Hartzell Propeller Inc., in response to market interest in reduction of the weight of its propeller systems, has earned a Type Certificate from the FAA for the manufacture of a new lighter-weight hub that can be used in conjunction with its ASC-II™ composite blades. The first unit, certified and delivered to Cirrus Aircraft in December for its SR22 aircraft, saves 4+ lb over the original. This is in addition to the 12 lb. saved by using ASC-II™ blades versus the standard aluminum blades.  

Since Hartzell composite blades are lighter than metal equivalents, the company was able to reduce the amount of material in the hub and certify it to a lower centrifugal load limit of 25,000 pounds per blade. The standard hub with all-metal blades is certified to 50,000 lbs Cf. Propeller system weight reductions will vary depending on the number of blades and the length of the hub extension.  

"In aviation, every ounce counts," said Hartzell senior vice-president, marketing and customer services, Mike Disbrow. "And when Hartzell customers speak, we listen. Four+ lb., carried far forward on the airframe, can make a real difference in CG and loading. We continue to lead the market in R&D of stronger, lighter and more efficient propeller systems."  

Hartzell's ASC-II™ true-composite blades comprise a proprietary layup of carbon fiber and Kevlar® with an integral stainless steel shank and co-molded electroformed nickel leading edges.  

"With the immediate success of the first application, on the Cirrus, we plan to roll this design out across future ASC-II propeller applications," Disbrow added. "Naturally, the 50% reduction in the Cf requirement for this hub was a direct result of the development and certification of our increasingly popular composite blades."  

Cirrus president Brent Wouters added, "Since the beginning of the Cirrus-Hartzell partnership, we have worked closely to develop propeller systems that deliver the most performance and the best economy. We have achieved many milestones in our collaboration and have delivered ever-increasing customer value along the way.  Now, with the introduction of the latest lighter-hub system, we enter a new phase in both our working relationship and in product excellence."