Choosing the Right Propeller for Your Rotax Engine:
When building or upgrading your aircraft, the combination of the engine and propeller is one of the most important decisions you can make. It influences not only performance but also efficiency and reliability. For those using Rotax engines — known for their lightweight design, fuel efficiency, and reliability — matching the right propeller can significantly enhance your flight experience. Here, we break down the benefits and best fits for some of the most popular Rotax engines paired with key propeller models, including MT34, Airmaster WWR72B, Airmaster SNR72K, Eprop V20, and Eprop Glorieuse.
Rotax Engine Overview
Before diving into the propeller matches, let's first look at some popular Rotax engines:
| Engine Model | Weight (kg) | Horsepower (hp) | Estimated Cost (ZAR) | Fuel Type | Fuel Consumption (l/h) | Turbocharged |
|---|---|---|---|---|---|---|
| 912iS | 63.6 | 100 | 500,000 | Unleaded Mogas | 21 | No |
| 912ULS | 63.0 | 100 | 400,000 | Unleaded Mogas | 24 | No |
| 914 | 64.8 | 115 | 600,000 | Unleaded Mogas | 28 | Yes |
| 915iS | 85.8 | 141 | 800,000 | Unleaded Mogas/Avgas | 29 | Yes |
| 916iS | 85.8 | 160 | 1,000,000 | Unleaded Mogas/Avgas | 30 | Yes |
Each engine offers a different balance of weight, horsepower, and turbocharging options, making them suited to different aircraft and missions. To maximize performance, choosing the right propeller is critical.
Propeller Comparison
| Propeller Model | Weight (kg) | Blade Material | Diameter (inches) | Adjustability | Number of Blades | Estimated Cost (ZAR) |
|---|---|---|---|---|---|---|
| MT34 | 10.5 | Wood Composite | 72 | Constant Speed | 3 | 95,000 |
| Airmaster WWR72B | 8.5 | Carbon Fiber | 72 | Constant Speed | 2 | 85,000 |
| Airmaster SNR72K | 8.0 | Carbon Fiber | 72 | Constant Speed | 3 | 90,000 |
| Eprop V20 | 4.5 | Carbon Fiber | 70 | Fixed | 2 | 60,000 |
| Eprop Glorieuse | 5.2 | Carbon Fiber | 70 | Fixed | 3 | 75,000 |
Propeller Recommendations for Rotax Engines
Now that we have a sense of the engine and propeller specifications, let’s match the best propellers to each Rotax engine based on weight, adjustability, thrust needs, and use cases.
Rotax 912iS (100 hp, 63.6 kg)
-
Recommended Propeller: Airmaster WWR72B
- Propeller Weight: 8.5 kg
- Why?: The Airmaster WWR72B offers a lightweight design with carbon fiber blades and constant speed adjustability, ideal for maximizing fuel efficiency and optimizing performance in varying flight conditions. This propeller is a great match for aircraft using the 912iS, which is often found in light sport aircraft and ultralights where weight and efficiency are priorities.
- Additional Benefits: Reduced pilot workload through automated constant speed adjustments, providing the best mix of performance and fuel economy.
Rotax 912ULS (100 hp, 63.0 kg)
-
Recommended Propeller: Eprop V20
- Propeller Weight: 4.5 kg
- Why?: The Eprop V20 is an ultra-lightweight fixed-pitch propeller that offers simplicity and efficiency, making it a perfect match for the 912ULS. This setup is ideal for recreational flyers and sport pilots looking to minimize weight and complexity while still getting the most out of their engine.
- Additional Benefits: The Eprop V20 allows for lower fuel consumption and easier installation, perfect for those who want a straightforward flying experience without the need for constant adjustments.
Rotax 914 (115 hp, 64.8 kg, Turbocharged)
-
Recommended Propeller: Airmaster SNR72K
- Propeller Weight: 8.0 kg
- Why?: The Airmaster SNR72K is a carbon fiber, constant-speed propeller with three blades, providing enhanced thrust and climb performance. For a turbocharged engine like the Rotax 914, which is used in bush flying or high-altitude conditions, this propeller allows you to fully leverage the engine’s power, particularly during takeoff and climb.
- Additional Benefits: The additional blade and constant-speed capabilities make it easier to adapt to various altitudes and loads, a must-have for those operating in more challenging environments.
Rotax 915iS (141 hp, 85.8 kg, Turbocharged)
-
Recommended Propeller: MT34
- Propeller Weight: 10.5 kg
- Why?: The MT34 is a wood composite, constant-speed propeller designed for higher-powered engines. Its smooth operation, combined with the ability to handle the increased horsepower of the 915iS, makes it the perfect choice for aircraft requiring robust performance and reliability.
- Additional Benefits: The MT34 can reduce vibration, offering smoother flight experiences, and it is ideal for heavy-duty applications where engine power needs to be fully utilized.
Rotax 916iS (160 hp, 85.8 kg, Turbocharged)
-
Recommended Propeller: MT34
- Propeller Weight: 10.5 kg
- Why?: Similar to the 915iS, the Rotax 916iS benefits from the durable, 3-blade MT34 propeller. The extra horsepower makes the MT34 an ideal choice for pilots needing the utmost reliability and thrust during demanding bush or adventure flying scenarios.
- Additional Benefits: With the MT34’s ability to handle higher torque, it ensures longevity and optimal performance, especially when paired with the top-tier 916iS engine.
Conclusion
Choosing the right propeller is key to getting the most out of your Rotax engine. Whether you’re looking for lightweight efficiency with the 912ULS, high-altitude performance with the 914, or robust power with the 916iS, matching the propeller to your engine’s capabilities will enhance your aircraft’s performance, fuel efficiency, and overall flying experience.
- For light sport and ultralight aircraft, propellers like the Eprop V20 offer simplicity and fuel savings.
- For bush flying or heavy-duty applications, constant-speed propellers like the MT34 or Airmaster SNR72K ensure you get maximum power and control.
By taking into account factors such as weight, adjustability, and thrust requirements, you can make an informed decision that aligns with your flying needs.