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Frequently Asked Questions

QUESTION: How is International Vibration Technology (IVT) able to make the aircraft smoother with less balancing adjustments?

ANSWER:     Our technology adapts to nonlinear conditions of the individual aircraft, using learning or self-refining mathematical algorithms to calculate a smoothing solution.  Other balancing technologies are based on linear or repeatable conditions that are averaged over a large number of the same “type” of aircraft.  It was always assumed that the balancing adjustments will respond in the same way for all aircraft of the same type.  Therefore, one balance model should work for all aircraft of the same type.  For the past many years, this assumption has proven to be incorrect.  With today’s modern complex rotor systems, using this “one model fits all” approach, you have about a 20% chance that this method will actually work on your individual aircraft.  Over time and normal wear and tear on rotor components, linear vibrations will become nonlinear; causing the rotor system to drastically change from your Balancer’s predetermined balancing model.  Case in point, did you ever wonder why you could never reach the balancing results as predicted by your Balancer – the balancing model, within your Balancer, doesn’t completely match your individual aircraft.  This became more apparent with complex rotor systems (composite and elastomeric rotor components).  The quick fix for this problem was to raise the balancing limit to a higher vibration level – somewhere above the normal standard of 0.2 ips.  In fact, some aircraft are now allowed to vibrate to a 0.5 ips or higher.  In other words, the “one model that fits all” approach isn’t very effective.

QUESTION: If this “one model fits all” approach doesn’t work effectively, why is it still being used as the primary method in smoothing rotors?

ANSWER:     This question requires two separate responses:

First- Education and the low number of vibration experienced mechanics is a major problem.  Unfortunately, within the military, this problem has worsened.  Computer Balancers were first developed in the 1980’s to replace the low number of experienced mechanics by automating the track and balance process – simplifying this process enabled less experienced mechanics to accomplish this difficult procedure.  Education was then designed around how to operate this new Computer Balancer – theory in dynamic balancing was no longer a part of the training.  The helicopter industry basically lost a generation of knowledgeable mechanics that accomplished dynamic balancing utilizing paper Polar Charts to manually calculate smoothing adjustments – most mechanics today don’t even know what a Polar Chart is.  In fact, in the military, so much confidence was placed on these new Computer Balancers that Polar Charts were soon removed from the mechanic’s Maintenance Manual; the process was now fully automated.  Bad idea...  Experienced mechanics today had to overcome this setback by learning how to pick and choose which separate adjustment(s), out of a combination of many that were calculated, to actually make on the rotor system for better results.  Over time the mechanic had learned that the combination of adjustments that was calculated did not always work as predicted.  Remember, it is very rare that anyone has or will ever reach the Balancer’s predicted smoothing result from its own calculated solution.

Second- If only one type of a balancing adjustment can be used and only one vibration sensor was needed to measure rotor vibration while flying only one flight profile to collect the vibration data, it would then become more popular to use the learning algorithm method vs. the “one model fits all” to calculate a smoothing solution; unfortunately, that is not the case for smoothing a helicopter main rotor system.  Multiple sensors (vertical, lateral, forward/aft, etc.), multiple flight profiles (Ground, Hover, inflight, etc.) and multiple rotor adjustments (Trim Tab, Pitch Link, Weight, etc.) are all required to smooth a main rotor system in all of its different flight profiles.  If one specific adjustment out of a combination of many responds unpredictably during a specific flight regime, the Computer Balancer is unable to isolate which adjustment, out of many, responded nonlinearly and would then come to a dead-end – not knowing how to respond to the next solution calculation.  This is why a predetermined model (“one model fits all”) is used to calculate the next balancing solution.  No matter which adjustment(s) responded unpredictably, it would still use the same unchangeable template or model to calculate the next solution.  The mechanic would repeat this process until a smooth rotor is achieved.  To use the learning mathematical algorithms method, a mechanic would have to choose a specific regime to fly and smooth first; then decide which one type of an adjustment to balance with.  This method would take great skill and experience in deciding which type of an adjustment to use for what flight profile you want to smooth and still insure a positive smoothing response on all other flight profiles.  Basically, the mechanic will revert back to the good old days of manual track and balance.  The time or number of flights it takes to complete this process will depend on the mechanic’s experience, returning us back to square one on why the Computer Balancers first came out in the 1980’s.  This is why the “one model fits all” approach is still the primary method in smoothing rotors.

QUESTION: How is IVT able to make these learning algorithms work without the aid of an experienced mechanic or reverting back to the older methods of balancing?

ANSWER:     Our process will use the same data as those balance programs “one model fits all” technologies and uses a mathematical self-refining algorithm to formulate a working solution for the specific aircraft involved.  Our advanced software, Vibration Intelligent Balance Solution (VIBS), is fully automated from start to finish for all flight profiles.  Utilizing our embedded proprietary NIAB decision-making protocols, VIBS has the ability to calculate a fully automated solution for maximum smoothing results and still adapt to nonlinear conditions minimizing the total number of adjustments with maximum results of 0.0XX ips on all flight profiles.  In fact, our proprietary applications can actually use much of the data supplied by many different brands of balancing equipment.  VIBS averages about 70% fewer adjustments when compared to the “one model fits all” method Balancers.