Propellers Are Not Done: Why Russian and Other Aircraft Still Use Them

There's a persistent myth that all modern aircraft have moved away from propeller-driven engines in favor of jets. However, this couldn't be further from the truth. Propellers continue to thrive in the aviation industry, particularly in small aircraft. This article investigates why propellers are still relevant and why they are not being replaced by jet engines in many cases.

Understand the Basics: Engines Drive Propellers

Before delving into why propellers are still widely used, it's crucial to understand a fundamental principle in aviation: engines drive propellers, not the other way around. Propellers are simply tools that convert the rotational energy of an engine into thrust, propelling the aircraft forward.

The Cost Factor

One of the main reasons why small aircraft continue to use propellers is cost. Jet engines are significantly more expensive than piston engines. For small aircraft, the cost of a jet engine would typically exceed the entire price of a light aircraft with a piston engine. Additionally, many jet engines are more powerful than what most small aircraft need, making them cost-ineffective.

Practical Advantages and Limitations of Propellers

Despite their lower cost, propeller engines still offer several practical advantages, including:

High Altitude Performance: Turbines, which often power jets, offer advantages at high altitudes where drag is reduced and power settings can be very low. Light aircraft typically lack the provisions for oxygen or pressurization needed to fly at these altitudes. Efficiency: Turbines can achieve maximum efficiency at high altitudes and very low temperatures. However, they require more fuel at low altitudes, which can offset the benefits.

Given these considerations, small aircraft manufacturers continue to find uses for propellers. Some examples include the Piper and Cessna, where adding a turbine would likely reduce range and increase fuel consumption due to the thirsty nature of turbines.

Special Cases and Custom Conversions

There are special cases where propeller-driven aircraft have been modified with jet engines. For instance, the Wilga aircraft was modified with a PT6 engine, resulting in significant performance gains. However, such modifications are rare and expensive. The owner of this aircraft estimates the cost to be over a million dollars, a hefty price tag that most private plane owners cannot afford.

Historical Examples: Coors Silver Bullet

Historically, there have been rare instances of small aircraft being modified for jet propulsion. One notable example is the Coors Silver Bullet, which was sponsored by Coors and featured a jet conversion to the standard BD5 kitplane. While the conversion was impressive, it was not cost-effective for most pilots, as the addition of jet engines required significant modifications to the aircraft, including avionics, oxygen systems, and structural changes.

These special cases highlight the challenges associated with adding jet engines to small aircraft. Modern pilot training and certification further complicate the adoption of jets in light aircraft. Typically, operating a turbine requires additional certification, making it a less attractive option for most private pilots.

Conclusion

While the aviation industry has indeed seen a shift towards jet engines, it's important to recognize that propellers remain a valuable and efficient option for small aircraft. The cost, practical advantages, and special cases demonstrate that propellers are not being abandoned but continue to play a significant role in the aviation industry. Whether powered by propellers or jets, the choice ultimately depends on the aircraft's intended use, the operator's budget, and the specific requirements of the flight mission.