More thrust. Less noise. Stunning ramp appeal.
Raisbeck Engineering and Hartzell Propeller have teamed to develop and certify Swept Blade Turbofan Propellers using practical swept-wing theory as an integral part of its design for 350-Series (B300) King Airs.
SEVEN CUSTOMER-DRIVEN REASONS WHY RAISBECK'S PROPS ARE IN YOUR 350'S FUTURE
Our 4-Blade Swept Propellers carry a 2016 list price of $98,500 outright, well below the $145,000 our 5-Blade Composite Propellers were scheduled to sell for.
The in-flight cruise cabin sound levels of our highly-swept 4-Blade Propellers are also quieter than our 5-Blade composite versions, due in large part to the much greater sweep obtainable from aluminum blades. Composite blades, whether 21st Century Composite or wood composite, are limited in their ability to sustain the twisting moment of the greater sweep necessary to combine high performance with low noise. The harsh sound impact of a straight blade at its outer diameter compares unfavorably with the subtle whoosh of our aluminum Swept Blades. While the blade-passing frequency goes up with 5-blade props, the overall noise energy levels of our 4-bladers are dramatically less than all 5-bladers at the 4-blade 100 Hertz frequency (1500 RPM). That is where all noise-suppression devices such as tuning forks have been optimized by the Beechcraft and after-market noise attenuation systems.
Taxi speed in ground-fine is a respectable 17-20 knots for our 4-way, versus 35 knots for our 5-way, and 43 knots for another brand’s tested 5-blade version. Takeoff acceleration, single-engine climb, twin-engine climb to altitude, and deceleration after landing are all improved and noticeable to the pilot. Importantly, there is no floating tendency during landing flare-out. Cruise speeds are the same for both Raisbeck 4-way and 5-way props, and 2 knots faster at 28,000 feet than the OEM propellers they replace. All 5-blade propellers we tested showed an increase in Vmc over the OEM. This increase has a negative effect on FAA-certified takeoff performance and operational safety. Our 4-way propellers maintain the OEM Vmc, thus no FAA takeoff compromise.
4. RAMP APPEAL
The uniquely large blade sweep of our Raisbeck/Hartzell propellers, first introduced in 2012 on the King Air 200 family and in 2013 on the C90 family, has proven to be an eye-catcher when parked at the ramp. That same appeal now transfers to and includes the King Air 350 family.
5. AVAILABILITY & MAINTENANCE
Our 4-blade Swept Propellers are available for purchase and installation now, and are being manufactured and delivered by Hartzell in Piqua, Ohio at a fast-enough rate to be able to ship on short notice. Shipping them assembled in the United States is inexpensive and immediate, the same procedures we have been using since 1984 for our propeller programs with Hartzell. Being constructed of aluminum, all the usual filing techniques and other maintenance procedures including overhaul are well known to virtually every prop shop around the world.
6. INSTALLED WEIGHT SAVINGS
The installed weight reduction when replacing the OEM propellers with our 4-Blade Propellers is 39.8 pounds. This is due to the thin blade airfoils and new lightweight aluminum hubs, which replace the OEM steel hubs.
7. FUTURE EPIC PERFORMANCE
Raisbeck’s engineers are continuing to develop a companion King Air 350 EPIC Performance Package, which has as one of its goals a 10 knot increase in cruise speed at 28,000’ and Max. Cruise Power. When available, it will become integral with the Swept Blade Propellers, and be offered to existing Raisbeck King Air 350 Propeller operators at an attractive price.