intro_to_aviation_block_2_20180401181925 Flashcards
(141 cards)
What are the two ways piston engines are cooled
air cooled and liquid cooled
how do liquid cooled engines get cooled
circulate a liquid through the jackets of the pistons, then being sent back through a radiator to be cooled again
how do air cooled engines get cooled
allow airflow pushed by propellers and movement throug the air into the engine flowing by the cylinders, the air absorbs the heat and carries it away
what are the two common cylinder arragments in todays engines
radial and horizontally opposed
what is the shape of a radial engine
a circle with 5 7 or 9 pistons
what are the advantages of a radial engine
compact, accessible for maintnece and are light weight
what are the disadvantages of a radial engine
that they are poorly shaped, which leads to poor visibility and considerable drag
What are the advantages or a horizontally opposed engine
they have better visibility, have reduced drag
what are the disadvantages of a horizontally opposed engine
they have cooling problems if more then 6 cylinders, and there is increased drag from air scoops
what is the shape of a horizontally opposed engine
they have an even amount of cylinders that are set opposite from one another
what are the two types of Turbo engines
Turbo jet and turbo fan
Explain the workings of a turbo jet engine
-take air from outside- compass the air- force it into the combustion chamber- mix with fuel- ignite the fuel
What determines the amount of power the turbo jet engine produces
the weight of the air it consumes
Turbo jet RO
Air at lower altitudes is denser, so more fuel is required to produce the right Fuel to Air ratio. Engine power decreases with altitude because of this. However high altitude loss in engine power is offset by reduced aircraft friction to the surrounding air (DRAG). low altitude operations are no economical.
What are the advantages or a turbo jet engine
- few moving parts- good power to weight ratio - reduced drag
What are the disadvantages
they can become expensive with how excessive the amount of fuel is consumed at low altitudes.
Explain the workings of a Turbo Fan engine
Turbo fans are the new and improved version of the turbojet, this engine has a fan attached ahead of the compressor that accelerates air backwards and bypasses the core of the engine or behind the turbines . The outside diameter of the fan is greater then that of the engine proper so that the air, passing through the blades at their outer part, is accelerated backwards on the outside of the engine. This extra power/thrust is available for increase take off climb and cruise performance, reduced fuel consumption and hence better payload range
What is this engine desired for
High speed and high altitude usage, efficiency improves as the altitude increases. Prime efficiency is between 33 000 or 37 000 feet
What are some turbo fan advantages over the turbo jet
Greater fuel efficiency, quieter operation, better low altitude performance, and lower landing speeds
What are the disadvantages
Compared to a piston engine, they also have a high fuel consumption are low alritudes
Explain the workings of a turbo prop engine
contains properties of both a jet and prop plane, the gas turbine engine can be used to drive a propeller instead of producing pure jet power
how much of the power generated is used to power the turbine and how much is used for thrust
90-95% of the power goes to the turbine
Turbo Prop RO
- Engine efficiency improves with altitude (like Jet engines) the propeller efficacy drops off at higher altitudes do to the thin air. The propeller is more efficient in low speeds and altitudes where the air is denser. Generally they operate most efficiently in the range of 13 000 to 25 000
What is the advantages of a turbo prop
There is a greater horsepower for less weight when compared to a piston engine