RMIT Flight Training
Constant Speed Unit
CONSTANT SPEED UNIT
Aim: To understand the principles behind the operation and use of a variable-pitch propeller (CSU). Application: - Anytime when flying an aircraft fitted with a CSU - C182 or PA28R Revision: Fixed-pitch Propeller - Same rotational velocity, low forward velocity = high AOA, and vice versa.
Definitions: Fine Pitch - small blade angles, used at low airspeeds. Coarse Pitch - large blade angles, used at high airspeeds. Feather - when the blade chordline is parallel with the aircraft’s relative airflow, minimising drag. Pitch Stops - variable pitch propellers are typically limited to angles between 15 and 25. Between these stops (fine/coarse pitch stops) the propeller acts as a CSU. At the stops it becomes a fixed-pitch propeller. Governor - once set, the governor maintains a constant propeller speed, therefore constant RPM. This is done through speeder springs and flywheels. Principles: - By employing a CSU, a more efficient blade angle can be obtained during most phases of flight. - Low airspeeds, blade angle small, therefore fine pitch. - High airspeeds, blade angle large, therefore coarse pitch.
RMIT Instructor Rating Mass Briefs Issue 1 /2004 Page 1
Brief 26
飞行翻译公司 www.aviation.cn 本文链接地址：RMIT飞行训练课件 26.恒速装置 26 RFT Constant Speed Units.pdf
Constant Speed Unit
CONSTANT SPEED UNIT
Aim: To understand the principles behind the operation and use of a variable-pitch propeller (CSU). Application: - Anytime when flying an aircraft fitted with a CSU - C182 or PA28R Revision: Fixed-pitch Propeller - Same rotational velocity, low forward velocity = high AOA, and vice versa.
Definitions: Fine Pitch - small blade angles, used at low airspeeds. Coarse Pitch - large blade angles, used at high airspeeds. Feather - when the blade chordline is parallel with the aircraft’s relative airflow, minimising drag. Pitch Stops - variable pitch propellers are typically limited to angles between 15 and 25. Between these stops (fine/coarse pitch stops) the propeller acts as a CSU. At the stops it becomes a fixed-pitch propeller. Governor - once set, the governor maintains a constant propeller speed, therefore constant RPM. This is done through speeder springs and flywheels. Principles: - By employing a CSU, a more efficient blade angle can be obtained during most phases of flight. - Low airspeeds, blade angle small, therefore fine pitch. - High airspeeds, blade angle large, therefore coarse pitch.
RMIT Instructor Rating Mass Briefs Issue 1 /2004 Page 1
Brief 26
飞行翻译公司 www.aviation.cn 本文链接地址：RMIT飞行训练课件 26.恒速装置 26 RFT Constant Speed Units.pdf
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