Rolls Royce

Spin pits are specialized test facilities used in the development and testing of jet engine components and other high-speed rotating machinery. These facilities provide a controlled environment where engineers can subject components to conditions that mimic or exceed what will be seen in service. 

At Barbour Stockwell, Inc. (BSi), we specialize in providing reliable spin pits built to our customers’ unique specifications and requirements. Learn more about the key components, applications, and benefits of our spin pits below. 

Key Components & Features of a Spin Pit

Spin pits consist of the following key components and features:

  • Test Chamber. The test chamber is typically a vacuum vessel with containment to ensure that no fragments can escape in the event of a rotor burst. 
  • Drive System. The drive system is a powerful motor or turbine that can accelerate the test component to the desired rotational speed.
  • Instrumentation. This includes a variety of sensors and instruments to monitor test conditions, including speed, temperature, strain, and real-time growth. In addition to these process variables, instrumentation is employed to monitor the health of the rig, including shaft vibration.   
  • Safety Systems. Safety systems terminate the test if readings from the instrumentation exceed pre-programmed limits. This is done either by braking or coasting to a halt, depending on the fault that has occurred. 

Applications in Jet Engine Development

A wide variety of tests can be performed in a spin pit to ensure the integrity of jet engine rotors and other high-speed rotating components. Common spin pit applications include:

Overspeed Testing

Overspeed testing involves driving a rotor to a speed that exceeds the speed it will experience in service. This type of testing is commonly performed for quality assurance reasons, but it is also often part of the production process. Before final machining, high-speed jet engine rotors are frequently driven to speeds beyond which the bore starts to yield. This results in improved part stability during final machining, and the residual compressive stresses improve the lifespan of the end product.  

Burst Testing

During burst testing, the rotor is driven to a specific speed until it reaches the point of failure to ensure an adequate margin between service speeds and burst. During jet engine manufacturing, burst testing is performed for a variety of reasons, including:

  • Qualifying a new jet engine rotor design
  • Calibrating analytical prediction methods
  • Assessing new materials

Low-Cycle Fatigue Testing

Low-cycle fatigue (LCF) testing evaluates the fatigue life of a rotor by cycling a test rotor between low and high speeds thousands of times. This is typically performed at elevated temperatures. LCF testing is used to calibrate analytical prediction methods and test new rotor designs and materials. 

High-Cycle Fatigue Testing

High-cycle fatigue (HCF) testing involves subjecting rotor blades to excitation while it is rotating. The excitation is generated by impinging jets of oil or air on the blades. The purpose of this test is to identify and analyze blade resonance while the rotor is exposed to the effects of centrifugal forces. 

Benefits of Spin Pit Testing

Testing jet engine components in a spin pit is not only far more economical than tests performed in a full engine, but it also allows for more precise control and easier monitoring of test conditions. Additionally, spin pit testing does not require the availability of a complete built-up engine.  

Spin Pit Testing Services & Products from BSi

At BSi, we have decades of experience designing and building custom spin pits for testing high-speed jet engine components. We can adapt spin pits to perform numerous types of spin tests, with the ability to reliably generate over 200,000 rpm test after test. For more information about our spin pit capabilities, contact us or request a quote today.