The Horizontally Opposed Engine
Motor Symbols
G geared
T turbocharged
S supercharged
I injected
Motor Symbols
Cylinder arrangement O opposed, I inline, R radial
L left turning engine
A acrobatic engine
V vertical helicopter
Four Stroke, Five Event Cycle
Intake
Compression
Ignition
Combustion
Exhaust
Firing order 1324
4 Stroke 5 Event Cycle
Engine Structure And Components
Crank
Connecting rods
Wrist pins
Piston, waffle piston
Valves
Camshaft
Engine Structure And Components
Push rods
Rocker arms
Case
Magnetos
Alternator
Vacuum pump
Pressure pump
Crankshaft And Camshaft
Basic Engine Parts
Engine Structure And Components
Oil pan, oil pump
Cooling fins, 3 locations
Cylinder head, cylinder barrel, and piston
Float Type Carburetor
B-19 Carburetor With Carb Heat Valve
B-19 Carburetor
B-19 Fuel Pump
Carburetor Ice
Carb ice
Carb ice can occur in high humidity between 20 and 70 degrees F
The vaporization of fuel causes lower temps inside the carb
Carburetor Ice Formation
Carburetor
Accumulation at low power settings is possible
Detection: a gradual loss of rpm or manifold pressure
Checking For Carb Ice
1. Pull on carb heat
2. Rpm reduce engine may run rough as ice melts
3. Slow increase in rpms
4. Take heat off, engine rpm will be higher than when you started
Carburetor
Keep in mind with carb heat on you are getting unfiltered air
Air density decreases
Mixture richens thus the drop in rpm
Engine performance decreases
Mixture Control
Mixture control prevent mixture from becoming too rich at high altitudes
Conserve fuel
Provide optimum power
Fuel Injection
Fuel Injection
Fuel injected into the intake valve
More even fuel distribution to the cylinders
No chance of carburetor ice (sometimes intake ice)
Usually more horsepower (better efficiency)
Hard to start when hot
Can be prone to vapor lock
Turbo And Superchargers
Turbo runs off exhaust discharge
Supers are belt or gear driven
Ignition System
Dual ignition system 2 Mags
Increased safety
More complete and even combustion
Totally independent of the electrical system
Pre-ignition And Detonation
Preignition ignition of fuel before the spark plug fires
Caused by something hot igniting fuel
Hot valves, pieces of carbon, hot spark plug
Pre-ignition
Detectible through small loss of power
Corrective action– try to cool it enrichen mixture to enhance cooling, reduce power, use cruise climb, level off, open cowl flaps
Detonation
Sudden explosion inside cylinder
Caused by wrong grade fuel, Mags out of time
Up to 4000 psi inside cylinder
Will probably occur in all cylinders
Can’t be heard like in car
Detonation
Detectable by unexplained high cylinder head temp
Whitish orange flame out exhaust
No power at high power settings
Corrective action– adjustment of engine controls
Detonation
Use the right grade of fuel
For detonation during climb, lower the nose slightly to increase airspeed
Detonation
May only occur in 1 or 2 cylinders
Corrective action– try to cool it enrichen mixture to enhance cooling, reduce power, use cruise climb, level off, open cowl flaps
Fuel Tanks
Hard cell
Bladder
Integrated
Fuel System Diagram
Cessna Fuel System Diagram
Usable Vs Unusable Fuel
59.8 gal, 7.8 unusable (52 usable) 2,4,5,59
2.6 unusable (57.2 usable) rest of the C-23’s and B-19’s
Fuel Grades
80/87
100/130
100ll
115/145
Jet A
Octane Grade And Substitution
Next higher grade
Fuel weights 6lbs per gal
Lubrication
We use mostly aeroshell 15-50
Oil pressure should show some indication by 30 seconds in summer and 60 seconds in winter
Oil Has 4 Purposes
1. Cooling, removes heat and reduces friction
2. Helps seal between cylinder wall and piston rings
3. Cleans
4. Prevents corrosion
Propeller
2 or more small airfoils spun by the engine to create thrust
All propellers have a few things in common
Geometric twist
Tip rotates faster than the hub
Propeller
Angle of attack becomes less the faster you go
This is why the engine speeds up the faster you go
As increase in altitude rpm increases because less drag caused by less dense air
Propeller
Geometric pitch:
Distance a propeller would advance if it were rotated through a solid medium, (think Jello) doesn’t account for slippage
Effective pitch:
The actual distance a propeller moves through the air in one revolution, accounts for slippage
Propeller (Fixed Pitch)
Throttle controls rpm
Simple to operate
Lower cost
Less weight
Less expensive to overhaul
Propeller (Constant Speed Or Variable Pitch)
Constant speed prop controlled by governor
Explain governor
Pilot can control the pitch from the cockpit prop control lever
Propeller (Constant Speed Or Variable Pitch)
Pitch on bonanza 12.5 to 34º
Longer engine life
Less pilot fatigue
More efficient operation
Can reduce drag in emergency glide configuration
Engine controls for a constant speed prop engine
Mixture control
Same as that for fixed pitch prop engine
Leaning the engine Rule of thumb whenever power is 75% or less or above 5000 feet
Leaning Procedures
B-19 lean until peak rpm (engine may run rough if you go too lean) enrichen back to peak rpm then a little more
C-23 use peak egt then enrichen for 50 degree drop
F-33A use peak egt then enrichen for 100 degree drop
Propeller Control
Hooked to speeder spring in governor
Control rpm by reference to tachometer
Throttle Control
Manifold pressure gauge measures pressure in the intake manifold in inches of mercury
Control power by reference to this instrument
Electrical System
Electrical System
Buss
Battery
Circuit breakers
Fuses
Starter
Alternator
Regulator
Overvoltage relay
Buss Items
Pitot heat
Landing light
Beacon
Nav lights
Cockpit lighting
Boost pump
Stall horn
Hobbs meter
Intercom
Ammeter
Fuel gauges
Nav/comm
Clock
Turn coordinator