mer fly Flashcards
Which four forces acts on an airplane to make it airborne?
Lift, thrust, weight and drag
Can you explain lift?
While in flight the airplane is supported by lift. Lift is the force acting opposite of gravity and is generated whenever air flows smoothly over and under the wings. As relativeair flows over and under the wing, the air that flows over the wing, as speed increases will loose pressure, but the relative air on the bottom side of the wing, will experience more pressure, witch will force the wings up and create an upward force. Low pressure on top of the airfoil and high pressure on the bottom of the airfoil is creating lift.
Witch force is caused by gravity and acts to pull the airplane towards the ground?
Weight
What is the force that opposes lift?
drag
What is the two things that is important to create lift?
relative wind and shape of the airfoil
Explane Bernoullis principle
As velocity of a moving fluid increases, the pressure within that fluid decreases.
(more pressure)——-less pressure-faster movement
What is the angle of attack?
Its the angle at which the wing Is slanted toward the airflow. Generally increasing at the angle of attack increases the lift. This is why an airplanes nose is pointing upwards in a climb.
what can happen at high angles of attack?
When the air on top of the airfoil has to travel a further way it can become turbulent. The air no longer flows along the top of the wing, but starts to leave its path and circulate upwards, witch makes the air on top even lighter(even less pressure) since the air no longer is close on the airfoil. The air on the bottom of the wing will hit the airfoil harder and cause more pressure, since it’s so difficult to get around to the other side. This can cause the plane to stall. Looses a lot of lift all at once.
Can you mention 5 types of wind in aviation?
propellar wash, relative wind, headwind, tailwind and wind caused by the thrust of the plane
witch wind directly opposes the direction the airplane is traveling?
relative wind
What is the wing of an airplane called?
an airfoil
For every action there is an equal an opposite reaction.
Newtonts 3. law
What is stalling?
When an airplane has a rapid loss of lift. When we increase the angle of attack too much, air doesn’t want to flow around the surface og the wing anymore. The air on top of the wing starts to get separated from the upper part of the wing. This means we don’t have good laminar airflow anymore. If you continue to increase the angle of attack even more, the wing will no longer be able to support the weight of the aircraft. When this happens, we get a rapid loss of lift. This rapid loss of lift, is what we call a stall.
laminar airflow?
as air flows above and below the wing, it does so in very thin layers. (Definition of laminar airflow is in fact thin horizontal layers)
When the air on top of the wing starts to get separated from the upper part of the wing. What is a word for this?
Boundry layer separation
What is the critical angle of attack?
Right before an airplane stall, it reaches a point where the corde line on the airfoil is at its greatest angle with the relative wind. If this angle increases at all at this point, the aircraft will stall. This angle of attack, is what we call critical angle of attack.
When you exceed the wings critical angle of attack the airplane will….
stall
How to fix an airplane in stall?
first, reduce the angle of attack.(pitch down or revise some of that backtick on the yoke.)
What is an aggravated stall?
Spin
What is spin?
When an airplane stalls, it’s possible for one wing to stall more than the other. This is called an aggravated stall. Yaw is introduced and causes a downward corkscrew path
When the vertical aksis of the aircraft is not aligned with the direction of travel, what is that called?
side slip
What is PARE?
Spin recovery procedure
What does the P in spin recovery procedure stand for?
Power- idle
What does the A in spin recovery procedure stand for?
Alerons and elevator- neutral
What does the R in spin recovery procedure stand for?
Ruddler- opposite(until the spinning stops)
What does the E in spin recovery procedure stand for?
Elevator up(to recover level flight)
In a spin, are both wings stalled?
YES
Which three axis is the pilot able to use to control the airplane in flight?
Lateral axis(pitch axis), longitudinal axis(roll axis) and vertical axis(yaw axis)
What is the point on the airplane where you can hang the airplane from a string and it would balance perfectly?
The centre of gravity. Its normally where the centre of movement of all three axis.
What Is stability
The ability an aircraft has to correct for disturbances in its equilibrium and return to its original flight plan. for eks. if you are pushed up by turbulence, a stable airplane will be able to pitch back down to its original flight path.
Why are fighter jets less stable aircraft?
because they are designed to be more maneuverable
What is the two types of stability that affects our three axis?
Static and dynamic stability
What is negative static stability?
When the airplane would continue to pitch beyond set degree
What is neutral static stability?
When the airplane continues in the same altitude as you pitched for
What is positive static stability?
If you pitch your airplane up a few degrees, and the airplane just descends back down