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Propulsive efficiency comparison for various gas turbine engine configurations. In the 1970s, Hamilton Standard described its propfan as "a small diameter, highly loaded multiple bladed variable pitch propulsor having swept blades with thin advanced airfoil sections, integrated with a nacelle contoured to retard the airflow through the blades thereby reducing compressibility losses and ...
In 1919 L. E. Baynes patented the first automatic variable-pitch airscrew. Wallace Rupert Turnbull of Saint John, New Brunswick, Canada is credited in Canada for creating the first variable pitch propeller in 1918. [5] The French aircraft firm Levasseur displayed a variable-pitch propeller at the 1921 Paris Air Show. The firm claimed that the ...
One advantage of the variable fan option is that varying the fan pitch offers the possibility of reversing engine thrust without the need for heavy blocker doors, cascades, etc. The pitch of the fan can be reversed through Feather as with the Turbomeca Astafan. [2] or through Fine Pitch as employed in the Rolls-Royce/SNECMA M45SD-02. [3] [4]
Variable-pitch propeller can refer to: Variable-pitch propeller (marine) ... This page was last edited on 30 August 2021, at 05:49 (UTC).
The 501-M78B had the same 13-stage compressor, combustor, 2-stage gas producer turbine, and 2-stage free power turbine used on the XT701 and 570-K, but it was connected through a 6.797 reduction ratio gearbox to a 9 ft diameter (2.7 m) Hamilton Standard single-rotation propfan, containing propfan blades that were swept back 45 degrees at the tips.
The reversible, variable-pitch propeller holds eight blades, each having a carbon spar enclosed by a composite shell and a polyurethane coating. [39] Its blades have a scimitar shape [ 34 ] that results in a sweep angle of about 55 degrees at the blade tips, [ 40 ] which have a helical speed of 290 m/s (951 ft/s; 1,044 km/h; 648 mph) at the ...
The requirement for pitch variation is shown by the propeller performance during the Schneider Trophy competition in 1931. The Fairey Aviation Company fixed-pitch propeller used was partially stalled on take-off and up to 160 mph (260 km/h) on its way up to a top speed of 407.5 mph (655.8 km/h). [36]
In marine propulsion, a variable-pitch propeller is a type of propeller with blades that can be rotated around their long axis to change the blade pitch. Reversible propellers—those where the pitch can be set to negative values—can also create reverse thrust for braking or going backwards without the need to change the direction of shaft revolution.