Key Terms, Ch.1 A&p Mechanic-Powerplant, Jeppesen

Front 1

rotary-type radial engines

Back 1

used during WWI because of high power to weight ratio. Cylinders are mounted radially around crankcase and rotates with propeller.

Front 2

static-type radial engines

Back 2

Developed in the late 20's. Much more reliable than previous designs.Significant difference is the crankcase remains stationary while the crankshaft rotates the engine

Front 3

single-row radial engines

Back 3

typically have an odd number of cylinders arranged around the crankcase(5-9)

Front 4

multiple-row radial engines

Back 4

Contain two or more rows of cylinders connected to a single crankshaft.

Front 5

double-row radial endines

Back 5

...typically has 14 or 18 cylinders Cooling air flow is increased by staggering the pattern.

Front 6

V-type engines

Back 6

Developed during WWII. Achieved the higest hp rating. It has two banks of cylinders angled at 45, 60,or 90 degrees apart. Most have 8 or 12 cylinders.

Front 7

cylinder pad

Back 7

surface on which a cylinder mounts to the crankcase.

Front 8

nose section

Back 8

is mounted at the front of a radialengine crankcase and bolts directly to the power section

Front 9

power section

Back 9

the second section of a radial engine of a radial engine crankcase. It absorbs the stresses from the crankshaft and cylinders.

Front 10

supercharger section

Back 10

located directly behind the power section, it is a section that houses a device that compresses air for the engine's cylindrers, enabling the engine to produce more power.

Front 11

accessory section

Back 11

Usually cast in one or two pieces in aluminum alloy or magnesium. Houses accessories such as magnetos, carburetors, pumps, starters, and generators

Front 12

main bearing journals

Back 12

The centerline of the crankshaft runs through these journals which support the crankshaft as it rotates. absorbs and transmits stresses from the shaft to the case.

Front 13

crankpins

Back 13

also known as throws, crank throws and connecting rod journals...offset from the main bearing journals, they provide an attachment point for connecting rods.

Front 14

throws

Back 14

also known as crankpins, crank throws and connecting rod journals...offset from the main bearing journals, they provide an attachment point for connecting rods.

Front 15

crank throws

Back 15

also known as crank pins throws, and connecting rod journals...offset from the main bearing journals, they provide an attachment point for connecting rods.

Front 16

connecting rod bearing journals

Back 16

also known as crankpins, throws, crank throws...offset from the main bearing journals, they provide an attachment point for connecting rods.

Front 17

sludge

Back 17

dirt carbom deposits and other foreign material.

Front 18

counterweights

Back 18

used to balance the crankshaft

Front 19

static balance

Back 19

when the weight of the assembly is balanced around its axis of rotation on balancing block test stands

Front 20

dynamic balance

Back 20

when centrfugal forces and power pulses are balanced with counter weights

Front 21

dynamic damper

Back 21

counter weight that is fastened to the crankshaft on the crank cheek...dynamic dampers oscillate with pulse from the firing cylinder to absorb some of the force.

Front 22

single throw crankshaft

Back 22

aka the 360 crankshaft, it is the simplest type of crankshaft...consists of a single crankpin and two crank cheeks

Front 23

two-throw crankshaft

Back 23

twin-row radial engines require this crankshaft... set 180 degrees apart. two cylinder opposed engines uncommonly use two throw crankshaft

Front 24

four-throw crankshaft

Back 24

Used on four cylinder opposed engines...two throws set 180 degrees apart...has either three or five main bearings

Front 25

six-throw crankshaft

Back 25

Used on six cylinder opposed and in-lines and 12 cylinder V-type engines...has four bearings six throws 60 degrees apart.

Front 26

busnings

Back 26

smaller bearings used to support various accessory drive shafts.

Front 27

bearing retainer

Back 27

keeps the ball or rollers to the ball bearings in place

Front 28

bearing races

Back 28

provides smooth surface for balls or rollers to roll over.

Front 29

straight roller bearings

Back 29

Are suitable when the bearings are subjected to radial loads only.

Front 30

tapered roller bearings

Back 30

cone-shaped inner and outer races that enable the bearing to withstand radial and thrust loads

Front 31

crankpin end

Back 31

the crankshaft end of the connecting rod

Front 32

piston end

Back 32

the piston end of the connecting rod

Front 33

master rod

Back 33

the main rod in a master and articulated piston-rod assembly

Front 34

articulated rods

Back 34

rods in a master-articulated rod assembly that are driven by the master rod asembly.

Front 35

piston pin bearing

Back 35

a bearing pressed into the piston end of the connecting roe which reduces friction at the connection between the piston head and the connecting rod

Front 36

crankpin bearing

Back 36

a bearing pressed into the crankshaft end of the connecting rod which reduces friction between the crankpin and

Front 37

master rod bearing

Back 37

same as "crankpin bearing"

Front 38

one-piece rod

Back 38

used on multi-piece crankshafts

Front 39

multiple-piece master rod

Back 39

used on single piece crankshafts

Front 40

split-type master rod

Back 40

same as "multiple-piece master rod"

Front 41

knuckle pin

Back 41

hinged between the master rod and the articulating rod
(pressed in)

Front 42

full-floating knuckle pins

Back 42

hinged between the master rod and the articulating rod (loosely held in place often by lock plates.

Front 43

fork connecting rod

Back 43

used on v-type engines,the part of the fork and blade rod assmebly that splits/forks at the crankshaft.

Front 44

blade connecting rod

Back 44

used in V-type engines... the blade(flat) component of the fork and black rod assembly that fits between the prongs of the fork component.

Front 45

ring grooves

Back 45

grooves machined into side of the piston

Front 46

ring land

Back 46

portion between the ring grooves.

Front 47

piston head

Back 47

top surface of the piston

Front 48

piston pin boss

Back 48

hole in the piston for the piston pin that allows one to connect the piston to the connecting rod

Front 49

piston skirt

Back 49

an extension at the base of the piston use to help align the piston with the cylinder

Front 50

cam-ground piston

Back 50

an very slight oval shapeness of the piston that compensates for the differential expansion of the cylinder as it gets hotter.

Front 51

blow-by

Back 51

when combustion gases leak past the piston rings into the crankcase resulting in loss of power and increased oil consumption.

Front 52

seated

Back 52

a ring the matches its cylinder

Front 53

compression rings

Back 53

located in the ring grooves just below the piston head

Front 54

oil rings

Back 54

control the amount of oil applied to the cylinder walls and prevent oil from entering the combustion chamber.

Front 55

oil control rings

Back 55

placed in piston ring grooves placed below the compression rings with the primary purpose of regulating the thickness of the oil film on a cylinder wall.

Front 56

ventilated oil control rings

Back 56

through small slots machined around the ring, excess oil can return to the engine sump .

Front 57

oil scraper/ wiper ring

Back 57

regulates the amount of oil that passes between the poston skirt and the cylinder wall...(is beveled and located at the bottom of the cylinder).

Front 58

piston/ wrist pin

Back 58

joins the piston to the connecting rod

Front 59

stationary piston pins

Back 59

secured to the piston by a setscrew that prevents rotation.

Front 60

semifloatin poston

Back 60

pins are loosely attached to the connecting rod by clamping arounf a reduced-diameter section of the pin

Front 61

full-floating pins

Back 61

rotate freely in both the connecting rod and the piston; these pins are used in most modern aircraft engines

Front 62

circlet

Back 62

snap-ring (used on earlier piston engines) that fits into the piston boss to hold piston pin in place

Front 63

spring ring

Back 63

spring ring (used on earlier piston engines) that fits into the piston boss to hold piston pin in place.

Front 64

piston-plug

Back 64

the current practice of holding piston pin in place by inserting plugs on each end of the piston

Front 65

(cylinder) skirt

Back 65

the end of the cylinder barrel that projects into the crankcase

Front 66

mounting flange

Back 66

used to attach the cylinder to the crankcase.

Front 67

cooling fins

Back 67

thin projection on the exterior of cylinder walls that create deep grooves used to cool the cylinder.

Front 68

cylinder bore

Back 68

the inside of a cylinder

Front 69

choke bore cylinder

Back 69

a slightly tapered cylinder with the diameter at the top of the cylinder smaller than the skirt.

Front 70

nitriding

Back 70

hardening method that changes the surface strength of steel by infusing the metal with a hardening agent. disadvantage -is it is suseptical to corrosion identified by blue stripe.

Front 71

chrome/ electro-plating

Back 71

hardening method of applying a thin coating of chromium to the inside of the barrel. advantage- less susceptible to corrosion and wears longer, disadvantage-cylinder does not hold oil well.

Front 72

chrome channeling

Back 72

process to compensate for the disadvantage of chrome-plating. A reverse current applied to the cylinder creates microscopic cracks that can hold oil in the cylinder wall

Front 73

CermiCrome, Nu-Crome

Back 73

discontinued plating process that mechanically impregnates silicone particles into the cylinder wall.

Front 74

CermiNil™, Nickel+Carbide™, or Nikasil®

Back 74

plating process that uses nickle (rather than chromium) infused with silicon carbide particles to increase hardness and retain lube oil

Front 75

Heli-Coil® inserts

Back 75

made of stainless steal, they are heat shrunk and screwed into cylinder head to facilitate the installation and removal of spark plugs

Front 76

intake valve

Back 76

controls the amount of fuel/ air mixture that enters through the intake port

Front 77

exhaust valve

Back 77

lets the exhaust gases exit the cylinder through the exhaust port.

Front 78

poppet valve

Back 78

the most common type of valve used in aircraft engines

Front 79

flat-headed head, semi-tulip head, tulip head, mushroom head

Back 79

has a flat, semi-concaved, concaved, and convexed head.

Front 80

Stelite®

Back 80

an alloy of cobalt and chromium that is welded to the valve face for durability

Front 81

valve stem and tip

Back 81

keeps the valve head properly aligned as it opens and closes; the tip is hardened to withstand hammering

Front 82

rotator cap

Back 82

is placed over the valve tip to increase service life.

Front 83

split key

Back 83

keeps the valve-spring retaining washers in place and holds the valve in the cylinder head