You may have heard of GE and Rolls Royce producing some of the best airplane engines. Since these are car manufacturers, why can’t fuel-efficient vehicle engines be used in an airplane?
Well, there are a few good reasons why even the best of car engines is a poor aircraft engine. From power outputs to cost, different systems like OBD2, cooling systems, and more, here I will discuss the similarities and differences between an automotive and airplane engine.
Let’s get started!
Table of Contents
What Do They Have In Common?
Before we look at why you can not use a car engine in an aircraft, let’s look at what they have in common.
Piston engines
Some older planes and smaller propeller planes have a similar engine to the car. Both offer a piston engine that works differently. In a car, a piston engine turns the wheels while on an aircraft it turns the propeller.
Fuel-injected engines
Fuel-injected engines play a significant role in an aircraft and come with all modern planes. These ensure a precise amount of air/fuel mixture into each cylinder of the engine.
Modern cars also come with fuel-injected engines as it is more efficient and produces relatively more power than the previous carburetor system. The disadvantage of having carburetors is that it does not provide the precise air/fuel mixture into each cylinder. Twin carburetors were another solution to combat this issue however these are too difficult to tune.
Aluminum made
The two engines are made from aluminum alloy as it weighs lighter than steel. It reduces the costs and emissions and increases fuel efficiency and performance. Aluminum also increases safety and durability.
Automotive Vs. Airplane Engine Comparison Chart
| Features | Automotive engine | Airplane engine |
|---|---|---|
| Power | Requires less power while at cruise speeds | Might need full power even while cruising |
| Cooling systems | Uses a radiator to keep the engine cool | Uses air for cooling the engine |
| Weight | Weighs more for the power it produces | Weights much lighter in terms of power production |
| Extreme Environments | Not capable of operating in extreme shifts in temperatures | Can handle swift changes in temperatures |
| Engine Settings | Automatic systems that take control of some functions | Manual systems allowing pilots to take control |
| Maintenance | Needs overhaul upon engine failure | Needs overhaul after a certain number of hours |
| Safety | Failure of the engine brings the car to a standstill | An engine failure activates different safety features |
| Forced Induction | It increases horsepower in a car | It maintains full power in high altitudes |
Why Can’t You Use A Car Engine In An Airplane?
Now that I’ve gone over the similarities between the two, let’s explore why you can’t use a car engine to power a plane.
Airplanes need power
A car engine uses the bare minimum horsepower when cruising at a speed of 60 to 70 mph. However, this is not the same for an airplane’s engine. An aircraft may use 100% of its engine’s power at any stage of the flight, even while cruising!
A car’s engine operates at 10% output for most of its life while needing a bit more power during acceleration or racing. On the other hand, an airplane’s engine operates at around 70% to 80% during its lifespan.
Airplanes operate in extreme environment
An airplane’s engine gets built according to extreme fluctuations in temperatures. It may be 100 degrees on the ground but within minutes, the aircraft is thousands of feet in the sky where temperatures fall below zero.
Cars have radiators to keep the engine cool while an aircraft uses air to cool its engine. If an airplane were to have radiators, it would increase its weight. More weight means more power required that would further increase weight. It would become an endless loop of weight and power issues.
Airplanes have manual settings
To ensure that the airplane is flying safely and as smoothly as possible, pilots are required to monitor temperatures and throttle, adjust fuel mixture settings, and more. While these things are pivotal in a car, a modern car comes with automatic systems that do it for you.
Airplanes have high maintenance requirements
Modern cars only require periodic fluid changes, especially if the automobile has gone past the 100,000 miles mark. On the other hand, an airplane engine needs a “tune-up” at least once a year to ensure that all electricals and components are working fine.
A car has an onboard diagnostic system that helps car owners diagnose any problems with the engine. You can use an OBD2 scanner to view the fault codes or pay attention to the engine symptoms for diagnosing purposes (It’s much easier if you have experience).
However, for a plane, this is not possible. Pilots can’t wait for symptoms to show up mid-flight. Strict maintenance procedures must be followed which is expensive and requires a high level of expertise.
Airplane engines have extra safety features
While driving, if you have an engine failure, you pull your vehicle over to the side of the road. For an airplane, this is not possible as it needs to make an unplanned landing at the nearest airport or body of water.
For such situations, an airplane engine comes loaded with extra safety precautions to minimize the chances of a catastrophe.
Airplane engine’s forced induction performs differently
In an automotive engine, forced induction increases the horsepower of the vehicle. Smaller engines are now fitted in large vehicles delivering great fuel efficiency.
Forced induction on an airplane engine does not increase horsepower but maintains full power at high altitudes.
Reading all this information might be confusing, so let’s sum this all up in the table below.
Conclusion
It may be simple enough to say that automotive and airplane engines are similar since they help run the vehicle or plane. However, they only share a few similarities such as the components and materials used to build the engine.
Aircraft engines are more advanced, have a lot of power, and get designed efficiently. Each component in it is made as light as possible to avoid the constant power and weight dilemma. The need for regular maintenance and additional safety precautions further adds to the complexities of an aircraft engine.
The engine built for an aircraft also takes into consideration the weight, extreme temperatures, air pressure, and many other factors. Even if you were to replace an aircraft engine with a similarly powerful car engine, it will not get the airplane in the air as it would just be too heavy.
What’s interesting is that even though these two engines are different in many ways, the automotive and the aviation industry have exchanged ideas on working together. It is because the manufacturing plants of the two can complement each other helping bring down costs of the engines and perhaps even improve them.
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