C-3317-230 - Hartzell Propeller Hub O-Ring Seal for HC-B4TN Propellers

C-3317-230 – Hartzell Propeller Hub O-Ring Seal for HC-B4TN Propellers

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The Hartzell C-3317-230 is a genuine OEM, flight-critical O-ring seal engineered for the main hub assembly of Hartzell constant-speed propellers, including the HC-B4TN-1 model. The function of this component is absolutely indispensable: it creates the primary static seal between the propeller hub halves, containing the high-pressure engine oil that is used to actuate the propeller's pitch change mechanism. The integrity of this single seal is directly responsible for both the function of the constant-speed system and the retention of the engine's entire oil supply.

This is not a generic O-ring. It is manufactured by Hartzell from a specific Nitrile (Buna-N) compound and to dimensional tolerances (corresponding to AS568-230) that are precisely engineered to withstand the unique and extreme environment inside a propeller hub. It must maintain a positive seal against high-pressure oil while being subjected to immense, continuous centrifugal force and the dynamic loads of propeller operation. A failure of this seal would be catastrophic, resulting in a rapid and total loss of engine oil.

Key Features

• Genuine Hartzell Propeller OEM Part: The only component guaranteed to meet the exact material, durometer, and dimensional specifications required for a safe, leak-free propeller assembly.

• Contains High-Pressure Propeller Actuating Oil: Forms the critical barrier that contains the engine oil used by the propeller governor to hydraulically control blade pitch.

• High-Specification Nitrile (Buna-N) Compound: Manufactured from a specific Nitrile elastomer chosen for its excellent resistance to petroleum-based engine oil and its resilience under pressure and high-g loading.

• Designed to Withstand High Centrifugal Loads: Engineered to maintain its shape and sealing force in its groove while spinning at thousands of RPM, resisting the tendency to stretch or extrude.

• Mandatory Single-Use Component: A flight-critical seal that must be replaced at every propeller overhaul or any time the hub is separated to ensure the integrity of the assembly.

Technical Specifications

• Part Number: C-3317-230

• Component Type: Propeller Hub O-Ring Seal

• OEM Manufacturer: Hartzell Propeller Inc.

• Material: Nitrile Rubber (Buna-N / NBR).

• Hardness: 70 or 75 Durometer Shore A (per Hartzell specification).

• Size Standard: Corresponds to AS568-230.

• Dimensions (AS568-230):

  • Inside Diameter: 2.734 inches (69.44 mm)

  • Cross-Section: 0.139 inches (3.53 mm)

Propeller Compatibility

The C-3317-230 is the specified hub O-ring for several Hartzell propeller models, most notably the compact hub series used in high-performance and aerobatic applications.

• HC-B4TN-1

• Other Hartzell propeller models as specified in the applicable maintenance documents.

Crucial Note: The correct part number for a specific propeller model and serial number must be verified using the latest revision of the official Hartzell Propeller Illustrated Parts Catalog and Overhaul Manual.

Applications

This O-ring is a mandatory replacement part during any maintenance that requires the separation of the propeller hub.

• Complete Propeller Overhaul

• Blade replacement or resealing.

• Hub inspection or repair.

Why Choose C-3317-230?

Choosing a genuine Hartzell C-3317-230 is a non-negotiable matter of flight safety. The failure of the propeller hub O-ring is not a minor drip; it is a high-pressure rupture that will empty the engine's oil sump in a matter of minutes, leading to a guaranteed loss of propeller control and subsequent catastrophic engine seizure. Using a non-certified, generic O-ring introduces unacceptable risks of incorrect material (not compatible with engine oil or grease), improper durometer (too hard to seal, too soft to resist pressure), or incorrect dimensions. The genuine Hartzell part is the only way to ensure the certified quality required for this zero-failure-tolerance application.

The C-3317-230 O-ring must maintain a positive seal in one of the most challenging dynamic environments on an aircraft. Beyond containing high-pressure oil (200-300+ PSI), it must do so while being subjected to immense centrifugal force. At a typical 2700 RPM, the forces acting on the O-ring's mass attempt to stretch it radially outward, which can unseat it from its precisely machined groove. The O-ring groove depth and the O-ring's material properties—specifically its modulus of elasticity and durometer—are specified by Hartzell to create a gland that counteracts this tendency and maintains the necessary compressive squeeze. Furthermore, the seal must accommodate microscopic fretting and movement between the hub halves under fluctuating propeller torque and thrust loads. The Nitrile (NBR) material provides the required resilience and elasticity to maintain intimate contact with the groove walls under these dynamic, high-g loading conditions, ensuring the integrity of the seal and preventing a catastrophic loss of engine oil.

Note: This is a flight-critical, single-use component. This O-ring MUST be replaced with a new one every time the propeller hub is assembled. Re-using an O-ring that has been compressed, age-hardened, or exposed to operational stresses will lead to a catastrophic oil leak. All propeller maintenance, including the installation of this seal, must be performed by a certified and properly rated propeller technician or repair station in strict accordance with the applicable Hartzell Propeller Overhaul Manual and all other service documents.

Documentation

The definitive part number applicability and installation procedures are detailed in the applicable Hartzell Propeller Overhaul Manuals and Illustrated Parts Catalogs for the specific propeller model.