G4 stands for “Generation IV” and represents the latest technology developed by the US Air Force for fighter engine testing. The origins of the technology, Generation I, date back to the 1970’s. EDAS markets the G4 technology under a cooperative research and development agreement with the US Air Force. Now you can benefit from nearly forty years of development and countless hours of critical test experience.
A Brief History-

• G1 - Early 1970’s – Generation 1 developed by the US Air Force at the Arnold Engineering Development Center (AEDC)
• G2 - Mid 1970’s to Mid 1990’s – varying amounts of development within engine companies
• G3 - Late 1990’s – US Air Force awards contract to advance NSMS for military application
• G4 - Early 2000’s – Contract completion results in Generation 4

In June of 2007 EDAS and the US Air Force at AEDC signed Cooperative Research and Development Agreement (CRDA) transferring the rights of NSMS-G4 to EDAS. EDAS continues to improve the technology making it easier to use and more flexible for a wider customer base. EDAS also integrated Tip-Timing into its EDAS-DS Monitoring and Analysis product making it a simple system anyone can use, to acquire accurate data with less test cost and time.

Tip-timing, also known as NSMS (Non-interference Stress Measurement System) is used to measure blade vibration in turbomachinery. By measuring the time each blade passes by a sensor, we can derive blade vibratory displacements and HCF margins. While laser sensors are most common, other kinds of sensors, like eddy current and capacitance probes, can also be used. Because these probes are mounted to the case and not the blades themselves, the measurements don’t interfere with the dynamics. It also makes for less expensive testing compared to strain gages. Plus, all blades are measured. So, when you think about tip-timing, think less expensive, non-intrusive, and all blades. Easy.

NSMS (Non-interference Stress Measurement System) is the newest technology available for vibration and HCF testing. It allows you to record every blade and will save you time and money on every test. NSMS, also known as “Tip Timing” acquires blade time of arrival measurements to determine blade vibratory deflection levels and HCF margins. This system typically utilizes lasers with fiber-optic probes mounted to turbo machinery casing and uses beam-interrupt, or beam reflection to determine time of arrival. The NSMS system can utilize various kinds of probes including line laser, spot laser, eddy-current, capacitance, LED, and others.

The design used by EDAS to create its SignalBoss, NSMS G4 System was derived as part of the DoD “Generation 4” (G4) development program undertaken to advance the art of NSMS. The design has been proven over five years of testing at many DoD test facilities and is being transitioned to EDAS.

The NSMS G4 acquisition hardware accepts up to 16 channels of NSMS measurements from multiple rotors. The acquisition system includes monitoring software that provides easy to understand indicators of data quality and blade vibrations to ensure safe engine operation.

The post processing NSMS G4 software has advanced algorithms to evaluate blade vibratory state for integral and non-integral vibrations. The processed data is stored in a format that is compatible with other EDAS post-test evaluation software, such as SignalBoss Analysis. The post processing software is available now for evaluating NSMS data acquired from other acquisition systems. The Complete Solution
DUAL NSMS Straing Gage Technology – The next Generation Available 2009

SignalBoss-NSMS G4 systems can be bundled with a variety of probe types and comes with a 300 MHz electro-optic receiver with USB2 connectivity, commercial grade Dell server and G4M software for system control and EDAS-DS for monitoring. The system is highly portable and comes in a hardened travel case. This turn-key system allows you to measure every blade with easy set-up, and more accurate results.

In early 2008, EDAS, Inc was awarded an SBIR Phase 2 contract to advance multi-source digital signal processing and analysis for characterization of vibrations in turbo-machinery blades. Within the project, EDAS will develop unique interfaces between our SignalBoss software, GageMap and NSMS-G4 products to improve accuracy and information content for your turbomachinery test. Look for significant, industry leading advances in the state of the art of tip-timing and strain gage data acquisition and processing over the next two years. You deserve to be impressed!

Some of the features of this solution are:


• Strain gage & NSMS sensor location optimization.
• Simplified determination of NSMS limits with virtual
  NSMS sensors within our GageMap product.
• Strain gage and NSMS acquisition & monitoring in one application.
• Information sharing to improve online data processing and accuracy.