AMS 271, Recip. Engines - Unit 2, AMS 271 Unit
2 Exam Study Guide
What is 1HP in ft-lbs per minute? - ANSWER 33,000 ft-lbs per minute
Indicated Horsepower (IHP) - ANSWER Refers to the amount of power formed in the
engine combustion chambers without friction loss
Work - ANSWER Force moving an object
Work Formula - ANSWER Work(W) = Force(F) x Distance(D)
Power Formula - ANSWER Power(P) = Work(W) / Time(T)
Work vs. Power - ANSWER Power is the time work takes
IHP Formula - ANSWER IHP = PLANK / 33,000
P - pressure (PSI)
L - Length of stroke (FT)
A - Area (A=π r²)
N - Number of rotations
, K - Number of cylinders
Friction Horsepower - ANSWER Power required to overcome friction and energy loss
Brake Horsepower (BHP) - ANSWER Power actually delivered to the propeller
BHP Formula - ANSWER BHP = 2π x Torque x RPM / 33,000
Thermal Efficiency (TE) - ANSWER The efficiency of a heat engine measured by the ratio
of the work done by it to the heat supplied to it
TE Formula - ANSWER TE = (HP x 33,000) / (Fuel x 20,000 x 778)
Volumetric Efficiency (VE) - ANSWER the efficiency with which the engine can move the
charge of fuel and air into and out of the cylinders
VE Formula - ANSWER VE = (Volume of Mix...) / Total Displacement
True or False: The VE of naturally aspirated engines is typically less than 100%. - ANSWER
True
True or False: The VE of turbocharged engines is typically more than 100%. - ANSWER
True
2 Exam Study Guide
What is 1HP in ft-lbs per minute? - ANSWER 33,000 ft-lbs per minute
Indicated Horsepower (IHP) - ANSWER Refers to the amount of power formed in the
engine combustion chambers without friction loss
Work - ANSWER Force moving an object
Work Formula - ANSWER Work(W) = Force(F) x Distance(D)
Power Formula - ANSWER Power(P) = Work(W) / Time(T)
Work vs. Power - ANSWER Power is the time work takes
IHP Formula - ANSWER IHP = PLANK / 33,000
P - pressure (PSI)
L - Length of stroke (FT)
A - Area (A=π r²)
N - Number of rotations
, K - Number of cylinders
Friction Horsepower - ANSWER Power required to overcome friction and energy loss
Brake Horsepower (BHP) - ANSWER Power actually delivered to the propeller
BHP Formula - ANSWER BHP = 2π x Torque x RPM / 33,000
Thermal Efficiency (TE) - ANSWER The efficiency of a heat engine measured by the ratio
of the work done by it to the heat supplied to it
TE Formula - ANSWER TE = (HP x 33,000) / (Fuel x 20,000 x 778)
Volumetric Efficiency (VE) - ANSWER the efficiency with which the engine can move the
charge of fuel and air into and out of the cylinders
VE Formula - ANSWER VE = (Volume of Mix...) / Total Displacement
True or False: The VE of naturally aspirated engines is typically less than 100%. - ANSWER
True
True or False: The VE of turbocharged engines is typically more than 100%. - ANSWER
True
