Technologies for the next generation of regional airliners are coming into focus today at Dowty Propellers as the company evaluates integrated turboprop propulsion system (ITPS) concepts to improve the operating efficiency and safety of aircraft while reducing their noise levels and increasing passenger comfort.
An eight-bladed propeller concept with axially-staggered blade rows defined by Dowty Propellers is shown in this computer-generated image.
Dowty Propellers’ efforts include trade studies that assess optimised, custom-tailored installation for specific aircraft, and apply Dowty Propellers’ own expertise as a propeller system innovator – while benefiting from the company’s cooperation with institutes and agencies in the United Kingdom and Europe.
“We have set our sights on the future,” explained Oliver Towers, the President of Dowty Propellers. “The on-going studies build on a track record of innovation that includes our company’s pioneering use of all-composite aircraft propeller blades, along with introduction of the first electronic propeller control and the first integrated propeller/engine control.”
Among the new concepts being evaluated by Dowty Propellers are the unequal circumferential spacing of propeller blades around the hub, along with axially-staggered blade rows. Such configurations offer the promise of reduced noise and vibration levels, as they break up the rotating propellers’ blade-passing frequencies, according to Jonathan Chestney, the Business Growth Leader at Dowty Propellers.
New concepts and techniques
A cut-away view details a propeller hub design patented by Dowty Propellers for an axially-staggered configuration, with its eight blade arranged in two rows.
Initial analytical studies of these configurations have been completed, with follow-on steps to include evaluating passenger perception to the concepts, Chestney added. As part of the development work, Dowty Propellers has received patents for certain designs, including a propeller hub configuration that accommodates a total of eight axially-staggered propeller blades.
Dowty Propellers is also investigating new refinements in propeller ice protection. These new techniques could replace traditional electrical propeller de-icing systems, eliminating the need for the wiring, slip rings, brushes and timers – thereby reducing weight, increasing reliability and lowering maintenance costs.
The concepts are “passive,” resulting in the natural shedding of ice early in its accretion on propellers, and they reduce pilot workload by eliminating a crewmember’s need to activate electrical de-icing systems at the right time, while contributing to increased overall operational safety.
Testing of these concepts is underway to explore performance and durability of the solutions.