, causes less drag and allows the aircraft to fly faster at high altitudes. One can expect optimum fuel efficiency from them at altitudes below 25, feet. Turboprops can further reach a ceiling altitude of 30, feet.

Turboprop engines are built to generate thrust primarily through the rotation of the propellers. These propellers work more efficiently at lower altitudes where the air is denser. This is because they can push a larger amount of air and generate more thrust in the process. Because turbojets fly at higher altitudes, they are less susceptible to crashes resulting from changing weather conditions than turboprops. Turbojets are highly optimized for high-velocity flight.

The faster the speed of the incoming air, the more the pressure that can be generated by the compressor. Turbojets are perfect for flights with cruising speeds between and knots — miles per hour. This makes them optimal for covering longer distances over a shorter period of time.

The range of turbojets can typically go as high as 8 nautical miles as demonstrated in the case of the Gulfstream ER. This also reduces the overall cycles of the aircraft.

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