The Need For High-Purity Wash Water
High precision helicopter turbines are susceptible to damage by minuscule particulate accumulation or corrosion. Even an accumulation of minute amounts of ash can make a noticeable difference in horsepower. Salt residue can corrode and even ruin these expensive engines. According to manufacturer’s recommendations, high precision helicopter turbines should be flushed out with high purity water after each flight in order to protect the expensive engines from damage caused by particulates or corrosion.
Companies that don’t follow these recommendations risk down time, employee safety and potentially severe damage to their expensive helicopter engines. Engine manufacturers will deny warranty claims on ruined engines if the problem is found to be from insufficient cleaning based on manufacturer’s cleaning specs.
Common solutions include reverse osmosis, deionization, simple distillation or even outsourced bottled water. These solutions cannot offer the consistent level of purity that is needed to protect expensive high precision helicopter turbines.
TurboPureWater is a manufacturing company that provides specialized, ultrapure water solutions for high precision helicopter turbine rinse water. In addition, TurboPureWater offers unmatched global support solutions.
Q: What is a leading factor contributing to higher maintenance costs?
Q: What is corrosion?
A: Corrosion is the loss of integrity of a metal resulting from either:
- Direct chemical attack on the metals of the engine or airframe OR
- Electrolysis – the electrical “Electrolytic Corrosion” which occurs when dissimilar metals are in contact in the presence of an electrolyte, such as contaminated water enhanced with heat.
Q: What causes corrosion?
A: Impurities in the air from a number of sources can settle on metal parts in of the airframes and be inhaled into the engine where they impact the components of the compressor and turbine through the normal processes of engine operation. The impact of these impurities upon the engines and on the airframe, start chemical reactions at a microscopic level. For example, when low flying aircraft fly over the ocean they are often sprayed with salt-water which contains chlorides. Chlorides are highly corrosive when in contact with certain metals in the turbines. Other chemicals such as sulfates, and metal salts are also corrosive.
Even over land, the air itself can be contaminated with:
- Particulate pollutants
- Gaseous pollutants
- Sulfur dioxide
- Nitrogen oxide
- Acid rain
- Wildfire ash
- Volcanic dust
Q: What is the Mechanism for Corrosion to Occur?
A: There are several possible mechanisms:
- The salts hold moisture on the surface and promote corrosion in unprotected metals.
- Chloride solutions break down the protective film on magnesium and aluminum, furthermore, corrosion increases with humidity.
- Inlets and compressor sections’ protective coatings can be chipped which promotes corrosion.
- Sulfidation is a hot-corrosion process that affects the hot sections of the engine primarily the turbine blades
- Sodium from atmosphere, sea water, and sulfur from fuels are sufficient to cause blistering and scaling of the blades
Q: What is the impact of corrosion on turbine blades?
A: Corrosion can cause degradation of the compressor and turbine (hot section) blades surfaces. This changes the profile of the blades and therefore the airflow patterns.
This can lead to:
- Low Engine Power Check numbers
- More frequent turbine replacement and rework.
Q. How can I tell if I have corrosion on the airframe?
A. During maintenance inspections, look for minute bubbles of paint. These bubbles can be indicative of
corrosion occurring on the metal surface under the paint.
Q. What do the manufacturers recommend?
A. Turbomeca, Rolls Royce and others have maintenance procedures that call for the use of a chemical wash to remove the contaminants, followed by high purity water as a final rinse.
Q. Why Should the Helicopter Operator Care About Water Quality?
A: Not all water is the same. Water is the world’s greatest solvent and because of that, can have a myriad of contaminants in it. Even if water looks clear, smells okay, and tastes ‘normal’, it can have contaminants in it that could harm your equipment. The scale that quickly forms inside kettles is visual evidence of contaminants in the water.
Q: Should I use tap water for turbine rinse?
A: Tap water is likely to contain corrosion enhancing impurities. Tap water quality can vary widely from location to location and can even vary from season to season at the same location. It may contain large quantities of minerals including sulfates, sodium, calcium & magnesium as well as chlorides, sulfates and other salts that can corrode or leave residues on the engine.
Q Should I use Bottled Water Instead of Tap Water?
A: Locally-produced bottled water can vary widely in purity and may not meet the manufacturers’ specifications.
Q: Can I use filtered or Reverse Osmosis Water?
A: Typically a filter or R.O. are not sufficient as they utilize “barrier technology” and purity decreases over time.
Q: What Water Should I Use?
A: We have found that distillation produces water of high purity consistently over time. This consistency is important in order to achieve the best corrosion protection. We enhance the distillation process with deionization and we provide purity measurement or alert systems to ensure you are receiving water of the highest quality.
Q: What are the Manufacturers Specifications for Water?
A: Turbine-rinse water must meet ISO-3696. The US Coast Guard requires water that meets that specification and requires that environmental standards be met as well as confirmatory independent third party laboratory testing on water purity.
Q: What is the best way for an operator to get water that meets these specifications?
A: The best way to get water that consistently and reliably meets these high standards is to use water purification systems that provide water purity controls and are designed for the specific purpose of turbine rinse water. The TurboPureWater Systems meet these standards using multiple technologies based around distillation. Distillation offers high purity water that does not decline in quality over time.
Q: How much final rinse water is needed per engine?
A: This can vary from one model of helicopter to another. The Turbomeca HH-65 requires approximately 2 gallons per turbine engine.
In all cases, follow the recommendations in the engine manufacturer’s manuals.