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POWERPLANT ASA/BAKER 'S SCHOOL
LIST OF FAA ORAL QUESTIONS | 443
QUESTIONS WITH 100% CORRECT
ANSWERS | UPDATED & VERIFIED | 69 PAGES
Question :What is the main advantage of a horizontally
opposed engine over a radial engine for powering modern aircraft
Correct answer:The horizontally opposed engine has a much
smaller frontal area & is easier to streamline than a radial engine.
Question :How many throws are there in the crankshaft of a
six-cylinder horizontally opposed engine
Correct answer:Six.
Question :What kind of connecting rod arrangement is used in
a radial engine
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Correct answer:A master rod connects the single throw of the
crankshaft with the piston. All of the other pistons are connected to the master rod with link rods.
Question :Of what material are most piston rings made
Correct answer:Gray cast iron.
Question :What is the reason for using hydraulic valve lifters
in an aircraft engine
Correct answer:Hydraulic valve lifters keep all of the
clearance out of the valve operating mechanism. This decreases the wear of the valve train components.
Question :At what speed does the camshaft turn, relative to
the crankshaft speed in a horizontally opposed engine
Correct answer:The camshaft turns at one half of the
crankshaft speed.
Question :What kind of main bearings are used in a
horizontally opposed engine
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Correct answer:Steel-backed, lead-alloy bearing inserts.
Question :On what stroke is the piston of a reciprocating
engine when the intake valve begins to open
Correct answer:On the exhaust stroke.
Question :On what stroke is the piston of a reciprocating
engine when the exhaust valve begins to open
Correct answer:On the power stroke.
Question :Why are both the hot & cold valve clearances given
for most radial engines
Correct answer:The hot clearance is given for valve timing
purposes. The timing is adjusted with the valves in cylinder number one, set with the hot clearance. When the timing is set, all of the valves are adjusted to their cold clearance.
Question :What is meant by a cam-ground piston
Correct answer:A piston that is not perfectly round. Its
dimension parallel with the wrist pin is several thousandths of
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an inch less than its dimension perpendicular to the wrist pin.When the piston reaches operating temperature, the metal in the piston pin boss expands enough that the piston becomes perfectly round.
Question :Where is the piston in a reciprocating engine when
the ignition spark occurs
Correct answer:About 30 degrees of crankshaft rotation
before the piston reaches top center of the compression stroke.
Question :What is meant by a full-floating wrist pin
Correct answer:A wrist pin that is not clamped in either the
piston or the connecting rod. Full-floating wrist pins are kept from scoring the cylinder walls by soft metal plugs in their ends.
Question :Why do most aircraft reciprocating engines use
more than one spring on each valve
Correct answer:By using more than one spring & having the
wire diameter & pitch of the spring different, valve float is minimized. The springs have different resonant frequencies,