According to the International Civil Aviation Organisation (ICAO), an aircraft is defined as an aircraft that is heavier than air and obtains its lift in the air primarily through aerodynamic reactions on surfaces that are at an appropriate angle to the direction of flow. This definition covers a wide range of aircraft, including motorised aircraft, gliders and even drones, provided they meet the above criteria.
Aircraft categories
Aircraft can be divided into several categories based on their size, intended use and type of propulsion. The most important categories are
Civil and military aircraft: Civil aircraft are used for commercial, private or general aviation purposes, while military aircraft are specifically designed for defence and war purposes.
By intended useThese include passenger aircraft, cargo aircraft, training aircraft, agricultural aircraft, fire-fighting aircraft and many others.
According to drive typePropeller aircraft, which are powered by piston or turboprop engines, and jet aircraft, which are powered by jet engines or turbofans. Piston and turboprop engines are particularly relevant for general aviation, which is why we want to go into a little more detail here.
Piston and turboprop engines
To understand how piston engines and turboprop engines work in aircraft, it is helpful to look at the basic principles and differences between these two engine types. Both are designed to generate thrust or propulsive power in aircraft, but they do so in very different ways.
Piston engine
The piston engine, often referred to as a reciprocating engine, is a type of internal combustion engine used in many smaller aircraft. It works on the principle of internal combustion, similar to the engines in most cars.
1. intake: In the intake phase, the intake valve opens and the piston moves downwards, creating a vacuum that draws a mixture of air and petrol into the cylinder.
2. compression: The inlet valve closes and the piston moves upwards, compressing the air/petrol mixture.
3. work: Shortly before the piston reaches its highest point, a spark plug ignites the compressed mixture, causing a rapid expansion of the gases, which pushes the piston downwards. This movement is then converted into rotary motion via the crankshaft.
4. exhaust: The exhaust valve opens and the piston moves upwards to push the combustion gases out of the cylinder.
This cycle is repeated several hundred or thousand times per minute. The rotary motion generated is usually transmitted via a gearbox to a propeller, which generates thrust.
Turboprop engine
The turboprop engine is a type of gas turbine engine specially designed to power propellers. It combines some of the technologies of a jet engine with the efficiency of a propeller at lower speeds and altitudes.
Functionality
1. air intake and compression: Air is drawn in at the front of the engine and compressed by several compressor stages. This compression increases the temperature and pressure of the air.
2. combustion: The compressed air is fed into the combustion chamber, where it is mixed with fuel and ignited. Combustion generates a high-speed flow of hot gases.
3. expansion and propulsion: The hot gases expand through the turbine, using some of their energy to drive the compressor and other auxiliary equipment. The gases also drive one or more turbines that are mechanically connected to the propeller to turn it.
4. exhaust: The remaining gases are expelled through the exhaust system, which can generate additional thrust, but the main purpose of the turboprop engine is to drive the propeller.
Differences between piston and turboprop engines
Turboprop engines are generally more efficient than piston engines at higher airspeeds and altitudes, as their performance does not decrease as much with the density of the air (although there are turbocharged propeller aircraft as an alternative, which also address this issue). Turboprop engines are generally more complex and more expensive to purchase and maintain than piston engines. However, they can run longer between maintenance intervals. They generally deliver higher power and can power larger aircraft. Although turboprop engines are more expensive to purchase, they can be more cost-effective for certain operations due to their higher efficiency.
To summarise, the choice between a piston engine and a turboprop engine depends on many factors, including desired performance, operating costs, flight altitude and speed, complexity and ease of maintenance.
Subdivisions and types
Within the aforementioned aircraft type categories, there are further subdivisions based on specific characteristics or functions of the aircraft. Some examples:
- Passenger aircraft: These can be further subdivided into narrow-body and wide-body aircraft, depending on fuselage width and passenger capacity.
- Cargo aircraft: These include pure cargo aircraft and converted passenger aircraft.
- Military aircraft: This category includes fighter aircraft, transport aircraft, reconnaissance aircraft and trainers.
Here are some examples:
| Category | Type | Examples |
| Civil aircraft | Passenger aircraft | Airbus A320, Boeing 737 |
| Cargo aircraft | Boeing 747-8F, Airbus A330-200F | |
| Military aircraft | Fighter aircraft | F-22 Raptor, Eurofighter Typhoon |
| Transport aircraft | C-130 Hercules, Airbus A400M | |
| According to drive type | Propeller aeroplane | Cessna 172, Beechcraft King Air |
| Jet aeroplane | Boeing 777, Airbus A350 | |
| By intended use | Training aircraft | T-6 Texan II, Embraer Super Tucano |
| Agricultural aircraft | Air Tractor AT-802, Grumman Ag Cat |
Many flight schools use Cessna or Piper models for flight training.
Cessna, now part of Textron Aviation, is one of the best-known aircraft manufacturers in the world, offering a wide range of aircraft from light aircraft to business jets and turboprops. Below - simply by way of example - you will find a simplified list of some of the aircraft types manufactured by Cessna, together with a brief description.
| Aircraft type | Description of the |
| Cessna 152 | Two-seater aircraft mainly used for flight training |
| Cessna 172 Skyhawk | The best-selling aeroplane in the world, a four-seater, single-engine light aircraft, ideal for training and recreational flying. |
| Cessna 182 Skylane | A single-engine light aircraft with higher performance and capacity than the Cessna 172, popular for personal and commercial use. |
| Cessna 206 Stationair | A robust single-engine aircraft with a high payload capacity, ideal for transporting freight and passengers to remote areas. |
| Cessna 208 Caravan | A single-engine turboprop aircraft known for its versatility in cargo and passenger configurations, including water landings with floats. |
| Cessna Citation family | A range of business jets of different sizes and ranges, known for comfort and efficiency in business travel. Examples are Citation Mustang, Citation CJ4, and Citation Longitude. |
| Cessna 400 Corvalis TT | A single-engine, high-performance light aircraft with fixed landing gear and the highest speed in its class. |
| Cessna 310 | A light, twin-engine aircraft that is appreciated for its performance and its ability to cover longer distances. |
Please note that this list is not exhaustive and is only intended to give a few examples. Each model has its own specific characteristics and applications, from general aviation to commercial use. Over the years, Cessna has developed a wide range of aircraft designed for different requirements and preferences of pilots and companies worldwide.
Equally often used in flight training are the models from Piper. Piper Aircraft is another renowned manufacturer in the aviation industry, known for its wide range of single and twin-engine aircraft used for everything from flight training to high-performance business flights. Here is a simplified list of some current Piper aircraft types and a brief description of each. Please note that Piper's product line may change over time and new models may be added or older models retired.
| Aircraft type | Description of the |
| Piper Archer LX | A single-engine light aircraft with 4 seats, known for its reliability and suitability for flight training. |
| Piper Archer TX | A variant of the Archer LX, specially equipped for flight schools with robust avionics systems. |
| Piper Arrow | A single-engine, 4-seater aircraft with retractable landing gear, ideal for advanced flight training. |
| Piper M350 | A luxurious, pressurised, single-engine, 6-seat aircraft designed for comfort and higher performance. |
| Piper M500 | A 6-seat turboprop aircraft that offers high performance, efficiency and range. |
| Piper M600/SLS | The top model among Piper aircraft, a turboprop with state-of-the-art avionics and safety systems. |
| Piper Seminole | A twin-engine light aircraft with 4 seats, often used for multi-engine flight training. |
| Piper Seneca | A high-performance, twin-engine aircraft with 6 seats, suitable for business trips and demanding personal flights. |
| Piper Pilot 100/100i | A single-engine, 3-seater entry-level aircraft designed to provide cost-effective flight training. |
This table provides an insight into the diversity of the Piper Aircraft product range, which extends from training aircraft to high-performance turboprops. Each model has its own niche and target audience, from student pilots and training organisations to experienced pilots and business travellers who value speed, range and comfort.
Official legal texts and references
For a detailed examination and official definitions of aircraft types and categories, you can consult the legal texts of the respective aviation authorities. In Germany, this would be the Air Traffic Act (LuftVG), at European level the regulations of the European Aviation Safety Agency (EASA) and internationally the ICAO.
These legal texts and regulations not only define the different types of aircraft, but also specify safety standards, certification requirements and operating regulations.
Summary
The variety of aircraft types and their specific applications demonstrate the breadth and depth of the aviation industry. Although this article provides an overview, aviation is a constantly evolving field, with new technologies and innovations being introduced on a regular basis.
Source references:
Germany: Air Traffic Act (LuftVG)