27/04/2003
Rapco: Your Trusted Partner for Aircraft Components
Rapco Inc. stands as a prominent supplier in the aviation industry, renowned for its commitment to providing a wide array of high-quality components essential for the safe and efficient operation of aircraft. With a focus on precision engineering and adherence to stringent industry standards, Rapco offers a diverse product line that caters to the critical needs of aircraft maintenance and repair. This article delves into the extensive range of products offered by Rapco, exploring their applications, common issues, and best practices for maintenance, providing valuable insights for aircraft owners, engineers, and maintenance professionals.
Comprehensive Product Offerings from Rapco
Rapco's product catalogue is meticulously curated to address various systems within an aircraft, with a particular emphasis on braking systems, pneumatic systems, and related components. Their dedication to quality is evident in every part they supply, ensuring reliability and optimal performance.
Braking Systems: Ensuring Safe Landings
The braking system is arguably one of the most critical safety components on any aircraft. Rapco provides a comprehensive suite of parts designed to maintain and enhance braking performance:
- Brake Assemblies: These are the core of the braking system. Rapco offers complete assemblies and critical sub-components designed for a wide range of aircraft models.
- Brake Discs: Essential for dissipating the immense kinetic energy generated during braking, Rapco's brake discs are manufactured to exacting specifications to prevent overheating and warping.
- Brake Linings: Whether organic or metallic, Rapco's brake linings are engineered for durability and consistent stopping power. The choice between organic and metallic linings often depends on the aircraft's operational requirements and weight class.
- Brake Rivets & Mounting Pins: These small but crucial fasteners ensure the integrity of the brake assemblies. Rapco supplies both rivets for organic linings and mounting pins for metallic linings, emphasizing the importance of proper installation.
- Brake Shim Insulators: Particularly important in aircraft with metallic brake linings that generate significant heat, these insulators prevent heat transfer to the brake cylinder, safeguarding brake fluid and O-rings from overheating and potential failure.
Common Braking System Issues and Solutions
Rapco's FAQ section addresses several common issues encountered with aircraft braking systems:
Brakes Not Rotating Freely or Ineffective Stopping: Often attributed to over-torqued back plate tie bolts, which can damage the magnesium or aluminum brake cylinder casting. This misalignment leads to constant pressure on the brake disc, hindering rotation and reducing stopping effectiveness. The solution involves inspecting for depressions on the mounting surface and replacing damaged cylinders and bolts, ensuring proper torque specifications are followed.
Uneven Wear on Brake Linings: This is frequently caused by over-torqued back plate bolts, leading to a warped mating surface on the cylinder. This results in uneven pressure distribution across the lining, causing premature wear and reduced braking performance. Adhering to correct torque specifications is paramount.
Brake Pedal Pulsation: Can be a symptom of brake discs worn below minimum thickness, developing hot spots, or warping. Over-temping due to excessive braking or binding calipers from over-torqued bolts or debris in the system can also cause this. Regular inspection and replacement of worn discs are crucial.
Brake Disc Heat Checking: Tiny cracks on the disc surface, typically starting from the outer edge, are a result of overheating. Discs worn below minimum thickness are more prone to this condition due to insufficient mass to absorb kinetic energy. Replacing discs that are worn or exhibit heat checking is essential.
Warped Brake Discs: Known as 'coning,' this occurs when the disc wear surfaces are no longer parallel. Overheating or uneven pressure from damaged brake assemblies can cause this. Discs with a coning exceeding 0.015 inches must be replaced.
Noise from Brake Assemblies: Worn or loose components within the brake assembly can increase vibrations, leading to audible noise. Thorough inspection of linings, rivets, mounting pins, pressure plates, back plates, guide pins, and torque plate bushings is recommended.
Break-in Procedures: Rapco provides specific service letters (RASL-004) for the correct break-in procedures for new brake discs and linings, which are vital for ensuring optimal performance and longevity.
Distinguishing Between Cleveland and McCauley Assemblies
Rapco also provides guidance on identifying different wheel and brake assemblies, particularly Cleveland and McCauley, which is crucial for selecting the correct replacement parts. Cleveland wheels typically have a solid, dish-like appearance, while McCauley wheels often feature a six-spoke design and were commonly used on certain Cessna and other aircraft models.
| Feature | Cleveland Wheels | McCauley Wheels |
|---|---|---|
| Appearance | Solid, dish-like | Six-spoke appearance |
| Common Aircraft | Widespread use | Early 1970s-1980s Cessna, Reims Cessna, Bellanca, Fuji, etc. |
| Part Number Prefix | Varies | B-30..., C-30..., D-30... (Original) |
Pneumatic Systems: Powering Instruments and More
Rapco is also a leading supplier of components for aircraft pneumatic systems, which are vital for driving instruments, de-icing systems, and other essential functions:
- Dry Air Pumps & Pneumatics: These pumps generate the vacuum or pressure required for various aircraft systems. Rapco offers a range of dry air pumps, including different series (200, 240, 400) designed for specific performance requirements and altitudes.
- Suction Gauge: Used to monitor the vacuum or pressure provided by the pneumatic system, ensuring proper operation of connected instruments.
- Vacuum Regulators: These components regulate the airflow within the pneumatic system to maintain consistent pressure or vacuum levels, critical for instrument accuracy.
Understanding Dry Air Pump Operation and Maintenance
Rapco's resources address common questions regarding dry air pumps:
Rattling Sound: A rattling sound when handling a dry air pump is normal. It's caused by the graphite carbon vanes sliding within the rotor slots. Centrifugal force during operation keeps them engaged with the stator wall.
Drive Spline Resistance: Larger series dry air pumps (240 and 400) may have a spring-loaded pressure plate that creates friction, making the drive spline difficult to turn by hand. This is normal and indicates the pump is designed for higher output at altitude.
Vane Wear: Instructions for checking vane wear in Rapco pumps are available via Service Letter RASL-006.
Replacement Intervals: While aircraft maintenance manuals should be consulted, the original equipment manufacturer (Parker Airborne) recommended replacement at 500 hours or 6 years, whichever comes first. Rapco pumps may have specific service letter recommendations.
Lifespan Variations: Factors influencing dry air pump lifespan include the engine's accessory drive ratio (higher RPM means shorter life), operating temperature, and airflow for cooling. Poorly ventilated installations or heat from turbochargers can shorten lifespan.
Premature Failure Causes: Common culprits include contamination (carbon debris from previous pump failures, Teflon tape particles, hose deterioration), lack of proper airflow for cooling, and oil or solvent contamination. Thorough system cleaning after a pump failure is crucial, as is replacing hoses every six years and avoiding sealants in pneumatic systems.
Digital Displays and Pump Life: Installing digital displays and removing gyro instruments can sometimes reduce airflow in the pneumatic system, leading to dry air pump overheating. Using a vacuum restrictor valve and ensuring filtered air is recommended.
Overhaul Kits: Rapco does not sell overhaul kits for dry air pumps, as FAA-approved processes and test benches are required for legal overhauls. Attempting DIY overhauls is not recommended due to potential safety risks and lack of warranty.
Specific Pump Requirements (-9 Pumps): Pumps like the 211CC-9 and RAP215CC-9 are designed for vertical mounting on engines like the Continental O-200, where oil contamination is a higher risk. Rapco's new pumps feature proprietary oil seals to mitigate this. Always consult your aircraft parts manual for correct pump selection.
New vs. Overhauled Pumps: New Rapco pumps are FAA-PMA approved, feature inspection ports, caliper for vane monitoring, oil seals, and a longer warranty. They also have no core charge. Overhauled pumps are a cost-effective alternative but may have shorter warranties.
Pump Series Differences:
| Series | Description | Capacity |
|---|---|---|
| 200 Series | Lower altitude operation, no cooling fins (211CC, 212CW) or with fins (215CC, 216CW) | 2 pneumatic instruments |
| 240 Series | Maintains output at higher altitudes | 3 pneumatic instruments, or 2 instruments + autopilot/door seal |
| 400 Series | Maintains output at higher altitudes | 4 pneumatic instruments, or 2 instruments + de-ice/door seals |
Mounting Direction: While ports-up is common, pumps can be mounted in any position, provided adequate airflow for cooling is maintained.
Torque Specifications: Consult your aircraft maintenance manual. If not specified, the original equipment manufacturer recommended torquing mounting nuts to 70-inch pounds with a new gasket.
Other Essential Components
Beyond braking and pneumatic systems, Rapco also supplies:
- De-Ice Brushes and Wire Harnesses for Propeller: Critical for anti-icing systems, ensuring safe flight in icing conditions.
- Exhaust Gaskets: Vital for sealing exhaust systems, preventing leaks and erosion. Rapco provides guidance on proper installation for various gasket types (solid, spiral wound) and stresses that re-torquing after a hot run and replacing gaskets after removal are crucial for maintaining a proper seal. Reusing gaskets is strongly discouraged due to their crush-fit nature.
- Fuel Pumps: Essential for delivering fuel to the engine. Rapco addresses common failure modes, such as continuous operation when only intermittent use is required, contamination from Foreign Object Debris (FOD), and improper priming or running dry. They also clarify part number suffixes like 'NV' and 'RX' and differences in specific part numbers related to aircraft models and engine installations.
Conclusion: Rapco's Commitment to Aviation Safety
Rapco Inc. plays a vital role in the aviation aftermarket by providing a comprehensive range of reliable and high-quality components. Their detailed product information, coupled with extensive FAQs that address common maintenance challenges, empowers aircraft professionals to make informed decisions, ensuring the continued safety and airworthiness of aircraft worldwide. By adhering to Rapco's guidance and utilizing their precisely manufactured parts, operators can maintain peak performance and minimize the risk of component failure.
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