RECIPROCATING ENGINE PART 3

Some aircraft engine manufacturers equip their product with choked or taper-ground cylinders in order to. provide a straight cylinder bore at operating temperatures. flex the rings slightly during operation and reduce the possibility of the rings sticking in the grooves. increase the compression pressure for starting purposes.

Which of the following will decrease volumetric efficiency in a reciprocating engine?. Full throttle operations, low cylinder head temperatures, and high carburetor air temperatures. Low cylinder head temperatures, improper valve timing, and sharp bends in the induction system. Improper valve timing, sharp bends in the induction system, and high carburetor air temperatures.

If an engine operates with a low oil pressure and a high oil temperature, the problem may be caused by a. leaking oil dilution valve. sheared oil pump shaft. clogged oil cooler annular jacket.

If air-fuel ratio is proper and ignition timing is correct, the combustion process should be completed. 20 to 30° before top center at the end of the compression stroke. when the exhaust valve opens at the end of the power stroke. just after top center at the beginning of the power stroke.

What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines?. Increased strength and resistance to cracking. Reduced valve operating temperatures. Greater resistance to deterioration at high valve temperatures.

What will be the likely result if the piston ring gaps happen to be aligned when performing a differential pressure compression check on a cylinder?. Little or no effect. The rings will not be seated. A worn or defective ring(s) indication.

What is the purpose of installing two or more springs on each valve in an aircraft engine?. To equalize side pressure on the valve stem. To eliminate valve spring vibration or surging. To help equalize valve face loading.

Engine operating flexibility is the ability of the engine to. deliver maximum horsepower at a specific altitude. meet exacting requirements of efficiency and low weight per horsepower ratio. run smoothly and give the desired performance at all speeds.

Valve overlap is defined as the number of degrees of crankshaft travel. during which both valves are off their seats. between the closing of the intake valve and the opening of the exhaust valve. during which both valves are on their seats.

If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is. low oil supply. broken or weak pressure relief valve spring. air lock in the scavenge pump intake.

During routine inspection of a reciprocating engine, a deposit of small, bright, metallic particles which do not cling to the magnetic drain plug is discovered in the oil sump and on the surface of the oil filter. This condition. may be a result of abnormal plain type bearing wear and is cause for further investigation. is probably a result of ring and cylinder wall wear and is cause for engine removal and/or overhaul. is normal in engines utilizing plain type bearings and aluminum pistons and is not cause for alarm.

To what altitude will a turbo charged engine maintain sea level pressure?. Critical altitude. Service ceiling. Pressure altitude.

Why does the smoothness of operation of an engine increase with a greater number of cylinders?. The power impulses are spaced closer together. The power impulses are spaced farther apart. The engine has larger counterbalance weights.

Excessive valve clearance in a piston engine. increases valve overlap. increases valve opening time. decreases valve overlap.

Which air-fuel mixture will result in the highest engine temperature (all other factors remaining constant)?. A mixture leaner than a rich best-power mixture of .085. A mixture richer than a full-rich mixture of .087. A mixture leaner than a manual lean mixture of .060.

An aircraft reciprocating engine using hydraulic valve lifters is observed to have no clearance in its valve-operating mechanism after the minimum inlet oil and cylinder head temperatures for takeoff have been reached. When can this condition be expected?. During normal operation. When the lifters become deflated. As a result of carbon and sludge becoming trapped in the lifter and restricting its motion.

On which part of the cylinder walls of a normally operating engine will the greatest amount of wear occur?. Near the center of the cylinder where piston velocity is greatest. Near the top of the cylinder. Wear is normally evenly distributed.

After spark plugs from an opposed engine have been serviced, in what position should they be reinstalled?. Next in firing order to the one from which they were removed. Swapped bottom to top. Next in firing order to the one from which they were removed and swapped bottom to top.

A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates. a cracked exhaust stack. exhaust valve blow-by. worn piston rings.

When does valve overlap occur in the operation of an aircraft reciprocating engine?. At the end of the exhaust stroke and the beginning of the intake stroke. At the end of the power stroke and the beginning of the exhaust stroke. At the end of the compression stroke and the beginning of the power stroke.

Which of the following is a characteristic of a thrust bearing used in most radial engines?. Tapered roller. Double-row ball. Deep-groove ball.

When cleaning aluminum and magnesium engine parts, it is inadvisable to soak them in solutions containing soap because. some of the soap will become impregnated in the surface of the material and subsequently cause engine oil contamination and foaming. the soap can chemically alter the metals causing them to become more susceptible to corrosion. the parts can be destroyed by dissimilar metal electrolytic action if they are placed together in the solution for more than a few minutes.

What is required by 14 CFR Part 43 Appendix D when performing an annual/100-hour inspection on a reciprocating engine aircraft?. Magneto timing check. Cylinder compression check. Valve clearance check.

The floating control thermostat, used on some reciprocating engine installations, helps regulate oil temperature by. controlling oil flow through the oil cooler. recirculating hot oil back through the sump. controlling air flow through the oil cooler.

Engine crankshaft runout is usually checked. during an annual inspection. during engine overhaul and after a 'prop strike' or sudden engine stoppage. after a 'prop strike' or sudden engine stoppage and during an annual inspection.

Standard aircraft cylinder oversizes usually range from 0.010 inch to 0.030 inch. Oversize on automobile engine cylinders may range up to 0.100 inch. This is because aircraft engine cylinders. have more limited cooling capacity. have relatively thin walls and may be nitrided. operate at high temperatures.

Which of the following conditions would most likely lead to detonation?. Late ignition timing. Use of fuel with too high an octane rating. Use of fuel with too low an octane rating.

The actual power delivered to the propeller of an aircraft engine is called. friction horsepower. brake horsepower. indicated horsepower.

Which statement is correct regarding a four-stroke cycle aircraft engine?. The intake valve closes on the compression stroke. The exhaust valve opens on the exhaust stroke. The intake valve closes on the intake stroke.

Grinding the valves of a reciprocating engine to a feather edge is likely to result in. normal operation and long life. excessive valve clearance. preignition and burned valves.

What is likely to occur if a reciprocating engine is operated at high power settings before it is properly warmed up?. Oil starvation of bearings and other parts. Excessive engine oil pressure. Thermal shock of cylinders.

Some cylinder barrels are hardened by. nitriding. honing. quenching.

If an engine cylinder is to be removed, at what position in the cylinder should the piston be?. Bottom dead center. Top dead center. Halfway between top and bottom dead center.

An increase in manifold pressure with a constant RPM will cause the bearing load in an engine to. decrease. remain relatively constant. increase.

Increased water vapor (higher relative humidity) in the incoming air to a reciprocating engine will normally result in which of the following?. Decreased engine power at a constant RPM and manifold pressure. Increased power output due to increased volumetric efficiency. A leaning effect on engines which use non-automatic carburetors.

Which of the following engine servicing operations generally requires engine pre-oiling prior to starting the engine?. Engine oil and filter change. Engine installation. Replacement of oil lines.