Reciprocating Engines

Question 1

In what position should the crankshaft be when a magneto is being timed to the engine?

Answer 1

The piston in cylinder #1 should be in the correct position for ignition to occur. this is normally 30 degrees before top dead center on compression stroke.

Question 2

What is the purpose of a cold cylinder check?

Answer 2

A cold cylinder check determines which cylinder is not firing. Run engine for a few minutes at speed, and on magneto, at which it runs roughest. shut it down and feel exhaust stacks. cold stack is not firing.

Question 3

What is checked on engine startup to determine the operational condition of the engine?

Answer 3

Idling rpm and manifold pressure, engine acceleration, max static rpm and manifold pressure, magneto drop, ignition switch safety check, prop pitch change, prop feathering, oil pressure, fuel pressure, fuel flow

Question 4

how can you determine the firing order of an 18 cylinder engine?

Answer 4

begin with cylinder 1, add 11 and subtract 7, whichever will keep the numbers between 1 and 18. 1-12-5-16-9-2-13-6-17-10-3-14-7-18-11-4-15-8

Question 5

what are two main causes of a cylinder having low compression?

Answer 5

piston rings not seating or broken, and valves not seating or burned.

Question 6

what is a hydraulic lock in an aircraft engine?

Answer 6

oil has drained past the piston rings and filled the combustion chamber of cylinders that are below the center line of engine. if the crankshaft is turned over with this oil in the cylinder it will lock, and probably the piston, cylinder, connecting rod will be damaged.

Question 7

how is hydraulic lock removed from an aircraft engine?

Answer 7

remove a spark plug from locked cylinder and drain oil out. clean plug and reinstall.

Question 8

What is a low tension ignition system?

Answer 8

Ignition system using a magneto with brush type distributor and a coil with no secondary winding. low voltage is directed from the magneto to a transformer mounted on the cylinder head. the low voltage is boosted to a high voltage and is directed through a short high tension lead to the plug. one transformer per plug.

Question 9

what is a floating cam ring on a large radial engine?

Answer 9

it is a cam ring that rides on a shelf type bearing with a large amount of clearance between the bearing and the ring. when adjusting the valves on an engine with a floating cam ring the pressure of the valve springs on the opposite side of the engine must be removed so the cam ring will be tight against the bearing for the valves being adjusted.

Question 10

why is valve clearance adjusted on radial engines, but not on horizontally opposed engines?

Answer 10

most horizontally opposed engines have hydraulic valve lifters that keep all of the clearance out of the valve train. radial engines have solid lifters.

Question 11

why are both hot and cold valve clearances given for most radial engines?

Answer 11

the hot clearance is given for valve timing purposes. timing is adjusted with the valves in cylinder number one, set with the hot clearance. when timing is set, all of the valves are adjusted to cold clearance.

Question 12

what must be inspected to determine the airworthiness of an engine installation?

Answer 12

the prop, lubrication system, ignition system, fuel metering system, cooling system, and exhaust system.

Question 13

what checks should be made to determine proper operation of reciprocating engine installation?

Answer 13

idle rpm and mixture, static rpm, prop pitch change operation, magneto check, ignition switch safety check, and carburetor heat check.

Question 14

where can you find correct grade of fuel and amount of engine oil for engine?

Answer 14

type certificate data sheet

Question 15

what are the basic steps in troubleshooting an engine install?

Answer 15

know how the system operates. observe how it is operating. divide system to find problem. look for obvious problems first.

Question 16

where do you find the procedures to follow when correcting a defective condition in an engine?

Answer 16

engine maintenance manual.

Question 17

where do you find instructions for removing an engine from an aircraft?

Answer 17

aircraft maintenance manual.

Question 18

what must normally be done to a nose wheel airplane before removing engine?

Answer 18

support the tail.

Question 19

what should be done to the cylinders to protect them from rust and corrosion when preparing the engine for long time storage?

Answer 19

spray preservative oil inside the cylinders and replace spark plugs with desiccant plugs.

Question 20

what should be used to cover the ends of fuel and oil lines that have been disconnected?

Answer 20

correct plugs or caps. never tape.

Question 21

what is meant by QEC engine assembly?

Answer 21

an engine that has been prepared for a quick engine change. the engine is on its mount and all accessories have been installed. minimum time is required to change engines. all that is needed is for controls, wiring, fluid lines to be connected to firewall.

Question 22

what is meant by rigging the engine controls so they have cushion?

Answer 22

the control on the engine component must contact its stop before the control handle in the cockpit reaches its stop. this causes the control handle to spring back a slight amount when it is moved to the extent of its travel.

Question 23

what are the 2 ways of pre oiling?

Answer 23

before the park plugs are installed and after the oil tank is filled, turn the engine over with the starter until oil runs out of the fitting to which the oil pressure gauge connects… using pre oiler tank, air pressure forces oil through all of passages until some flows from oil pressure gauge fitting.