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Brainteasers
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January 26, 2006

Brainteasers
Interactive Quiz #103:
More Power To Ya

If power corrupts, and absolute power corrupts absolutely, then many pilots strive for the ultimate in degradation by strapping on bigger engines to reach beyond our grasp of powerplant knowledge. Let's see how power-hungry you absolutely are.

INSTRUCTIONS: Answer the questions as best you can, then click on the "Score my quiz answers" button to see your score and read the explanations. If you don't like your score the first time around, you can change some of your answers and resubmit. To get the most out of this quiz, we suggest you keep trying until you get a perfect score.

NOTE: When more than one answer is true, only the most complete, correct answer will be scored as correct. The answers are assumed to apply within the United States unless otherwise noted.

1. After mustering out of the Air Force, your cousin -- who's flown nothing but macho jets for the past 10 years -- now wants to transition to your Cessna 152 and is having a little trouble adjusting to civilian flight life. You demonstrate how to clean the windshield and fuel the tanks with 100LL, and then review the very basics of the reciprocating piston engine, beginning with the four strokes of the operating cycle. Those four strokes are:
a. Ingest, Compression, Ignition and Exhaust.
b. Mixture, Compression, Power and Idle.
c. Intake, Compression, Power and Exhaust.
d. Ingest, Compassion, Powder and Exhume.
2. Lusting for more power, you buy a Beech Sport. (We didn't promise more style, just power). You now have 160 horses swinging a fixed-pitch, metal propeller. This Sport is not fuel-injected and doesn't have turbo or supercharging. Hey, it's a Sport, about as exciting as your Mom's Chevy Nova. The OAT (Outside Air Temperature) is 5 °C. The relative humidity is 90 percent. Carburetor ice is a possibility, so what is a good first indication of carb. icing? (There's no carburetor temperature gauge.)
a. Decrease in manifold pressure
b. Decrease in RPMs
c. Increase in Gross Weight
d. Engine roughness
3. Not satisfied with the Sport (who is?) you trade up to a Beech Sierra, which looks like a Sport except the wheels go up and down, the propeller is adjustable, and the engine is fuel-injected, producing 200 brake horsepower (BHP), resulting in amazingly uninspiring performance. By switching from a carburetor to fuel injection, you've eliminated any possibility of carburetor icing.
a. True
b. False
4. While it's fun to toss around terms such as "BHP," it's even more impressive to define them, so impress your friends by picking the best definition of brake horsepower:
a. Brake horsepower is the horsepower actually delivered to the output shaft. Brake horsepower is the actual usable horsepower.
b. Brake horsepower is the thrust produced by a turbojet or turbofan engine.
c. Brake horsepower is the horsepower equivalent of the thrust produced by a turbojet or turbofan engine.
d. Brake horsepower is the sum of the shaft horsepower (SHP) delivered to the propeller and the thrust horsepower (THP) produced by the exhaust gases.
e. Brake horsepower is the cost of added horsepower, which will put the brakes on any outside social activities.
5. "Supercharger" and "turbocharger" are more powerplant terms bandied about with reckless disregard for their respective definitions. Before you bandy with abandon, please select the best definition for a supercharger:
a. An exhaust-driven air pump or compressor that increases manifold pressure and forces the fuel/air mixture into the cylinders.
b. An engine-driven air pump or compressor that increases exhaust manifold pressure and forces the fuel/air mixture into the cylinders.
c. An electrically-driven air pump or compressor that increases manifold pressure and forces the fuel/air mixture into the cylinders.
d. An engine-driven air pump or compressor that increases manifold pressure and forces the fuel/air mixture into the cylinders.
6. Waste gate sounds like a political scandal involving New Jersey trash collectors, but for our purposes, the waste gate is (choose best answer):
a. A controllable valve in the intake system of a reciprocating engine equipped with a turbocharger. The valve is controlled to vary the amount of ram air forced through the turbocharger turbine.
b. A port in the exhaust system of a fuel-injected engine equipped with a turbosupercharger. The port's aperture limits the amount of exhaust gases forced through the turbocharger splines.
c. A controllable valve in the exhaust system of a reciprocating engine equipped with a turbocharger. The valve is controlled to vary the amount of exhaust gases forced through the turbocharger turbine.
d. A controllable valve in the exhaust system of a turbine engine equipped with a turbinecharger. The valve is controlled to vary the amount of total inlet gases (TIG) forced through the turbocharger turbine inlet.
7. When you're under pressure -- shooting an ILS to minimums, picking up ice, talking to FSDO -- your body produces excess heat. OK, you're way too cool for that, but compressed air does get warm. So, to reduce this temperature many turbocharged engines use an (_____) to cool the hot compressed air. Please fill in the blank with the best choice.
a. Intercooler
b. Impulse coupler
c. Oil cooler/separator
d. Intercharger
8. Here's a term that's not only misunderstood but also often misapplied. Detonation (according to FAA H-8083-25, the Airplane Flying Handbook) means:
a. A controlled, explosive ignition of the fuel/air mixture within the cylinder's combustion chamber.
b. An uncontrolled, explosive ignition of the fuel/air mixture within the cylinder's combustion chamber.
c. The uncontrolled combustion of the fuel/air mixture in advance of the normal ignition.
d. An uncontrolled, explosive ignition of the fuel/air mixture within the turbocharger or supercharger's inlet meter.
9. Just one more bandiable term, and then we promise we'll quit. Your cousin's jet buddies like to discuss this phenomenon: "An imbalance between the two vector quantities, inlet velocity and compressor rotational speed ... the compressor blades' angle of attack exceeds the critical angle of attack. At this point, smooth airflow is interrupted and turbulence is created with pressure fluctuations. (_____) cause air flowing in the compressor to slow down and stagnate, sometimes reversing direction." Fill in the blank.
a. Hydroplanes
b. Afterburners
c. Compressor stalls
d. Post-ignition compressions
10. An oft-overlooked AD (Airworthiness Directive) is AD 76-07-12, 8-30-77, which applies to certain Bendix ignition switches found on a wide range of type-certificated GA airplanes. It's a simple AD that requires someone (pilot or mechanic) to turn the switch from BOTH to OFF while the engine is running (usually prior to shutdown). With the mixture rich and the fuel selector ON, the engine should quit running when the switch is placed in the OFF position. This happens because in the OFF position, electricity is interrupted between the battery and spark plugs.
a. True
b. False