Since the first turboprop was built in 1940, this engine has become a popular choice for planes where performance and efficiency are key – but where does it fit in the future of flight? Let’s take a look at the history, current status, and expected future of the turboprop.
A Brief History
The earliest known turboprop engine was built in Hungary in 1940, based on designs submitted in 1926. In less than ten years, production exploded as early problems were ironed out and countries realized the kind of power and efficiency these engines offered.
The public began to take notice of the engines in 1944 (after a favorite magazine of the time detailed what the engines might end up looking like), and the first true turboprop plane took off in 1948.
World War II had been over for years at this point, but both the United States and the Soviet Union considered the engines a viable alternative to the new turbojets. In fact, the United States had mixed the turboprop and the turbojet in 1945 to create the XP-81 (an escort fighter), but production issues stopped the project before it could go much further.
Development has continued ever since, with the turboprop continuing to be produced in the United States, the Czech Republic, the EU, the People’s Republic of China, Ukraine, Russia, France, Canada, and the United Kingdom.
The Turboprop engine typically sees use in two areas: small bush planes where a lot of power is needed in a short takeoff zone and large transport planes (often for military use, but occasionally for passenger flights as well). When we look at how an engine works in the field, the way the turboprop performs on short runways makes it ideal for landing in less-developed parts of the world.
The biggest factor in its usage is the engine’s overall efficiency. At speeds up to 400 mph, a turboprop plane is significantly more fuel-efficient than High Bypass, Low Bypass, or even Turbojet engines. At its highest point, it’s about 20% more efficient than the closest competitor – and more than 40% more efficient than turbojet engines.
For those not well-versed in fuel efficiency, this is a huge difference. Unfortunately for turbojets, efficiency drops like a rock above 400 mph, and that’s where other engines start to become more viable.
Together, these factors have carved out the niche that turboprop engines currently occupy: they’re the engine of choice for slower vehicles, especially when those vehicles need to be flown on a regular basis over short distances. The impressive fuel efficiency in this area makes them more cost-effective over time.
Speaking of prices, there’s one major drawback here: The price. Turboprop engines are quite expensive, and they need to see quite a lot of use before they start to offer cost savings compared to their cheaper competitors. Over the long run, they’re more affordable, but the higher barrier to entry means they’re not as popular as they could be.
The Future Of Turboprops
For the foreseeable future, turboprops are likely going to be safe in their niche. In our modern society, we’re accustomed to thinking of newer and faster as better – but that doesn’t hold true in aviation. Most people don’t need to spend a lot more money to get somewhere a little faster – and they’re not going to.
This is especially true for military transport in and around small areas, where it’s fairly easy to work with whatever schedule the most affordable option requires. Until and unless an even more effective engine comes along, turboprops aren’t going anywhere. That said, technical limitations stop them from expanding their horizons.
Propeller-based engines just aren’t effective past certain speeds – that’s when jets start to make more sense. To the best of our knowledge, turboprops physically can’t perform well enough much above 400 mph to make them more sensible.
There is one thing that could change their viability: energy storage. Our current technology is, frankly, bad at storing electricity without heavy battery units. There’s a reason we don’t have electric jets, even when electric cars are starting to take over the road. However, as explained by CNN, small electric aircraft are currently viable.
The real challenge is finding a way to store electricity that’s viable for heavy, mid-range flights. If we can manage to create a proper electric turboprop engine and retain the high efficiency, turboprops may proliferate as the engine of choice for transportation that’s not time-sensitive. Electricity itself is cheap – and the range of turboprops could be drastically extended if we put solar panels on plane wings.
What Sort Of Planes Are Using Turboprop Engines Right Now?
Now that we’ve looked at the history, current use, and future of turboprops let’s take a look and see how they’re currently being used around the world.
The European Union
The most iconic use of turboprops in the EU is on the Airbus A400M Atlas, a mid-size military transport plane that performs well in rough landing areas. While it’s usually used for transporting supplies, it’s also capable of supporting mid-air refueling and evacuating injured personnel.
While production has been delayed several times and dogged by a few issues, Airbus remains optimistic about the plane’s overall performance. Most notably, the UK’s Royal Air Force had already flown over 300 sorties with the A400M by September 2015, and the reliability of the plane was unusually high for something so new.
China’s main use of turboprops appears on the Xian Y-7, a transport plane based on the Soviet Antonov An-24. Like the turboprop engine itself, initial production and development were slow. The original Chinese model had its first flight at the end of 1970, but the impacts of China’s Cultural Revolution slowed production, and it didn’t start to be produced in earnest until 1982.
Since that time, however, China has built more than 100 planes in this series, with the most important being the Xian Y-7-100 (a redesigned and more efficient model). Several of the Xian Y-7’s models have been adapted for military use, while the Xian MA60 variant is designed to be more appealing to international buyers.
The most iconic turboprop plane from Ukraine is the Antonov An-24, which the Xian Y-7 above was based on. This plane is no longer in production – the line ended in 1979 – but well over 1000 were produced, and many continue to see use throughout Africa and Asia.
That said, the real value in this plane is the number of other aircraft it inspired. Many modern turboprop planes owe at least some of their design elements to the An-24, and there are quite literally dozens of variations currently seeing use. Several things set this plane apart from much of the competition.
First, the high-wing setup helps to protect the wings and engine from debris during landings. This is critical since the plane is intended to perform well even from rougher landing strips and airports with little or no runway to speak of. Also, the durable frame and the unusually high power for its weight ensure it can withstand the shaking and heavy loads.
In many ways, the An-24 is the ideal turboprop plane. It may not be the fastest transport, but it’s reliable and efficient over short and medium trips.
Major variants and derivatives include the Xian Y-7 (above), the An-24PRT (a search-and-rescue model), the An-24T (a testbed designed to see how well many new sensor systems performed), and the An-30 (a surveying a photography plane).
The DHC-5 Buffalo is a short takeoff and landing plane most notable for the extremely short distances it needs to get into the air. In fact, despite its size and weight, it performs better than most light aircraft. While it’s not the most popular aircraft – only 122 were produced in the original production lines between 1965 and 1986 – this plane is especially notable as a demonstration of what turboprops can do.
In recent years, this plane has seen a bit of a resurgence as Viking Air (who’s been manufacturing replacement parts) acquired the type certificates and the rights to manufacture the DHC-1 through DHC-7 aircraft models. Several companies have delivered letters of intent for the new DHC-5NG model, which serves to demonstrate the steady demand for high-performance specialty planes.
Turboprops aren’t the fastest or flashiest engine available, but they are (and will continue to be) one of the most important parts of the industry. Their reliability, efficient use of fuel at low speeds, and high power make them ideal for a variety of specialist tasks. They’re also popular in many shorter-range civilian aircraft since most of those don’t need extended ranges.
Ultimately, the turboprop is relevant. It’s hard to say if this engine will ever grow beyond the niche it currently occupies, but if nothing else, the specialty uses ensure that turboprops will have a place in aviation fleets until something better comes along.
(You may also be interest on How To Decide If You Need A Black Box On Your Plane .)