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An aircraft defies gravity to fly in the air, but with the advent of different types of aircraft, the difference between a jet and a plane can become unclear.
You might even wonder if both are the same and whether you can use these terms interchangeably.
A jet uses a jet engine to propel itself, like the Airbus A380. An airplane is a heavier-than-air aircraft with fixed wings and an engine. In short, all jet aircraft are airplanes, but not all airplanes are jet aircraft. An example of an airplane that isn't a jet is the Bombardier Dash 8.
Although “airplane” is a general term for jet and propeller aircraft, it can be harder to differentiate between them if you don't have sufficient knowledge about how their engines work, their design, and their history. Nowadays, almost every airplane is a jet due to its observable advantages over propeller-driven aircraft.
In this article, I will explain the subtle differences between jets and other types of airplanes, the basics of both jet propulsion as well as turboprop propulsion (the main type of propulsion for non-jet airplanes) as well as a comparison of the two.
Are Jets and Airplanes The Same Thing?
Yes and no. While all jets are airplanes, not every airplane can be considered a jet. 'Airplane' is a broader term for any heavier-than-air, fixed-wing aircraft capable of controlled flight.
Airplanes include jets, cargo planes, passenger planes, and propeller planes.
There is also a broader term than an airplane: aircraft. Aircraft includes flying vehicles, such as hot air balloons, airplanes, helicopters, and even simple flying surfaces.
On the other hand, a jet is an airplane that uses jet engines to propel itself forward. A jet airplane can have more than one jet engine on each side of the fuselage.
So, what is the difference between a jet engine and other engines?
Basics of a Jet Engine
A jet engine is an internal combustion engine that throws back a jet of hot exhaust air to generate thrust. Types of jet engines are turbofan, turbojet, ramjet, and scramjet.
Among the four, turbofan and turbojets are gas turbine engines that require a compressor to compress air before sending it to the combustion chamber.
On the other hand, ramjets and scramjets use their forward motion to compress the approaching air.
Turbojets and turbofans are commonly used jet engines in jets these days, with turbofans used more widely due to their several advantages. Such as, turbofan has a low exhaust velocity, corresponding to less jet noise. They consist of four basic components: compressor, combustion chamber, turbine, and nozzle.
The working principle is the same for both types. Air enters the compressor, which is compressed and passed to the combustion chamber. The air is mixed with fuel, and an igniter ignites the air-fuel mixture. The hot air-fuel mixture passes into the turbine, where it rotates the shaft that drives the compressor.
The exhaust gasses then jet through the nozzle producing thrust.
Basics of a Turboprop Engine
Airplanes with jet engines connected to a propeller aren't exactly jets but propeller-driven planes, such as passenger turboprops. Such airplanes have a turboprop engine: a combination of a core engine and a propeller.
The core engine is similar to a jet engine. However, instead of generating its entire thrust from a stream of high-velocity exhaust air like jets do, it generates most of its thrust from a propeller.
A gear reduction connects the turbine to the propeller in a turboprop engine. After the hot air-fuel mixture drives the turbine, it also drives the shaft the turbine is connected to. In turn, the shaft moves the reduction gear that drives the propeller, generating thrust.
Does a Jet Fly Higher Than a Plane?
It depends on the type of jet you’re talking about. A commercial jet airplane can fly between 30,000 to 42,000 feet. That is a very high altitude.
Fuel efficiency is the main factor that determines how high a plane can fly. At a higher altitude, the air is thinner than at sea level; thus, an airplane consumes less fuel, increasing fuel efficiency.
On the other hand, private jets, such as the Bombardier Global Express, can fly even higher: up to 51,000 feet. This is mainly because private jets are a luxury few can afford and are used when time is of the essence. They also fly higher than other planes to avoid air traffic and bad weather.
In contrast, propeller-driven planes operate at altitudes ranging from 25,000 to 30,000 feet. They can’t fly higher than this because air density decreases with altitude, and the propeller has less and less air to throw back to produce enough thrust to propel the airplane forward.
In conclusion, jets can fly higher than other planes because they don’t rely on a propeller to generate thrust. Also, jet engines’ fans spin thrice or five times more than the propeller's speed, thus producing more thrust.
Are Jets Faster Than Planes?
Jets are more efficient at high speeds than other planes. They are used so you can get to your destination quickly. A light jet cruises at speeds ranging from 370 to 450 knots and can travel above Mach 1.
The reason jets are faster than turboprop engines is related to how both engines work. We know that thrust of an airplane equals the product of the mass flow rate of air going into the engine and the exhaust velocity of air.
While jet engines do a large amount of work on a small amount of air, turboprops ingest a small amount of work on a large amount of air.
Because jets fly better at high altitudes, the lesser amount of air doesn't affect the airplane's thrust. On the other hand, a propeller-driven aircraft is most efficient at lower speeds: 250 to 400 mph, because of high propeller efficiency. However, at high speeds, turboprops become inefficient and noisy.
Are Jets Safer Than Planes?
Because jets have a greater fuel efficiency when they fly at high altitudes at high speeds, they also stay above bad weather conditions and turbulence. This can render jets a bit safer than turboprops.
Propeller-driven planes can only go up to a maximum altitude of 25,000 to 30,000 feet, making them more susceptible to worsening weather conditions. They can't fly off to a higher altitude to avoid the weather's wrath like jets, and you can be in for a bumpy ride.
Turboprops are better suited for shorter runways because of their low speeds. This is because the propellers generate a lot of drag, allowing the pilot to quickly stop the aircraft. This is an advantage over jets because the pilot can quickly stop the aircraft during takeoff if they think something is wrong.
Propeller-driven planes can take off at 32000 ft, unlike jets that need a runway as long as 5000 ft. So, traveling in a propeller-driven airplane is safer when there are shorter runways than in a jet.
Another factor to consider is maintenance. Almost every reputable company is heavily regulated to ensure that the airplane is safe to fly. However, some companies don't carry out strict regulations. For example, 14% of private jets in Europe fly without proper maintenance or license.
In conclusion, there is little difference between a jet and a plane regarding safety.
Is a Jet Bigger Than a Plane?
Jets are usually bigger than planes like turboprops because the bigger a jet engine is, the better it can perform. This is because jet engine efficiency increases as the engine get bigger.
A larger engine corresponds to less wasted energy while maintaining the same amount of thrust. In fact, jet engines will keep getting bigger to hit the optimal diameter of around 13 feet.
Today, the biggest jet engine on an airplane is the General Electric GE9X, which was made for the Boeing 777X. It has a large fan spanning 11 feet in diameter and produces 134,300 pounds of thrust, the greatest amount to date.
In contrast, turboprops are lighter engines than jets and aren't used as extensively.
Is a Passenger Plane a Jet?
It can be, although it isn’t always the case. Many commercial airplanes that employ jet engines are passenger jets as they carry passengers.
Different types of commercial jet airplanes that are passenger planes are:
- Light Passenger Jets: These are small-sized jets that carry around 60 to 100 passengers. An example is the Embraer 170.
- Medium-Sized Passenger Jets: These can carry up to or more than 350 passengers, such as the Boeing 737-800.
- Jumbo-Sized Passenger Jets: These jets are wide-body commercial airplanes with more than 400 passengers, such as the Airbus A380, the Airbus A350, and the Boeing 777.
- Private Jets: These carry about 8 to 18 passengers (usually celebrities, business executives or other VIPs). Examples include the Bombardier Global 6500 and the Embraer Praetor 500.
However, not every passenger plane is a jet. Passenger turboprops are used in smaller regions where runways are shorter. These are less expensive and allow up to 80 or fewer passengers. An example is the European Bombardier DHC 8 402 Q400, also known as the Dash 8.
Are Jets More Expensive Than Planes?
Jets are generally more expensive than other planes like turboprops. Although it depends on the travel distance, turboprops do have the edge when it comes to cost.
According to the Aircraft Owners and Pilots Association’s (AOPA) survey in 2016, jets have higher operating costs than propeller-driven airplanes. Also, jets have higher maintenance costs because of their complex engines.
On the other hand, propeller-driven planes have greater fuel efficiency and consume less fuel per hour than jets. Also, because a turboprop engine consists of a limited number of moving parts, it doesn't require as much maintenance as jets.
In short, owning, maintaining, and operating a jet is more expensive than propeller-driven planes.
Jets vs. Airplanes: Which One is Better?
How to know if you should travel on a jet or an airplane equipped with a propeller? While one is suited for a low-altitude, slower flight, the other can take you to places faster and operate at high altitudes.
Ultimately, deciding which one is better depends on the type of mission at hand.
A turboprop is best for flights that are short, affordable, and require a shorter runway. In contrast, a jet is a better option if you want to travel long-distance and want to cut back on flight time as much as possible. You should also consider a jet to avoid excessive turbulence and cabin noise.