RTP Company: The Global Leader in Specialty Compounding

End-Use Case Study —

Propeller

Stealth Propulsion, Inc. reduced manufacturing costs for its Stealth Propeller (for 15 hp. outboard motors) by 80%. The savings stem from lower cost for material, tooling and manufacturing. The part was previously made of stainless steel.

Stiffness and impact resistance, in an aqueous environment, are critical to the application. The specialty compound, glass-reinforced RTP 2399X, rigid polyurethane, features a flexural strength of 48,000 psi and un-notched impact strength of 27 ft. lbs./in.

The propeller's varying thickness posed design and molding challenges. Ample material dispersion while avoiding knit lines were equally important during production.

RTP Company professionals worked closely with Stealth and molder PTA Corporation, of Des Plaines, IL, to address these concerns during development. Excellent teamwork was critical to the project's success, according to Stealth's Vice President of Manufacturing, Frank Pellicori.

The propeller design improves planing and maneuverability. The patented outer ring directs most of the thrust back, which traditional designs lose to the blade ends. The ring limits noise and side wake, while providing inherent safety benefits.

PTA specializes in new product development and injection molding from 1,000 to 100,000 parts. PTA is known for fat product delivery and engineering expertise.

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