What Octane is Aviation Fuel?
Aviation fuel, also known as avgas, is a type of refined petroleum product used to power aircraft engines. But what about octane? Is aviation fuel high-octane or low-octane? Let’s dive into the world of aviation fuels and explore the answer.
What is Octane?
Octane is a measure of a fuel’s resistance to engine knock or pinging, which occurs when the fuel ignites prematurely in the combustion chamber. Higher octane fuels are more resistant to engine knock, meaning they can withstand higher compression ratios and higher engine temperatures without knocking or pinging.
What Octane is Aviation Fuel?
Aviation fuel is typically a low-octane fuel, with an average octane rating of 80-91. The most common types of aviation fuel are:
- 100LL (Low Lead): This is the most widely used aviation fuel, with an octane rating of 100. It is a low-lead fuel, meaning it contains less than 0.04 grams of lead per pound.
- 100F (Full Flash Point): This fuel has an octane rating of 100 and is designed for use in engines that require a higher octane fuel.
- mogas (Motor Gasoline): This is a non-aviation fuel that is used in automobiles, but can be used in some small aircraft engines with proper conversion.
Why is Aviation Fuel Low-Octane?
There are several reasons why aviation fuel is typically low-octane:
- Higher compression ratios: Aircraft engines typically operate at higher compression ratios than automotive engines, which requires a lower-octane fuel to prevent engine knock.
- Engine design: Aviation engines are designed to run at high temperatures and pressures, which can cause the fuel to ignite prematurely, leading to engine knock.
- Fuel type: Aviation fuel is typically a refined product, whereas automotive fuel can be a blended product with a higher octane rating.
Aviation Fuel Specifications
Here are the specifications for common types of aviation fuel:
| Fuel Type | Octane Rating | Lead Content | Flash Point | Freezing Point |
|---|---|---|---|---|
| 100LL | 100 | <0.04g/lb | 125°F (52°C) | -50°F (-45.6°C) |
| 100F | 100 | 0g/lb | 150°F (65.6°C) | -50°F (-45.6°C) |
| mogas | 87-91 | 0g/lb | 100°F (37.8°C) | -20°F (-28.9°C) |
Conclusion
In conclusion, aviation fuel is typically a low-octane fuel, with an average octane rating of 80-91. The main reasons for this are higher compression ratios, engine design, and fuel type. Understanding the specifications of aviation fuel is important for aircraft operators and mechanics to ensure safe and efficient operation.
