Utilizing your notes and past knowledge answer the following questions: 1) What are the two types of induction systems used on an aircraft? 2) What is the chief disadvantage of a float-type carburetor? 3) Where are carburetors normally calibrated and what position is the fuel/air mixture set? 4) Describe what happens to the fuel mixture as the aircraft gains altitude? 5) Describe what must be done to the mixture as an aircraft descends from high altitude? Warm-Up – 1/30 – 10 minutes

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Utilizing your notes and past knowledge answer the following questions: 1) What are the two types of induction systems used on an aircraft? 2) What is the chief disadvantage of a float-type carburetor? 3) Where are carburetors normally calibrated and what position is the fuel/air mixture set? 4) Describe what happens to the fuel mixture as the aircraft gains altitude? 5) Describe what must be done to the mixture as an aircraft descends from high altitude? Warm-Up – 1/30 – 10 minutes

Aircraft Systems Induction Systems Two types of induction systems are commonly used in small aircraft engines: 1. The carburetor system, which mixes the fuel and air in the carburetor before this mixture enters the intake manifold.

Aircraft Systems Induction Systems 2. The fuel injection system, which mixes the fuel and air immediately before entry into each cylinder or injects fuel directly into each cylinder.

Utilizing your notes and past knowledge answer the following questions: 1) What are the two types of induction systems used on an aircraft? 2) What is the chief disadvantage of a float-type carburetor? 3) Where are carburetors normally calibrated and what position is the fuel/air mixture set? 4) Describe what happens to the fuel mixture as the aircraft gains altitude? 5) Describe what must be done to the mixture as an aircraft descends from high altitude? Warm-Up – 1/30 – 10 minutes

Aircraft Systems Carburetor Systems The chief disadvantage of the float carburetor, however, is its icing tendency.

Utilizing your notes and past knowledge answer the following questions: 1) What are the two types of induction systems used on an aircraft? 2) What is the chief disadvantage of a float-type carburetor? 3) Where are carburetors normally calibrated and what position is the fuel/air mixture set? 4) Describe what happens to the fuel mixture as the aircraft gains altitude? 5) Describe what must be done to the mixture as an aircraft descends from high altitude? Warm-Up – 1/30 – 10 minutes

Aircraft Systems Mixture Control Carburetors are normally calibrated at sea-level pressure, where the correct fuel-to-air mixture ratio is established with the mixture control set in the FULL RICH position.

Utilizing your notes and past knowledge answer the following questions: 1) What are the two types of induction systems used on an aircraft? 2) What is the chief disadvantage of a float-type carburetor? 3) Where are carburetors normally calibrated and what position is the fuel/air mixture set? 4) Describe what happens to the fuel mixture as the aircraft gains altitude? 5) Describe what must be done to the mixture as an aircraft descends from high altitude? Warm-Up – 1/30 – 10 minutes

Aircraft Systems Mixture Control However, as altitude increases, the density of air entering the carburetor decreases, while the density of the fuel remains the same.

Utilizing your notes and past knowledge answer the following questions: 1) What are the two types of induction systems used on an aircraft? 2) What is the chief disadvantage of a float-type carburetor? 3) Where are carburetors normally calibrated and what position is the fuel/air mixture set? 4) Describe what happens to the fuel mixture as the aircraft gains altitude? 5) Describe what must be done to the mixture as an aircraft descends from high altitude? Warm-Up – 1/30 – 10 minutes

Aircraft Systems Mixture Control During a descent from high altitude, the mixture must be enriched, or it may become too lean.

Questions / Comments

 January — Sikorsky's HSS-1 (Model S-58) piston- engined helicopter, developed for anti- submarine operations, makes its first flight. THIS DAY IN AVIATION

 January — First United States satellite, “Explorer 1,” launched into orbit. THIS DAY IN AVIATION

 January — Boeing's long- range 747SP “Friendship One” returns to Seattle to set a round- the-world record of 36 hours 54 minutes 15 seconds. THIS DAY IN AVIATION

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SUNDAYMONDAYTUESDAYWEDNESDAYTHURSDAYFRIDAYSATURDAY Chapter 5 Flight Controls Primary Flight Controls 78 Chapter 5 Flight Controls Ailerons Adverse Yaw Elevators Stabilators 910 Chapter 5 Flight Controls Quiz Chapter 5 Flight Controls Canards Flaps 1516 Chapter 5 Flight Controls Trim Systems Autopilot Chapter TEST Grades Due 17 NO SCHOOL NO SCHOOL 2122 Chapter 6 Aircraft Systems 2324 Chapter 6 Aircraft Systems Chapter 6 Aircraft Systems 2930 Chapter 6 Aircraft Systems 31 January 2014

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Chapter 6 – Aircraft Systems FAA – Pilot’s Handbook of Aeronautical Knowledge

 Mission:  Identify in writing the primary systems found on most aircraft.  Describe the basic operation and characteristics of the primary aircraft systems.  EQ: Describe the importance of Aeronautical Knowledge for the student pilot learning to fly. Today’s Mission Requirements

Aircraft Systems Carburetor Icing As mentioned earlier, one disadvantage of the float- type carburetor is its icing tendency. Carburetor ice occurs due to the effect of fuel vaporization and the decrease in air pressure in the venturi, which causes a sharp temperature drop in the carburetor.

Aircraft Systems Carburetor Icing If water vapor in the air condenses when the carburetor temperature is at or below freezing, ice may form on internal surfaces of the carburetor, including the throttle valve. The reduced air pressure, as well as the vaporization of fuel, contributes to the temperature decrease in the carburetor.

Aircraft Systems Carburetor Icing Ice generally forms in the vicinity of the throttle valve and in the venturi throat. This restricts the flow of the fuel/air mixture and reduces power. If enough ice builds up, the engine may cease to operate.

Aircraft Systems Carburetor Icing Carburetor ice is most likely to occur when temperatures are below 70 degrees Fahrenheit (°F) or 21 degrees Celsius (°C) and the relative humidity is above 80 percent. Icing can occur even with temperatures as high as 100 °F (38 °C) and humidity as low as 50 percent.

Aircraft Systems Carburetor Icing This temperature drop can be as much as 60 to 70 °F (15 to 21 °C). Therefore, at an outside air temperature of 100 °F (37 °C), a temperature drop of 70 °F (21 °C) results in an air temperature in the carburetor of 30 °F (-1 °C).

Aircraft Systems Carburetor Icing The first indication of carburetor icing in an aircraft with a fixed-pitch propeller is a decrease in engine rpm, which may be followed by engine roughness.

Aircraft Systems Carburetor Icing In an aircraft with a constant-speed propeller, carburetor icing is usually indicated by a decrease in manifold pressure, but no reduction in rpm. Although carburetor ice can occur during any phase of flight, it is particularly dangerous when using reduced power during a descent.

Aircraft Systems Carburetor Icing Under certain conditions, carburetor ice could build unnoticed until power is added. To combat the effects of carburetor ice, engines with float-type carburetors employ a carburetor heat system.

Aircraft Systems Carburetor Heating Carburetor heat is an anti-icing system that preheats the air before it reaches the carburetor, and is intended to keep the fuel/air mixture above the freezing temperature to prevent the formation of carburetor ice.

Aircraft Systems Carburetor Heating Carburetor heat can be used to melt ice that has already formed in the carburetor if the accumulation is not too great, but using carburetor heat as a preventative measure is the better option. The carburetor heat should be checked during the engine runup.

Aircraft Systems Carburetor Heating If detected, full carburetor heat should be applied immediately, and it should be left in the ON position until the pilot is certain all the ice has been removed.

Aircraft Systems Carburetor Heating The use of carburetor heat causes a decrease in engine power, sometimes up to 15 percent, because the heated air is less dense than the outside air that had been entering the engine.

Aircraft Systems Carburetor Heating When ice is present in an aircraft with a fixed- pitch propeller and carburetor heat is being used, there is a decrease in rpm, followed by a gradual increase in rpm as the ice melts.

Aircraft Systems Carburetor Heating The engine also should run more smoothly after the ice has been removed.

Aircraft Systems Carburetor Heating It is imperative for a pilot to recognize carburetor ice when it forms during flight because a loss of power, altitude, and/or airspeed will occur. These symptoms may sometimes be accompanied by vibration or engine roughness.

Aircraft Systems Carburetor Heating Once a power loss is noticed, immediate action should be taken to eliminate ice already formed in the carburetor, and to prevent further ice formation. Applying full carburetor heat, which will cause a further reduction in power, and possibly engine roughness as melted ice goes through the engine.

Aircraft Systems Carburetor Heating These symptoms may last from 30 seconds to several minutes, depending on the severity of the icing. Carburetor heat must remain in the full-hot position until normal power returns.

Aircraft Systems Outside Temperature Gauge Most aircraft are also equipped with an outside air temperature (OAT) gauge calibrated in both degrees Celsius and Fahrenheit. It provides the outside or ambient air temperature for calculating true airspeed, and also is useful in detecting potential icing conditions.

Aircraft Systems Fuel Injection Systems In a fuel injection system, the fuel is injected directly into the cylinders, or just ahead of the intake valve.

Aircraft Systems Fuel Injection Systems A fuel injection system usually incorporates six basic components: an engine-driven fuel pump a fuel/air control unit fuel manifold (fuel distributor) discharge nozzles an auxiliary fuel pump fuel pressure/flow indicators.

Aircraft Systems Fuel Injection Systems The auxiliary fuel pump provides fuel under pressure to the fuel/air control unit for engine starting and/or emergency use.

Aircraft Systems Fuel Injection Systems After starting, the engine-driven fuel pump provides fuel under pressure from the fuel tank to the fuel/air control unit.

Aircraft Systems Fuel Injection Systems This control unit, which essentially replaces the carburetor, meters fuel based on the mixture control setting, and sends it to the fuel manifold valve at a rate controlled by the throttle.

Aircraft Systems Fuel Injection Systems After reaching the fuel manifold valve, the fuel is distributed to the individual fuel discharge nozzles.

Aircraft Systems Fuel Injection Systems The discharge nozzles, which are located in each cylinder head, inject the fuel/air mixture directly into each cylinder intake port.

Aircraft Systems Fuel Injection Systems A fuel injection system is considered to be less susceptible to icing than the carburetor system.

Aircraft Systems Fuel Injection Systems Advantages of fuel injection: Reduction in evaporative icing Better fuel flow Faster throttle response Precise control of mixture Better fuel distribution Easier cold weather starts

Aircraft Systems Fuel Injection Systems Disadvantages of fuel injection: Difficulty in starting a hot engine Vapor locks during ground operations on hot days Problems associated with restarting an engine that quits because of fuel starvation

Class Summary – Icing / Heaters Carburetor ice occurs due to the effect of fuel vaporization and the decrease in air pressure in the venturi, which causes a sharp temperature drop in the carburetor.

Class Summary Carburetor Heating Carburetor heat is an anti-icing system that preheats the air before it reaches the carburetor, and is intended to keep the fuel/air mixture above the freezing temperature to prevent the formation of carburetor ice.

Class Summary Fuel Injection Systems In a fuel injection system, the fuel is injected directly into the cylinders, or just ahead of the intake valve.

Class Summary Fuel Injection Systems Advantages of fuel injection: Reduction in evaporative icing Better fuel flow Faster throttle response Precise control of mixture Better fuel distribution Easier cold weather starts

Class Summary Fuel Injection Systems Disadvantages of fuel injection: Difficulty in starting a hot engine Vapor locks during ground operations on hot days Problems associated with restarting an engine that quits because of fuel starvation

Questions / Comments

Lesson Closure - 3 – List 3 things you learned today. 1. Create (1) quiz question with answer about today’s lesson. 2. List 2 things you have questions about today’s lesson.