The Dash 7 often landed with only 900 RPM, and took off at only 1, 210 RPM . The propellers on the Dash-7 are constant speed propellers which change the blade angle to push more or less air as needed.
32.
The first propellers were fixed pitch and if the propeller blade angle is set to give good take off and climb performance, the propeller would be inefficient in cruising flight because the blade would be at too low an angle.
33.
Aerodynamic improvements including splitting the compressor into two separately rotating parts, incorporating variable blade angles for entry guide vanes and stators and bleeding air from the compressor enabled later turbojets to have overall pressure ratios of 15 : 1 or more.
34.
To provide crisp thrust control during hover, movement of the power lever caused a direct adjustment of blade angle, analogous to the collective pitch control of a helicopter, with the propeller cpu governor making a follow-up adjustment of blade angle to maintain the selected rpm.
35.
To provide crisp thrust control during hover, movement of the power lever caused a direct adjustment of blade angle, analogous to the collective pitch control of a helicopter, with the propeller cpu governor making a follow-up adjustment of blade angle to maintain the selected rpm.
36.
A ladder whose rungs were butcher knives, blades angled up, leaned against each unit to let people know that she intended to stay . ( The set itself remains on view through Dec . 21 . ) A metronome counted seconds as if they were heartbeats.
37.
Normally the workpiece is held flat on the table and so table swiveling will produce a miter cut ( blade vertical and angled across work piece ), head rotation a bevel cut ( blade angled from vertical and square across work piece ), and in combination a compound cut.
38.
Most classic kitchen knives maintain a blade angle between 40 and 45 degrees ( a bilateral 20 to 22.5 degree shoulder, from cutting edge ); Japanese knives typically incorporate a chisel-tip ( sharpened on one side ), and maintain a more extreme angle ( 10 to 15 degree shoulder ).
