Lecture 9 Flashcards
List characteristics of a high wing aircraft*
Better lift/drag ratio
Better lateral (roll) stability
Shorter landing distance
List characteristics of a low wing aircraft*
Easier to build strong landing gear support
Better roll maneuverability (less lateral stability)
Shorter take off distance
What type of aircraft are more susceptible to ground effect?*
Why?
Low wing aircraft
Wingtip vortexes impact the ground and cause less induced drag
List pro(s) and con(s) of a tee-tail horizontal stabilizer*
Pros:
Allows airflow over the rudder at a high AOA
Keeps horizontal stabilizer and rudder out of the main wing downwash
Keeps horizontal stabilizer out of the way of the engines
Con:
Vertical stabilizer must be larger and heavier
What types of drag are reduced by using a v-tail horizontal stabilizer? How?
Interference drag: eliminating the number of acute angles
Pressure drag and skin friction drag: eliminating one of the horizontal flight controls
List pro(s) and con(s) of a v-tail horizontal stabilizer*
Pros:
Lighter
Less wetted surface area
Reduced drag
Increased stealth (reduces radar reflection and infrared signature)
Improves safety and reduces cabin noise
Con:
Vertical stabilizer must be larger and heavier
Require a complex control system
Structurally more robust due to increased load
The amount of control surfaces required for operating the ruddervators are higher
The horizontal surface on a v-tail aircraft is called a _____.
ruddervator
On a v-tail aircraft, how do you yaw the nose left?*
Move the pedals left which deflects the left-hand ruddervator down and left and the right-hand ruddervator up and left
On a v-tail aircraft, how do you pitch the nose up?
Move the control stick back which deflects the left-hand ruddervator up and right and the right-hand ruddervator up and left
What is the purpose of having an H or split vertical stabilizer?
How would this help fighter aircraft?*
Fuselage tends to block the airflow to a normal single vertical stabilizer and rudder
To help stabilize in the event of damage and reduce the height needed for full control
What aircraft had a triple vertical stabilizer?
Lockheed Constellation
What do flying wires do?*
Where are they located?*
Transmit the lift back to the fuselage
Wire stretching from top wing to the bottom of the fuselage
What do landing wires do?*
Where are they located?*
Transmit the downward impact of landing on the wings back to the fuselage
Wire stretching from bottom wing to top wing
What do interplane struts do?*
Where are they located?*
Transmit the lift loads and landing loads between the top and bottom wings
Makes a biplane sturdier than a monoplane
Bars between the top and bottom wing located towards the wing tips
What do cabane struts do?*
Where are they located?*
Support the top section of wing above the fuselage and transmit the lift loads of the wing roots to the fuselage
Bars from the top wing to the fuselage
What is the center section?*
Where is it located?*
An airfoil shaped section above the fuselage to which the upper wings attach
Usually one of the only parts of the plane made of aluminum
Located where the two pieces of the top wing come together
What are biplane wings usually made out of?
Wood ribs and fabrics skin to make it as light as possible
What causes interplane interference?*
The gap between airfoils on a biplane are closer than a chord length apart
The high pressure from the bottom of the top wing to mix with the low pressure from the top of the bottom wing
What is the “gap” when talking about biplanes?
The distance between the chord of the top wing and the chord of the bottom wing
What is decalage?*
What does it affect?*
What is it at normally?*
When one of the wings is set to a higher angle of incidence than the other wing
On a fixed-wing aircraft: the angle of difference between the upper and lower wings of a biplane
Interplane interference
Typically zero with both wings having equal incidence
What is the NASA AD-1?
An oblique wing aircraft
Wings could be pivoted obliquely from zero to 60 degrees during flight
Who designed the NASA AD-1?
Who proposed the first oblique wing design?
Designed by Burt Rutan
Richard Vogt proposed the Blohm & Voss P.202 in 1942
How does a tandem wing aircraft create lift?
How does this design achieve pitch stability?
Two wings, both wings lift up and there is no horizontal stabilizer pulling down
The front and rear wings at different angles
List pro(s) and con(s) of a tandem wing aircraft*
Pro:
No horizontal stabilizer pulling down
Cons:
Pitch stability is very difficult to control
Very limited center of gravity range
What is a canard wing aircraft?
How does this design create lift?
Special type of tandem wing
Both wings lift, but the Canard (small front wing) should carry no more than 25% of the total weight
List pro(s) and con(s) of a canard wing aircraft*
Pro:
More lift efficient because both wings provide lift
Con:
No tail pulling down so not as stable in pitch as conventional aircraft
What type of aircraft did the Wright Brothers make?*
Biplane canard aircraft
How do you fix stability in pitch on a canard wing aircraft?*
Swept back wings
Making the canard wing stall before the main wing
Canard wing stops making lift before the main wing, and the aircraft does not pitch up too far
Most airplanes we do not have to worry about _____ movements left and right.*
Center of Gravity
List pro(s) and con(s) of a flying wing*
Pro:
Drag is reduced
Con:
Stability is difficult
What are the flight controls for the flying wing? *
Where is each located?
Split rudders: at the wingtips
Elevons: move the ailerons towards the center and combine them with the elevators
