Reciprocating Engine Daily Assessment

In a reciprocating internal combustion engine, the swept volume of a cylinder is defined as the volume displaced by the piston as it moves between dead centers.Which of the following correctly represents the swept volume?

Product of piston area and stroke length

Which of the following design or operating features is most effective in increasing the volumetric efficiency of a reciprocating aircraft engine?

Increasing valve overlap to improve cylinder scavenging

During the power (expansion) stroke of a four-stroke reciprocating engine, combustion has already occurred and the high-pressure gases expand to do work on the piston. What is the general trend of gas temperature during this process?

It decreases as the gases expand and perform work on the piston

As altitude increases, the density of the atmosphere decreases, affecting the air–fuel ratio in a naturally aspirated reciprocating engine. What adjustment is required to maintain the correct mixture?

The mixture control must be leaned to compensate for reduced air density

In a reciprocating aircraft engine, excessive valve clearance (lash) alters the effective valve timing. What is the most likely effect of excessive valve clearance on valve overlap?

It decreases valve overlap due to delayed intake opening and early exhaust closing

The primary purpose of piston rings is to:

Seal combustion gases and control oil

The camshaft of a four-stroke engine rotates at:

One-half crankshaft speed

What is the primary purpose of nitriding the crankshaft crankpins and journals?

Increase surface hardness and wear resistance

A reduction gear system with a ratio of 0.5:1 means that:

Propeller speed is half engine speed

In a horizontally opposed engine, the firing order is designed primarily to:

Reduce vibration and distribute loads evenly

In an aircraft equipped with a constant-speed propeller and operating near maximum brake mean effective pressure (BMEP), what is the correct procedure to reduce engine power?

Reduce manifold pressure using the throttle before reducing RPM with the propeller control

The primary purpose of a magneto is to:

Generate ignition current independent of the aircraft battery

Which component prevents dirt from entering the induction system?

Air filter

Which force tends to twist a propeller blade toward a low-pitch angle?

Centrifugal twisting force

Which component senses propeller RPM in a constant-speed propeller governor?

Flyweights

During an engine run-up, a larger-than-normal magneto drop may indicate:

Fouled spark plugs or timing problems

In a pressure carburetor system, fuel discharge is primarily controlled by:

Impact air pressure and venturi suction differential

Propeller efficiency decreases at high tip speeds because:

Compressibility effects increase near Mach 1

Which cylinder is typically the hottest in an air-cooled engine?

The rear cylinder, furthest from the intake

Why is the exhaust valve opened before the piston reaches Bottom Dead Center (BDC) on the power stroke?

To reduce the pressure in the cylinder and assist in scavenging.

What is defined as the volume displaced by the piston moving from Bottom Dead Center (BDC) to Top Dead Center (TDC)?

Piston displacement.

Which condition is most likely to cause engine overheating?

Lean mixture at high power settings

What is "ashless dispersant" (AD) oil?

A type of oil that prevents sludge formation and keeps engine parts clean.

What is the primary difference between Detonation and Pre-ignition?

Detonation is an explosive burn after the spark; Pre-ignition is burning before the spark.

What happens if the 'intake valve closing' is timed too late?

Fresh air-fuel charge is pushed backward into the intake manifold.

What does a valve timing chart represent?

The angular position of the crankshaft when valves open and close.

What occurs if the oil pressure relief valve becomes stuck in the open position?

The oil will bypass the filter entirely.

What is indicated by a red radial line on an engine instrument?

Never-exceed limit

Which symptom might indicate a "dead cylinder"?

Engine roughness accompanied by vibration

What is the significance of the "Over-Square" rule?

It prevents high internal cylinder pressures that may exceed structural limits

What is the purpose of an STC (Supplemental Type Certificate)?

To modify an aircraft from its original factory design

During a ground check, what is indicated if the RPM drop is excessive?

Fouled spark plugs or bad ignition timing

Which instrument directly reflects the engine's power output in many systems?

Manifold pressure gauge

When an engine cannot reach static RPM, the recommended troubleshooting step is:

Performing a differential compression test

Engine instrument range markings are calibrated based on:

Manufacturer recommendations found in the TCDS

If an engine is backfiring, what should be inspected regarding ignition?

The magneto-to-engine timing

Why does an induction system leak lead to engine roughness?

It causes an incorrect fuel/air ratio

During a differential compression test, if air is heard escaping from the oil filler cap, what does this indicate?

Worn, broken, or stuck piston rings.

During a 100-hour inspection, how is tachometer accuracy typically verified?

By using an optical tachometer

When a differential compression test is performed for "Low Static RPM," what is being verified?

Engine cylinder sealing integrity