Lesson 1 Aircraft General Systems

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Airplane Structure
Main Components
Fuselage
Wings
Empennage
Landing gear
Powerplant
Sub Components
Airframe
Electrical system
Flight controls
Brakes

Overall Structure

Fuselage
4 types:
Truss type
Monocoque
Semi-Monocoque
Composite

Truss
Series of welded tubes called longerons and struts
Hard to make a good streamlined shape
Usually covered in fabric
Old technology

Monocoque
Stressed skin construction method
Almost all load is supported by the skin
Any dents in the skin can cause serious strength issues.
Pop cans have this type of construction

Semi-monocoque
This is the most common structure
The B-19 is of this type of construction
Uses Bulkheads, formers, and stringers
These help the skin with the load
The Bulkhead between the engine and the cockpit is referred to as the firewall

B-19 Tailboom

Composites
Can be made of several materials:
Fiberglass
Carbon fiber
Kevlar
A mixture of all
These fibers are embedded in an epoxy resin
Advantages:
Enables just about any shape
Smooth finish = less drag
Light weight and strong
Doesn’t corrode
No metal fatigue because of flexing
Disadvantages:
Very hard to detect damage
Can be hard to repair
Susceptible to heat damage

Wing Design
Cantilever, Like Beechcraft
Semi-Cantilever, Like Cessna
Cantenary, Like the P-38 or Cessna 337

Semi/Full Cantilever

Cantenary

Wing Construction
Primary parts of a wing:
Spars
They carry the load
Made of aluminum or wood
Shaped like an I beam
Ribs
Made of aluminum or wood
Give the wing its airfoil shape
Stringers
Add stiffness and strength
Fuel tanks
May be integral, bladder or aluminum
Wing Attachment
Wings may be attached low, high or in the middle

Wings
B-19 wing attachment point
B-19 Spar/Wing Root
Empennage
Vertical stabilizer
Rudder
Ruddervator

B-19 Rudder Peddles
B-19 Rudder Peddles
B-19 Rudder Peddles

Horizontal stabilizer
Elevator
Stabilator

Flight controls
Primary
Secondary

Primary Flight Controls
Ailerons, control bank about the longitudinal axis
Elevator/Stabilator, controls pitch about the lateral axis
Rudder, controls yaw about the vertical axis
Flaperons
Canards

Rudder
Purpose of the Rudder
What is adverse yaw?
The yaw developed by the drag created when the downward moving aileron creates lift in a turn.
Does NOT turn the plane
The horizontal component of lift does that

Primary Flight controls
Stabilator, controls pitch about the lateral axis
Cheaper to build
Needs an anti-servo tab to lessen sensitivity

Axis of an Airplane

Secondary Flight Controls
Flaps
Leading edge devices
Speedbrakes
Spoilers
Vortex generators
Trim tabs
Secondary Flight controls
Flaps
Pitching moments
Main function of the flaps increase the angle of descent without increasing the airspeed.
Decrease both takeoff and landing rolls
Decreases stall speed

Types of Flaps
There are 4 types:
Plain
Split
(Least Pitching moment)
Fowler
(Most pitching moment)
Slotted

Leading Edge Devices
These are all designed to enhance lift at slow speeds
Lower stall speed

Trim Tabs
Fixed trim tab
Riveted right to the control surface
Adjustable from the ground only
Adjustable trim tab
May be moved by the pilot or autopilot in flight
May be present on all primary control surfaces
Servo tab
Used on transport aircraft to move a bigger surface
Antiservo tab
Used to lessen the sensitivity of a control surface (B-19)
Moves in the same direction as the surface
Balance tab
Increases sensitivity of a control surface
Moves in the opposite direction of the surface

Landing Gear
Tricycle gear advantages:
Better visibility
Better braking without nosing over
Better control ie no ground loop

Conventional Gear
Requires an endorsement
Usually found on STOL aircraft

Shock absorption
Bungy
Hydraulic strut
Rubber donuts (elastomers)
Spring Steel

Brakes
Toe brakes, heal brakes, parking brake
Hydraulically operated disk brakes
Drum brakes
Brake operation including glazing
Brake fluid (MIL 5606 has red dye for ease of leak checking
Spongy pedals may indicate air in the lines
Steady decrease in peddle pressure may indicate a leak

Environmental Schematic
You should know where your air comes from
Which vents give heat?
Which vents give fresh air?
Where would CO poisoning come from?
Which should you close off to prevent further CO contamination?
Red knobs vs white knobs

Electrical System
Most GA aircraft operate on 14 or 28 volt systems
Your B-19 is a 14 volt system, the C-23 is either depending on serial #, the Bonanza is 28 volts
The electrical system is totally independent of the ignition system
Each electrical component should have it’s own circuit breaker
This allows isolation from the system when there is a problem

Electrical System
Electrical system components:
Alternator or generator
Battery
Master or battery switch
Bus bar, fuses and/or circuit breakers
Voltage regulator
Ammeter/load meter
Wiring

Electrical System
Electrical equipment:
Lights
Radios
Turn coordinator
Fuel gauges
Boost pump
Stall horn
Pitot heat
Starter motor
Electrical System
Alternator

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