January 2, 2013 – Seattle, Wash. – Working under a corporate veil of complete secrecy for the past three years, Raisbeck Engineering and Hartzell Propeller have teamed to develop and certify the first business aviation turbine propeller using practical swept-wing theory as an integral part of its design.
The effort has culminated in the FAA certification of the Raisbeck/Hartzell Swept Turbofan Propeller for the King Air 200/B200/B200GT. The new Swept Propeller has been added to Raisbeck Engineering’s Airplane Flight Manuals, making it compatible with all combinations of Raisbeck Performance Systems for these aircraft and carrying with it all these systems’ FAA-approved increased performance levels.
The swept-back design required a new Hartzell-supplied forging before production could begin. Hartzell is currently in the manufacturing cycle. For development and FAA certification flight testing, blades machined from large aluminum blocks were used. Deliveries commence March 1st, 2013 from Hartzell’s factory near Dayton, Ohio, to Raisbeck’s customers of record.
The technology behind the Swept Turbofan Propeller centers around the aerodynamic swept-wing theory, which allows for measurably lower drag on aircraft wings flying at high-subsonic Mach when swept aft. This principle has been incorporated into the new Raisbeck/Hartzell family of Turbofan Propellers, giving them an entirely new look, not previously seen outside the military anywhere in the world.
“Sexy, I’d say,” commented James Raisbeck, CEO of Raisbeck Engineering. “The overall performance improvements relative to both the OEM 3-blade and 4-blade Hartzell propellers are large, and result in greatly improved FAA-certified takeoff, climb, and landing capabilities. Their enhancement over our current Raisbeck/Hartzell Turbofan Power Props is also measurable,” he added.
Hartzell Propeller president Joe Brown applauded Hartzell’s long-term relationship with Raisbeck Engineering, going back 30 years. "Hartzell's first development with Raisbeck resulted in the Raisbeck Quiet Turbofan Propeller System for all King Air models and is still in production. Over 2600 of these Hartzell/Raisbeck propellers have been delivered to date, making this the most successful aftermarket program in Hartzell's history," he commented.
The research and design phase of the new Swept Turbofan’s development took over three years, and was led by Hartzell’s Michael Schulte and Raisbeck’s Davud Kasparov. Working together between Dayton and Seattle, they honed an attractive, efficient, evolutionary propeller. According to Schulte, “These new blades are a thing of beauty and offer the kind of rational expansion of our product development with Raisbeck Engineering that our companies have enjoyed together for the last 30 years.”
After studying multiple designs and iterations, the chosen configuration is designated the HC-D4N-3A/D9515K for the King Air 200 family. It incorporates aluminum blades and hubs to keep both weight and cost to a minimum. No shot-peening was required and ground minimum RPM remains at a low 1150. Overhaul times are a high and generous 4,000 hour/6 year cycle. Propeller diameter has been increased to 96?, a full 2? greater than Raisbeck’s current offerings for the King Air 200 family. They are a large 3? greater than the OEM propellers installed on the King Air B200 and its current production 250. Yet perceived sound levels are reduced slightly, due to the effect of blade sweep. Also, because of the new high-subsonic airfoils utilized in the design, weight remains unchanged. Much of the low-speed performance increases occur from the increased diameter, while the high-speed (and high propeller-Mach) improvements and reduction in cockpit and cabin noise are attributable to the swept-back blade design.
Davud Kasparov, Raisbeck’s resident CFD and propeller design expert, took over the program’s full responsibilities, and became its Project Engineer and Program Manager. He has successfully integrated Raisbeck’s in-house capabilities with Hartzell’s, and added outside technical consultants and DER engineers as necessary. Kasparov said the whole experience has been exhilarating. “Seeing a new concept through from the beginning sketches to the finished product and delivered to the end user is a real thrill, and an ample technical reward for me,” he commented.
The test and certification airplane, BB-1611, was supplied by long-time Raisbeck customer Ballard Aviation of Wichita, Kansas. The flight tests, conducted by AeroAcoustics of Everett, Washington included direct comparisons of performance and noise levels for three different propellers: the existing Hartzell/Beech B200/B200GT 93? OEM prop, the existing Raisbeck/Hartzell 200/B200/B200GT 94? Turbofan Power Prop, and the new 96? Swept Turbofan Propeller. Only after positive comparison was the decision made to complete certification.
Now in the hands of Raisbeck’s Marketing and Sales team, the Swept Turbofan Propeller is available for purchase directly from Raisbeck and through its 100+ dealers throughout the world. The Swept Turbofan Propeller can be purchased alone or in combination with all other Raisbeck Performance Systems, including its EPIC PLATINUM Performance Package. 2013 price for a complete shipset of the Swept Turbofans is $83,400. This represents a premium of $8,900 per shipset over the prices of the current Raisbeck Turbofan Power Props whether alone or in combination with other Raisbeck Systems. Raisbeck’s current Turbofan Power Props will remain in production and continue to be offered as well. Complete EPIC package pricing is $149,850 for those King Airs not equipped with any of the EPIC elements. These include Ram Air Recovery System (RARS), Enhanced Performance Leading Edges (EPLE), and Dual Aft Body Strakes (DABS). Credit is given for each of these systems already installed.
Raisbeck Engineering continues the tradition of its founder, James D. Raisbeck. It is dedicated to improving personal, business and corporate aircraft by positively affecting the performance, productivity, safety and comfort. Raisbeck does this through infusion of advanced technology with currently flying fleets. To learn more about Raisbeck, visit our website at: www.raisbeck.com.