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Hartzell Promotes Propeller Efficiency over Turbofans

Date: October 19, 2009 Category: Press Releases
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Times call for rational decisions on choice of business aircraft.

Orlando, FL, October 19, 2009……..As the market retraction in business aviation hits full stride, Piqua, Ohio-based Hartzell Propeller offers up some timely counsel to business-aircraft owners and operators. Its message, simply put, is that for highest efficiency and lowest direct operating cost, nothing beats propellers for propulsion.

“We know the allure of the turbofan ‘jet’ among business aircraft operators, and for long trips turbofans are preferred, but so far, nothing beats the constant-speed propeller for ‘pure efficiency’ in all phases of flight”, says Mike Disbrow, senior VP marketing and customer services at Hartzell.

“We’ve been exhibiting at NBAA for over thirty years and have seen a lot of progress in propulsion technology,” Disbrow says, “but that doesn’t apply only to jets. We have been investing in and applying a lot of aerodynamic and materials R&D over the years, and it shows. In addition to advanced designs we offer for aircraft coming off the line, we offer new metal-blade designs in our best-selling line of Top Prop™ propellers or from STC holders we’ve worked with to improve the performance of older turboprops as well. We also intend to apply our ASC-II™ carbon blade technology to future turboprop applications” he adds.

Hartzell admits that the practical limit to the speed you can get out of propellers is not as high as that of turbofans, yet most flights made by business aircraft are shorter than two hours in duration, according to NBAA statistics. “On stage lengths like that, turboprops make a lot of economic sense,” Disbrow says.

Variable-pitch constant-speed propellers also allow broad blade pitch ranges to maintain high efficiency for takeoff, climb, cruise and approach conditions. as opposed to fans which can only be optimized for one point in the flight regime.

The ability to customize the propeller for the aircraft mission permits flexibility with a properly sized engine core as opposed to the fixed-diameter turbofan.

Further, the large diameter of the propeller versus a fan provides improved low-end thrust for take-off and climb, which permits use of smaller engine core for optimum fuel efficiency. Propellers create a given amount of thrust with minimum power by accelerating a relatively large mass of air to a relatively low velocity compared to a turbofan. According to basic aerodynamic principles, this characteristic is responsible for the inherent fuel efficiency advantage of a propeller-driven aircraft.

“We’ve been making the world’s most advanced propellers since 1917,”Disbrow says. “Today, with NBAA members alone owning and operating more than 3,500 propeller driven turbine and piston aircraft, we’re at the forefront of propulsion technology, and we intend to stay there.”

Hartzell Propeller is widely recognized as the leader in advanced propeller design and manufacturing technology. The company has developed the next generation of propellers based upon innovative “blended airfoil” technology and is manufacturing these blades on revolutionary machining centers, or with its new ASC-II™ composite technology, to provide mission-optimized performance for its customers. Hartzell traces its beginnings in 1917 to a supply relationship with Orville Wright and was founded on the principle of “Built on Honor” – a tradition that continues today.

Hartzell Propeller