Aircraft Engines Flashcards
(25 cards)
P.A.M.P.R.C.C.O.G.H. (Pamper C Cough)
Engine Information:
- Piston Arrangement (PA)
- Manufacturer and Model Number (M)
- Propellor Type (P)
- Maximum RPM (R)
- Number of Cylinders (C)
- Engine Cooling System (C)
- Engine Oxidizer System (O)
- Gears (G)
- Horsepower (H)
A Controllable Prop Helps a Pilot…
Keep performance efficiency in all phases of flight
In an air cooled engine, if experiencing overtemp, you may….
Pitch down to increase airspeed and air into the engine
What is a Direct Drive Engine
An engine without any gears, where the propellor receives power directly from the engine.
Turning the Ignition Key….
Ungrounds the magnetos via the ground wire
P-Lead
Ground wire between the magnetos and the ignition switch
If ground wire between magneto and ignition switch is disconnected….
The engine could accidentally start if the propellor is moved with fuel in the cylinder.
Why are there two magnetos?
For redundancy. If you have a four cylinder engine, you will likely have 8 magneto wires going to 8 spark plugs. Usually one on the top and one at the bottom, which also helps provide a cleaner engine burn
The engine is killed by….
Cutting the fuel to the engine
Rotational Motion of the Propellor Shaft converts to…..
Translational Motion of the pistons in and out, connected by crank shafts and crank rods.
Four Strokes of the Engine
- Intake Stroke - piston moves out and expands the space in the cylinder, allowing the mixture of fuel and air in from the carburetor.
- Compression Stroke - Piston moves in and compresses the fuel/air mixture.
- Power Stroke - The compression of the mixture combined with spark provided by magnetos to the spark plugs causes combustion in the cylinder.
- Exhaust Stroke - Exhaust valve opens and the intake valve closes, as the gases from the combustion exhaust.
Once you have started the engine, you should immediately….
Adjust for appropriate RPM and check the engine gauges.
Because the density of air decreases as we increase altitude….
The optimal fuel to air mixture also changes. You are much more rich at higher altitudes, unless you lean the mixture (give engine less fuel).
When leaning the mixture slowly, the RPM….
Will slowly rise. At a certain point, the RPM will drop suddenly. By adding a little bit more fuel, you will find the optimal mixture.
How is mixture related to combustion temperature?
A leaner mixture leads to increased combustion temperature.
A rich mixture leads to a cooler combustion temperature.
Any drop or rise in engine oil temperature or pressure should….
Put you on high alert.
Most dangerous engine oil scenarios are…
High oil temp with low oil pressure
OR
High oil temp with high oil pressure
Excessively High Engine Temperatures in the air or on ground…
Will cause a loss of power, excessive oil consumption, and potential permanent internal engine damage.
High engine oil temperature and pressure could be caused by
- A bad valve, an obstruction in the oil line
- Could also be caused by using fuel that is lower octane than required for the aircraft.
High engine oil pressure and normal or low temperature
Not an immediate emergency, a pilot should divert to land. Could be caused by a bad valve, obstruction in the oil line, or bad gauge. Keep an eye on the engine oil temperature.
High engine oil temperature and normal pressure
It’s difficult to know for sure what is going on. Can be caused by a high electrical load, leading to a higher gauge reading.
Could also be caused by low engine oil level.
Using the wrong engine oil could cause this as well.
Running the engine at high power and too lean of a mixture could cause high oil temperature. A pilot should never lean the mixture during climb or over 80% or more power. Could cause detonation and pre-ignition.
High engine oil temperature and low pressure
This is the worst possible situation for your aircraft engine. An emergency should be declared immediately, to get the aircraft to the ground as fast as possible.
This could have been caused by an obstruction in the oil line, a busted valve, gasket, seal, or oil line.
The aircraft could also be low on oil or using the wrong type of oil.
Low engine oil pressure and normal or low engine oil temperature
It is safe to call an emergency. A loss of oil pressure means that the engine isn’t holding oil at the place of the oil pressure probe. This could be caused by an obstruction in the line, a blown gasket, broken seal, or broken oil line.
When you see low engine oil pressure, you should assume the engine is not getting oil. When an engine doesn’t get oil, an engine failure is on its way.
Detonation
Explosion of the fuel air mixture in the cylinder of an aircraft engine.
Occurs in reciprocating engines usually at high power settings, when the fuel mixture ignites instantaneously instead of burning progressively evenly.
Sparks cause a controlled burn that is well-timed.
The abrupt explosion causes vibration, noise, and high engine temperatures.
High cylinder temperature and wrong fuel can cause detonation.
