Aeroplane Fly in Which Layer of Atmosphere?
Aircraft · 3 min read
Knowing where an aircraft flies is important for aviation professionals to understand, as it can help inform decisions such as fuel consumption, altitude, and speed.
Helicopters are a fascinating type of aircraft with several interesting features that make them special such as the fact of landing and taking off without the need for a runway. However, there are some characteristics that make them similar to other aircraft like needing fuel to operate.
Now, have you ever wondered what type of fuel helicopters uses? Is it jet fuel? Or aviation gasoline? If you want to discover it, we invite you to keep reading as we share all the details here below.
Before answering this very common question, it is important to make clear that the type of fuel used by a helicopter will ultimately depend on the engine type powering the helicopter. Therefore, there are different types of fuels used by helicopters, including jet fuel and aviation gasoline.
So, the quick answer would be yes, helicopters run on jet fuel, but not all of them. Let’s define the two different types of helicopters.
Turbine powered helicopters are usually medium to large helicopters that are usually equipped with jet engines. Naturally, this type of helicopters is much more powerful than those equipped with piston engines, but they are more expensive to operate and maintain as well. At the same time turbine engine helicopters provide more reliability, lift and power than a regular piston engine helicopter.
Larger turbine powered helicopters can carry anywhere from 4 all the way to 12 people, provide more luggage space, more comfortable seating, slightly less noise, and capable of flying at night.
The increased comfort comes with extra weight of the helicopter, so that ramps up the fuel usage as well, but more on that in a moment.
This type of helicopters is usually much smaller than their turbine counterparts. They can usually seat only a couple of people, that’s why they are often first choice for training, personal transportation, and sightseeing. It is worth mentioning that often the police use piston powered helicopters for general surveillance due to their high maneuverability.
Piston helicopters are undoubtedly great if it is used for an occasional flight, they are much cheaper to look after and much less fuel thirsty than turbines, however, if you are looking to transport more than 3 people or operate in cold climates, it is more economic to look into a turbine helicopter.
The name aviation turbine fuel is another name for jet fuel, perhaps the most popular aviation fuel nowadays since it is used in most aircraft, including helicopters apart from the biggest passenger and cargo airplanes.
Turbine-powered helicopters are the ones operating on jet fuel, a type of fuel that is the same used in airplanes with turbine engines. Jet fuel A is the most popular grade used in the United States, but other grades like jet fuel A-1 are more common in other countries.
In general, all aviation fuels are either a direct byproduct of petroleum or a combination of them with synthetic fuel blends. In this case, jet A and jet A-1 are usually described as kerosene-based fuels.
You can learn more about jet fuel A and the other grades of jet fuel in our beginners’ guide to aviation turbine fuel.
A fun fact is that, while sometimes gas turbine engines are thought to use gasoline-based fuel because of their name, the truth is that all turbine engine helicopters run on the aviation fuel mentioned above.
Although many people believe the name aviation gasoline covers all types of fuel used in aviation, the truth is that this is a type of fuel that is different from aviation turbine fuel. This aviation fuel is used in piston engine-powered aircraft, including helicopters.
Piston-powered helicopters in North America and Western Europe generally fill their fuel tank with aviation gasoline grade 100LL, gasoline containing three times the amount of tetraethyl lead per liter found in car gasoline. Other gasoline grades found in aviation are the AVGAS 100, and the AVGAS 82UL.
The function of the tetraethyl lead is to prevent detonations during combustion that may result in the failure of the piston engine. However, this is a toxic substance that should be handled carefully, and the main reason it has been eliminated from car gasoline.
Now that we know that there are different fuel types, and that jet engines use a different type of fuel than piston engines, the question is how to differentiate them to make sure we are using the right one.
A simple way that has been in place for a long time is dying the fuel during production. This is only applied to aviation gasoline, also known as aviation gas or simply avgas. The main reason is to differentiate the different grades because the higher the grade the more pressure the avgas can resist without detonation.
In addition, fuel suppliers use a standard that identifies the fuel trucks and all the refueling equipment with the color of the grade by using paints and decals with the corresponding identification.
While jet A, Jet A-1, and jet B fuels are colorless or straw-colored, these paints and decals in black, gray, and yellow correspondingly make it easier to identify the fuel tank is being filled up with the right type of fuel. Another characteristic used to identify jet A and jet A-1 fuels is the fact that they smell like diesel.
Yet, the advantage of avgas being dyed is that the identification can be achieved even before it gets into the fuel trucks. The colors used are purple for AVGAS 82UL, green for AVGAS 100, and blue for AVGAS 100LL.
In general, the price of fuel for helicopter fuel is the same as the price of fuel for any other aircraft since it only depends on the type. The difference in costs comes from how much fuel they can hold in the fuel tank, and how much fuel they burn.
For example, the owner of a turbine engine-powered helicopter will pay the same as a jet owner per kiloliter of jet A or jet A-1 fuel. Yet, considering the frequency, the total amount of money they will pay will be different.
The answer to this question is that it will depend on the type of helicopter. Of course, larger helicopters can take more fuel in their tanks than smaller helicopters. However, fuel efficiency is not only affected by the size, it also depends on the type of engine and fuel.
Also, it is important to consider the design of a helicopter when compared to other aircraft. Airplanes use their wings to generate lift, so the engines only need to burn fuel to generate thrust.
On the contrary, helicopters generate thrust from their rotors, thus requiring the engines to burn fuel in the process, affecting their fuel efficiency. And this is especially true while hovering, one of the main advantages of helicopters over other aircraft.
Moreover, fuel economy is better in piston-powered helicopters because these piston-equipped aircraft burn fuel at a lower rate than gas turbine-powered helicopters, a good reason to own the smaller type of helicopters and piston engines for training purposes.
The more fuel-efficient small piston engine helicopters burn fuel at a rate of 5-20 gallons/19-76 liters per hour while larger ones running on turbines burn it at a rate of 25-1100 gallons/95-4165 liters per hour, according to pilotteacher.com.
A good example of the latter is the MIL MI-26, a Soviet/Russian transport helicopter that burns an amazing amount of 1,000 gallons of fuel per hour.
Although we said it depends, we understand you may want to get some numbers that will help you have a better idea of how expensive owning or operating a helicopter could be.
Considering a price of 6$ per gallon for avgas, and 5$ per gallon for aviation turbine fuel, to fuel one of the most popular helicopters and considered the most economical in the world, the Robinson R22, you would need $156 because it has a 26-gallon fuel tank.
Similarly, to fuel the most popular helicopter in the world running on turbines, the Bell 206 JetRanger, you would need $350 as it has a 70-gallon tank.
In India, filling the tank of the Bell 206 JetRanger would cost around 30,952 Indian Rupees since the fuel price has been raised to 116.8 per liter.
The more fuel a helicopter carries in its tank does not necessarily mean the more or the longer it can fly. A bigger helicopter with a bigger tank will weigh more, and this means it will need to burn more fuel to generate the required power to move that weight.
In general, the majority of helicopters are designed to carry sufficient fuel to fly between 1.5 and 3 hours with a 20-minute reserve.
Also, the less hovering that is required and the less drag the helicopter needs to overcome the longer the autonomy will be since these are the two moments when more power is needed and more fuel is burned.
Drag is usually generated by the fuselage, this is called “Parasite Drag“, and by the higher pitch angle of each rotor blade as it moves through the air, causing the drag known as “Profile Drag”
Finally, it is relevant to highlight that while it seems that fuel efficiency and autonomy are weaknesses of the helicopters, there are plenty more advantages that make them a great choice for many circumstances.
For example, being a very versatile vehicle that can stay relatively stable in the air without moving, and that can take off from and land on many different surfaces make the helicopter the best choice for rescue operations, both inland and offshore.
What’s more, helicopters have the potential to continue evolving and taking advantage of continuous developments within the aviation industry. We might see them using alternative energies which could help reduce the costs and increase their autonomy. Time will tell, but we can be very optimistic about the future.
Helicopters as opposed to fixed-wing aircraft are a versatile craft that is able to perform a myriad of tasks with great maneuverability, land on virtually any solid surface and travel substantial distances. These features make helicopters great not only for personal and recreational use, but also for law enforcement and medical purposes.
However, as fuel prices are quite high, it is very important to evaluate your needs before you decide to purchase or lease a helicopter. Keep in mind that while turbine helicopters offer you a dash of luxury, a small piston engine might just be an overall better choice economically.