GMN Precision Angular Contact Bearings for Microturbines

In the aerospace and defense industry, failure is not an option. Applications such as microturbines require reliable components for critical situations that operate at high speeds under extreme temperatures. This is where GMN’s precision angular contact bearings come into play, delivering the extreme rotational accuracy and thermal stability needed for the success of microturbine applications.

Microturbine Technology

Small or miniature turbines (also known as microturbines) can be used in many defense applications, including long-range drone or UAV (unmanned aerial vehicle) and munitions applications. 

UAVs utilize a small turbine for its propulsion efficiency to require a small amount of fuel to be carried on board.  This is important for all drone applications, but especially important for long-range UAVs that must come back and land safely for reuse. 

Turbine applications for munitions are also very common for their efficiency, and their high power-to-weight ratio.  Turbines can propel an object at a high rate of speed with minimum issues or fuel usage for minutes at a time – the usual life requirement for this application. 

GMN precision bearings are used across several microturbine applications. When choosing a bearing for your UAV or munitions applications, there are several factors to consider to ensure safety and bearing longevity.

Microturbine Bearing Lubrication

Although many small turbine applications exceed 1MM ndm, grease lubrication can very much be an option pending the overall requirements of the application.  There are many high-speed, high temp greases that exist to fulfill these requirements for a successful application.  However, other application parameters can prevent grease from being the best lubrication choice.  This is where GMN Bearing USA engineers are here to help.

Extended storage requirements can be an issue for grease because of degradation.  The oil can separate from its thickener and not recombine because of contaminates in the air or the container that the bearings are stored in.  Dry lubrication such as Moly DiSulfide, Dicronite, Gold, Silver, etc. are all potential options pending the specific requirements of the application.  Each dry lubrication option has pros and cons for each specific scenario. 

It has also become common for the fuel itself to act as the bearing lubricant.  Fuel has lubristic qualities that can pass through the bearings as a lubricant and reduce temperatures for the bearings to be successful during the minutes of required bearing life.  This might be unconventional, but GMN Bearing USA has had experience with multiple applications where the turbine fuel itself has proven to be a reasonable lubricant for the required bearing life. 

In the end, lubrication for these types of turbine applications can and should be creative to come up with the best solution for your particular application. GMN engineers are pros at identifying the best bearing lubrication for a range of specific needs; contact us to discuss your application requirements with a real technical expert.

Storage Requirements for Microturbine Bearings

Many microturbine applications for government usage have a long storage requirement. This type of storage is possible, but specific choices need to be made when bearing reliability is required after 7-10 years of storage.

First, the storage preparation needs to be correct. It is strongly preferred if the entire bearing system or entire assembly is sealed within a plastic bag. The thicker the bag, the better, to prevent humidity and other potential issues including sunlight damage. Sunlight can be an issue not only due to high temperatures, but the sunlight itself can cause deterioration and damage.

Secondly, many greases will not last extended periods of time in a useful state.  The air within the storage bag itself can cause grease breakdown issues, and any air seepage will break down the grease, reducing its life once it is required within the application.

For this reason, GMN Bearing USA strongly suggests different types of dry lubrication to not only survive the lengthy storage requirement, but also be ready to lubricate the bearing for a successful application.  Dry lubrications have little to no degradation if stored properly and carry a useful life of ~1000 hours.  This is typically much higher than the running life requirement of most defense applications. Our team of experts are here to help you choose the best bearing for your microturbine application. Contact us today.

Bearing RPM Considerations

The speed ability of a microturbine application can also be a fun part of the design process. The bearings need to be sized and designed to carry the application loads, RPM duty cycles, and overall demands of the application. As stated, this can be storage for an extended period of time, long life of rotation, or only a short life requirement.

All of these aspects of duty cycles, RPM, Load, etc., need to be considered during the initial bearing choice and design process. There are times a larger bearing can be utilized to handle a higher load with a short life expectation, and other times a smaller bearing can be utilized under destructive application parameters knowing the life requirement is only minutes. 

GMN’s Aerospace Expertise

With decades of experience under our belts working with aerospace and defense applications, we have an engineering-focused approach when it comes to problem solving and helping our OEM partners find the best solutions for their unique applications.

Our team of engineers, certified bearing specialists, and technical experts are here to help. Contact us today!