81 terms

Airframe- M1-Structures & Application

Airframe (8212-8292)- Aerodynamics & Rigging
The auxiliary (tail) rotor of a helicopter permits the pilot to compensate for and /or accomplish what?
Torque and directional control.
The vertical flight of a helicopter is controlled by
collective pitch changes.
A reduction in anti-torque thrust will cause the
tail to pivot in the direction of torque rotation around the main rotor axis.
In rotorcraft external-loading, the ideal location of the cargo release is where the line of action passes
through the center of gravity at all times.
The acute angle formed by the chord line of a wing and the relative wind is known as the
angle of attack.
A helicopter in forward flight, cruise configuration changes direction by
tilting the main rotor disk in the desired direction.
The purpose in checking main rotor blade tracking is to determine the
relative position of the blades during rotation.
In hovering helicopter equipped with a tail rotor, directional control is maintained by
varying the pitch of the tail rotor blades
If a single-rotor helicopter is in forward horizontal flight, the angle of attack of the advancing blade is
less than the retreating blade.
Main rotor blades that do not cone by the same amount during rotation are said to be out of
One purpose of the freewheeling unit required between the engine and the helicopter transmission is to
automatically disengage the rotor from the engine in case of an engine failure.
What statement is correct concerning torque effect on helicopters?
Torque direction is the opposite of rotor blade rotation.
What is the purpose of the free-wheeling unit in a helicopter drive system?
It disconnects the rotor whenever the engine stops or slows below the equivalent of rotor RPM.
Movement about the longitudinal axis (roll) in a helicopter is effected by movement of the
cyclic pitch control.
Movement about the lateral axis (Pitch) in a helicopter is effected by movement of the
cyclic pitch control
Wing dihedral, a rigging consideration on most airplanes of conventional design, contributes most to stability of the airplane about its
longitudinal axis.
Other than the manufacturer maintenance manual what other document could be used to determine the primary flight control surface defection for an imported aircraft that is reassembled after shipment?
Aircraft type certificate data sheet.
If a pilot reports that an airplane flies left wing heavy, this condition may be corrected by
increasing the angle of incidence of the left wing, or decreasing the angle of incidence of the right wing, or both.
If the vertical fin of a single-engine, propeller-driven airplane is rigged properly, it will generally by parallel to
the vertical axis but not the longitudinal axis.
An airplane which has good longitudinal stability should have a minimum tendency to
As the angle of attack of an airfoil increases, the center of pressure will
move toward the leading edge.
The angel of incidence is that acute angle formed by
a line parallel to the wing chord and aline parallel to the longitudinal axis of the aircraft.
An airplane's center of lift is usually located aft of its center of gravity
so that the airplane will have a nose-heavy tendency.
An airplane is controlled directionally about its vertical axis by the
The elevators of a conventional airplane are used to provide rotation about the
lateral axis.
Washing-in the left wing of a monoplane, for purposes of rigging corrections after flight test, will have what effect on the lift and drag of that wing?
Both drag and lift will increase due to increased angle of attack.
What type of flap system increases the wing area and changes the wing camber?
Fowler flaps.
If the right wing of a monoplane is improperly rigged to a greater angle of incidence than designated in the manufacturer's specifications, it will cause the
airplane to be off balance both laterally and directionally
The chord of a wing is measured from
leading edge to trailing edge.
When the lift of an airfoil increases, the drag will
also increase.
What physical factors are involved in the aspect ratio of airplane wings?
Span and chord.
Improper rigging of the elevator trim tab system will affect the balance of the airplane about its
lateral axis
An airplane that has a tendency to gradually increase a pitching moment that has been set into motion has
poor longitudinal stability.
The purpose of wing slats is to
reduce stalling speed.
The angle of incidence of an airplane at rest
does not change when in flight.
Buffeting is the intermittent application of forces to a part of an airplane. It is caused by
an unsteady flow from turbulence.
Movement of an airplane along its lateral axis (roll) is also movement
around or about the longitudinal axis controlled by the ailerons.
The primary purpose of stall strips is to
stall the inboard portion of the wings first.
Rigging and alignment checks should not be under-taken in the open; however, if this cannot be avoided, the aircraft should be positioned
with the nose into the wind.
The correct dihedral angle can be determined by
using a dihedral board and bubble level along the front spar of each wing.
The dihedral angle of a wing may be measured by placing a straightedge and level protractor on the
front spar.
Where would you find precise information to perform a symmetry alignment check for a particular aircraft?
Aircraft Service or maintenance manual.
Where is the buttock line or buttline of an aircraft?
A width measurement left or right of, and parallel to, the vertical center-line.
Where is fuselage station No. 137 located?
137 inches aft of the zero or fixed reference line.
Proper wing twist in a sheet metal constructed wing can usually be checked by utilizing a
bubble level and special fixtures described by the manufacturer.
The vast majority of aircraft control cables are terminated with swaged terminals, that must be
checked with a go-no-go gauge before and after, to show compliance with the manufacturer's requirements after the swaging operation.
What nondestructive checking method is normally used to ensure that the correct amount of swaging has taken place when installing swaged-type terminals on aircraft control cables?
Use a terminal gauge to check the diameter of the swaged portion of the terminal.
When inspecting a control cable turnbuckle for proper installation, determine that
the safety wire ends are wrapped a minimum of four turns around the terminal end shanks.
If all instructions issued by the swaging tool manufacturer are followed when swaging a cable terminal, the resultant swaged terminal strength should be
the full rated strength of the cable.
What is an acceptable safety device for a castle nut when installed on secondary structures?
Cotter pin
When used in close proximity to magnetic compasses, cotter pins are made of what material?
Corrosion resisting steel.
When a fiber or nylon insert-type, self-locking nut can be threaded on a bolt or stud through the insert with only the fingers, it should be
The purpose of the vertical fin is to provide
directional stability.
How are changes in direction of a control cable accomplished?
What is the smallest size cable that may be used in aircraft primary control systems?
1/8 inch.
After repairing or re-covering a ruder, the surface should be rebalanced
to manufacturer's specifications.
Placing a piece of cloth around a stainless steel control cable and running it back and forth over the length of the cable is generally a satisfactory method of
inspecting for broken wires.
The cable-operated control system of an all-metal aircraft, not incorporating a temperature compensating device, has been rigged to the correct tension in a heated hanger. If the aircraft is operated in very cold weather, the cable tension will
decrease when the aircraft structure and cables become cold.
Very often, repairs to a control surface require static re-balancing of the control surface required static rebalanced of the control surface. Generally, flight control balance condition may be determined by
the behavior of the trailing edge when the surface is suspected from its leading edge in the stream line position and checking weight distribution.
Excessive wear on both of the sides of a control cable pulley groove is evidence of
pulley misalignment.
Fairleads should never deflect the alignment of a cable more than
3 degrees
Where does the breakage of control cable wires occur most frequently?
Breakage usually occurs where cables pass over pulleys and through fairleads.
What system is differential control associated?
What statement concerning the 100-hour inspection of an airplane equipped with a push-pull tube-type control system is true?
The threaded rod ends should be checked for the amount of thread engagement by means of the inspection hole provided.
If control cables are adjusted properly and the control surfaces tend to vibrate, the probable cause is
worn attachment fittings.
Aircraft flight control trim systems must be designed and installed so that the
pilot can determine the relative position of the trim tab from the cockpit.
Stability about the axis which runs parallel to the line of flight is referred to as
lateral stability.
The purpose of spring tabs or servo tabs is to
assist the pilot in moving the control surfaces.
If the control stick of an aircraft with properly rigged flight controls is moved rearward and to the left, the right aileron will move
down and the elevator will move up.
Movement of the cockpit control toward the nose-down position during a ground operational check of the elevator trim tab system will cause the trailing edge of the trim tab to move in which direction?
Upward regardless of elevator position.
If the control stick of an aircraft with properly rigged flight controls is moved forward and to the right, the left aileron will move
down and the elevator will move down.
If the travel of an airplane's controls is correct but the cables are rigged exceptionally tight, what probable effect will this have when flying the airplane?
The airplane will be heavy on the controls.
During inspection of the flight control system of an airplane equipped with differential-type aileron control, side-to-side movement of the control stick will cause
each aileron to have a greater up travel (from the streamlined position) than down travel.
A universal propeller protractor used to measure the degree of aileron travel should be zeroed
with the aileron in the NEUTRAL position.
The universal propeller protractor can be used to measure
degrees of flap travel.
(refer to figure 8.) Identify the cable that is used in primary control systems and in other places where operation over pulleys is frequent.
Number 3 which shows 7 strains of 19 wires or 7 x 19 cable.
A tension regulator in the flight control cable system of a large all-metal aircraft is used primarily to
retain a set tension.
(refer to figure 9.) When the outside air temperature is 80 degrees F, select the acceptable 3/16 cable tension range.
117 pounds min, 143 pounds max.
Differential control on an aileron system means that
the up travel is more than the down travel
Why is it generally necessary to jack an aircraft indoors for weighing?
So the air currents do not destabilize the scales.
What should be accomplished before jacking an aircraft?
Install critical cress panels or plates.