Jeppesen 01A - Reciprocating Engines

Piston pin

A ______ joins the piston to the connecting rod.

Ball bearing

A _______ assembly consists of grooved inner and outer races, one or more sets of polished steel balls, and a bearing retainer.

Rectangular

A ________ compression ring fits flat against a cylinder wall with a large contact area to provide a tight seal. However, the large contact area also takes longer to seat, or wear enough so that the contour of the ring exactly matches the contour of the cylinder wall.

Rocker arm

A ________ is a pivoting lever located in the cylinder head that changes the lifting movement of the push rod into the downward motion needed to open a valve. Typically it is made of forged steel and has a cup-shaped socket to hold the push rod end and a flat surface that pushes against the valve tip.

Cam ground

A ________ piston is machined with a slightly oval shape. That is, the diameter of the piston parallel to the piston boss is slightly less than the diameter perpendicular to the piston boss. This oval shape compensates for any differential expansion and produces a round piston at normal operating temperatures.

Dynamic damper

A _________ is a weight which is fastened to a crankshaft's crank cheek assembly in such a way that it is free to move back and forth in a small arc.

Valve spring retainer seat

A _________ is usually located between the cylinder head and the bottom of the valve spring, while a valve spring retainer is installed on the top of the valve spring.

It may be chrome plated back to its original size.

A certain benefit of chrome plating is that once a cylinder wears beyond its usable limits, _______.

Statically balanced

A crankshaft is ________ when the weight of an entire crankshaft assembly is balanced around its axis of rotation.

Factors to consider when designing and constructing a cylinder

A cylinder assembly must be comparatively easy and inexpensive to manufacture, inspect, and maintain.

Factors to consider when designing and constructing a cylinder barrel

A cylinder barrel must possess good bearing characteristics as well as high tensile strength.

Factors to consider when designing and constructing a cylinder

A cylinder must be strong enough to withstand the internal pressures developed during engine operation yet be lightweight to minimize engine weight.

Must be composed of material that is strong enough to withstand the pressure imposed on it, while allowing rotation or movement between two parts with a minimum of friction and wear.

A good bearing, ________.

Split key or keeper key

A groove is machined around the valve stem near the tip for a _______ which acts as a lock ring to keep the valve spring retaining washers in place and hold the valve in the cylinder head.

Sludge chamber

A hollow crankpin serves as a collection chamber for sludge, dirt, carbon deposits, and other foreign material. Once these substances reach a crankpin chamber, or ______________, centrifugal force throws them to the outside of the chamber to keep them from reaching the outside crankpin surfaces.

1

A number "1" indicates the connecting rod or cap belong with the number ___ cylinder and piston assembly.

Laterally

A piston pin must be held in place ______ to prevent it from rubbing and scoring the cylinder walls.

A reverse current is sent through a cylinder for a controlled period of time after the chromium has been applied.

A problem associated with chrome plating cylinders is that, in its natural state, chromium is so smooth that it will not retain enough oil to provide adequate lubrication for the piston rings. To overcome this problem, _________.

Chrome channeling

A problem associated with chrome plating cylinders is that, in its natural state, chromium is so smooth that it will not retain enough oil to provide adequate lubrication for the piston rings. To overcome this problem, a reverse current is sent through a cylinder for a controlled period of time after the chromium has been applied. The current causes microscopic surface cracks to open up and form a network of interconnecting cracks that help hold lubricating oil on the cylinder wall. This procedure is often referred to as _______.

Split

A radial engine power section can be either one, two, or three pieces. A ______ power section is typically manufactured from aluminum or magnesium and then bolted together.

One-piece

A radial engine power section can be either one, two, or three pieces. A _______ power section usually consists of a solid piece of aluminum alloy.

Rocker arm bosses

A rocker arm is supported by a shaft that is suspended between a set of __________.

Disk-type

A second type of hydraulic lifter uses a ________ check valve instead of a ball check valve.

Master spline

A spline is a rectangular groove that is machined into the propeller shaft. Most splined shafts have a ________ that is approximately twice the size of any other spline. This assures that a propeller is attached to a propeller shaft a specific way so that vibration is kept to a minimum.

Tubular

A typical connecting rod is forged and has a cross-sectional shape of either an "H" or an "I." However, there are a few connecting rods that are _________.

Chromium-nickel molybdenum steel

A typical crankshaft has one or more cranks, or throws, located at specified points along its length. These throws are formed by forging offsets into a crankshaft before it is machined. Since crankshafts must withstand high stress, they are generally forged from a strong alloy such as _______.

Cast aluminum alloy

A typical horizontally opposed engine crankcase consists of two halves of _______ that are manufactured either with sand castings or by using permanent molds.

Nickel-steel alloy

A typical piston pin is machined in the form of a tube from a ______ forging that is case-hardened.

Single-row

A typical radial engine configuration consists of five to nine cylinders evenly spaced on the same circular plane with all pistons connected to a single crankshaft.

Bronze

A typical valve seat is made of either ______ or steel and machined to an oversize fit.

Solid

A valve lifter that consists of a solid metal cylinder that transmits the lifting force from the camshaft to the push rod.

Hydraulic

A valve lifter that uses oil pressure to cushion the impact of the cam lobe striking the lifter and removes any play within the valve operating mechanism.

Valve spring retainer

A valve spring retainer seat is usually located between the cylinder head and the bottom of the valve spring, while a _________ is installed on the top of the valve spring.

Cylinder

A valve's face must seat firmly against the ________ head.

Spark plug bushings

After a cylinder head is cast, _________, or inserts, are installed.

Piston ring gap

After a ring is made, it is ground to the desired cross-section and then split so it can be slipped over a piston and into a ring groove. The point where a piston ring is split is called the_______.

Aluminum alloy

Air-cooled cylinder heads are generally made of either forged or die-cast _______ because aluminum conducts heat well, is lightweight, and is durable.

Splined

All ______ propeller shafts are identified by an SAE number. For example, SAE 50 identifies a splined shaft that meets SAE design specifications for a 50 size shaft. The SAE number does not refer to the actual number of splines.

2

All crankshafts require at least _____ main journals to support the crankshaft, absorb the operational loads,and transmit stress from the crankshaft to the crankcase.

Heat energy

All heat engines convert _______ into mechanical energy by taking in a specific volume of air and heating it through the combustion of a fuel.

Cam ground

All pistons expand as they heat up. However, due to the added mass at the piston boss, most pistons expand more along the piston boss than perpendicular to the piston boss. This uneven expansion can cause a piston to take on an oblong, or oval shape, at normal engine operating temperatures, resulting in uneven piston and cylinder wear. One way to compensate for this is with a _______ piston.

Valve operating mechanism

All reciprocating engines require a _______ to open each valve at the correct time, hold it open for a certain period, and then close the valve.

Exhaust valve

Allows the exhaust gases to exit the cylinder through the exhaust port.

Propeller ground clearance

An advantage of the in-line engine is that, when mounted with the cylinders inverted, the crankshaft is higher off the ground, allowing greater ______ which permitted the use of shorter landing gear.

Maintenance manual

An engine manufacturer's ________ specifies either a cold or hot valve clearance. As its name implies, a cold clearance is set when the engine is cold and is typically less than the hot or running clearance, which is set when the engine is hot.

Aerodynamic drag

An opposed engine's compact cylinder arrangement reduces the engine's frontal area and allows a streamlined installation that minimizes ______.

Bearing

Any surface which supports and reduces friction between two moving parts.

Lock plate

Articulated rods are attached to the master rod by knuckle pins, that are pressed into holes in the master rod flanges during assembly. A knuckle pin ________ is then installed to retain the pins.

Single-piece

As a general rule, a multiple piece, or split type master rod is used with _______ crankshafts.

Multiple-piece

As a general rule, a one piece rod is used on _______ crankshafts while a multiple piece, or split type master rod is used with single piece crankshafts.

The plating channels retain more oil than the piston rings can effectively scavenge.

As a general rule, engines with chrome plated cylinders tend to consume slightly more oil than engines with nitrided or steel cylinders. The reason for this is that ______.

Mounting lugs

As a general rule, lower-horsepower engines use _______ that are cast into the crankcase, while higher-powered engines employ ________ that are bolted to the crankcase.

Propeller reduction gear system

As a general rule, the faster an engine turns, the more power it produces; however, this same rule does not apply to propellers. most propellers must be operated at a specific speed to achieve maximum efficiency. Therefore, to allow an engine to run at the speed required to produce its maximum rated power output while, at the same time, maintain a reasonable propeller speed, some high-powered engines must use a ______________.

Tappet

As the camshaft rotates, the lobe raises the valve lifter. A valve lifter, or _______, transmits the lifting force of the cam to the push rod. Valve lifters in opposed engines can be solid or hydraulic.

Power section

As with an opposed engine crankcase, a radial engine ______ section contains machined bosses that rigidly support the crankshaft bearings and the crankshaft.

Metal key

As you can see, a tapered propeller shaft changes in diameter along its length and utilizes a ______ to keep a propeller from rotating.

1/8

Assume that you want to know how fast the cam turns on a certain nine cylinder radial engine. If the cam ring has four lobes and rotates opposite the crankshaft, the cam ring turns at _____ the crankshaft speed.

Straight roller bearings

Bearings that are suitable when the bearing is subjected to radial loads only. Most high-power aircraft engines use these as crankshaft main bearings.

Tapered roller bearings

Bearings that have cone-shaped inner and outer races that allow the bearing to withstand both radial and thrust loads.

The knuckle pin holes in the master rod flange are positioned at varying distances from the center of the crankpin.

Because of the varying angularity of articulating rods with respect to the master rods, all pistons do not move an equal amount in each cylinder for a given number of degrees of crankshaft rotation. To compensate for this, _______.

Thrust load

Because of their construction, ball bearings are well suited to withstand ______ and are, therefore, used as thrust bearings in large radial and gas turbine engines.

The oil film on the cylinder wall not allowing the necessary wear, or seating, of the piston rings during the break-in period.

Chrome plated cylinders are typically more difficult to seal, or break-in, immediately after an engine is overhauled. This is caused by ______.

Chromed cylinders tend to wear longer.

Chromed cylinders are less susceptible to rust or corrosion because of chromium's natural corrosion resistance. Therefore, _____.

Electroplating

Chromium is a hard, natural element which has a high melting point, high heat conductivity, and a very low coefficient of friction. The process used to chrome plate a cylinder is known as ________.

Plain connecting rod

Connecting rods used in opposed and in-line engines.

Engine identification code

Consists of a letter or series of letters followed by a number and model designation.

Radial engine

Consists of a row, or rows of cylinders arranged radially about a central crankcase.

Intake valve

Controls the amount of fuel/air mixture that enters a cylinder through the intake port.

Permanent mold process

Crankcases manufactured through the ________, or per-mamold, as it is called by some manufacturers, are denser than those made by sand casting.

Permanent mold process

Crankcases that underwent this process have denser construction that allows to have thinner walls than a sand cast crankcase and exhibit less tendency to crack due to fatigue.

The rear of an engine and is specified as either clockwise or counterclockwise.

Crankshaft rotation is referenced from _________.

Mounting flange

Cylinder barrels are machined from a forged blank, with a skirt that projects into the crankcase and a ________ that is used to attach the cylinder to the crankcase.

Cylinder pad

Cylinders are attached around the perimeter of the radial engine power section to machined _______.

Four-throw

Depending on the size of the crankshaft and power output of the engine, a _______ crankshaft has either three or five main bearings.

Reciprocating engine

Derived their name from the back-and-forth, or reciprocating movement of their pistons. It is this reciprocating motion that produces the mechanical energy needed to accomplish work.

More fin area is provided around the portion of the cylinder head that contains the exhaust valve.

Due to the temperature differences across the cylinder head, it is necessary to provide more cooling-fin area on various sections of a cylinder head. Since the exhaust valve region is typically the hottest part of the internal surface, ______.

Knuckle pin

Each articulated rod is hinged to the master rod by a ________.

1

Each cylinder has at least ____ intake valve/s and ____ exhaust valve/s.

2

Each cylinder must have at least one intake and one exhaust valve; however, on some high powered engines, at least ____ intake and ____ exhaust valve/s are provided for each cylinder.

I

Engine identification code for: Fuel Injected

G

Engine identification code for: Geared nose section (propeller reduction gearing)

H

Engine identification code for: Horizontal mounting (for helicopters)

0

Engine identification code for: Horizontally opposed engine

1

Engine identification code for: In-line engine

L

Engine identification code for: Left-hand rotation (for multi-engine installations)

A

Engine identification code for: Modified for aerobatics

R

Engine identification code for: Radial engine

S

Engine identification code for: Supercharged

T

Engine identification code for: Turbocharged

V

Engine identification code for: V-type engine

V

Engine identification code for: Vertical mounting (for helicopters)

The engine is turned until the piston in the cylinder being adjusted is at the beginning of the power stroke. With the piston in this position, there is no pressure applied to either of the push rods and the rocker arm is as far from the valve tip as possible.

Engines that require valve adjustments have adjustment screws and locknuts mounted in their rocker arms at the push rod fitting. What should be done to set the valve clearance?

Hydraulic

Engines utilizing _______ lifters do not require periodic valve adjustments since they automatically maintain a zero running valve clearance during normal operation. Because of this, these lifters are often called zero clearance, or zero lash lifters.

Engine vibration

Excessive ________ can cause metal structures to become fatigued and fail or wear excessively. In some instances, it is caused by an unbalanced crankshaft.

Radial and thrust loads

For a bearing to provide efficient and quiet operation, it must hold two parts in a nearly fixed position with very close tolerances. Furthermore, bearings must be able to withstand ________ or a combination of the two.

An engine will run poorly, and valve damage could result.

For an engine to run properly, the correct valve clearance must be maintained. During normal engine operating temperatures, the cylinder assemblies expand and force the cylinder head, along with its valve operating components, further away from the crankcase. However, due to their relatively small mass, the push rods expand less. As a result, the clearance between the rocker arm and valve stem increases. If this valve clearance is not controlled, ________.

On a four-stroke engine, each cylinder fires once for every two crankshaft rotations. Therefore, each valve must open and close once for every two rotations of the crankshaft.

For an opposed engine, the camshaft is supported by several bearing journals that ride in a set of camshaft bosses which are cast into the crankcase. The force used to rotate a camshaft is derived from the crankshaft through a set of gears. The speed of rotation is always one-half that of the crankshaft. What is the reason for this?

Lobes

For an opposed engine, typical camshaft consists of a round shaft with a series of cams, or ______, that transform the circular motion of the crankshaft to the linear motion needed to actuate a valve.

Mounting lugs

For opposed engines, mounting points, sometimes called _______, are typically cast as part of the crankcase. However, some of it may be a bolt-on addition.

Nose section

For radial engine crankcases, it usually houses and supports a propeller governor drive shaft, the propeller shaft, a cam ring, and a propeller reduction gear assembly if required. In addition, it has mounting points for magnetos and other engine accessories.

Four-throw

Four cylinder opposed engines and four cylinder inline engines use ________ crankshafts. On some, two throws are arranged 180 degrees apart from the other two throws.

Planetary gears

Gears that are used on some horizontally opposed engines, as well as radial and turboprop engines.

Spur gears

Gears that have their teeth cut straight across their circumference and can be either external or internal.

2

How many crank cheeks, or crank arms, are required to connect the crankpin to the crankshaft?

Oil scraper ring

If carbon due to oil entering the combustion chamber should enter the ring grooves or valve guides, it can cause the valves and piston rings to stick. Furthermore, carbon buildup can cause spark plug misfiring as well as detonation, preignition, or excessive oil consumption. To help prevent this, a/an _______ is used to regulate the amount of oil that passes between the piston skirt and the cylinder wall.

120

If three piston rings are installed on one piston, it is common practice to stagger the ring gaps _______ degrees from each other.

The oil will burn and leave a thick coating of carbon on the combustion chamber walls, the piston head, the spark plugs, and the valves.

If too much oil enters the combustion chamber, ______.

2, 16

In a nine cylinder engine there is one master rod and eight articulating rods, while a double row 18 cylinder engine has ____ master rods and _____ articulating rods.

Steel

In a plain connecting rod, the bushing is typically pressed into the connecting rod and then reamed to the dimension required by the piston pin. The crankpin end, on the other hand, is usually fitted with a two-piece bearing and cap which is held on the end of the rod by bolts or studs. In this case, the main bearing insert is typically made of ______ that is lined with a nonferrous alloy such as babbitt, lead, bronze, or copper.

The propeller reduction gearing and the front end of the power section.

In a single row radial engine, the cam ring is usually located between ______________.

The rear end of the power section and the supercharger section.

In a twin row radial engine, a second cam for the valves in the rear row is installed between ___________.

The camshaft is driven at one-half the crankshaft's rotational speed.

In a typical opposed engine, the camshaft timing gear has twice as many teeth as the gear on the crankshaft. In this configuration, __________.

Camshaft bosses

In addition to the transverse webs that support the main bearings, a set of ________ are typically cast into a crankcase. These bosses support the camshaft which is part of the valve operating mechanism.

CermiCrome, NuChrome

In an effort to overcome the shortcomings of chrome plated and nitrided cylinders, some new plating processes have been developed. One of these processes involves mechanically impregnating silicon carbide particles onto a chromed cylinder wall, instead of channeling. The silicon carbide provides a somewhat rough finish so it retains lubricating oil, yet is still smooth enough to allow effective oil scavenging. Furthermore, the silicon carbide provides a surface finish that is more conducive to piston ring seating during the engine break-in period. This plating process is commonly referred to as either _____ or ______ plating.

CermiNil

In another type of plating process called ________, nickel with silicon carbide particles, is used for the plating material. The nickel, although not as durable as chromium, provides for an extremely hard finish while the silicon carbide particles increase the hardness of the material and aid in lubricating oil retention. A unique characteristic in this process is that the silicon carbide particles are infused throughout the plating instead of only to the surface. This tends to further increase the cylinders wearability while the surface finish is smooth enough to allow for effective oil scavenging.

Bearing race

In applications of ball bearings where thrust loads are heavier in one direction, a larger ________ is used on the side of the increased load.

Choke bore cylinder

In most reciprocating engines, the greater mass of the cylinder head retains heat and expands thereby causing the upper portion of the cylinder to expand more than the lower portion. However, with a ______, the diameter at the top of the cylinder is less than the diameter at the bottom of the cylinder which helps compensate for the uneven expansion.

Exert equal pressure on the entire cylinder wall as well as provide a gas-tight fit against the sides of the ring grooves.

In order for piston rings to seal against the cylinder wall, the rings must press against the cylinder wall snugly. Furthermore, the rings must _______.

Numbered

In order to identify a specific cylinder, all engine cylinders are ________.

Cam rollers

In place of a cam follower face, a radial engine uses ________. It consists of a small wheel that rolls along the cam track.

Counterweight

In some designs, the crank cheek extends beyond the journal to form a _________ that helps balance the crankshaft.

Static-type

In the late 1920s, the Wright Aeronautical Corporation, in cooperation with the U.S. Navy, developed a series of five-, seven-, and nine-cylinder ______ radial engines. These engines demonstrated reliability far greater than any other previous designs.

Planetary gear system

In this gear system, the propeller shaft is attached to a housing which contains several small gears called planetary gears. The planetary gears rotate between a sun gear and a ring or bell gear. The crankshaft drives either the sun gear or ring gear, depending on the individual installation. This system keeps the propeller shaft aligned with the crankshaft, transmits power with a minimum of weight and space, and keeps the propeller's direction of rotation the same as the engine.

Splined

Increases in engine power demanded a stronger method of attaching propellers. Therefore, most high powered radial engines use ______ propeller shafts.

Chrome, nickel, or tungsten steel

Intake valves operate at lower temperatures than exhaust valves and, therefore, are typically made of _____.

Cylinder head

It acts as a lid on the cylinder barrel to provide an enclosed chamber for combustion.

Cylinder head

It contains intake and exhaust valve ports, spark plugs, valve actuating mechanisms, and also serve to conduct heat away from the cylinder barrels.

Crankcase

It contains the engine's internal parts and provides a mounting surface for the engine cylinders and external accessories.

Valve clearance

It describes the clearance, or space, between the tip of the valve stem and the rocker arm face.

Cylinder

It houses the piston and connecting rod assembly as well as the valves and spark plugs.

Cam rings

It is a circular piece of steel with a series of raised cam lobes on its outer edge. Typically has three or four lobes for seven cylinder engines while has four or five lobes in a nine cylinder engine.

Valve seat

It is a circular ring of hardened metal that provides a uniform sealing surface for the valve face.

Piston

It is a cylindrical plunger that moves up and down within a cylinder in a reciprocating engine.

Valve guide

It is a cylindrical sleeve that provides support to the valve stem and keeps the valve face aligned with the valve seat. Typically it is made of steel, tin-bronze, or aluminum-bronze and is installed in a cylinder head with a shrink fit in the same manner as a valve seat.

Nitriding

It is a form of case hardening that changes the surface strength of steel by infusing the metal with a hardening agent.

Supercharger

It is an engine accessory that is used to compress air and distribute it to the engine's cylinders.

Choke bore cylinder

It is designed to compensate for the uneven expansion caused by the higher operating temperatures and larger mass near the cylinder head.

Nose section

It is mounted at the front of a radial engine crankcase and bolts directly to the power section. Typically made of an aluminum alloy that is cast as one piece with a domed or convex shape.

Cylinder pad

It is simply a surface where a cylinder is mounted to a crankcase.

Valve face

It is that portion of the valve that creates a seal at the intake and exhaust ports. It is typically ground to an angle of between 30 and 60 degrees to form a seal against the valve seat when the valve is closed.

Crankshaft

It is the backbone of a reciprocating engine.

Crankcase

It is the foundation of a reciprocating engine.

Connecting rod

It is the link which transmits the force exerted on a piston to a crankshaft.

Propeller reduction gear system

It permits a propeller to turn slower than the engine.

Cylinder

It provides a combustion chamber where the burning and expansion of gases takes place to produce power.

Crankcase

It provides a tight enclosure for the lubricating oil as well as a means of attaching a complete engine to an airframe.

Dynamically balanced

It refers to balancing the centrifugal forces created by a rotating crankshaft and the impact forces created by an engine's power impulses.

Pratt and Whitney R-4360

It was the largest practical radial engine used in aviation which consisted of 28 cylinders arranged in four staggered rows of seven cylinders each and developed a maximum 3,400 horsepower.

Poppet valve

Its basic components include the valve head, valve face, valve neck, valve stem, and valve tip.

Crankshaft

Its main purpose is to transform the reciprocating motion of the pistons and connecting rods into rotary motion to turn a propeller.

Power section

Like an opposed engine crankcase, this radial engine crankcase section absorbs intense stress from the crankshaft assembly and the cylinders.

Nitriding

Like main journals, crankpins undergo _______ to resist wear and provide a suitable bearing surface.

Steel alloy

Master rods are typically manufactured from a ________ forging that is machined and heat-treated for maximum strength. Articulated rods are constructed of a forged _________ in either an I- or H- cross-sectional profile.

Aluminum alloy

Most aircraft engine pistons are machined from ______ forgings.

Ring grooves

Most aircraft engine pistons are machined from aluminum alloy forgings. ______ are then cut into a piston's outside surface to hold a set of piston rings. As many as six of these grooves may be machined around a piston.

Valve float

Most aircraft engines utilize two or more valve springs of different sizes and diameters to prevent a phenomenon called ________ or valve surge. It occurs when the frequency of a valve spring begins to vibrate at its resonant frequency. When this occurs, the spring loses its ability to hold the valve closed.

Steel alloy

Most connecting rods are made of a durable ____________.

Aluminum

Most connecting rods are made of a durable steel alloy; however, _________ can be used with low horsepower engines.

Crankpins

Most crank cheeks have drilled passage ways that allow oil to flow from the main journal to the _______.

Crankshaft bearings

Most crankcase halves split vertically and are aligned and held together with studs and bolts. Through bolts are typically used at the _______ while smaller bolts and nuts are used around the case perimeter.

Case perimeter

Most crankcase halves split vertically and are aligned and held together with studs and bolts. Through bolts are typically used at the crankshaft bearings while smaller bolts and nuts are used around the ________.

Any force applied to a crankpin in a direction other than parallel to the crankshaft center line causes the crankshaft to rotate.

Most crankpins are forged directly into a crankshaft and are offset from the main bearing journal. This offset design means that ________.

Flat-head

Most modern aircraft engines use _____ pistons.

Flanged

Most modern horizontally opposed aircraft engines use a ______ propeller shaft. With this type of propeller shaft, a flat flange is forged directly onto the end of a crankshaft and a propeller is bolted to the flange.

Use the proper tools to avoid damaging the bearing and its seals.

Most of the ball bearings you will work with as a technician are used in accessories such as magnetos, alternators, turbochargers, and vacuum pumps. Many of these bearings are pre-lubricated and sealed to provide trouble-free operation between overhauls. However, if a sealed ball bearing must be removed or replaced, it is important that you __________.

Cylinder pad

Most opposed crankcases are approximately cylindrical, with smooth areas machined to serve as a _______.

Hydraulic

Most opposed engines use what kind of valve lifters?

Cast iron

Most piston rings are made of high-grade gray _____.

Chrome-plated mild steel

Most piston rings are made of high-grade gray cast iron. However, in some engines, ______ piston rings are used because of their ability to withstand high temperatures.

Rotator cap

Most valve stems are surface hardened to resist wear and are joined to the valve head at the valve neck. The tip of a valve stem is also hardened to withstand both wear and hammering. In some cases, a ________ is placed over a valve tip to increase service life.

Supercharger section

Mounting lugs for radial engines are spaced about the periphery of the ______ to attach the engine to the engine mount. The mounting lugs may either be integral with this section or detachable.

Tapered

Of the three different ring cross sections, the _______ face presents the narrowest bearing edge to the cylinder wall to help reduce friction and hasten ring seating.

Plain bearing

Of the three most common types of bearings used in reciprocating engines, the __________ relies on the sliding movement of one metal against another, while both roller and ball bearings have one surface roll over another.

Oil control rings

Oil rings that are placed in the grooves immediately below the compression rings. Its primary purpose is to regulate the thickness of the oil film on the cylinder wall.

180

On a four cylinder engine, the number one and four throws are ______ degrees apart from the number two and three throws.

Mounting lugs

On all engines, ________ support the entire powerplant including the propeller and, therefore, must be designed to withstand various engine, centrifugal, and g-loading conditions.

Camshaft

On an opposed engine, valve operation begins with a _______.

A return path for the oil that is pumped up to the cylinder head.

On most aircraft reciprocating engines, the push rods are enclosed by a thin metal shroud, or tube, that runs from the cylinder head to the crankcase. In many cases, these tubes provide ____________.

Heli-Coil

On older engines, spark plug openings consisting of bronze or steel bushings were shrunk and screwed into the cylinder head. However, in most modern engines, stainless steel ______ spark plug inserts are used. The use of _______ inserts allows for the repair of damaged threads by replacing the insert.

Cylinder

On some engines, a passage is drilled in the crankpin to allow oil from the hollow crankshaft to be sprayed onto the ________ walls.

Cooling fins

On some pistons, _______ are cast into the underside of the piston to provide for greater heat transfer to the engine oil.

Safety circlet

On some radial engines, the valve stems have an additional groove below the split key groove. This second groove is used to hold a _________, or spring ring, which prevents the valve from falling into the cylinder in the event the valve tip breaks off.

Compensate for any dimensional changes in the valve operating mechanism caused by heating.

Once the camshaft rotates and the cam lobe strikes the follower face, the lifter body and cylinder move outward. This action causes the check valve to seat and trap oil in the oil pressure chamber. This trapped oil acts as a cushion to dampen the abrupt pressure applied to the push rod. Once the valve is off its seat, some oil leaks between the plunger and the cylinder to _______.

Crankpin end

One end of a connecting rod connects to the crankshaft and is called the ________, while the other end connects to the piston and is called the piston end.

Piston end

One end of a connecting rod connects to the crankshaft and is called the crankpin end, while the other end connects to the piston and is called the ________.

Valve stem

One end of this rocker arm is cup-shaped to hold a push rod, while the other end is machined smooth to push against the tip of a _________. When rotated by the push rod, the rocker arm pivots on its center bushing and depresses the valve.

Planetary gears

One of the best ways to reduce vibration is to keep the propeller shaft and crankshaft perfectly aligned. A gear reduction system that does this is the ________ reduction system.

Double-row

One of the most common multiple-row radial engines consisted of two single row engines in line with each other connected to a single crankshaft. This type of engine is sometimes referred to as a ______ radial engine and typically has a total of 14 or 18 cylinders.

The cylinder walls should be coated with a sticky preservative oil.

One of the problems with nitrided cylinders is that they do not hold oil for extended periods of time. This problem increases a cylinder's susceptibility to corrosion and, for this reason, if an engine is left out of service for any extended period, ___________.

Oil impregnated porous oilite

One type of bushing that is used in aviation is the _________ bushing. With this type of bushing, the heat produced by friction draws the impregnated oil to the bearing surface to provide lubrication during engine operation.

An internal-tooth spur gear on the propeller shaft and an external-tooth spur gear on the crankshaft.

One way to overcome some of the drawbacks of a simple spur gear arrangement is to use ______________.

Keeps the propeller shaft more closely aligned with the crankshaft, thereby eliminating much of the stress placed on the crankcase.

One way to overcome some of the drawbacks of a simple spur gear arrangement is to use an internal-tooth spur gear on the propeller shaft and an external-tooth spur gear on the crankshaft. In addition to allowing the propeller to turn in the same direction as the engine, this arrangement ____________.

Two-piece

One-piece crankshafts are used with a connecting rod that splits so it can be installed on the crankpin. However, with a _________, the crankpin separates, allowing the use of a one piece connecting rod.

Static-type

Outstanding reliability coupled with a high power-to-weight ratio made these radial engines ideal for powering early military and civilian transport aircraft.

Wrist pin

Piston pins are sometimes called _____ because of the similarity between the relative motions of the piston and the connecting rod and that of the human arm.

Head design

Pistons are often classified according to their _______.

Transmit the force produced by combustion to the crankshaft.

Pistons perform two primary functions; first, they draw fuel and air into a cylinder, compress the gases, and purge burned exhaust gases from the cylinder; second, ______.

Nonferrous metals

Plain bearings are usually made of __________ such as silver, bronze, babbitt, tin, or lead. One type of plain bearing consists of thin shells of silver-plated steel, with lead-tin plated over the silver on the inside surface only.

Flange-type

Plane bearings are typically subject to radial loads only. However, _______ plain bearings are often used as thrust bearings in opposed reciprocating engines.

Head design

Poppet valves are classified according to their ______ which may come in four basic designs: the flat-headed valve, the semi-tulip valve, the tulip valve, and the mushroom valve.

Piston ring

Prevent leakage of gas pressure from the combustion chamber.

Rollers

Radial engine rocker arms have adjusting screws and lock screws that allow adjustment of the push rod-to-rocker arm clearance. In addition, many radial engine rocker arms are equipped with _______ on their valve ends to reduce friction, eliminate side loading on the valve stem, and lessen tip deformation.

Cam rings

Radial engines utilize some of the same components in their valve operating mechanisms as opposed engines, but there are some significant differences. For example, in place of a camshaft, a radial engine uses one or two ________, depending on the number of cylinder rows.

Piston ring

Reduce oil seepage into the combustion chamber.

Spur gears; planetary gears

Reduction gear systems currently used on aircraft engines utilize _________, or a combination of the two.

Chrome plating

Refers to a method of hardening a cylinder by applying a thin coating of chromium to the inside of aircraft cylinder barrels.

Accessory end

Regardless of how an engine is mounted in an aircraft, the propeller shaft end is always referred to as the front of an engine, and the ________ is always the rear of an engine.

Propeller shaft end

Regardless of how an engine is mounted in an aircraft, the_______ is always referred to as the front of an engine, and the accessory end is always the rear of an engine.

Engine vibration

Regardless of the number of throws or the number of pieces used in construction, all crankshafts utilize the same basic parts. These parts include the main bearing journal, the crankpin, and the crank cheek. In addition, although they are not true parts of the crankshaft, counterweights and dampers are often installed on many crankshafts to reduce _______.

Engine valves

Regulate the flow of gases into and out of a cylinder by opening and closing at predetermined times in the combustion process.

Compression ring

Rings that are installed in the upper ring grooves and help prevent the combustion gases from escaping by a piston.

Oil ring

Rings that are installed near the middle and bottom of a piston and control the amount of oil applied to the cylinder wall.

Oil ring

Rings that control the amount of oil that is applied to the cylinder walls as well as prevent oil from entering the combustion chamber.

Compression ring

Rings that prevent gas from escaping past the piston during engine operation and are placed in the ring grooves immediately below the piston head.

Cam ground

Several engines now use _______ pistons to compensate for the greater expansion parallel to the piston boss during engine operation. Its diameter measures several thousandths of an inch larger perpendicular to the piston boss than parallel to the piston boss.

Wedge

Since compression rings receive the least amount of lubrication and are closest to the heat of combustion, they are more prone to sticking. Therefore, most compression rings are ______ shaped.

Inconel, silicon-chromium or cobalt-chromium alloys

Since exhaust valves must endure much higher temperatures than intake valves, they are usually made of more heat resistant metals such as _______.

Applying a band of blue paint around the cylinder base, or to certain cooling fins.

Since nitriding is not a plating or coating, it changes a cylinder bore by only two to four ten thousandths of an inch. This dimensional change requires a cylinder to be honed to an accurate, micro-smooth finish after the nitriding process is complete. Most manufacturers identify a nitrided cylinder by _______.

Crankpin

Since the flange holes on a master rod encircle the center of the crankpin, the _______ is the only portion of a master rod assembly that travels in a true circle as the crankshaft rotates. The remaining knuckle pins travel in an elliptical path.

Silk thread

Since the oil supply in most modern horizontally opposed engines is carried inside the crankcase, provisions are made to seal the case to prevent leakage. To ensure that the seal does not interfere with the tight fit for the bearings, in addition to the gasket material, on some engines a fine ________ extending around the entire case perimeter is imbedded in the compound.

Non-hardening gasket compound

Since the oil supply in most modern horizontally opposed engines is carried inside the crankcase, provisions are made to seal the case to prevent leakage. To ensure that the seal does not interfere with the tight fit for the bearings, most crankcase halves are sealed with a very thin coating of a _________.

Result in the ring faces binding against each other and the cylinder wall causing cylinder wall scoring.

Since the piston rings expand when the engine reaches operating temperature, the ring must have a specified clearance between the ring gap faces. If the gap is insufficient, ______.

The two forces will not close up enough to provide an adequate seal.

Since the piston rings expand when the engine reaches operating temperature, the ring must have a specified clearance between the ring gap faces. If the gap is too large, ______.

Six-throw

Six cylinder opposed and in-line engines and 12 cylinder V-type engines use ________ crankshafts. Typically it is forged as one piece and consists of four main bearings and six throws that are 60 degrees apart.

Bushings

Smaller bearings, such as those used to support various accessory drive shafts, are called _________.

Never be cut, broken, or handled in a manner that would allow the sodium to come in contact with air and must be disposed of in an appropriate manner.

Sodium is a dangerous material that burns violently when exposed to air. Because of this, sodium filled valves should ____________.

Radial load

Some bearing races have a deep groove that matches the curvature of the balls to provide more support and allow a bearing to carry high _________.

Cylinder

Some crankshafts are made from a single piece of steel, while others consist of several components. A typical crankshaft can have as few as one throw or as many as eight and varies depending on the number of ______ and engine type.

Model change or modification to a basic engine

Some engine identification codes include a letter designation after the displacement to indicate:

Lateral movement

Some knuckle pins are pressed into the master rod so they do not rotate in the flange holes, while other full floating knuckle pins have a loose fit that allows them to rotate in both the flange holes and articulated rods. In either type of installation, a lock plate on each side retains the knuckle pins and prevents _________.

Floating cam ring

Some large radial engines incorporate a _______ that requires a special procedure when adjusting valve clearance. To obtain the correct adjustment, the cam ring must be seated to eliminate cam bearing clearance. This usually involves depressing two valves to seat the cam ring, allowing an accurate measurement on a third valve. This procedure is repeated for each cylinder.

Ventilated-type

Some pistons use ______ oil control rings which typically consist of two or more pieces with small slots machined around the ring. These slots allow excess oil to drain into the ring groove so it can return to the crankcase.

Oil scraper ring

Sometimes called an oil wiper ring, it usually has a beveled face and is installed in a ring groove at the bottom of the piston skirt.

Crankcase

Static-type radial engines differ from rotary-type radial engines in that the ______ is bolted to the airframe and remains stationary. This dictates that the crankshaft rotates to turn the propeller.

Power lever

The Porsche Flugmotoren (PFM) 3200 is a direct descendant of the 214 horsepower engine used in the Porsche 911 sports car. It utilizes a single engine control called a ______. This control automatically governs the throttle, mixture, and propeller pitch settings. This reduces pilot workload and, at the same time, maintains the engine's peak performance for the given conditions.

Valve stem

The ______ acts as a pilot to keep the valve head properly aligned as it moves back and forth.

Piston

The ______ compresses the fuel mixture and transmits the power produced by combustion to the crankshaft through the connecting rods.

Cylinder

The ______ forms a chamber where the fuel/air mixture is compressed and burned.

Semi-tulip

The ______ poppet valve has a slightly concave area on its head.

Piston pin boss

The _______ is an enlarged area inside the piston that provides additional bearing area for a piston pin which passes through the ________ to attach the piston to a connecting rod.

Accessory section

The _______ is usually cast of either an aluminum alloy or magnesium. On some engines, it is cast in one piece and then machined to provide a means for mounting accessories such as magnetos, carburetors, pumps, starters, and generators. However, on other engines, it consists of an aluminum alloy casting and a separate cast magnesium cover plate on which the accessories are mounted.

Tulip

The _______ poppet valve has a deep, wide indented area on its head.

Flat-head

The _______ poppet valve has a flat head and is typically used only as an intake valve in aircraft engines.

Main bearing journals

The _______, or main journals, represent the center line of a crankshaft and support the crankshaft as it rotates in the main bearings.

Valve seat insert

The ________ provides a sealing surface for the valve face.

Valve guide

The _________ supports the valve and keeps it aligned with the seat.

Cylinder

The arrangement of the crankpins varies with the type engine and allows each piston to be at a different position in the cranking cycle as the crankshaft rotates. On opposed engines, the number of crankpins must correspond with an engine's ________ arrangement.

Bearing retainer

The balls of a ball bearing are held in place and kept evenly spaced by the ________, while the inner and outer bearing races provide a smooth surface for the balls to roll over.

Bearing race

The balls of a ball bearing are held in place and kept evenly spaced by the bearing retainer, while the inner and outer ________ provide a smooth surface for the balls to roll over.

Torque effect

The biggest disadvantage rotary-type radial engines possessed was that the ______ produced by the large rotating mass of the propeller and cylinders made aircraft somewhat difficult to control.

Allows oil to flow from the oil supply chamber to the oil pressure chamber.

The cam follower face is the smooth hardened surface of the lifter that rides on the cam lobe. When the follower face is on the back side of a cam lobe, the hydraulic plunger spring forces the hydraulic plunger outward so that the push rod socket presses firmly against the push rod. As the hydraulic plunger moves outward, a ball check valve moves off its seat and __________.

Cam ramp

The cam lobes in a radial engine differ from those in an opposed engine in that each lobe is constructed with a ______ on each side of a lobe. This ramp reduces the initial shock of an abruptly rising lobe.

The number of lobes on the cam ring, the cam ring's direction of rotation relative to the crankshaft, and the number of cylinders on the engine.

The cam ring is mounted concentrically with the crankshaft and is driven by the crankshaft through a series of gears. However, unlike a camshaft, the speed at which a cam ring rotates varies. To determine a given cam ring's rotation speed, you must know _________.

Case halves

The crankcase is also an integral part of the lubrication system. Oil passages are drilled throughout the _______ to allow lubricating oil to be delivered to the moving parts housed within the crankcase.

Power section

The cylinder assembly along with the piston assembly, connecting rods, crankshaft, and crankcase constitute the ______ of a reciprocating engine.

Crankshaft

The cylinders of a rotary-type radial engine are mounted radially around a small crankcase and rotate with the propeller, while the ______ remains stationary.

Inverted V-type engine

The cylinders on a V-type engine could be above the crankshaft or below it, in which case the engine is referred to as a _______.

Diameter

The difference in ________ between the pins and the holes allows the dynamic damper to oscillate back and forth.

Supercharger section

The diffuser or ________ is located directly behind the radial engine power section and is generally made of cast aluminum alloy or magnesium.

30, 45

The engine manufacturer specifies the exact valve face angle which is based on airflow, efficiency, and sealing ability. In some engines, the intake valve face is ground to ____ degrees while the exhaust valve face is ground to ____ degrees.

Cooling fins

The exterior of a cylinder barrel consists of several thin _____ that are machined into the exterior cylinder wall and a set of threads that are cut at the top of the barrel so that it can be screwed into the cylinder head.

Cylinder arrangement and basic configuration

The first letters of engine identification codes indicate:

1791

The first patent for a heat engine was not taken out until _____ by John Barber.

Two-piece

The forked rod is split at the crankpin end to allow space for the blade rod to fit between the prongs. The fork-and-blade assembly is then fastened to a crankpin with a ______ bearing.

Cylinder

The groove near the tip of a valve stem allows a split retainer key to hold spring tension on a valve as well as keep the valve from falling into the _______.

O-ring

The inner circumference of a cylinder pad is sometimes chamfered or tapered to permit the installation of a large rubber ______ around the cylinder skirt. This ______ effectively seals the joint between the cylinder and the cylinder pads.

Semi-spherical

The inner shape of a cylinder head may be flat, semi-spherical, or peaked, to resemble the shape of a house roof. However, the ___________ type has proved to be the most satisfactory because it is stronger and provides for more rapid and thorough scavenging of exhaust gases.

Choke bore cylinder

The inside of a cylinder, or cylinder bore, is usually machined smooth to a uniform, initial dimension and then honed to a final dimension. However, some cylinder bores are machined with a slight taper. In other words, the diameter of the top portion of the barrel is slightly smaller than the diameter at the cylinder skirt. This is called a _______.

Nitriding and chrome plating

The inside wall of a cylinder barrel is continually subject to the reciprocating motion of the piston rings. Therefore, in an effort to minimize cylinder barrel wear and increase barrel life, most cylinder walls are hardened. The two most common methods used to provide a hard wearing surface are through _______.

Cylinder

The intake valve allows the fuel/air mixture into the ______ while the exhaust valve lets the exhaust gases out of the ______.

Allow oil to flow from the valve lifter to the valve components in the cylinder head.

The lifting force of the cam lobe is transmitted through a lifter and a push rod. A typical push rod consists of a hollow steel or aluminum alloy tube with polished ends. Push rods typically have holes drilled on each end to ____________.

The less inertia it produces when the rod and piston stop and then accelerate in the opposite direction at the end of each stroke.

The lighter a connecting rod is, _____________.

Keep oil from draining into the combustion chamber and causing hydraulic lock after an engine has been shut down.

The lower cylinders on radial engines and all the cylinders on inverted engines typically employ cylinders with extended cylinder skirts. The longer skirt helps ______.

Master rod bearing

The master rod serves as the only connecting link between all the pistons and the crankpin. The small end, or piston end of a master rod, contains a plain bearing called a piston pin bearing which receives the piston pin. The crankpin end of a master rod contains the crankpin bearing, sometimes called a _______.

Factors to consider when designing and constructing a cylinder barrel

The material used to construct a cylinder barrel must be as light as possible, yet have the proper characteristics for operating under high temperatures and pressures.

Factors to consider when designing and constructing a cylinder

The materials used in the construction of a cylinder must have good heat-conducting properties for efficient cooling.

Dynamic damper

The most common means of dynamically balancing a crankshaft is through the use of __________.

Reciprocating engine

The most common type of heat engine is the ________.

Poppet valve

The most common type of valve used in aircraft engines is the ______ which gets its name from the popping action of the valve.

Chromium-molybdenum steel

The most commonly used material for cylinder barrels is a high-strength steel alloy such as _________, or nickel chromium molybdenum steel.

Nickel chromium molybdenum steel

The most commonly used material for cylinder barrels is a high-strength steel alloy such as chromium-molybdenum steel, or ________.

Engine

The number of compression rings used on each piston is determined by the type of _____ and its design. However, most aircraft engines typically use two or three compression rings on each piston.

320 inches

The numbers in an engine identification code indicate an engine's piston displacement in cubic inches. For example, an 0-320 indicates a horizontally opposed engine with a displacement of _______.

Engine's piston displacement in cubic inches

The numbers in an engine identification code indicate:

The scraper ring retains surplus oil above the ring on the upward piston stroke, and this oil is returned to the crankcase by the oil control rings on the downward stroke.

The oil scraper ring can be installed with the beveled edge away from the piston head or in the reverse position, depending upon cylinder position and engine design. If the bevel is installed so that it faces away from the piston head, _______.

The ring pushes oil downward toward the crankcase.

The oil scraper ring can be installed with the beveled edge away from the piston head or in the reverse position, depending upon cylinder position and engine design. If the bevel is installed so that it faces the piston head, ______.

Laterally

The oval shape of a cam ground piston holds the piston centered in the cylinder during engine warmup and helps prevent the piston from moving _____ within a cylinder.

Bronze

The piston end of a plain connecting rod is fitted with a ________ bushing to accommodate the piston pin.

Butt joint

The piston ring gap can be a simple butt joint with flat faces, an angle joint with angled faces, or a step joint. Of the three types of joints used in piston ring gaps, the ______ is the most common in aircraft engines.

Piston head

The piston's top surface is called the ______ and is directly exposed to the heat of combustion.

Ring land

The portion of the piston between the ring grooves is commonly referred to as a ______.

Degrees

The position of the crankpins on a crankshaft in relation to each other is expressed in ________.

Mounting lugs

The radial engine supercharger section incorporates _______ to secure the engine assembly to the engine mounts.

The crankshaft turn three revolutions for every two revolutions of the propeller shaft.

The reduction rate that a particular planetary gearing arrangement achieves is found by the formula (in the pic): Notice that neither the number of teeth on the planetary gears nor the number of planetary gears attached to the spider enter into the computation for gear reduction. For example, if there are 72 teeth on the ring gear and 36 teeth on the sun gear, the propeller turns at a ratio of 1.5 to 1. However, reduction ratios are traditionally expressed in whole numbers, so this example is expressed as a 3-to-2 reduction. In other words, _____________.

Power section

The second portion of a radial crankcase is referred to as the _______ and represents the section of the crankcase where the reciprocating motion of the pistons is converted to the rotary motion of the crankshaft.

Valve duration

The shape of a cam lobe determines ________, the length of time a valve is held open.

Valve lift

The shape of a cam lobe determines _________, which is the distance a valve is lifted off its seat.

Single-throw

The simplest crankshaft is the ______ or 360 degree crankshaft used on single-row radial engines. It consists of a single crankpin with two main journals that support the crankshaft in the crankcase. It may be constructed out of either one or two pieces.

The propeller acts like a gyroscope and places severe torsional loads on the engine case. This requires the use of a stronger and heavier crankcase.

The simplest type of reduction gearing consists of two external tooth spur gears, one small gear on an engine crankshaft and one larger gear on the propeller shaft. However, this reduction system does have some disadvantages. For example, when using two external tooth spur gears, the propeller turns opposite the crankshaft. Furthermore, since the propeller shaft is off-center from the engine crankshaft, _____________.

Cam track

The smooth area between the lobes is called the _______. On a single row radial engine a single cam ring with two cam tracks is used. One track operates the intake valve while the second track operates the exhaust valve.

.020

The steel in the cylinder barrel contains a small percentage of aluminum and the nitrogen combines with the aluminum to form a layer of hard, wear-resistant aluminum nitrides. The depth of a nitrided surface depends on the length of time it is exposed to the ammonia gas but a typical thickness is approximately _____ inch.

Two-throw

The throws on a _________ crankshaft are typically set 180 degrees from each other and may consist of either one or three pieces. Although they are not commonly encountered, two cylinder opposed engines also use these crankshafts.

Rotary-type

The two basic types of radial engines include the ______ and the static-type.

Static-type

The two basic types of radial engines include the rotary-type and the ______.

Cylinder arrangement with respect to the crankshaft

The two most common means of classifying reciprocating engines are by _______ and the method of cooling.

Method of cooling

The two most common means of classifying reciprocating engines are by cylinder arrangement with respect to the crankshaft and _______.

Cylinder

The type of crankshaft used on a particular engine depends on the number and arrangement of an engine's ________.

Split valve key

The valve spring retainer is fitted with a ________ that locks the valve spring retainer to the valve stem.

Valve spring retainer

The valve springs are held in place by a ___________ and a split valve key.

One is by the sliding movement of one metal against another, and the second is for one surface to roll over another.

There are two ways in which bearing surfaces move in relation to each other to which reciprocating engines use bearings that rely on these both types of movement.

Ball bearing

These bearings have the least amount of rolling friction.

Teledyne Continental

These cylinders are treated with a gold paint that turns pink when subjected to an overheat condition.

Textron-Lycoming

These cylinders are typically painted with a gray enamel that appears burned when exposed to excessive heat.

Opposed-type engine

These engines are the most popular reciprocating engines used on light aircraft.

Opposed-type engine

These engines are typically mounted in a horizontal position when installed on fixed-wing aircraft, but can be mounted vertically to power helicopters.

V-type engine

These engines had 8 or 12 cylinders and were either liquid-cooled or air cooled.

V-type engine

These engines had a reasonable power-to-weight ratio while retaining a small frontal area.

V-type engine

These engines have cylinder arranged around a single crankshaft in two in-line banks that are 45, 60, or 90 degrees apart.

Opposed-type engine

These engines have high power-to-weight ratios because they have a comparatively small, lightweight crankcase.

In-line engine

These engines have relatively low power-to-weight ratios and when air-cooled, the rearmost cylinders receive relatively little cooling air and so were typically limited to only four or six cylinders.

V-type engine

These engines provide an excellent combination of weight, power, and small frontal area.

In-line engine

These engines were used primarily on tail-wheel aircraft, where the shorter main gear provided for increased forward visibility on the ground.

Transverse webs

These webs form an integral part of the crankshaft structure and, in addition to housing the bearings that support the crankshaft, the webs add strength to the crankcase.

Opposed-type engine

They always have an even number of cylinders, and a cylinder on one side of a crankcase "opposes" a cylinder on the other side.

Cooling fins

They are cast or machined onto the outside of a cylinder head and provide an effective means of transferring heat from the cylinder head to the surrounding air.

Plain bearing

They are generally used for crankshaft main bearings, cam ring and camshaft bearings, connecting rod end bearings, and accessory drive shaft bearings. These bearings are typically subject to radial loads only.

Valve springs

They are helical-coiled springs that are installed in the cylinder head and provide the force that holds the valve face firmly against the valve seat.

Roller bearing

They are similar in construction to ball bearings except that polished steel rollers are used instead of balls. The rollers provide a greater contact area and a corresponding increase in rolling friction over that of a ball bearing.

Cooling fins

They are sometimes cast into the piston interior to help dissipate heat.

Valve springs

They close the valve and are held in place by a valve retainer and a split valve key.

Propeller reduction gear system

This allows an engine to turn at a relatively fast speed and a propeller to turn at a more efficient slower speed.

Supercharger

This engine accessory's compression increases the air density so the engine can operate at high altitudes and still produce the same amount of power as it would at sea level.

Opposed-type engine

This engine combines a good power-to-weight ratio with a relatively small frontal area. It powers most light aircraft in use today.

In-line engine

This engine has a comparatively small frontal area and, therefore, allows for better streamlining. Because of this, they were popular among early racing aircraft.

Planetary gear system

This gear system keeps the propeller shaft aligned with the crankshaft, transmits power with a minimum of weight and space, and keeps the propeller's direction of rotation the same as the engine.

In-line engine

This generally has an even number of cylinders that are aligned in a single row parallel with the crankshaft. This engine can be either liquid-cooled or air cooled and the pistons can be located either upright above the crankshaft or inverted below the crankshaft.

Lenoir's engine

This is the first practical piston engine that employs a battery ignition system and natural gas as fuel which was used to operate industrial machinery such as lathes.

Supercharger section

This radial engine crankcase section houses the supercharger and its related components.

Accessory section

This radial engine section houses gear trains containing both spur- and bevel-type gears that drive various engine components and accessories.

Master-and-articulated rod

This rod assembly is commonly used in radial engines

Fork-and-blade rod

This rod assembly is used primarily in V-type engines and consists of a fork connecting rod and a blade connecting rod.

Spring ring

Three devices that are used to hold a piston pin in place are circlets, spring rings, and metal plugs. A ______ fits into grooves cut into the ends of a piston boss but consists of a single circular spring-steel coil.

Circlet

Three devices that are used to hold a piston pin in place are circlets, spring rings, and metal plugs. A ______ is similar to a snap ring that fits into a groove cut into each end of the piston boss.

Piston-pin plug

Three devices that are used to hold a piston pin in place are circlets, spring rings, and metal plugs. The more current practice is to install a plug of relatively soft aluminum called a ______. These plugs are inserted into the open ends of the piston pins and provide a good bearing surface against the cylinder walls. However, due to the plug's soft aluminum construction and cylinder lubrication, the metal-to-metal contact causes no damage to the cylinder walls.

Transverse webs

To allow a crankcase to support a crankshaft, a series of _______ are cast directly into a crankcase parallel to the case's longitudinal axis.

Ring land

To allow an oil control ring to remove excess oil and return it to the crankcase, small holes are drilled in the piston ring grooves, or______.

Multi-row

To further increase a radial engine's power, while maintaining a reasonable engine frontal area, ______ radial engines were developed.

Piston skirt

To help align a piston in a cylinder, the piston base is extended to form the ________.

Staggered

To help cool a multiple-row radial engine, the rear rows of cylinders are ______ so they are behind the spaces between the front cylinders. This configuration increases the amount of airflow past each cylinder.

Metallic sodium

To help dissipate heat better, some exhaust valve stems are hollowed out and then partially filled with _________.

Circulate naturally due to the up and down motion of the valve and helps carry heat from the valve head into the stem where it is dissipated through the cylinder head.

To help dissipate heat better, some exhaust valve stems are hollowed out and then partially filled with metallic sodium. When installed in an operating engine, the sodium melts when the valve stem reaches approximately 208 degrees Fahrenheit. What will the melted sodium do?

Nitriding

To help minimize wear, most main bearing journals, or crank journals, as they are sometimes called, are hardened through ________ to resist wear.

A band of orange paint may be applied around the cylinder base or to some of the cooling fins.

To help you identify a cylinder that has been chrome plated, ________.

Mandrel

To install a valve seat, the cylinder head is heated and the valve seat is chilled and then pressed into the head with a special tool called a ________.

Valve face

To install a valve seat, the cylinder head is heated and the valve seat is chilled and then pressed into the head with a special tool called a mandrel. When the assembly cools, the cylinder head shrinks and firmly retains the valve seat. Once installed, the valve seat is precisely ground to provide a sealing surface for the _______.

Engine vibration

To prevent _________, most crankshafts are balanced both statically and dynamically.

The end of the shaft is threaded to receive a propeller retaining nut.

To prevent a propeller hub from rotating on a tapered shaft, one or more key slots are milled into the shaft. In addition, _____________.

A metal seal is generally used with the exhaust manifold.

To provide an adequate seal for machining intake and exhaust ports, a synthetic rubber seal is typically used between the cylinder head and intake manifold. However, because of the heat associated with the exhaust gases, ______________.

It should always be replaced in the same cylinder and in the same relative position.

To provide proper fit and balance, connecting rods are often matched with pistons and crankpins. Therefore, if a connecting rod is ever removed, __________.

Connecting rods and caps are sometimes stamped with numbers to identify the cylinder and piston assembly with which they should be paired.

To provide proper fit and balance, connecting rods are often matched with pistons and crankpins. Therefore, if a connecting rod is ever removed, it should always be replaced in the same cylinder and in the same relative position. To help do this, ____________.

Cast aluminum alloy

To provide the strength and rigidity required while maintaining a relatively light weight, most aircraft crankcases are made of ______.

Hollow

To reduce total crankshaft weight, crankpins are usually _______. This construction also provides a passage for lubricating oil.

Bending moments

To remain functional, a crankcase must be capable of absorbing forces and still maintain its integrity. For example, due to the internal combustion forces exerted on the cylinders and the unbalanced centrifugal and inertial forces inflicted by a propeller, a crankcase is constantly subjected to ______ which change continuously in direction and magnitude.

The lock-nut in the rocker arm is loosened and the adjustment screw is turned until the face of the rocker arm just touches the feeler gauge. The locknut is then tightened to hold the adjustment screw in place.

To set the valve clearance, the engine is turned until the piston in the cylinder being adjusted is at the beginning of the power stroke. Once this is done a thickness gauge of the correct dimension is placed between the rocker arm and the valve stem. If you cannot insert the thickness gauge between the two surfaces, or if the thickness gauge moves too freely between the surfaces, the clearance must be adjusted. To do this, ______________.

The outside main journals are placed on two knife edge balancing blocks. If the shaft tends to rotate toward any one position during the test, it is out of static balance.

To test a crankshaft for static balance, ___________.

Two pieces

Today, most crankcases consist of at least _______; however, there are some one-piece and up to five-piece case assemblies.

Piston ring

Transfer heat from the piston to the cylinder walls.

Two-throw

Twin-row radial engines require a _______ crankshaft, one throw for each bank of cylinders.

Accessory drive shafts

Typical areas where bearings are used in an aircraft engine include the main journals, crankpins, connecting rod ends, and ________.

Valve operating mechanism

Typically consists of an internally driven camshaft or cam ring that pushes against a valve lifter. The valve lifter, or tappet, transmits the force from the cam to a push rod, which in turn, actuates a rocker arm to depress and open the valve against the valve spring tension that holds the valve closed.

Valve operating mechanism

Typically has components that include a camshaft or cam ring, a tappet or lifter, a push rod, and a rocker arm.

Opposed-type engine

Typically vibrate less than other engines because its power impulses tend to cancel each other.

2

Typically, each cylinder head has _____ spark plugs for increased performance.

The angular difference produces an interference fit that sometimes results in more positive seating.

Typically, the valve seat is ground to the same angle as the valve face. However, there are some instances where a valve face may be ground to an angle that is one quarter to one degree shallower than the valve seat...

Cylinders are numbered consecutively same as single-row but all odd-numbered cylinders are in the rear row, and all even numbered cylinders are in the front row.

Unlike opposed engines, all radial engines are numbered in the same way. For double-row radial engines, _________.

Cylinders are numbered consecutively starting with the top cylinder and progressing clockwise as viewed from the rear of the engine.

Unlike opposed engines, all radial engines are numbered in the same way. For single-row radial engines, _________.

Stellite

Valve faces are often made more durable by welding _______, an alloy of cobalt and chromium, to the valve face. Once applied, the face is ground to the correct angle. It resists high temperatures and corrosion and withstands the shock and wear associated with valve operation.

The chance of failure due to breakage caused by heat or metal fatigue.

Valve float occurs when the frequency of a valve spring begins to vibrate at its resonant frequency. When this occurs, the spring loses its ability to hold the valve closed. By installing two or more springs of different sizes, it is nearly impossible for both springs to vibrate at the same time, leaving one spring free to close the valve. Furthermore, two or more springs reduce _________.

Valve lift and valve duration

What does the shape of a cam lobe determine?

It is a good practice to mark the propeller hub and flange. This makes reattaching the propeller easier since you can identify how the propeller should be positioned.

What should be done before you remove a propeller from a flanged propeller shaft?

Rotary-type

What type of radial engines were used almost exclusively because they produced the greatest horsepower for their weight during World War I?

Four-cylinder in-line engine

What type of reciprocating engine did the Wright Brothers used for their Wright Flyer I?

1483

What year did Leonardo da Vinci conceived a flying machine he called the aerial screw?

1860

What year did a truly practical piston engine was built by Etienne Lenoir of France?

1876

What year did the major breakthrough in piston engine development came when Dr. August Otto developed the four-stroke, five-event cycle which is the operating cycle used by most modern reciprocating aircraft engines?

Mechanical energy

When heat engines convert heat energy into mechanical energy, the heated air expands, creating a force that is converted into ________ to drive a propeller or other device.

Blow-by

When installing piston rings, the ring gaps must be staggered, or offset, to ensure that they do not align with each other. This helps prevent combustion chamber gases from flowing past the rings into the crankcase. This _______, as it is often called, results in a loss of power and increased oil consumption.

Teledyne Continental engines do not use sodium filled valves, while many Textron Lycoming engines use sodium filled exhaust valves.

When overhauling an aircraft engine, you must determine if the old valves are sodium filled or not. As a general rule, _________.

You are viewing the engine from the rear or accessory end.

When referring to either the right or left side of an engine, always assume that _________.

Determine which type of valve should be installed and follow the manufacturer's recommendations and instructions.

When replacing old valves with new ones you must, in all cases, _________.

Tappet

When the cam roller rides over a lobe on the cam ring, the roller pushes against a ______ that is enclosed in a tappet guide. It actuates a push rod that performs the same function as an opposed engine push rod.

Gasket material and silk thread

When the crankcase halves are bolted together with the proper torque, this type of setup form an effective oil seal without interfering with bearing fit.

Quill shaft

Whenever a reduction gear is used that does not keep the propeller shaft perfectly aligned with the crankshaft, additional vibration is induced into an engine. To help minimize this vibration, some engines use a ______ between the crankshaft and propeller shaft. It is a hardened steel shaft that is splined on both ends and installed between two gears, or shafts, to absorb torsional vibration.

Cylinder numbering starts from the most rearward cylinder.

While both Teledyne Continental and Textron-Lycoming make four- and six-cylinder horizontally opposed engines, each manufacturer uses a different cylinder numbering system. For Continental, ______.

Cylinder numbering begins with the most forward cylinder.

While both Teledyne Continental and Textron-Lycoming make four- and six-cylinder horizontally opposed engines, each manufacturer uses a different cylinder numbering system. For Lycoming, ______.

The odd numbered cylinders are on the right while the even numbered cylinders are on the left.

While both Teledyne Continental and Textron-Lycoming make four- and six-cylinder horizontally opposed engines, each manufacturer uses a different cylinder numbering system. The only similarity between the two systems is that _________.

Air-cooled

While some opposed engines are liquid-cooled, the majority are ______.

Multiple-piece

With a _______ master rod, the crankpin end of the master rod and its bearing are split and installed on the crankpin. The bearing cap is then set in place and bolted to the master rod.

Single-piece

With a ________ master rod, the master-and-articulated rods are assembled and installed on the crankpin before the crankshaft sections are joined together.

0.03, 0.05

With a choke bore cylinder, the greater expansion at the top of the cylinder is compensated for by the taper, resulting in a uniform cylinder diameter at normal operating temperatures. The amount of choke is usually between _______ inches.

1/2

With a gear reduction system that uses two externally driven spur gears, the amount of reduction is determined by the ratio of the gear teeth. For example, if the drive gear has 25 teeth and the driven gear has 50 teeth, a ratio of 1:2 exists and the propeller turns at _____ the crankshaft speed.

Two-piece

With a one-piece, single-throw crankshaft, the entire crankshaft is cast as one solid piece. However, with a clamp type _______ crankshaft, the two pieces are held together by a bolt that passes through the crankpin.

Master-and-articulated rod

With this type of assembly, one piston in each row of cylinders is connected to the crankshaft by a master rod. The remaining pistons are connected to the master rod by articulated rods.

Studs

_______ are installed into threaded holes in the power section to provide a means of retaining the cylinders.

Oil galleries

_______ are machined into the case halves of the crankcase to scavenge, or collect, oil and return it to the main oil tank or sump.

Tapered

_______ compression rings are beveled to reduce their contact area which help reduce friction and hasten ring seating.

Wedge

_______ compression rings have a beveled face that promotes ring seating. The beveled shape also helps prevent the ring from sticking in the groove.

Spur-type

_______ gears are generally used to drive more heavily loaded accessories or those requiring the least play or backlash in the gear train.

Bevel-type

_______ gears permit angular location of short stub shafts leading to the various accessory mounting pads.

Full-floating

_______ piston pins are free to rotate in both the connecting rod and the piston, and are used in most modern aircraft engines.

Stationary

_______ piston pins are held tightly in place by a setscrew that prevents movement.

Semifloating

_______ piston pins are retained stationary in the connecting rod by a set clamp that engages a slot in the pin.

Mushroom

_______ poppet valves have convex heads and are not commonly found on aircraft engines.

Bronze

________ bushings are pressed into the bores in each end of the articulated rod to serve as bearings.

Crankpins

________, or connecting-rod bearing journals, serve as attachment points for the connecting rods.

Tapered

_________ propeller shafts were used on most of the early, low-powered engines. On this propeller shaft, the shaft tapers, or gets smaller in diameter, as you move out toward the end of the shaft.