Tuesday, August 19, 2008

TECHNICAL SEMINARS

TECHNICAL SEMINAR ON AIRBUS A380 BY KEERTHANA PRIYADARSHINI

Airbus A380

Airbus A380

A300 · A310 · A320 · A330 · A340 · A350 · A380

Singapore Airlines 9V-SKA, the first A380 in commercial service

Role

Airliner

Manufacturer

Airbus

First flight

27 April 2005

Introduced

25 October 2007 with Singapore Airlines

Primary users

Singapore Airlines
Emirates
Qantas

Produced

2004 – present

Number built

18 as of August 2008

Unit cost

US$317.2-337.5 million

INTRODUCTION:

The Airbus A380 is a double-deck, wide-body, four-engine airliner manufactured by the European corporation Airbus, anEADS subsidiary. The largest passenger airliner in the world, the A380 made its maiden flight on 27 April 2005 fromToulouse,France and made its first commercial flight on 25 October 2007 from Singapore to Sydney with Singapore Airlines. The aircraft was known as the Airbus A3XX during much of its development phase, but the nickname Super jumbo has since become associated with it.

The A380's upper deck extends along almost the entire length of the fuselage, and its width is equivalent to that of a widebody aircraft. This allows for a cabin with 50% more floor space than the next-largest airliner, the Boeing 747-400, and provides seating for 525 people in standard three-class configurationor up to 853 people in all economy class configuration.The A380 is offered in passenger and freighter versions. The A380-800, the passenger model, is the largest passenger airliner in the world, but has a shorter fuselage than the Airbus A340-600 which is Airbus' next biggest passenger aeroplane. The A380-800F, the freighter model, is offered as one of the largest freight aircraft, with a listed payload capacity exceeded only by the Antonov An-225.The A380-800 has a design range of 15,200 kilometres (8,200 nmi), sufficient to fly from New York to Hong Kong for example, and a cruising speed of Mach 0.85 (about 900 km/h or 560 mph at cruising altitude).

Development

Background

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Airbus started the development of a very large airliner (termed Megaliner by Airbus in the early development stages) in the early 1990s, both to complete its own range of products and to break the dominance that Boeing had enjoyed in this market segment since the early 1970s with its 747.McDonnell Douglas unsuccessfully offered its smaller, double-deck MD-12 concept for sale. As each manufacturer looked to build a successor to the 747, they knew there was room for only one new aircraft to be profitable in the 600 to 800 seat market segment. Each knew the risk of splitting such a niche market, as had been demonstrated by the simultaneous debut of the Lockheed L-1011 and the McDonnell Douglas DC-10: both planes met the market’s needs, but the market could profitably sustain only one model, eventually resulting in Lockheed's departure from the civil airliner business. In January 1993, Boeing and several companies in the Airbus consortium started a joint feasibility study of an aircraft known as the Very Large Commercial Transport (VLCT), aiming to form a partnership to share the limited market.

In June 1994, Airbus began developing its own very large airliner, designated the A3XX. Airbus considered several designs, including an odd side-by-side combination of two fuselages from the A340, which was Airbus’s largest jet at the time.The A3XX was pitted against the VLCT study and Boeing’s own New Large Aircraft successor to the 747, which evolved into the 747X, a stretched version of the 747 with the fore body "hump" extended rearwards to accommodate more passengers. The joint VLCT effort ended in April 1995, and Boeing suspended the 747X program in January 1997. From 1997 to 2000, as the East Asian financial crisis darkened the market outlook, Airbus refined its design, targeting a 15 to 20 percent reduction in operating costs over the existing Boeing 747-400. The A3XX design converged on a double-decker layout that provided more passenger volume than a traditional single-deck design.

Design phase

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The first completed A380 at the "A380 Reveal" event in Toulouse, France.

On 19 December 2000, the supervisory board of newly restructured Airbus voted to launch a 8.8 billion program to build the A3XX, re-christened as the A380, with 55 orders from six launch customers. The A380 designation was a break from previous Airbus families, which had progressed sequentially from A300 to A340. It was chosen because the number 8 resembles the double-deck cross section, and is a lucky number in some Asian countries where the aircraft was being marketed.The aircraft’s final configuration was frozen in early 2001, and manufacturing of the first A380 wing box component started on 23 January 2002. The development cost of the A380 had grown to €11 billion when the first aircraft was completed.

Boeing, meanwhile, resurrected the 747X programme several times before finally launching the 747-8 Intercontinental in November 2005 (with entry into service planned for 2009). Boeing chose to develop a derivative for the 400 to 500 seat market, instead of matching the A380's capacity.

Production

Major structural sections of the A380 are built in France, Germany, Spain, and the United Kingdom. Due to their size, they are brought to the assembly hall in Toulouse in France by surface transportation, rather than by the A300-600ST Beluga aircraft used for other Airbus models. Components of the A380 are provided by suppliers from around the world; the five largest contributors, by value, are Rolls-Royce, SAFRAN, United Technologies, General Electric, and Goodrich.

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A380 transporter ship Ville de Bordeaux

The front and rear sections of the fuselage are loaded on an Airbus Roll-on/roll-off (RORO) ship, Ville de Bordeaux, in Hamburg in northern Germany, from where they are shipped to the United Kingdom. The wings, which are manufactured at Filton in Bristol and Broughton in North Wales, are transported by barge to Mostyn docks, where the ship adds them to its cargo. In Saint-Nazaire in western France, the ship trades the fuselage sections from Hamburg for larger, assembled sections, some of which include the nose. The ship unloads in Bordeaux. Afterwards, the ship picks up the belly and tail sections by Construcciones Aeronáuticas SA in Cádiz in southern Spain, and delivers them to Bordeaux. From there, the A380 parts are transported by barge to Langon, and by oversize road convoys to the assembly hall in Toulouse.New wider roads, canal systems and barges were developed to deliver the A380 parts. After assembly, the aircraft are flown to Hamburg, XFW to be furnished and painted. It takes 3,600 litres (950 gallons) of paint to cover the 3,100 m² (33,000 ft²) exterior of an A380.

Airbus sized the production facilities and supply chain for a production rate of four A380s per month.

Testing

Five A380s were built for testing and demonstration purposes.

The first A380, serial number MSN001 and registration F-WWOW, was unveiled at a ceremony in Toulouse on 18 January 2005. Its maiden flight took place at 8:29 UTC (10:29 a.m. local time) 27 April 2005. This plane, equipped with Trent 900 engines, flew from Toulouse Blagnac International Airport with a flight crew of six headed by chief test pilot Jacques Rosay. After successfully landing three hours and 54 minutes later, Rosay said flying the A380 had been “like handling a bicycle”.

On 1 December 2005 the A380 achieved its maximum design speed of Mach 0.96 (versus normal cruising speed of Mach 0.85), in a shallow dive, completing the opening of the flight envelope.

On 10 January 2006 the A380 made its first transatlantic flight to Medellín in Colombia, to test engine performance at a high altitude airport. It arrived in North America on 6 February, landing in Iqaluit, Nunavut in Canada for cold-weather testing.

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A380 flying a banked turn at the ILA 2006

On 14 February 2006, during the destructive wing strength certification test on MSN5000, the test wing of the A380 failed at 145% of the limit load, short of the required 150% to meet the certification. Airbus announced modifications adding 30 kg to the wing to provide the required strength.

On 26 March 2006 the A380 underwent evacuation certification in Hamburg in Germany. With 8 of the 16 exits blocked, 853 passengers and 20 crew left the aircraft in 78 seconds, less than the 90 seconds required by certification standards.

Three days later, the A380 received European Aviation Safety Agency (EASA) and United States Federal Aviation Administration (FAA) approval to carry up to 853 passengers.

The maiden flight of the first A380 using GP7200 engines - serial number MSN009 and registration F-WWEA - took place on 25 August 2006.

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Flight test engineer's station on the lower deck of A380 F-WWOW .

On 4 September 2006 the first full passenger-carrying flight test took place. The aircraft flew from Toulouse with 474 Airbus employees on board, in the first of a series of flights to test passenger facilities and comfort.

In November 2006, a further series of route proving flights took place to demonstrate the aircraft's performance for 150 flight hours under typical airline operating conditions.

Airbus obtained type certificate for the A380-841 and A380-842 model from the EASA and FAA on 12 December 2006 in a joint ceremony at the company's French headquarters.The A380-861 model obtained the type certificate 14 December 2007.

As of February 2008, the five A380s in the test programme had logged over 4,565 hours during 1,364 flights, including route proving and demonstration flights.

Design

The new Airbus is sold in two models. The A380-800 was originally designed to carry 555 passengers in a three-class configuration or 853 passengers (538 on the main deck and 315 on the upper deck) in a single-class economy configuration. In May 2007, Airbus began marketing the same aircraft to customers with 30 fewer passengers (now 525 passengers in three classes) traded for 370 km (200 nmi) more range, to better reflect trends in premium class accommodation. The design range for the -800 model is 15,200 km (8,200 nmi).The second model, the A380-800F freighter, will carry 150 tonnes of cargo 10,400 km (5,600 nmi).Future variants may include an A380-900 stretch seating about 656 passengers (or up to 960 passengers in an all economy configuration) and an extended range version with the same passenger capacity as the A380-800.

The A380's wing is sized for a Maximum Take-Off Weight (MTOW) over 650 tonnes in order to accommodate these future versions, albeit with some strengthening required.The stronger wing (and structure) is used on the A380-800F freighter. This common design approach sacrifices some fuel efficiency on the A380-800 passenger model, but Airbus estimates that the size of the aircraft, coupled with the advances in technology described below, will provide lower operating costs per passenger than all current variants of Boeing 747. The A380 also features wingtip fences similar to those found on the A310 and A320 to alleviate the effects of wake turbulence, increasing fuel efficiency and performance.

Flight deck

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The flight deck

Airbus used similar cockpit layout, procedures and handling characteristics to those of other Airbus aircraft, to reduce crew training costs. Accordingly, the A380 features an improved glass cockpit, and fly-by-wire flight controls linked to side-sticks.The improved cockpit displays feature eight 15-by-20 cm (6-by-8-inch) liquid crystal displays, all of which are physically identical and interchangeable. These comprise two Primary Flight Displays, two navigation displays, one engine parameter display, one system display and two Multi-Function Displays. These MFDs are new with the A380, and provide an easy-to-use interface to the flight management system—replacing three multifunction control and display units. They include QWERTY keyboards and trackballs, interfacing with a graphical "point-and-click" display navigation system.One or two HUD (Head Up Display) is optional.

Engines

A Rolls-Royce Trent 900 engine on the wing of an Airbus A380

The A380 can be fitted with two types of engines: A380-841, A380-842 and A380-843F with Rolls-Royce Trent 900, and the A380-861 and A380-863F with Engine Alliance GP7000 turbofans. The Trent 900 is a derivative of the Trent 800, and the GP7000 has roots from the GE90 and PW4000. The Trent 900 core is a scaled version of the Trent 500, but incorporates the swept fan technology of the stillborn Trent 8104.The GP7200 has a GE90-derived core and PW4090-derived fan and low-pressure turbo-machinery. Only two of the four engines are fitted with thrust reversers.

Noise reduction was an important requirement in the A380's design, and particularly affects engine design.Both engine types allow the aircraft to achieve QC/2 departure and QC/0.5 arrival noise limits under the Quota Count system set by London Heathrow Airport, which is expected to become a key destination for the A380.

Fuel

The A380 can run on mixed synthetic jet fuel with a natural-gas-derived component. A three hour test flight on Friday, February 1, 2008 between the Airbus company facility at Filton in the UK to the main Airbus factory in Toulouse, France, was a success. One of the A380's four engines used a mix of 60 percent standard jet kerosene and 40 percent gas to liquids (GTL) fuel. The aircraft needed no modification to use the GTL fuel, which was designed to be mixed with regular jet fuel. Sebastien Remy, head of Airbus SAS's alternative fuel program, said the GTL used was no cleaner in CO2 terms than regular fuel but it had local air quality benefits because it contains no sulphur.

Advanced materials

While most of the fuselage is aluminium, composite materials make up 25% of the A380's airframe, by weight. Carbon-fibre reinforced plastic, glass-fibre reinforced plastic and quartz-fibre reinforced plastic are used extensively in wings, fuselage sections (such as the undercarriage and rear end of fuselage), tail surfaces, and doors. The A380 is the first commercial airliner with a central wing box made of carbon fibre reinforced plastic, and it is the first to have a wing cross-section that is smoothly contoured. Other commercial airliners have wings that are partitioned span-wise in sections. The flowing, continuous cross-section allows for maximum aerodynamic efficiency. Thermoplastics are used in the leading edges of the slats. The new material GLARE (GLAss-REinforced fibre metal laminate) is used in the upper fuselage and on the stabilizers' leading edges. This aluminium-glass-fibre laminate is lighter and has better corrosion and impact resistance than conventional aluminium alloys used in aviation. Unlike earlier composite materials, it can be repaired using conventional aluminium repair techniques.Newer weldable aluminium alloys are also used. This enables the widespread use of laser beam welding manufacturing techniques — eliminating rows of rivets and resulting in a lighter, stronger structure.

Passenger provisions

The A380 produces 50% less cabin noise than a 747 and has higher cabin air pressure (equivalent to an altitude of 1500 metres (5000 ft) versus 2500 metres (8000 ft)); both features are expected to reduce the effects of travel fatigue.The upper and lower decks are connected by two stairways, fore and aft, wide enough to accommodate two passengers side-by-side. In a 555-passenger configuration, the A380 has 33% more seats than a 747-400 in a standard three-class configuration but 50% more cabin area and volume, resulting in more space per passenger. Its maximum certified carrying capacity is 853 passengers in an all-economy-class configuration.The two full-length decks and wide stairways allow multiple seat configurations of the Airbus A380. The announced configurations go from 450 (Qantas) up to 644 passengers (Emirates Airline two-class configuration).

Compared to a 747, the A380 has larger windows and overhead bins, and 60 cm (2 ft) of extra headroom. The wider cabin allows for up to 48 cm (19 inch) wide economy seats at a 10 abreast configuration on the main deck,while 10 abreast seating on the 747 has a seat width of only 43.7 cm (17.2 inch) (seat pitch varies by airline).

Airbus' initial publicity stressed the comfort and space of the A380's cabin, anticipating installations such as relaxation areas, bars, duty-free shops, and beauty salons. Virgin Atlantic Airways already offers a bar as part of its "Upper Class" service on its A340 and 747 aircraft, and has announced plans to include casinos, double beds, and gymnasiums on its A380s.Singapore Airlines offers twelve fully-enclosed first-class suites on its A380, each with one full and one secondary seat, full-sized bed, desk, personal storage. Four of these suites are in the form of two "double" suites featuring a double bed. Qantas Airways has shown their product which features a long flat-bed that converts from the seat but does not have privacy doors. Emirates Airline's fourteen first-class private suites have shared access to two "shower spas". First and business class passengers have shared access to a snack bar and lounge with two sofas, in addition to a first-class-only private lounge.

Integration in the infrastructure

Ground operations

The A380's 20-wheel main landing gear

Early critics claimed that the A380 would damage taxiways and other airport surfaces. However, the pressure exerted by its wheels is lower than that of a Boeing 747 or Boeing 777 because the A380 has 22 wheels, four more than the 747, and eight more than the 777. Airbus measured pavement loads using a 540-tonne (595 short tons) ballasted test rig, designed to replicate the landing gear of the A380. The rig was towed over a section of pavement at Airbus' facilities that had been instrumented with embedded load sensors.

Based on its wingspan, the U.S. FAA classifies the A380 as a Design Group VI aircraft, and originally required a width of 60 m (200 ft) for runways and 30 m (100 ft) for taxiways, compared with 45 m (150 ft) and 23 m (75 ft) for Design Group V aircraft such as the Boeing 747. The FAA also considered limiting the taxi speed of the A380 to 25 km/h (15 mph) when operating on Group V infrastructure, but issued waivers related to the speed restriction and some of the proposed runway widening requirements.Airbus claimed from the beginning that the A380 could safely operate on Group V runways and taxiways, without the need for widening. In July 2007, the FAA and EASA agreed to let the A380 operate on 45 m runways without restrictions.

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The A380 was designed to fit within an 80 × 80 m airport gate, and can land or take off on any runway that can accommodate a Boeing 747. Its large wingspan can require some taxiway and apron reconfigurations, to maintain safe separation margins when two of the aircraft pass each other. Taxiway shoulders may be required to be paved to reduce the likelihood of foreign object damage caused to (or by) the outboard engines, which overhang more than 25 m (80 ft) from the centre line of the aircraft. Any taxiway or runway bridge must be capable of supporting the A380's maximum weight. The terminal gate must be sized such that the A380's wings do not block adjacent gates, and may also provide multiple jetway bridges for simultaneous boarding on both decks. Service vehicles with lifts capable of reaching the upper deck should be obtained, as well as tractors capable of handling the A380's maximum ramp weight.The A380 test aircraft have participated in a campaign of airport compatibility testing to verify the modifications already made at several large airports, visiting a number of airports around the world.

Takeoff and landing separation

In 2005, the ICAO recommended that provisional separation criteria for the A380 on takeoff and landing be substantially greater than for the 747 because preliminary flight test data suggested a stronger wake turbulence. These criteria were in effect while the ICAO's wake vortex steering group, with representatives from the JAA, Eurocontrol, the FAA, and Airbus, refined its 3-year study of the issue with additional flight testing. In September 2006, the working group presented its first conclusions to the ICAO, which rendered new interim recommendations on the issue in November 2006.

The ICAO advised that an aircraft trailing an A380 during approach should maintain a separation of 6 nmi, 8 nmi and 10 nmi respectively for non-A380 "Heavy", "Medium", and "Light" ICAO aircraft categories, compared with 4 nmi, 5 nmi and 6 nmi spacing for other "Heavy" aircraft. Another A380 following an A380 should maintain a separation of 4 nmi. On departure behind an A380, non-A380 "Heavy" aircraft are required to wait two minutes, and "Medium"/"Light" aircraft three minutes for time based operations. The ICAO also advised to use the suffix "Super" to the air traffic control to distinguish the A380 from other "Heavy" aircraft.

Airbus continued undertaking extensive comparative trials until December 2007 and expects the ICAO's wake vortex steering group to issue revised distances similar to those required by the Boeing 747.

Your browser may not support display of this image.MEASUREMENT:

Economy class fuselage-comparison between Airbus A380 and the front-section of Boeing 747, the next-largest passenger aircraft

Measurement

A380-800

A380-800F

Cockpit crew

Two

Seating capacity

525 (3-class)
644 (2-class)
853 (1-class)

12 couriers

Length

73 m (239 ft 6 in)

Span

79.8 m (261 ft 10 in)

Height

24.1 m (79 ft 1 in)

Wheelbase

30.4 m (99 ft 8 in)

Outside fuselage width

7.14 m (23 ft 6 in)

Cabin width, main deck

6.58 m (21 ft 7 in)

Cabin width, upper deck

5.92 m (19 ft 5 in)

Wing area

845 m² (9,100 sq ft)

Operating empty weight

276,800 kg (610,200 lb)

252,200 kg (556,000 lb)

Maximum take-off weight

560,000 kg
(1,235,000 lb)

590,000 kg (1,300,000 lb)

Maximum payload

90,800 kg
(200,000 lb)

152,400 kg (336,000 lb)

Cruising speed

Mach 0.85

Maximum cruising speed

Mach 0.89

Maximum speed

Mach 0.96

Take off run at MTOW

2,750 m (9,020 ft)

2,900 m (9,510 ft)

Range at design load

15,200 km (8,200 nmi)

10,400 km (5,600 nmi)

Service ceiling

13,115 m (43,000 ft)

Maximum fuel capacity

310,000 L (81,890 US gal)

310,000 L (81,890 US gal),
356,000 L (94,000 US gal) option

Engines (4 x)

GP7270 (A380-861)
Trent 970/B (A380-841)
Trent 972/B (A380-842)

GP7277 (A380-863F)
Trent 977/B (A380-843F)

Thrust (4 x)

311 kN (70,000 lbf)

CONCULSION:

Airbus A380-900

Airbus top sales executive and COO John Leahy confirmed the plans for an enlarged variant, the A380-900 which is a slight stretch of the A380-800 from 73m to 79.4m in length. This version would have a seat capacity of 650 passengers in standard configuration, and around 900 passengers in economy-only configuration. The development of the A380-900 is planned to start once production of the A380-800 variant reaches 40 planes per year, expected to be in 2010. Given this timeline, the first A380-900s could be delivered to customers around 2015 at about the same time as the freighter variant A380-800F. Airlines including Emirates,Virgin Atlantic, Cathay Pacific and Air France, as well as leasing company ILFC have already expressed interest in the extended model.According to an interview in Airliner World magazine's December issue, Singapore Airlines CEO Chew Choon Seng revealed at the delivery of their first A380-800 that the airline is keeping their options open with their order, by only defining their first ten A380s as -800s; the remaining nine aircraft could be switched to -900s.

Sunday, August 17, 2008

INDEPENDENCE DAY












15th Aguest










Flag ceremoney




















born in 15th aguest

TECHNICAL SEMINAR ON PROPELLER BY PRASAD

Introduction

A propeller is essentially a type of fan which transmits power by converting rotational motion into thrust for propulsion of a vehicle such as an aircraft, ship, or submarine through a mass such as water or air, by rotating two or more twisted blades about a central shaft, in a manner analogous to rotating a screw through a solid. The blades of a propeller act as rotating wings (the blades of a propeller are in fact wings or airfoils), and produce force through application of both Bernoulli's principle and Newton's third law, generating a difference in pressure between the forward and rear surfaces of the airfoil-shaped blades and by accelerating a mass of air rearward.



Propeller
A propeller is like a spinning wing. Instead of pushing air behind a plane, the airfoil shaped blades pull an airplane forward just as an airplane’s wings lift it upward. The amount of thrust created by a propeller depends on how fast and at what angle its blades cut through the air. Probably the most important parts of an airplane, after the wing, are the propeller and engine. The propeller (or, on jet aircraft, the jets) provides the thrust that moves the plane forward A propeller is really just a special, spinning wing. If you looked at the cross section of a propeller, you'd find that a propeller has an airfoil shape and an angle of attack. Just by looking at the propeller pictured above, you can see that the angle of attack changes along the length of the propeller -- the angle is greater toward the center because the speed of the propeller through the air is slower close to the hub. Many larger propeller aircraft have more elaborate three-blade or four-blade props with adjustable pitch mechanisms. These mechanisms let the pilot adjust the propeller's angle of attack depending on air speed and altitude.
The drawback of a prop plane is that it can't be very fast--if you need a plane that flies faster than 400 knots, you need a jet. Prop planes don't fly as high as jets do; a King Air will fly up to 31,000 feet above sea level, while business jets routinely ply the skies above 41,000 feet
Contra-rotating propellers, also referred to as coaxial contra-rotating propellers, apply the maximum power of a single piston or turboprop engine to drive two propellers in opposite rotation. Contra-rotating propellers are common in some marine transmission systems, in particular for medium to large size planing leisure crafts. Two propellers are arranged one behind the other, and power is transferred from the engine via a planetary gear transmission. Contra-rotating propellers should not be confused with counter-rotating propellers, a term which describes twin-engined aircraft with the airscrew on one engine turning clockwise and the other counter-clockwise.

Four Types of Airplane Propellers
Fixed Pitch

One of the first types of airplane propellers is the fixed pitch design. The pitch of these propellers is determined by the manufacturer. Therefore, the performance of your airplane will be limited by the propeller. You will often be given a choice of pitches best suited for climbing or cruising. Airplane propellers that are designed for climbing will have a relatively fine pitch. Those that are made for cruising will have a relatively coarse pitch.

In-flight Adjustable
One of the next types of airplane propellers is the in-flight adjustable design. These propellers allow you to adjust the pitch of the propeller during flight. This allows you to achieve many different power settings when combined with the throttle control. You will be able to stay within the constraints of the engine speeds while attaining a range of airspeeds.

Ground Adjustable
Another type of propeller is the ground adjustable variety. Instead of being able to adjust the pitch during flight, you will have to adjust these airplane propellers before takeoff. You will be able to adjust the pitch based on the type of flying you will be doing. These airplane propellers are a great way to test out different pitches. You can easily find the pitch that is best to use with your plane and your flying style.

Constant Speed
One of the final types of airplane propellers is the constant speed design. Instead of changing the pitch manually, it is changed automatically by a governor. All you have to do is tell the system what your desired engine speed is. When the propeller speed starts to increase, the governor will detect it and increase the pitch to correct it. If the speed starts to decrease, the governor will decrease the pitch of the airplane propellers.
The characteristics of a composite propeller:
1) Easy to fabricate.
2) Mold can be made using an existing metal or wooden propeller as a plug.
3) By making the mold flexible and adjustable props with slightly different pitch values can be made
4) A fiberglass/epoxy propeller is about 50 to 70 percent heavier than a wooden prop but is lighter than a metal prop.
5) The weight difference results in different torsional vibration characteristics in power plants having a reduction drive.
6) A composite prop is much stronger than a wooden propeller.

Aircraft fans
A fan is a propeller with a large number of blades. A fan therefore produces a lot of thrust for a given diameter but the closeness of the blades means that each strongly affects the flow around the others. If the flow is supersonic, this interference can be beneficial if the flow can be compressed through a series of shock waves rather than one. By placing the fan within a shaped duct – a ducted fan – specific flow patterns can be created depending on flight speed and engine performance. As air enters the duct, its speed is reduced and pressure and temperature increase. If the aircraft is at a high subsonic speed this creates two advantages – the air enters the fan at a lower Mach speed and the higher temperature increases the local speed of sound. While there is a loss in efficiency as the fan is drawing on a smaller area of the free stream and so using less air, this is balanced by the ducted fan retaining efficiency at higher speeds where conventional propeller efficiency would be poor. A ducted fan or propeller also has certain benefits at lower speeds but the duct needs to be shaped in a different manner to one for higher speed flight. More air is taken in and the fan therefore operates at an efficiency equivalent to a larger un-ducted propeller. Noise is also reduced by the ducting and should a blade become detached the duct would contain the damage. However the duct adds weight, cost, complexity and (to a certain degree) drag.
Usually propellers have two, three, or four blades; for highspeed or high-powered airplanes, six or more blades are used. In some cases these propellers have an equal number of opposite rotating blades on the same shaft, and are known as dual-rotation propellers.
A propeller blade advances through the air along an approximate helical path which is the result of its forward and rotational velocity components. This action is similar to a screw being turned in a solid surface, except that in the case of the propeller a slippage occurs because air is a fluid. Because of the similarity to the action of a screw, a propeller is also known as an airscrew. To rotate the propeller blade, the engine exerts a torque force. This force is reacted on by the blade in terms of lift and drag force components produced by the blade sections in the opposite direction. As a result of the rational forces reacting on the air, a rotational velocity remains in the propeller wake with the same rotational direction as the propeller. This rotational velocity times the mass of the air is proportional to the power input. The sum of all the lift and drag components of the blade sections in the direction of flight are equal to the thrust produced. These forces react on the air, giving an axial velocity component opposite to the direction of flight. By the momentum theory, this velocity times the mass of the air going through the propeller is equal to the thrust.
A propeller blade must be designed to withstand very high centrifugal forces. The blade also must withstand the thrust force produced plus any vibratory forces generated, such as those due to uneven flow fields. To withstand the high stresses due to rotation, propeller blades have been made from a number of materials, including wood, aluminum, hollow steel, and plastic composites. The most common material used has been solid aluminum. However, the composite blade constructions are being used for new turboprop installations because of their very light weight and high strength characteristics.
For a small, low-power airplane, very simple, fixed-pitch, single-piece, two-blade propellers are used. The rotational speed of these propellers depends directly on the power input and forward speed of the airplane. Because of the fixed-blade angle of this type of propeller, it operates near peak efficiency only at one condition. To overcome the limitations of the simple fixed-pitch propeller, configurations that provide for variable blade angles are used. The blades of these propellers are retained in their hub so that they can be rotated about their centerline while the propeller rotates. For the normal range of operation, the blade angle varies from the low blade angle needed for takeoff to the high blade angle needed for the maximum speed of the airplane.
we specified hi grade aluminum alloy, type 6061, per Mil STD and ASM specifications.

Working
As Newton stated, "actio est reactio". For the propulsion problem, this means that a device accelerating air or water in one direction, feels a force in the opposite direction. A propeller accelerates incoming air particles, "throwing" them towards the rear of the airplane, and thus feels a force on itself - this force is called thrust. Looking more closely at propellers shows, that a propeller adds a velocity to then incoming velocity v. The first half of this acceleration takes place in front of the propeller, and the second half behind the propeller. Because the mass of air passing through the stream tube must be constant (conservation of mass), the increased velocity leads to a contraction of the stream tube passing through the propeller disk (neglecting compressibility)
Besides the contraction of the stream tube, a propeller also adds a swirl component to its outflow (wake). The amount of swirl depends on the rotational speed of the engine and eats up energy, which is not available for thrust anymore. Typical, well designed propellers loose about 1% to 5% of their power in the swirl of the propeller wake. The swirl angle (about 1°...10°) may cause non symmetrical flow conditions on parts behind the propeller, e.g. at the tail planes. The stream tube of a low bypass ratio turbo jet engine looks completely different, because the acceleration of the flow is mainly performed through the thermal expansion of the heated air. Here the incoming stream tube will usually have a smaller diameter than the exhaust stream, depending on operating conditions. The final extreme is the rocket engine, which has no incoming stream tube, but creates its exhaust jet only by expanding the gases created by a chemical reaction (e.g. by burning a fuel/oxygen mixture). The total mass contained in the exhaust flow is carried inside the rocket (fuel plus oxydator). Thrust, Power and Efficiency - Momentum Theory
The Thrust of a propeller depends on the volume of air (or water) accelerated per time unit, on the amount of the acceleration, and on the density of the medium. Based on momentum considerations, it can be expressed by the following formula:
Examining the quite simple formula reveals, that the thrust T increases when the diameter D increases (the first term is the area of the propeller "disk") or when the density of the medium increases. The acceleration of a propeller depends on the velocity v, thus it is generally not true that increasing the velocity v increases the thrust. But it can be said, that increasing the additional velocity , increases the thrust. For a propeller of a fixed diameter, working in a certain medium at a certain speed, thrust depends on the velocity increase only.
Power is defined as force times distance per time. Using the available thrust T to drive a vehicle at a certain speed v (which already is distance per time) we can calculate the propulsive power (sometimes also called available power) from:

Now, thrust is the one thing, the power to create this thrust the other. Of course we want to create as much thrust as possible from the smallest amount of power, which can be expressed by the term efficiency.
Efficiency of a propeller is defined as the ratio of available power to the engine power which is

Note, that this definition for efficiency contains the velocity v, which means, that the efficiency approaches zero as the flight speed goes to zero, because the thrust cannot become infinitely large. So this definition is not useful for the special case of static thrust.
Neglecting rotational losses, the power absorbed by the propeller can also be expressed by

which can be used to combine the equations above into a relation between the velocity and the efficiency for a given power and diameter:
Optimum efficiency according to momentum theory versus flight speed for different power loadings P/D² in [W/m²].
The density of the air is assumed to be 1.225 kg/m³. Curves have been calculated by
A propeller's efficiency is determined by







Dimension of Koolprop
Koolprop is designed and made for different airscrew driven vehicles, included airboats, hovercraft, Ultra light and Light Sport aircraft. There are a lot of different models for different applications, right and left hand rotation 63”-73” As a standard, they have 3 blades and intended for engines 40-120HP. You can use them with a lot of engines from Rotax 440 to powerful Rotax 914 and Subaru-Suzuki auto conversions. For example one model 67”-69” is especially recommended for G10-G13 Suzuki with 2.2-2.5 reduction ratio. I got 386lb static thrust with this prop (standard TBI G10) and excellent performances with my Eagle trike. Special reinforced blades up to 160HP.
Their design is similar (in some points) to Kievprop which is well known in North America. For example, Koolprop hub has exactly the same design, CNC machined with D16T aviation aluninum and anodised. You can use your old Kievprop hub and spinner with Kool blades. I have in stock and tested in flight both Kool and Kiev and can compare them. There are some points making Kool preferable for me. It is also hand-made but it is made with carbon-glass composite instead of fiberglass. Kool blade is rigid, it helps reducing idle wobbling and vibration. Its finish is epoxy gelcoat, more hard and smooth. As Kiev, Kool has integrated strong leading edge protection, but it is made with stainless steel (not copper). It looks more beautiful (always shiny) and stronger.
Kool blade is straight, classical-style. It makes its blade a little more efficient than the same diameter scimitar-style one. It could be important, especially if you are restricted in diameter. Most Kool models have antivortex blade tips like wings of modern airplanes. Koolprop set included 3 blades, hub, all hardware, pitch protractor and soft blade covers. Finish is excellent black gelcoat with white tips. It can be ordered with Carbon-fiberglass 8”diam 9” length spinner and 60mm (2.25") hub spacer.Koolprop specifications.- Diameter 63"-73"- Maximum blade width 5.8"- Maximum speed of rotation 3000 rpm- Power of engine 40-120HP- Range of operation temperatures +55 -20C*- Stainless steel integrated LE protection.- Available in left and right hand rotation, for pusher and tractor plane.













Propeller engine: engine of propulsion or traction equipped with blades.
Carburetor: apparatus where fuel is mixed with to feed an internal combustion engine.
Crank: arm perpendicular to an axle used to create circular motion.
Piston: cylindrical part that moves up and down in a tube and transmits power produced by the fuel.
Cylinder: type of roller that applies uniform pressure.
Valve: regulation device.
Exhaust: device composed of parts that allow the expulsion of spent gases.
Propeller blade: blade, arm of the propeller.
Spark plug: ignition device of an internal combustion engine.

Propeller Angle of Attack
The diagram to the right shows the two blades on a typical propeller. Some propellers have more than two blades but all the concepts developed here will still apply.

Each blade cross-section is moving along an arc around the crankshaft as well as traveling forward. As a result its motion is a helix.

The drawbacks of a composite propeller:
1) It may be too strong! In an aircraft with retractable gear a belly landing may result in a damaged crankshaft.
2) However, the leading edge of the prop is not as hard as metal. Therefore, grit and gravel will damage the leading edge of the prop. A pusher prop in particular needs continuous maintenance on dirt air strips.
3) The hub of a composite propeller may shrink if made of poor plastics and if the prop flange gets too hot (eg pusher propellers).

CONCLUSION:
Using the quite simple momentum theory, we can already deduct important information about the performance of propellers. We can study the influence of the propeller diameter on efficiency as well as how it depends on flight speeder the density of the air (corresponding to a certain altitude). We learn that an efficient propeller should have a small power loading per disk area, i.e. a large diameter is required.
The momentum theory does neither take the platform of the blade into account nor the characteristics of the airfoil sections. For the design or the analysis of a propeller more sophisticated models are necessary, but the momentum theory always gives a good estimate for the maximum efficiency which we can expect.
It is possible to extend the momentum theory to include rotational losses, which results in an additional efficiency loss of 2 to 5 percent for typical propellers. These losses depend on the velocity of rotation and favor low torque, high rpm conditions.

Prasad.SS
AERO-DEPT
PMRIT.
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Wednesday, August 13, 2008

MA1201 ASSIGNMENT QUESTIONS

Questions for Mathematics Assignment-2


1. Determine bn in Fourier series expansion of f(x) =1/2(π-x) in 0

2. What is constant term a0 and an in Fourier series expansion of
f(x) =x-x^3 in (-π, π).

3. Find Half range sine series for f(x)=2 in 0

4. Find Fourier series for f(x)=|cosx| in interval (-π, π).

5. Find Fourier series up to second harmonic for following data

α

0

1

2

3

4

5

f(x)

9

18

24

28

26

20

6. Find Fourier series expansion of period 1 for

f(x) = x (0, 1/2) 1-x (1/2 , 1).

7. Find complex form of Fourier series for the f(x) = e^-x in (-1, 1).

8. Determine Fourier series
f(x) = -1+x (-π < style="">
1+x (0 < style=""> Hence deduce 1-1/3+1/5+…….. = π/4.

9. Find Fourier series for f’ (a) =x^2 is (-π, π).

Hence find 1/1^4 + 1/2^4 + 1/3^4+…….