TYPES OF STABLIZERS

SINGLE STABLIZER

Conventional tail

T-tail

Cruciform tail

MULTIPLE STABLIZER

Twin tail

Triple tail

V-tail

CONVENTIONAL TAIL

A Conventional Tail is one with the stabilizer mounted directly on the fuselage and is the usual

configuration of an aircraft.

ADVANTAGES

Conventional tail has better stall recovery

Conventional tails have advantage in terms of “system redundancy”

Conventional tails can more easily equipped with hydraulic, wire or mechanical systems

It has no single point of failure

Simplest to construct and seem to be most popular.

DISADVANTAGE

The conventional tail has the "elevators" directly behind the wing so it experiences air

disturbance from the wings

Rear mounted engine is not possible in conventional tail

A conventional tail tends to drag the stabilizer through the grass on landing, hooking tips

and causing massive bending loads on the tail boom

T –TAIL

A T-tail is an aircraft tail stabilizer configuration in which the horizontal surfaces (tailplane and

elevators) are mounted to the top of the vertical stabilizer.

ADVANTAGE

T tail will give better rudder authority at very high AOA and stall so as to prevent a spin

T-tail allows high performance aerodynamics and excellent glide ratio

The empennage is not affected by wing slipstream.

At slow speeds, the elevator on a T-tail aircraft must be moved through a larger number

of degrees of travel to raise the nose a given amount than on a conventional-tail aircraft.

DISADVANTAGE

The aircraft will tend to be much more prone to a dangerous deep stall condition.

Unfavorable C.G position if empty.

The control runs to the elevators are more complex, and elevator surfaces are much more

difficult to casually inspect from the ground.

CRUCIFORM TAIL

The cruciform tail is an aircraft empennage configuration which, when viewed from the aircraft's

front or rear, looks much like a cross. The usual arrangement is to have the horizontal stabilizer

intersect the vertical tail somewhere near the middle, and above the top of the fuselage.

ADVANTAGE

The cruciform tail gives the benefit of clearing the aerodynamics of the tail away from

the wake of the engine.

Not requiring the same amount of strengthening of the vertical tail section in comparison

with a T-tail design.

V –TAIL

The V-Tail is where both the fin and stabilizer are replaced with two surfaces mounted in a V-

shape approximately 45 degrees from the horizontal. The control surfaces mounted on a V-Tail

control the aircraft in both pitch and yaw.

ADVANTAGE

The V-tail is lighter, has less wetted surface area.

V -tail produces less drag.

DISADVANTAGE

Combining the pitch and yaw controls is difficult and requires a more complex control

system.

The V-tail arrangement places greater stress on the rear fuselage when pitching and

yawing.

TWIN TAIL

A twin tail is a specific type of vertical stabilizer arrangement found on the empennage of some

aircraft. Two vertical stabilizers often smaller on their own than a single conventional tail would

be are mounted at the outside of the aircraft's horizontal stabilizer.

ADVANTAGE

If one tail is damaged, the other may remain functional.

Separating the control surfaces allows for additional rudder area or vertical surface

without requiring a massive single tail.

A twin tail can also simplify hangar requirements.

TRIPLE TAIL

PELIKAN TAIL

The Pelikan tail is an experimental tail design for fighter jets. Originally conceived by Ralph

Pelikan

ADVANTAGE

Greater pitch control at high angles of attack.

Two tails would have a lower radar signature than four.

DISADVANTAGE

Using two larger control surfaces instead of four, might actually make the aircraft

heavier.

The bigger hydraulic pumps and cylinders needed to operate the larger surfaces would

add 800 to 900 pounds (360 to 410 kg) of weight to the design.

TYPES OF LANDING GEAR

Conventional Tricycle

CONVENTIONAL LANDING GEAR

Consists of two wheels forward of the aircraft's center of gravity and a third small wheel at the tail. This type of landing gear is most often seen in older general aviation airplanes. The two main wheels are fastened to the fuselage by struts. Without a wheel at the nose of the plane, it easily pitches over if brakes are applied too soon. Because the tailwheel is castered--free to move in any direction--the plane is very difficult to control when landing or taking off.

Two main wheels One tail dragger wheel

ADVANTAGE The ability to operate the aircraft over rough terrain. Due to its smaller size the tailwheel has less parasite drag than a nosewheel. Tailwheels are less expensive to buy and maintain than a nosewheel. If a tailwheel fails on landing, the damage to the aircraft will be minimal. Reduced landing gear weight

DISADVANTAGE Requires more skill in ground taxiing Suffer from poorer forward visibility on the ground. Conventional geared aircraft are much more susceptible to ground looping. Nose high attitude on the ground, propeller powered taildraggers are more adversely

affected. Aircraft lack sufficient rudder authority in some flight regimes.

EXAMPLES OF TAILWHEEL AIRCRAFT:

Cessna 170 de Havilland Canada DHC-2 Beaver Denny Kitfox Grumman Ag Cat Maule M-5 Piper J-3 Cub Vans RV-4

TRICYCLE LANDING GEAR

The landing gear on small aircraft consists of three wheels: two main wheels (one located on each side of the fuselage) and a third wheel positioned either at the front or rear of the airplane. Landing gear employing a rear-mounted wheel is called conventional landing gear. Airplanes with conventional landing gear are often referred to as tailwheel airplanes. When the third wheel is located on the nose, it is called a nosewheel, and the design is referred to as a tricycle gear. A steerable nosewheel or tailwheel permits the airplane to be controlled throughout all operations while on the ground.

Has nose wheel, which may be steerable. Main gear, on either side.

ADVANTAGE

Keeps aircraft level during take-off and landing. Its ease of ground handling. It allows more forceful application of the brakes during landings at high speeds without

causing the aircraft to nose over. It permits better forward visibility for the pilot during takeoff, landing, and taxiing. It tends to prevent ground looping (swerving) by providing more directional stability

during ground operation since the aircraft’s center of gravity (CG) is forward of the main wheels. The forward CG keeps the airplane moving forward in a straight line rather than ground looping.

DISADVANTAGE Greater summary mass of struts due to the bigger height of the nose strut hence bending moment which is

forced onto it by additional load from forces of inertia. Smaller permeability. The nose strut is reloaded because of inertia forces action and its

foot-pressure on ground is increased also during running. Considerably larger volumes in a fuselage indispensable for retracting the nose strut. It is

especially difficult when engine is positioned inside of a fuselage nose part. Longitudinal instability during movement of aircraft along an aerodrome with an elevated

front support during take-off run. Danger of emergency or even catastrophes during damage or breaking of front support. Possibility of appearance of self-energizing oscillations has freely orienting wheels of a

front support. Such oscillations are called ³shimmy.´The means for elimination of this phenomenon will

result in complicating and in weight increase of a structure

EXAMPLES OF NOSEWHEEL AIRCRAFT: Cessna 150 Cessna 172 Cessna 182 Piper PA-22 Tripacer

CLASSIFICATION OF LANDING GEAR

MAIN LANDING GEAR

Cushions landing impact Heavily stressed area Main Landing Gear consists of the main weight-bearing structure Auxiliary landing gear includes tail wheels, skids, nose wheels, etc.

NON-ABSORBING LANDING GEAR

Includes Rigid landing gear, Shock-cord landing gear, Spring landing gear Rigid:  helicopters, sailplanes.  No flexing other than the structure. Shock cord system:  uses “Bungee” cords Spring type uses spring steel (some Cessna’s)

SHOCK-ABSORBING LANDING GEAR

Dissipates landing energies by forcing fluid through a restriction This fluid generates heat, dissipated into the atmosphere Two types:  Spring Oleo, and Air-Oil Oleo Spring Oleo is history by now Air Oleos are all very similar:  a needle valve restricts fluid flow Air in the oleo holds the weight of the a/c on the ground Air Oleos present in both retractable and fixed gears

FIXED GEAR

Non retractable, usually bolted on to the structure Often uses fairings or wheel pants Cessna 152 Advantages:

Lighter weight Less complex Least costly

RETRACTABLE GEAR

Designed to eliminate drag (the greatest advantage) Can be either fully or partially retractable Direction of retraction depends on airframe model Methods of retraction:  hydraulic, electric, mechanical, pneumatic Critical area of aircraft maintenance for safety reasons

HULLS AND FLOATS 

Can be single float, or multiple Definition may include floating hulls (ex. “Lake” aircraft) Floating hulls may only require wing tip floats Skis used for snow and ice (wood, metal, composites) Skis may use shock cord to assist angle of ski attack Skis are mounted on the same strut as tires

HELICOPTER LANDING GEAR

Basic skid gear is common for small & mediums Wheel gear is used on sikorsky aircraft Retractable or cushioning gear may impart ground resonance Skid tubes are replaceable, and repairable Bending and deforming limits are established, and occasionally liberal Skid protectors are available, as are “bear paws” snow shoes Ground handling wheels are bolt-on towing additions

AIRCRAFT CONTROL SURFACES

Pilots control an aircraft by moving control surfaces.

AILERONS

The ailerons are on either side of the wings; these are controlled by the pilot rotating the yoke left and right.

Movement of the ailerons changes the shape of the wing, creating more curvature on one side (creating more lift) and drag on the opposite wing.

The ailerons are used in conjunction with the rudder to create a co-ordinated turn. Similar to a car on a race track with angled bends on the track, banking into the turn is much more comfortable than simply turning when at speed.

The aircraft 'rolls' when the ailerons are moved.

RUDDER

The rudder is a control surface on the tail.

The pilot controls the rudder by pressing on rudder pedals.

Pressing the left pedal causes the rudder to rotate to the left causing the tail to move right, in turn moving the nose of the airplane ot the left. Pressing the right rudder pedal does the opposite.

Rudder movement causes the aircraft nose to move left or right.

The aircraft 'yaws' when the rudder is moved.

ELEVATOR

The elevator is on the tail of the aircraft, moving the elevator causes the nose of the aircraft to go up or down, allowing the aircraft to climb or descent.

The pilot moves the elevator by pulling or pushing on the yoke.

Pulling on the yoke moves the elevator up causing the tail to go down, and the nose of the airplane to pitch up.

Pushing forward on the yoke pitches the aircraft down.

The aircraft 'pitches' when the elevator is moved.

LOCATION OF AIRCRAFT ENGINE

Engines may be placed in the wings, on the wings, above the wings, or suspended on pylons below the wings. They may be mounted on the aft fuselage, on top of the fuselage, or on the sides of the fuselage. Wherever the nacelles are placed, the detailed spacing with respect to wing, tail, fuselage, or other nacelles is crucial.

WING-MOUNTED ENGINES

Engines buried in the wing root have minimum parasite drag and probably minimum weight.

Their inboard location minimizes the yawing moment due to asymmetric thrust after engine failure.

However, they pose a threat to the basic wing structure in the event of a blade or turbine disk failure, make

It very difficult to maximize inlet efficiency, and make accessibility for maintenance more difficult.

If a larger diameter engine is desired in a later version of the airplane, the entire wing may have to be redesigned. Such installations also eliminate the flap in the region of the engine exhaust, thereby reducing CLmax.

AFT FUSELAGE ENGINE PLACEMENT

When aircraft become smaller, it is difficult to place engines under a wing and still maintain adequate wing nacelle and nacelle-ground clearances. This is one reason for the aft-engine arrangements. Other advantages are:

Greater CLmax due to elimination of wing-pylon and exhaust-flap interference, i.e., no flap cut-outs

Less drag, particularly in the critical take-off climb phase, due to eliminating wing-pylon interference.

Less asymmetric yaw after engine failure with engines close to the fuselage. Lower fuselage height permitting shorter landing gear and airstair lengths.

DISADVANTAGES The center of gravity of the empty airplane is moved aft - well behind the center of

gravity of the payload. Thus a greater center of gravity range is required. This leads to more difficult balance problems and generally a larger tail.

The wing weight advantage of wing mounted engines is lost. The wheels kick up water on wet runways and special deflectors on the gear may be

needed to avoid water ingestion into the engines. At very high angles of attack, the nacelle wake blankets the T-tail, necessary with aft-

fuselage mounted engines, and may cause a locked-in deep stall. This requires a large tail span that puts part of the horizontal tail well outboard of the nacelles.

Vibration and noise isolation for fuselage mounted engines is a difficult problem.

Aft fuselage mounted engines reduce the rolling moment of inertia. This can be a disadvantage if there is significant rolling moment created by asymmetric stalling. The result can be an excessive roll rate at the stall.

De Havilland Comet

De Havilland started about this design at the introduction of its DH Comet in 1949 which earned the name as the world’s first commercial jet airliner to reach production.

The success however was short-lived as the design was plagued by structural problems which ultimately changed the way airliners were constructed following a series of tragic crashes of the type.

This engine configuration was reflected on other British aircraft designs such as the Vickers-Armstrongs Valiant, the Handley Page Victor and the Avro Vulcan Bomber (V Bomber Force)

ENGINE PYLONS UNDER WING

Aircraft Classification Base on Purpose

An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general,

the atmosphere of a planet. It counters the force of gravity by using either static lift or by using

the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Aircraft are

produced in several different types optimized for various uses; military aircraft, which includes

not just combat types but many types of supporting aircraft, and civil aircraft, which include all

non-military types, experimental and model. The two major categories of classification are

Military

1 Combat aircraft

o 1.1 Fighter

o 1.2 Bomber

o 1.3 Attack aircraft

o 1.4 Electronic warfare aircraft

o 1.5 Maritime patrol aircraft

o 1.6 Multirole combat aircraft

2 Non-combat aircraft

o 2.1 Military transport aircraft

o 2.2 Airborne early warning and control

o 2.3 Reconnaissance and surveillance aircraft

o 2.4 Experimental Aircraft

Combat Aircraft

Fighter

A fighter aircraft is a military aircraft designed primarily for air-to-air combat against other

aircraft, as opposed to bombers and attack aircraft, whose main mission is to attack ground

targets. The hallmarks of a fighter are its speed, manoeuvrability, and small size relative to other

combat aircraft.

Many fighters have secondary ground-attack capabilities, and some are designed as dual-

purpose fighter-bombers. Often, aircraft that do not fulfill the standard definition are called

fighters. This may be for political or national security reasons, for advertising purposes or other

reasons.

A fighter's main purpose is to establish air superiority over a battlefield. Since World War I,

achieving and maintaining air superiority has been essential for victory in conventional

warfare. The success or failure of a belligerent's efforts to gain air supremacy hinges on several

factors including the skill of its pilots, the tactical soundness of its doctrine for deploying its

fighters and the numbers and performance of those fighters. Because of the importance of air

superiority, since the dawn of aerial combat armed forces have constantly competed to develop

technologically superior fighters and to deploy these fighters in greater numbers, and fielding a

viable fighter fleet consumes a substantial proportion of the defense budgets of modern armed

forces.

Interceptor aircraft

An interceptor aircraft (or simply interceptor) is a type of fighter aircraft designed specifically to

prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft, and destroy

them relying usually on great speed and powerful armament. Being used since the First World

War, after the late 1960s interceptors became less important due to shifting from bombers

to intercontinental ballistic missiles (ICBMs) for nuclear warfare.

Bomber

A bomber is a military aircraft designed to attack ground and sea targets, by dropping bombs on

them, firing torpedoes at them, or – in recent years – by launching cruise missiles at them.

Strategic bomber

A strategic bomber is a heavy bomber aircraft designed to drop large amounts of ordnance onto a

distant target for the purposes of debilitating an enemy's capacity to wage war. Unlike tactical

bombers, which are used in the battle zone to attack troops and military equipment, strategic

bombers are built to fly into an enemy's heartland to destroy strategic targets, e.g. major military

installations, factories and cities. In addition to strategic bombing, strategic bombers can be used

for tactical missions. The United States, Russia and China (leased from Russia) maintain

strategic bombers.

Tactical bomber

A tactical bomber is a bomber aircraft with an intended primary role of tactical bombing—

attacking tactical targets, such as enemy's troops and military equipment. This implies that either

aircraft's range or ordnance is insufficient to use it effectively as a strategic bomber.

All light bombers and most medium bombers fulfill the tactical role. Most heavy bombers are

strategic.

A variety of aircraft classes performed tactical bombings through the course of history, although

they are usually described using more precise names: ground-attack aircraft, interdictor, dive

bomber, light or medium bomber, and fighter aircraft (most notably fighter-bomber, strike

fighter, multirole fighter subclasses). Examples of aircraft that could be accurately described as

tactical bombers "by design" include the: Airco DH.4, Fairey Battle, B-25 Mitchell, B-26

Marauder, A-26 Invader, or more recently F-111 Aardvark, and F-117 Nighthawk.

Interdictor

An interdictor is a type of ground-attack aircraft that operates far behind enemy lines, with the

express intent of interdicting the enemy's military targets, most notably those involved

in logistics. The interdiction prevents or delays enemy forces and supplies from reaching the

battlefront.

The term has generally fallen from use. The strike fighter is a closely related concept, but puts

more emphasis on air-to-air combat capabilities 

Attack aircraft

Attack aircraft are military aircraft with primary role of attacking targets on the ground or sea,

with greater precision than bombers and prepared to face stronger low-level air defence. This

class of aircraft is ideal for close air support and naval air-to-surface missions. But they are also

employed in other missions, for example air interdiction or offensive counter air. In contrast

to fighter aircraft, attack aircraft are not necessarily intended for air-to-air combat. However,

they are often equipped with air-to-air missiles for self-defence.

Electronic warfare aircraft

An electronic warfare aircraft is a military aircraft equipped for electronic warfare (EW) - i.e.

degrading the effectiveness of enemy radar and radio systems.

Maritime patrol aircraft

A maritime patrol aircraft (MPA), also known as a patrol aircraft, maritime reconnaissance

aircraft, or by the older American term patrol bomber, is a fixed-wing aircraft designed to

operate for long durations over water in maritime patrol roles—in particular anti-submarine, anti-

ship and search and rescue.

Multirole combat aircraft

A multirole combat aircraft is an aircraft designed to perform different roles in combat. The air-

to-air combat role has been normally performed by fighter aircraft. So a multirole combat aircraft

with air combat role and other secondary role such as air-to-surface attack is as often called

a multirole fighter.

Fighter-bomber

A fighter-bomber is a fighter aircraft that is modified or used primarily as a light bomber in

the tactical bombing and ground attack roles. It differs from attack aircraft primarily in its

origins; attack aircraft are developed for the attack role first and any fighter capability is entirely

secondary, whereas fighter-bombers are designed as fighters and then adapted to other

roles. This term, although still used, has less significance since the introduction

of rockets and guided missiles into aerial warfare. Nowadays, aircraft that carry similar duties are

typically called multirole combat aircraft or sometimes strike fighters.

Strike fighter

In a current military parlance, a strike fighter is a multirole combat aircraft designed to operate

primarily in the air-to-surface attack role while also incorporating certain performance

characteristics of a fighter aircraft. As a category, it is distinct from fighter-bombers. Examples

of contemporary American strike fighters are the McDonnell Douglas F-15E Strike

Eagle, Boeing F/A-18E/F Super Hornet, and Lockheed Martin F-35 Lightning II.

Non Combat Aircraft

Military transport aircraft

Military transport aircraft or military cargo aircraft are typically fixed and rotary wing cargo

aircraft which are used to deliver troops, weapons and other military equipment by a variety of

methods to any area of military operations around the surface of the planet, usually outside of the

commercial flight routes in uncontrolled airspace. Originally derived from bombers, military

transport aircraft were used for delivering airborne forces during the Second World War and

towing military gliders. Some military transport aircraft are tasked to perform multi-role duties

such as aerial refuelling and, tactical, operational and strategic airlifts onto unprepared runways,

or those constructed by engineers.

Airborne early warning and control

An airborne early warning and control (AEW&C) system is an airborne radar system designed to

detect aircraft, ships and vehicles at long ranges and control and command the battle space in an

air engagement by directing fighter and attack aircraft strikes. AEW&C units are also used to

carry out surveillance, including over ground targets and frequently perform C2BM (command

and control, battle management) functions similar to an Airport Traffic Controller given military

command over other forces. Used at a high altitude, the radars on the aircraft allow the operators

to distinguish between friendly and hostile aircraft hundreds of miles away.

AEW&C aircraft are used for both defensive and offensive air operations, and are to

the NATO and USA forces trained or integrated Air Forces what the Command Information

Center is to a Navy Warship, plus a highly mobile and powerful radar platform. The system is

used offensively to direct fighters to their target locations, and defensively in order to counter

attacks by enemy forces, both air and ground. So useful is the advantage of command and control

from a high altitude, the United States Navy operates AEW&C aircraft off its Supercarriers to

augment and protect its carrier Command Information Centers (CICs)

Reconnaissance aircraft

Reconnaissance aircraft are primarily used to gather intelligence. They are equipped with

cameras and other sensors. These aircraft may be specially designed or may be modified from a

basic fighter or bomber type. This role is increasingly being filled by satellites and unmanned

aerial vehicles (UAVs).

Surveillance aircraft

A surveillance aircraft is an aircraft used for surveillance—collecting information over time.

They are operated by military forces and other government agencies in roles such as intelligence

gathering, battlefield surveillance, airspace surveillance, observation (e.g. artillery

spotting), border patrol and fishery protection. This article concentrates on aircraft used in those

roles, rather than for traffic monitoring, law enforcement and similar activities.

Surveillance aircraft usually carry no armament, or only limited defensive armament. A

surveillance aircraft does not necessarily require high-performance capability

or stealth characteristics. It may be a modified civilian aircraft. Surveillance aircraft have also

included moored balloons (e.g. TARS) and Unmanned Aerial Vehicles (UAVs).

Experimental Aircraft

An experimental aircraft is an aircraft that has not yet been fully proven in flight. Often, this

implies that new aerospace technologies are being tested on the aircraft, though the label is

broader.

The term "experimental aircraft" is also sometimes used to refer to aircraft flown with

an "Experimental" category airworthiness certificate. In the U.S. this includes most homebuilt

aircraft; many of which are based on conventional designs and hence are experimental only in

name.

Air-sea rescue

Air-sea rescue (ASR or A/SR, also known as sea-air rescue ) is the coordinated search and

rescue (SAR) of the survivors of emergency water landings as well as people who have survived

the loss of their sea-going vessel. ASR can involve a wide variety of resources

including seaplanes, helicopters, submarines, rescue boats and ships. Specialized equipment and

techniques have been developed. Military and civilian units can perform air-sea rescue.

Trainer (aircraft)

A trainer is a class of aircraft designed specifically to facilitate in-flight training of pilots and

aircrews. The use of a dedicated trainer aircraft with additional safety features—such as tandem

flight controls, forgiving flight characteristics and a simplified cockpit arrangement—allows

pilots-in-training to safely advance their real-time piloting, navigation and/or war fighting skills

without the danger of overextending their abilities alone in a fully featured aircraft.

Civilian pilots are normally trained in a light aircraft, with two or more seats to allow for student

and instructor. The aircraft may be modified to withstand the flight conditions imposed by

training flights.

Civil and Commercial

Civil aviation

Civil aviation is one of two major categories of flying, representing all non-military aviation,

both private and commercial. Most of the countries in the world are members of the International

Civil Aviation Organization(ICAO) and work together to establish common standards and

recommended practices for civil aviation through that agency.

Civil aviation includes two major categories:

Scheduled air transport , including all passenger and cargo flights operating on regularly

scheduled routes; and

General aviation  (GA), including all other civil flights, private or commercial

Although scheduled air transport is the larger operation in terms of passenger numbers, GA is

larger in the number of flights (and flight hours, in the U.S.) In the U.S., GA carries 166 million

passengers each year, more than any individual airline, though less than all the airlines

combined.

Some countries also make a regulatory distinction based on whether aircraft are flown for hire

like:

Commercial aviation  includes most or all flying done for hire, particularly scheduled

service on airlines; and

Private aviation  includes pilots flying for their own purposes (recreation, business

meetings, etc.) without receiving any kind of remuneration.

All scheduled air transport is commercial, but general aviation can be either commercial or

private. Normally, the pilot, aircraft, and operator must all be authorized to perform commercial

operations through separate commercial licensing, registration, and operation certificates.

General aviation

General aviation (GA) is one of the two categories of civil aviation. It refers to "all civil aviation

operations other than scheduled air services and non-scheduled air transport operations for

remuneration or hire." General aviation flights range from gliders and powered parachutes to

corporate jet flights. The majority of the world's air traffic falls into this category, and most of

the world's airports serve general aviation exclusively.

General aviation is particularly popular in North America, with over 6,300 airports available for

public use by pilots of general aviation aircraft (around 5,200 airports in the U.S., and over 1,000

in Canada). In comparison, scheduled flights operate from around 560 airports in the

U.S. According to the U.S. Aircraft Owners and Pilots Association, general aviation provides

more than one percent of the United States' GDP, accounting for 1.3 million jobs in professional

services and manufacturing.

General aviation covers a large range of activities, both commercial and non-commercial,

including private flying, flight training, air ambulance, police aviation, aerial firefighting, air

charter, bush flying, gliding, skydiving and many others. Homebuilt aircraft, light-sport

aircraft and very light jets have emerged in recent years as new trends in general aviation.

General aviation involves a wide range of aircraft types such as business jets

(bizjets), trainers, homebuilt, aerobatic types, racers, gliders, warbirds, firefighters and medical

transports, to name a few. The vast majority of aircraft today are general aviation types.

Glider (sailplane)

A glider or sailplane is a type of glider aircraft used in the sport of gliding. They have rigid

wings and an undercarriage. Some gliders, known as motor gliders are also used for gliding and

soaring, but have engines which can be used for extending a flight and, for some types, for take-

off. Aircraft such as hang gliders and paragliders are foot-launched and so are described in

separate articles, though their differences from sailplanes are covered below. Glider aircraft that

are used for purposes other than recreation, for example for military purposes, do not soar.

Sports gliders benefit from creating the least drag for any given amount of lift, and this is best

achieved with long, thin wings and a fully faired narrow cockpit. Aircraft with these features are

able to climb efficiently in rising air and can glide long distances at high speed with a minimum

loss of height in between.

Homebuilt aircraft

Also known as amateur-built aircraft or kit planes, homebuilt aircraft are constructed by persons

for whom this is not a professional activity. These aircraft may be constructed from "scratch,"

from plans, or from assembly kits.

Light-sport aircraft

A light-sport aircraft, also known as light sport aircraft or LSA, is a small aircraft that is simple

to fly and which meets certain regulations set by a National aviation authority restricting weight

and performance. For example, in Australia the Civil Aviation Safety Authority defines a light-

sport aircraft as a heavier-than-air or lighter-than-air craft, other than a helicopter, with a

maximum gross takeoff weight of not more than 560 kilograms (1,200 lb) for lighter-than-air

craft; 600 kilograms (1,300 lb) for heavier-than-air craft not intended for operation on water; or

650 kilograms (1,400 lb) for aircraft intended for operation on water. It must have a

maximum stall speed of 45 knots (83 km/h; 52 mph) in landing configuration; a maximum of

two seats; a maximum speed in level flight with maximum continuous power (Vh)—138 mph

(120 knots) CAS; fixed undercarriage (except for amphibious aircraft which may have

repositionable gear, and gliders which may have retractable gear); an unpressurized cabin; and a

single non-turbine engine driving a propeller if it is a powered aircraft.

Air ambulance

An air ambulance is a specially outfitted aircraft that transports injured or sick people in

an medical emergency or over distances or terrain impractical for a conventional

ground ambulance. These and related operations are called aeromedical. In some circumstances,

the same aircraft may be used to search for missing or wanted people.

Like ground ambulances, air ambulances are equipped with medical equipment vital to

monitoring and treating injured or ill patients. Common equipment for air ambulances

includes medications, ventilators, ECGs and monitoring units, CPR equipment, and stretchers. A

medically staffed and equipped air ambulance provides medical care in flight—while a non-

medically equipped and staffed aircraft simply transports patients without care in flight. Military

organizations and NATO refer to the former as Medical Evacuation (MEDEVAC) and to the

latter as Casualty Evacuation (CASEVAC).

Business jet

Business jet, private jet, or bizjet, is a term describing a jet aircraft, usually of smaller size,

designed for transporting groups of up to 19 individuals. Business jets may be adapted for other

roles, such as the evacuation of casualties or express parcel deliveries, and some are used by

public bodies, government officials or the armed forces. The more formal terms of corporate

jet, executive jet, VIP transport or business jet tend to be used by the firms that build, sell, buy

and charter these aircraft.

Police aviation

Police aviation is the use of rotary-wing aircraft, fixed-wing aircraft, nonrigid-wing aircraft

or lighter-than-air aircraft in police operations. Police services commonly use aircraft for traffic

control, ground support, search and rescue, high-speed car pursuits, observation, air patrol and

control of large-scale public order incidents. In some major cities, police rotary-wing aircraft are

also used as air transportation for personnel belonging to SWAT-style units. In large, sparsely

populated areas, fixed-wing aircraft are sometimes used to transport personnel and equipment.

Private aviation

Private aviation is the part of civil aviation that does not include flying for hire. In most

countries, private flights are always general aviation flights, but the opposite is not true: many

general aviation flights (such as banner towing, charter, crop dusting, and others)

are commercial in that the pilot is hired and paid. Many private pilots fly for their own

enjoyment, or to share the joys and convenience of general aviation with friends and family.

In private flight the pilot is not paid, and all aircraft operating expenses are generally paid by the

pilot. In some countries such as the United States, aircraft operating expenses for a flight may

optionally be divided with any passengers up to a pro rata amount. For example, if aircraft

operating expenses total $120 for a flight with pilot and three passengers, each of the three

passengers could pay not more than $30 (one fourth) of the expenses with the remainder paid by

the pilot.

In many countries, private aviation operates to less strict standards than commercial aviation. For

example, in Canada and the United States, aircraft owners are allowed to perform basic

maintenance tasks (such as oil or tire changes) on their own aircraft, but only licensed mechanics

may perform those tasks on aircraft used for commercial operations. Private pilots normally are

not required to demonstrate the same level of proficiency on their flight tests and take fewer and

less rigorous medical examinations, than are required for Commercial pilots who are paid for

operating an aircraft. The majority of active pilots hold a Private Pilot license.

It is the purpose of the flight, not the aircraft or pilot, which determines whether the flight is

private. For example, if a commercially licensed pilot flies a registered plane to visit a friend or

attend a business meeting, most countries would consider this to be a private flight. Conversely,

a private pilot could legally fly a multi-engine complex aircraft carrying numerous passengers

for non-commercial purposes (no compensation paid to the pilot, and a pro rata or larger portion

of the aircraft operating expenses paid by the pilot).

Warbird

Warbird is any vintage military aircraft now operated by civilian organisations and individuals

or, in some instances, by historic arms of military forces, such as the Battle of Britain Memorial

Flight, the RAAF Museum Historic Flight and the South African Air Force Museum Historic

Flight.

Commercial aviation

Commercial aviation is the part of civil aviation (both general aviation and scheduled airline

service) that involves operating aircraft for hire to transport passengers or cargo. In most

countries, a flight may be operated for money only if it meets three criteria:

the pilot must hold a valid commercial pilot's certificate

the aircraft must hold a valid commercial registration

the operator must hold a certificate or some other authorization for commercial

operations

There are some exceptions — for example, a flight instructor is normally allowed to fly for

money in a private aircraft owned by the student — but the above requirements hold for most

flights where money changes hands.

Typically, a commercial certificate or registration requires higher standards than a private one.

For example, a commercial pilot may have to demonstrate more maneuvers to a higher standard,

and may need to pass more frequent medical examinations. A commercially registered plane may

require more frequent or more extensive maintenance.

It is the purpose of the flight, not the type of aircraft or pilot that determines whether the flight is

commercial. For example, a two-seat Cessna 150 towing a banner for money would be a

commercial flight, while a large jet flown by its owners for a private vacation would not be, even

if the pilots were commercially certificated and the jet were commercially registered.

Cargo Aircraft

A cargo aircraft (also known as freight aircraft, freighter, airlifter, or cargo jet) is a fixed-wing

aircraft designed or converted for the carriage of goods, rather than passengers. They are usually

devoid of passenger amenities, and generally feature one or more large doors for the loading and

unloading of cargo. Freighters may be operated by civil passenger or cargo airlines, by private

individuals or by the armed forces of individual countries. However most air freight is carried in

special ULD containers in the cargo holds of passenger aircraft.

Fuselage

The word fuselage is based on the French word fuseler, which means "to

streamline”. Fuselage is the main structure of the aircraft, which holds both human and cargo,

depending on the type of the aircraft. The fuselage must be strong and streamlined since it must

withstand the forces that are created in flight.

Types of Fuselage

Types of Fuselage on the base of External Structure

1: Subsonic

2: High-speed / supersonic

3: High-capacity subsonic

4: High-maneuverability supersonic

5: Flying boat

6: Hypersonic

Types of Fuselage on the base of force-resisting structure

Tens ion

Tension is the stress which tends to pull things apart. When you try to break a length of rope,

you exert a type of stress which is called tension. (see figure 1-2a)

fig 1 - 2a tension stress

C o m p r e s s i o n

Compression is the opposite of tension. It is the stress which tends to push materials together.

When you grasp a football at both ends and push, the ball is subject to compression. The landing

gear struts of an aircraft are also subject to compression.

Bend ing

This type of stress combines tension and compression. You put a bending stress on a bar when

you grasp it with both hands and push the ends together or when you bend a paper clip. The wing

spars (interior structural members) are subjected to bending while the aircraft is in flight. The

lower side of the spar is subjected to tension, while the upper side is subjected to compression.

Obviously, some materials will break before they bend and often are unacceptable for aircraft

construction. (see figure 1-2c)

fig 1 - 2 c bending stress

Shear

   Shear stress is caused by forces tending to slip or slide one part of a material in respect to

another part. This is the stress that is placed on a piece of wood clamped in a vice and you Chip

away at it with a hammer and chisel. This type of stress is also exerted when two pieces of metal,

bolted together, are pulled apart by sliding one over the other or when you sharpen a pencil with

a knife. The rivets in an aircraft are intended to carry only shear. Bolts, as a rule, carry only

shear, but sometimes they carry both shear and tension. (see figure 1-2d)

1 - 2d shear stress

Tors ion

   Torsion is the stress which tends to distort by twisting. You produce a torsional force when

you tighten a nut on a bolt. The aircraft engine exerts a torsional force on the crankshaft or

turbine axis.

   All the members (or major portions) of an aircraft are subjected to one or more of these

stresses. Sometimes a member has alternate stresses, such as compression one instant and tension

the next. Some members can carry only one type of stress. Wire and cables, for example,

normally carry only tension. (see figure 1-2e)

Fig 1 - 2e torsional stress

Types of Fuselage on the base of numbers

Single Fuselage

Single fuselage contains only one payload area or contains only one fuselage in an

airplane.

Twin Fuselage

Twin fuselage contains two payload areas or contains two fuselages in an airplane.

Multi fuselage

Multi fuselage contains more than two payload areas or more fuselages in an airplane.

Fuselage construction

Truss structure

A truss is a rigid framework made up of members such as beams, struts and bars to resist

deformation by applied loads. The truss framed fuselage covered with fabric. All members of the

truss can carry both tension and compression loads steel tubing welded together or aluminum

alloy riveted or bolted into one piece with cross –bracing achieved by solid rods or tubes . The

truss type fuselage may be sub classified as

Pratt Truss type

The primary strength members are the four longerons were connected with rigid vertical

and lateral members were made of strong steel wire and were designed to carry tension only.

Warren Truss type

In this construction, the longerons are connected with only diagonal members normally al

members in the truss are capable of carrying both tension and compression. When load acting in

one direction, compression loads are carried every other member and the alternate members

carry the tension loads the space between the two bulkheads is bays.

Geodesic Construction

Geodesic airframe fuselage structure is exposed by battle damage Geodesic structural

elements were used by Barnes Wallis for British Vickers between the wars and into World War

II to form the whole of the fuselage, including its aerodynamic shape. In this type of construction

multiple flat strip stringers are wound about the formers in opposite spiral directions, forming a

basket-like appearance. This proved to be light, strong, and rigid and had the advantage of being

made almost entirely of wood. A similar construction using aluminum alloy was used in the

Vickers Warwick with fewer materials than would be required for other structural types. The

geodesic structure is also redundant and so can survive localized damage without catastrophic

failure. A fabric covering over the structure completed the aerodynamic shell (see the Vickers

Wellington for an example of a large warplane which uses this process). The logical evolution of

this is the creation of fuselages using molded plywood, in which multiple sheets are laid with the

grain in differing directions to give the monocoque type below.

Monocoque shell

In this method, the exterior surface of the fuselage is also the primary structure. A typical

early form of this (see the Lockheed Vega) was built using molded plywood, where the layers of

plywood are formed over a "plug" or within a mold. A later form of this structure uses fiberglass

cloth impregnated with polyester or epoxy resin, instead of plywood, as the skin. A simple form

of this used in some amateur-built aircraft uses rigid expanded foam plastic as the core, with a

fiberglass covering, eliminating the necessity of fabricating molds, but requiring more effort in

finishing (see the Rutan VariEze). An example of a larger molded plywood aircraft is the de

Havilland Mosquito fighter/light bomber of World War II. No plywood-skin fuselage is truly

monocoque, since stiffening elements are incorporated into the structure to carry concentrated

loads that would otherwise buckle the thin skin. The use of molded fiberglass using negative

("female") molds (which give a nearly finished product) is prevalent in the series production of

many modern sailplanes. The use of molded composites for fuselage structures is being extended

to large passenger aircraft such as the Boeing 787 Dreamliner (using pressure-molding on

female molds).

Semi-monocoque

Sectioned fuselage showing frames, stringers and skin all made out of aluminium

This is the preferred method of constructing an all-aluminum fuselage. First, a series of frames in

the shape of the fuselage cross sections are held in position on a rigid fixture. These frames are

then joined with lightweight longitudinal elements called stringers. These are in turn covered

with a skin of sheet aluminum, attached by riveting or by bonding with special adhesives. The

fixture is then disassembled and removed from the completed fuselage shell, which is then fitted

out with wiring, controls, and interior equipment such as seats and luggage bins. Most modern

large aircraft are built using this technique, but use several large sections constructed in this

fashion which are then joined with fasteners to form the complete fuselage. As the accuracy of

the final product is determined largely by the costly fixture, this form is suitable for series

production, where a large number of identical aircraft are to be produced. Early examples of this

type include the Douglas Aircraft DC-2 and DC-3 civil aircraft and the Boeing B-17 Flying

Fortress. Most metal light aircraft are constructed using this process.

Both monocoque and semi-monocoque are referred to as "stressed skin" structures as all or a

portion of the external load (i.e. from wings and empennage, and from discrete masses such as

the engine) is taken by the surface covering. In addition, all the load from internal pressurization

is carried (as skin tension) by the external skin.

The proportioning of loads between the components is a design choice dictated largely by the

dimensions, strength, and elasticity of the components available for construction and whether or

not a design is intended to be "self jigging", not requiring a complete fixture for alignment.

Materials

Early aircraft were constructed of wood frames covered in fabric. As monoplanes became

popular, metal frames improved the strength, which eventually led to all-metal aircraft with

metal covering all surfaces. Some modern aircraft are constructed with composite materials for

major control surfaces, wings, or the entire fuselage such as the Boeing 787. On the 787, it

makes possible higher pressurization levels and larger windows for passenger comfort as well as

lower weight to reduce operating costs.