Aircraft Propeller Systems Quiz

Week 1 Complete

• AVIA-1052 course is complete for Week 1
• Contact Matt C for corrections or improvements

Week 1 of 1 Day 1

• AVIA-1052, Week 1, Day 1 course content

Previously On AVIA-1052

• First class, no previous sessions
• Now this is first-class

Today On AVIA-1052

• Discussion of propellers
• Reviewing general propeller information
• Aircraft propeller theory
• Basic propeller controls

Where are we?

• Powerplant (Vol. 2) 7-2 to 7-6
• Start at General information
• Stop at Propeller Location
• FAA handbooks reference

Propellers

• The unit that absorbs engine power
• Propeller development
• Multiple stages of evolution
• Fabric-covered sticks, the first propellers
• Designed to push air backward

Powerplant 7-2

• Propeller started as a two-bladed wooden propeller
• Advancements have led to complex turboprop systems
• Variable-pitch, constant-speed feathering and reversing system
• Varying engine RPM to suit different conditions
• Increased efficiency when varying flight conditions

Constant-speed systems

• A flyweight-equipped governor unit
• Controls pitch angle of the blades to maintain constant engine speed

Normal propeller movement

• Different positions for low pitch, high pitch and feather when engine fails
• Zero to negative pitch into reverse pitch

Common Propeller Types

• Comparisons of propeller efficiency based on speed

Propellers (Further)

• Most propellers are two-bladed; great increases in power resulted in new designs
• Four- and six-bladed propellers
• Limited by revolutions per minute (RPM)
• Forces acting on the propeller as it turns: centrifugal force
• Tends to pull blades out of hub at high RPM
• Blade weight is critical for propeller design
• Excessive blade tip speed
• Rotating too fast may result in poor blade efficiency, fluttering, and vibration
• Aircraft speed limited by propeller speed
• Turbofan engines used for higher speeds

Propeller-driven aircraft advantages

• Easier and cheaper takeoff and landing procedures
• Less expensive maintenance
• Efficiency of propellers improved with new blade materials

Propeller Systems

• Many types of propeller systems have been developed for specific aircraft installations considering speed and operation type

Propeller Diagrams

• Basic nomenclature of parts of a simple fixed-pitch, two-bladed wood propeller
• Aerodynamic cross-section of a blade
• Terminology describing different blade areas

Aircraft Propeller Theory

• The aircraft propeller has two or more blades that are like rotating wings
• These blades produce forces that create thrust to push the airplane through the air
• The engine provides the power needed to rotate the propeller blades

Basic Propeller Principles (Mounted on Shaft)

• Low-horsepower engines use the crankshaft for propeller rotation
• High-horsepower engines use a propeller shaft coupled to their engine crankshaft for high-speeds The propeller transforms the engine's rotary power to thrust

Propeller Aerodynamic Process

• Airplanes experience drag during flight
• Thrust must be equal to drag to maintain level flight.
• Work done = thrust x distance
• Power = thrust x velocity
• Thrust horsepower is a measure of the power expended by thrust

Propeller Efficiency

• Propeller efficiency is the ratio of thrust horsepower to brake horsepower
• The efficiency of a machine is the ratio of its useful power output to its power input
• Propeller efficiency varies from 50 to 87% dependent on the amount of slippages during the process

Propeller Pitch

• Pitch is not equivalent to blade angle because pitch is determined by blade angle
• Increased / decreased pitch relates to increased / decreased blade angle respectively

Geometric Pitch

• Geometric pitch is the distance a propeller would advance in one revolution, with no slippage
• Calculated by a given formula

Effective Pitch

• Effective pitch acknowledges the slippage (difference) between geometric and effective pitch

The Chord Line

• Propeller blade's chord line is determined similar to airfoil chord line
• A propeller blade section is an airfoil section whose chord is the width of the blade section

Propeller Blade Parts

• Blade shank, thick and rounded, near the hub to support the blade
• Blade butt, also called the blade base or root, at the hub
• Blade tip, farthest from the hub, normally the last 6 inches of the blade

Propeller Forces

- Centrifugal force, tends to throw the rotating propeller blades outward away from the hub
- Torque bending, tends to bend propeller blades in the direction opposite of rotation

Propeller Excessive Blade Tip Speed

• Excessive blade tip speed can cause poor blade efficiency, fluttering, and vibration

Propeller Speed Limit

• Propeller-driven aircraft are limited to approximately 400 mph (644 kph)

Propeller Advantages

• Advantage of propeller-driven aircraft
• Takeoff and landing
• Cheaper maintenance

Many Different Propeller Systems

• Many types of propeller systems exist, specifically developed for specific aircraft setups

Basic Nomenclature of Propeller Parts

• Nomenclature of parts of a simple fixed-pitch, two-bladed wood propeller
• Aerodynamic cross-section of a blade, specific terminology defining areas such as chord line, blade face, and blade back

Propeller Systems, continued

• Various methods for changing speed and for adjusting propeller pitch
• Aircraft specific configurations

Propeller Governor Details

• A variety of devices and methods for controlling engine RPM and to maintain a consistent speed
• Constant speed propellers, used to ensure consistent speed
• Methods for monitoring RPM

Propeller Governor (Continued)

• Governor mechanisms, constant speed controls, and basic operational components

Types of Propellers

• Various types of Fixed-pitch propellers
• Ground-adjustable propellers
• Controllable-pitch propellers
• Constant speed propellers
• Feathering propellers
• Reverse-pitch propellers
• Propeller governor
• Details on the types of propellers

Propeller Location

• Tractor propellers
• Pusher propellers

Propeller Damage

• Pusher propellers are more susceptible to damage than tractor propellers, especially in land aircraft

Propellers Used in General Aviation Aircraft

• Fixed-pitch
• Ground-adjustable
• Controllable-pitch
• Constant-speed
• Feathering
• Reverse-pitch
• Propeller-governor

Metal Fixed-Pitch Propellers

• Metal versus wood
• Characteristics of the design

Hartzell Constant-Speed, Non-feathering

• Description of Hartzell constant-speed propeller design

Constant-Speed Feathering Propeller

• The various methods in use to control and adjust the speed of feathering propellers

Unfeathering

• Ways in which propellers can be unfeathered and the method required

Propeller Auxiliary Systems

• Ice control systems
• Anti-ice
• De-ice

Ice Control Systems

• How ice formation affects propeller performance
• Types of ice control systems

Deicing Systems

• Description of fluid and electric systems

Propeller Synchronization and Synchrophasing

• How a synchronization system works
• How it helps to prevent unwanted propeller vibration

Autofeathering System

• Autofeather systems assist propellers maintain a constant speed when engine power is lost

Propeller Inspection & Maintenance

• Important inspections to ensure that the propeller functions as intended
• Various tools for inspecting the different aspects of the propeller
• Various types of damage and how to look for it

Propeller Vibration Causes

• Various causes of vibration and how to troubleshoot them

Blade Tracking

• How blade tracking is done
• Explanation of how to inspect the blades and check for defects

Checking and Adjusting Propeller Blade Angles

• Procedures for checking and adjusting blade angles, including tools needed and proper usage

Universal and Digital Propeller Protractor

• Explanation and usage of the universal and digital propeller protractor

Propeller Balancing

• Static and dynamic balancing procedures
• Techniques and procedures necessary for achieving balance

Servicing Propellers

• General procedures and practices in maintaining and servicing propellers

Propeller Lubrication

• Lubrication procedures, including frequency and relevant information

Charging the Propeller Air Dome

• Procedures in ensuring a proper pressure for the propeller air dome

Propeller Overhaul Basics

• Overhaul procedures and how to approach the process

Propeller Reassembly

• Steps and procedures for reassembling parts after an overhaul occurs

Test your knowledge on the advantages and design of propeller-driven aircraft. This quiz covers topics such as takeoff and landing benefits, applications of new materials, and key factors in propeller system development. Perfect for aviation enthusiasts and students alike!