Air compressors and nitrogen generators have a variety of uses in the aerospace industry. Aircraft manufacturers, pilots, and maintenance workers all rely on air compressors, which play a critical role in the aerospace field — from building and manufacturing to in-flight control. Learn more about the different applications for compressed air in the aerospace industry and defense.
How Compressed Air Is Used in the Aerospace Industry
Compressed air is utilized extensively in the aerospace industry and defense sector to power tools and equipment, clean and prepare parts, power system controls, and test critical components and systems. Here are some common applications for compressed air systems in the aerospace field.
Aircraft Manufacturing
Aircraft manufacturing is a complex process involving numerous stages, and compressed air is an indispensable tool throughout these stages. Some of the most common applications include the following.
- Pneumatic tools: Compressed air powers a range of tools, such as rivet guns, screwdrivers, drills, and wrenches, which are critical for the assembly of aircraft parts. Air-powered shears and nibblers are used to cut and shape the sheet metal that forms the aircraft's body.
- Surface preparation and part cleaning: Before painting, coating, or metal finishing, surfaces need to be prepared. Air-powered sanders, grinders, and abrasive blasters are used for this purpose. Parts may also need to be thoroughly cleaned before assembly. High-pressure compressed air effectively removes contaminants, oil, or other residues from components.
- Painting and metal finishing: Compressed air is used for spray painting aircraft components, ensuring an even and smooth finish.
- Plastic molding: Compressed air can assist in the molding processes of various aircraft interior components, like overhead bins or seating elements.
- Aircraft engine manufacturing and engine cleaning: Jet engines and their components can be cleaned during their manufacturing process with compressed air to ensure that no residual contaminants are left that might affect performance. Compressed air may also be used for engine testing and cooling during aircraft engine manufacturing.
- Testing and quality control: Pressure testing is used to test essential components, especially those in the fuel or hydraulic systems, for leaks and durability. Compressed air is often used to apply this pressure. Compressed air may be used in cooling systems during rigorous avionics testing to replicate real-world conditions.
- Material handling and automation: Pneumatic actuators are used in automated systems to move or position parts during the manufacturing process. Some heavy components might be moved around the factory floor on an air cushion of compressed air, reducing friction and the risk of damage.
- Composite material production: Many modern aircraft use composite materials because of their strength and lightness. During the curing process of some composites, vacuum and pressure are applied, and compressed air can play a role here.
Aircraft and Heavy Equipment Maintenance
Compressed air plays an indispensable role in aircraft maintenance in both military and civilian realms, ensuring aircraft operate at their peak efficiency and safety. There are numerous applications of air compressors for aircraft maintenance and ground support equipment.
- Pneumatic tools: Compressed air is used for powering pneumatic tools such as drills, wrenches, and rivet guns.
- Engine cleaning: Compressed air can be used for cleaning engine components.
- Hydraulics and fuel lines: Pressure testing essential systems like hydraulics and fuel lines, ensuring they are leak-free and operational. Compressed air may also be used for fuel injection in some models of aircraft.
- Surface cleaning: High-pressure air blasts are used for surface cleaning, effectively removing debris, oil, and contaminants.
- Landing gear systems: Compressors may be used for testing and maintaining pneumatic components for landing gear.
- Other ground support equipment: Ground support equipment (GSE) encompasses a variety of other tools for aircraft tire service, cleaning, deicing, cabin air circulation, etc. Ground support equipment such as lifts and jacks may be powered by pneumatic air systems.
Missile and Weapons Systems
Air compressors are used by the defense industry for missile and weapons systems. Some applications include:
- Ejection mechanisms: Compressed air is used in some missile ejection systems from launch tubes or aircraft.
- Pneumatic controls: For certain guided missile systems and other weapon platforms.
Oxygen Generation Systems
In aviation, especially military aviation, onboard oxygen generation systems (OBOGS) may utilize compressed air as part of the process to supply breathable air to pilots, particularly during high-altitude or long-duration flights. These systems are designed to separate oxygen from the ambient air, supplying it to the pilots and potentially other crew members as needed. This air is then compressed using an onboard compressor, which is often integrated into the aircraft's engine system. The compression process raises the pressure of the air, making it easier to separate the oxygen from other gases.
Avionics Cooling
Compressed air can be employed to cool sensitive equipment in avionics, especially in military aircraft where reliability and performance are crucial and high temperatures prevail. Maintaining ideal operating conditions during flight is crucial for the optimal performance and reliability of electronic components and systems in high-performance aircraft. An onboard air compressor can be used to direct airflow at high-heat zones to ensure efficient cooling. Compressed air may also be used in systems for brake heat transfer. This rapid cooling can prevent overheating and prolong the life of the brake components.
UAVs (Unmanned Aerial Vehicles)
Compressed air can be used in the launching mechanism of certain drones or UAVs. Some UAVs, especially those deployed from naval vessels or ground vehicles, use compressed air catapult systems for launch. Onboard compressed air systems may also be used for pneumatic actuators, payload deployment, cooling, and emergency systems.
Compressed Air Equipment for the Aerospace Industry and Defense
Both rotary screw and reciprocating air compressors are widely used in the aerospace and defense industries. In addition, equipment such as air dryers, coolers, and other air treatment options may be needed, depending on the application. Compressed air equipment needs will depend on the volume and airflow of compressed air needed (CFM), air quality requirements, and where the air compressor will be used, among other considerations.
Air Compressors for the Aerospace Industry
- Rotary screw air compressors are commonly used for compressed air systems that require a continuous and reliable supply of compressed air, such as manufacturing processes and assembly of aircraft components. Their consistent air output, energy efficiency, and relatively quiet operation make rotary screw compressors ideal for these critical applications in the aerospace field where downtime or fluctuations in air supply could compromise safety or performance.
- Reciprocating air compressors are often used in aerospace and defense for smaller, more specialized compressed air systems that don't require a continuous air supply. Reciprocating air compressors are commonly found in mobile units for on-the-spot aircraft maintenance, backup systems, and small-scale manufacturing tasks. Due to their lower initial cost and ease of maintenance, reciprocating compressors are well-suited for deployments in remote locations or forward operating bases. However, these compressors are more suitable for intermittent rather than continuous use.
- High-pressure compressors may be used in specific applications like launching UAVs, filling high-pressure nitrogen cylinders, or other applications requiring high-pressure air. These high-quality air compressors are specifically designed to deliver high-pressure output, sometimes upwards of 6000 psi, which is necessary for some specialized applications.
- Specialty air compressors may be needed for specific applications like onboard oxygen generation systems (OBOGS) and other sensitive systems. These compressors are often customized to meet the exact needs of a specialized system, including size, weight, and output specifications, including pressure (PSI) and clean air requirements.
Other Compressed Air System Components
Compressed air requires treatment to ensure a consistent supply of cool, dry, clean air. Depending on the application, additional components may include:
- Air dryers (e.g., refrigerated dryers or desiccant dryers) to eliminate moisture in compressed air.
- Inline filters to remove particulates, oil carryover, and remaining moisture from compressed air.
- Oil/water separators to separate oil from condensate for safe disposal.
- Air receiver tanks to hold compressed air and stabilize pressure. Some air compressors (especially reciprocating or piston-style compressors) have an integrated air tank. In other cases, the air tank is separate.
- System components such as pressure regulators, after coolers, and condensate drains.
- Additional equipment like hoses and hose reels, quick couplers, belts, switches, etc.
- Aerospace manufacturing facilities that depend on compressed air for manufacturing and assembly operations will also require a compressed air distribution system to carry compressed air to each of the places where it is needed.
Considerations In Compressed Air System Design for Aerospace and Defense
Compressed air system design for the aerospace industry and defense will depend on the specific application. For optimal performance in aerospace applications, here are some key factors to consider:
- Air Quality: Clean air is a benefit for all aerospace and defense applications, but some are more sensitive than others. Air used for general manufacturing and assembly will not need to be as clean as air used in electronics assembly or for sensitive equipment, for example. Air purity requirements will influence the choice of compressors, filters, and dryers.
- Pressure Requirements: Different applications require different pressure levels. For general manufacturing applications, plant pressure (PSI) of about 100 PSI is usually adequate. Rotary screw air compressors are typically used for applications of 100-125 PSI. High-pressure applications may require specialized reciprocating compressors (e.g., multi-stage air compressors). Reducing pressure to the minimum PSI required will save energy and money.
- Flow Rate: The compressed air system must be designed to meet peak air demand (in Cubic Feet per Minute, or CFM) without compromising efficiency during periods of low usage. Sizing the air compressor and storage tanks appropriately is essential.
- Energy Efficiency: Given the often-high operational costs in aerospace and defense, choosing energy-efficient compressors (such as a variable speed drive air compressor) and dryers can lead to significant cost savings.
- Reliability and Redundancy: Air systems for the aerospace industry must be highly reliable. Backup compressors and other redundant systems may be necessary to ensure continuous operation and optimal performance.
- Compliance and Standards: Compressed air systems must meet various industry and governmental standards, including those related to safety, environmental impact, and performance.
- Location and Environment: The physical environment where the air compressors will be installed can affect its design. For example, a system on a naval vessel would need to be resistant to corrosion from salt water.
- Maintenance: Ease of maintenance, especially in remote or hard-to-access locations, is an essential consideration. The system should be designed to facilitate regular checks and quick replacements.
Are Oil-Free Air Compressors Needed for Aerospace Applications?
The need for oil-free compressors for aerospace applications depends on the specific application and its sensitivity to contaminants. In applications where even trace amounts of oil could compromise system integrity, functionality, or safety, oil-free compressors may be a requirement. For instance, compressed air used oxygen generation systems, and certain manufacturing processes that require high levels of purity would often benefit from the use of oil-free compressors.
Oil-free compressors eliminate the risk of oil contamination, reducing the need for extensive filtration systems to remove oil and thereby potentially improving system reliability and reducing maintenance costs. However, oil-free compressors are generally more expensive upfront and may also require more frequent maintenance than their oil-lubricated counterparts. This makes them less suitable for applications where oil contamination is not a critical concern.
Fluid-Aire Dynamics carries oil-free air compressors that keep contamination out of the air. The Atlas Copco oil-free reciprocating air compressors and Atlas Copco oil-free rotary screw air compressors are two non-lubricated models that work well for the aerospace industry. These prevent air contamination and are approved for rooms with electronics and other sensitive materials.
How Nitrogen Is Used in Aerospace and Defense
Nitrogen gas is extensively used in the aerospace and defense industries for a variety of applications, owing to its inert properties, low reactivity, and ability to reduce or eliminate the risk of combustion. On-site nitrogen generation can provide a steady supply of nitrogen for avionics. Here are some key uses for a nitrogen generator in the aerospace industry and defense applications.
Aircraft Manufacturing
- Inert Atmosphere: Nitrogen gas is used to create an inert atmosphere in certain manufacturing processes – such as welding, curing of composite materials, or certain heat treating or metal finishing processes – to improve the quality of the end product.
- Material Treatment: Processes like cryogenic milling use liquid nitrogen to keep materials at extremely low temperatures, allowing for easier manipulation and higher precision.
Aircraft Maintenance
- Aircraft Tire Inflation: Nitrogen gas is often used rather than air for the inflation of aircraft tires because nitrogen is less prone to expansion and contraction with temperature changes, which is crucial during take-offs and landings.
- Hydraulic Systems: Nitrogen is used as a backup or supplement for hydraulic systems in some aircraft.
- Shock Absorbers: Nitrogen is used in aircraft shock absorbers to provide the “spring” effect, returning the shock absorber to its original position after it is compressed.
- Leak Testing: Nitrogen gas is used for pressure testing fuel and hydraulic systems to check for leaks due to its inert quality.
- Oxygen Systems: Nitrogen can be used to purge and test aircraft oxygen systems to ensure they are free from contaminants before being filled with oxygen.
Fueling and Storage
- Fuel tank purging: Nitrogen can be used to purge the fuel tank to displace volatile vapors and inert the fuel tank prior to maintenance.
- Long-term Storage: Aircraft or equipment that is being stored for an extended period might have fuel tanks filled with nitrogen gas to prevent corrosion.
Ground Operations
- Fire Suppression: In areas where fire risk is a concern, nitrogen gas can be used as a fire suppression medium.
- Supporting Equipment: Ground support equipment, like mobile electric power generators or air conditioners, may use nitrogen in various capacities.
Avionics Safety Systems
Nitrogen gas canisters (sometimes in combination with CO2 gas) are used in high-pressure inflation systems for rapid inflation of aircraft slides and life rafts.
Military Applications
- Ammunition: Nitrogen gas is sometimes used in the manufacture of certain types of ammunition.
- Chemical, Biological, Radiological, and Nuclear (CBRN) Defense: Nitrogen can be used to create inert environments for the safe handling or deactivation of dangerous substances.
- Submarines: In submarines, nitrogen gas is sometimes used for fire suppression and to control the onboard atmosphere.
- Missile Systems: Nitrogen can also be used in the cooling systems of missile guidance electronics.
On-site Nitrogen Generation Equipment for Aerospace Applications
On-site nitrogen generation has significant benefits for the aerospace industry and defense industry in terms of cost savings, reliability, and operational flexibility.
- Cost-Efficiency: Traditional methods of nitrogen supply often involve transportation and rental fees, both of which can be mitigated by generating nitrogen on-site. Over the long term, on-site generation often proves to be a cost-effective alternative.
- Reliability: Having a nitrogen generation system on-site ensures a constant, reliable supply. This is crucial in aerospace and defense applications where the lack of a critical component like nitrogen gas can halt operations or compromise safety.
- Quality Control: On-site nitrogen generation allows for more precise control over the purity and pressure of the nitrogen, tailored to specific needs, whether it be for aircraft tire inflation, fire suppression, or sensitive equipment for avionics.
- Operational Flexibility: On-site systems can be scaled up or down relatively easily, allowing for greater responsiveness to changes in demand. This is particularly important in dynamic fields like aerospace and defense, where operational requirements can change rapidly.
- Reduced Logistics and Storage: Generating nitrogen on-site eliminates the need for storing large volumes of compressed or liquid nitrogen, reducing storage costs and safety risks associated with handling and storing high-pressure cylinders.
- Readiness: In mission-critical scenarios, the availability of essential supplies like nitrogen can be the difference between success and failure. On-site generation ensures that nitrogen is always available when needed.
Choosing a Nitrogen Generator for Aerospace and Defense
A twin-tower Pressure Swing Adsorption (PSA) nitrogen generator delivers nitrogen gas of consistent purity at an affordable cost. Titus TNP Series Generators use two towers to filter and regenerate a stream of pretreated compressed air, providing you with highly purified nitrogen. This purified gas is safe, efficient, and optimal for use in a variety of commercial and industrial applications. The TNP Series flows to 20,000 SCFH and purifies nitrogen gas up to 99.999%.
Aerospace and Defense Solutions from Fluid-Aire Dynamics
Fluid-Aire Dynamics designs compressed air systems for a variety of applications and sells, installs, and maintains industrial air compressors (including rotary screw and reciprocating compressors) and nitrogen generators. We can help you select quality air compressors or nitrogen generators for your application, streamline the air compressor installation process, and design efficient, cost-effective air systems.
In 2024, Fluid-Aire Dynamics acquired The Titus Company, which has a long history of serving the military and defense industry. Among other aerospace and military applications, Titus has been the largest supplier of air dryers to the United States Navy, the Royal Australian Navy, and the Royal Navy of the United Arab Emirates. That experience, expertise, and specialized equipment have been retained as part of Fluid-Aire Dynamics.
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