The world of general aviation has seen some interesting engine developments over the years, and one name that frequently comes up in discussions is Austro Engines. While not as immediately recognizable as some legacy aviation engine manufacturers, Austro Engines has carved a niche for itself by leveraging proven automotive technology, specifically from Mercedes-Benz. This article delves into the story of Austro Engines, exploring their reliance on Mercedes engines, the debate around engine block materials, and what the future might hold for this unique engine manufacturer in the competitive landscape of aircraft propulsion.
Austro Engines emerged from a strategic decision by Diamond Aircraft, a well-known manufacturer of light aircraft. Facing challenges with previous engine suppliers, Diamond sought to secure a reliable and modern engine for their popular DA42 and DA62 aircraft. The solution was to establish Austro Engines and base their initial engine designs on Mercedes-Benz automotive diesel engines, particularly the OM640. This wasn’t a simple off-the-shelf adaptation. Austro took the robust OM640 engine and re-engineered it for aviation use, creating the AE300 and AE330 series engines. This involved adding essential aircraft components like gearboxes, specialized engine control units (ECUs) from Bosch, and ensuring the engines met stringent aviation certification standards.
One of the key discussions within the aviation community, as reflected in online forums, revolves around the engine block of these Austro engines. The original Mercedes OM640 engine utilized a cast iron block, known for its durability but also its weight. There’s been speculation and debate about whether Austro would consider transitioning to an aluminum block for future engine iterations. Aluminum blocks offer a significant weight advantage, which is highly desirable in aviation to improve payload and performance. However, the switch to aluminum is not without its complexities.
Alt: Aviation forum participant avatar, discussing Mercedes-Benz derived aircraft engines.
As highlighted in discussions amongst aircraft owners and enthusiasts, the original Thielert aircraft engines, which also had ties to Mercedes, initially used an aluminum block in their 1.7-liter variant. However, when Mercedes upgraded to a 2.0-liter engine with a cast iron block (the OM640), Thielert adapted the new engine but controversially chose to revert to an aluminum block themselves. This decision, made partly to maintain weight and balance compatibility with Diamond aircraft, is speculated to have contributed to Thielert’s financial difficulties. Austro, in contrast, embraced the cast iron block of the OM640, and Diamond Aircraft adapted their airframes to accommodate the slightly increased weight. This decision by Austro avoided the costly and complex re-engineering of the engine core.
The reliance on the Mercedes OM640 engine has been a double-edged sword for Austro. Initially, Austro benefited from purchasing readily available OM640 engines directly from Mercedes-Benz. This allowed them to quickly establish production and get their engines certified and into service. However, as Mercedes moved on to newer generations of automotive diesel engines, production of the OM640 ceased. This has led Austro to a critical juncture. They are now facing the prospect of running out of their stock of original Mercedes OM640 engines.
Alt: Forum member profile image, involved in a discussion about Mercedes aircraft engine technology.
To address this challenge, Austro has reportedly secured a license from Mercedes-Benz to manufacture the OM640 engine core themselves. This allows them to maintain production of their AE300 and AE330 engines without requiring extensive and expensive re-certification processes for a completely new engine design. While some argue that Austro should have used this opportunity to adopt newer, potentially lighter, aluminum block Mercedes engines, the cost and complexity of re-certification in the aviation industry are substantial. For a relatively low-volume manufacturer like Austro, sticking with the proven and certified OM640 core, even with its cast iron block, appears to be the most economically viable and pragmatic approach.
Looking ahead, the future of Austro Engines will likely remain closely tied to Mercedes-Benz technology, at least for the foreseeable future. While the cast iron block OM640 might be considered somewhat ‘old technology’ in the fast-moving automotive world, its robustness and proven track record are valuable assets in aviation. The decision to manufacture the OM640 core in-house secures Austro’s engine supply and allows them to continue powering Diamond aircraft and potentially explore new applications for their Mercedes-derived aircraft engines in the broader general aviation market. The story of Austro Engines is a testament to the innovative ways in which automotive technology can be adapted and applied to the demanding world of aviation, offering a reliable and modern alternative in aircraft propulsion.
