Development underway on new Hartzell 5-blade props

Hartzell Propeller developmental activities for the company’s five-blade, swept-tip carbon fiber propellers will be featured at the 2014 National Business Aviation Association (NBAA) Convention in Orlando, Fla., Oct. 21-23, booth 1817. Hartzell is working on several other yet-to-be-announced composite five-blade programs for turboprop business aircraft.

DAHER-SOCATA’s new TBM 900 features the same Hartzell composite, five-blade, swept-tip props that are available for TBM 700/850 aircraft as a retrofit STC. With field installations already underway for the TBM 700/850 series, Hartzell Propeller is focusing its efforts on future structural composite developmental projects.

“Aviators will be seeing more of these true composite, highly engineered propellers on additional business aircraft in the future. We are delighted to be able to bring the latest propeller designs to NBAA, where the business aviation community will quickly recognize the performance advantages of the latest in propeller aerodynamics, engineering and manufacturing expertise,” said company President Joe Brown.

“These new swept five-blade carbon fiber props by Hartzell Propeller are a great way to quickly increase takeoff, climb and cruise performance, reduce noise and invigorate ramp appeal,” Brown said.

Hartzell Propeller has invested heavily in its structural composite propeller center of excellence, developing aggressive-looking five-blade propellers, according to Brown. Hartzell props feature aerospace conforming materials that include carbon fiber and epoxy resins and are produced on state of the art automated manufacturing equipment.

Hartzell’s five-blade propellers provide lower in-flight vibration and they produce greater static thrust for better takeoff and climb performance, according to company officials. Through optimized aerodynamic design, the low-end performance is in concert with improved cruise performance. The larger surface area and blockage effect of five-blade propellers provide quicker descents resulting in smoother touchdowns with less float, officials add.

In the single-engine TBM 700/850 Hartzell’s five-blade swept-prop generated as much as 10% faster takeoff acceleration, two knots higher cruise speeds, and 100-foot per minute better climb rate, along with measurably less noise in the cabin and at the airport compared to previous propellers, company officials report. When compared to wood-based propellers, the climb performance is even more pronounced and the cruise speed advantage goes up by as many as five knots.

Hartzell’s epoxy resin-injected carbon fiber blades have a tensile strength of 175 ksi (kilopound-force per square inch) compared to propellers made of beech wood (39 ksi) and spruce (8.7 ksi) construction. That means Hartzell’s aerospace-grade carbon fiber blades are five to 10 times stronger than wood-grade propeller blades, company officials said.

Hartzell’s new five-blade design features a composite wedge retention into its stainless steel alloy shank rather than the aluminum and lag screw construction used in other designs. Hartzell incorporates a nickel erosion mesh and field replaceable nickel-cobalt erosion shield to minimize foreign object damage.