Sikorsky CH-124 Sea King
The Sikorsky CH-124 Sea King is a twin-engined anti-submarine warfare helicopter designed for shipboard use by Canadian naval forces, based on the US Navy's SH-3. It served with the Royal Canadian Navy and Canadian Armed Forces from 1963 to 2018; the advent of nuclear-powered attack submarines in the late 1950s prompted RCN leaders to assess the new threat they posed. Although these craft were noisier than older submarines and could therefore be detected at longer ranges, they were capable of 30 knots while submerged, faster than the top speed of the RCN's new St. Laurent-class destroyer escorts at 28.5 knots. Some RCN leaders harbored serious doubts that the destroyers could pursue and destroy such fast vessels when operating in pairs. During a 25 February 1959 meeting of the Naval Board, it was decided that the Navy would counter the new threat by outfitting destroyers for helicopter operation; the RCN had examined the feasibility of operating ASW helicopters from small escorts when it modified the Prestonian-class frigate HMCS Buckingham in mid-1956 with a temporary helicopter landing platform.
Successful trials were held in October 1956 using a Sikorsky HO4S-3 and a larger temporary landing platform was soon installed on the new destroyer escort HMCS Ottawa. Operational trials were conducted using an RCAF Sikorsky S-58, a larger and heavier aircraft than the HO4S, the success of these tests led to approval of the concept; the RCN's current HO4S-3 utility helicopter could not operate safely in inclement weather with a heavy weapons and sensor load, which would be imperative for the ASW role. Initial 1959 studies identified two helicopters that seemed suitable – the Sikorsky S-61 and the Kaman K-20 - but neither aircraft had flown at the time, so no choice was made. After further studies concluded that the smaller Kaman would better satisfy RCN requirements, the Treasury Board approved an initial procurement of 12 HU2K helicopters for $14.5 million in December 1960. Despite this apparent setback for Sikorsky, several factors would derail the Kaman proposal; when the Naval Board held a follow-up meeting on 27 January 1961 to discuss the program, it was revealed that the asking price for the initial 12 units had nearly doubled to $23 million, a mere 6 weeks after the Treasury Board had approved the purchase.
The Naval Board continued to endorse the HU2K, but some RCN leaders had serious misgivings due to the drastic price increase and staff reports that Kaman's performance projections might be overly optimistic. The Naval Board decided to await upcoming USN sea trials of the HU2K before rendering a final decision; the USN trials confirmed the calculations of RCN staff members. The Sea King was chosen for production on 20 December 1961; the first of 41 helicopters would be delivered in 1963 carrying the designation CHSS-2 Sea King. The airframe components were made by Sikorsky in Connecticut but most CHSS-2s were assembled in Longueuil, Quebec by United Aircraft of Canada, a subsidiary of Sikorsky's parent company, United Aircraft. On 27 November 1963, the new landing platform aboard HMCS Assiniboine was used for the first operational destroyer landing of a production CHSS-2. Upon the unification of Canada's military in 1968, the CHSS-2 was re-designated CH-124. In the 1960s, the RCN developed a technique for landing the huge helicopters on small ship decks, using a'hauldown' winch, earning aircrews the nickname of'Crazy Canucks'.
The'Beartrap' allows recovery of the Sea King in any sea state. In 1968, the RCN, Royal Canadian Air Force and Canadian Army unified to form the Canadian Forces. In August 2011, the Canadian Forces reverted to the former structure of the Royal Canadian Navy, Canadian Army and Royal Canadian Air Force; the Sea Kings were assigned to the former Iroquois-class destroyers, Halifax-class frigates, the former Protecteur-class replenishment ships as a means of extending the surveillance capabilities beyond the horizon. When deployed, each Sea King is accompanied by several crews; each crew consists of two pilots, a Tactical Coordinator, an Airborne Electronic Sensor Operator. In order to find submarines, the Sea King's sonar uses a transducer ball at the end of a 450-foot cable, it can be fitted with FLIR to find surface vessels at night. The CH-124 has undergone numerous refits and upgrades with regard to the electronics, main gearboxes and engines, surface-search radar, secure cargo and passenger carrying capabilities.
In 2013 the CH-124 fleet averaged 9–14,000 flying hours, while Sea Kings of other fleets go as high as 40,000 hours. Although the CH-124 had frequent technical issues, none are serious, they could maintain an 87 percent serviceability rate. On December 1st, 2018, the CH-124 was retired in a ceremony at Vancouver Island, British Columbia, concluding 55 years of service. Of the surviving 28 Canadian Sea Kings, nine are destined for museums or to be displayed as monuments, 15 are to be sold, three scrapped, one retained as a training aid. From 1983 onward attempts were made to replace the aging Sea King helicopters. Due to a series of financial and political issues, the process was hampered by repeated delays. In the end the CH-148 Cyclone, a new version of
Pratt & Whitney Canada PW500
The Pratt & Whitney Canada PW500 is a series of medium thrust turbofan engines designed for business jet applications. The PW530 has a single stage fan, driven by a 2-stage LP turbine, supercharging a 2A/1CF axial-centrifugal HP compressor, driven by a single stage HP turbine. Rated at 2,887 pounds of thrust, it entered service in February 1997. Although similar in configuration, the PW535 has a T-stage, mounted on the LP shaft behind the fan, to increase overall pressure ratio and core flow, it entered service in September 2000 Similar to the PW535, the PW545 has an additional LP turbine stage to drive a larger diameter fan. It entered service in July 1998. Cessna Citation Bravo Cessna Citation V Cessna Citation Excel General Atomics Avenger Embraer Phenom 300 Related lists List of aircraft engines Pratt & Whitney Canada PW500 page
Canada is a country in the northern part of North America. Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering 9.98 million square kilometres, making it the world's second-largest country by total area. Canada's southern border with the United States is the world's longest bi-national land border, its capital is Ottawa, its three largest metropolitan areas are Toronto and Vancouver. As a whole, Canada is sparsely populated, the majority of its land area being dominated by forest and tundra, its population is urbanized, with over 80 percent of its inhabitants concentrated in large and medium-sized cities, many near the southern border. Canada's climate varies across its vast area, ranging from arctic weather in the north, to hot summers in the southern regions, with four distinct seasons. Various indigenous peoples have inhabited what is now Canada for thousands of years prior to European colonization. Beginning in the 16th century and French expeditions explored, settled, along the Atlantic coast.
As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces; this began an accretion of provinces and territories and a process of increasing autonomy from the United Kingdom. This widening autonomy was highlighted by the Statute of Westminster of 1931 and culminated in the Canada Act of 1982, which severed the vestiges of legal dependence on the British parliament. Canada is a parliamentary democracy and a constitutional monarchy in the Westminster tradition, with Elizabeth II as its queen and a prime minister who serves as the chair of the federal cabinet and head of government; the country is a realm within the Commonwealth of Nations, a member of the Francophonie and bilingual at the federal level. It ranks among the highest in international measurements of government transparency, civil liberties, quality of life, economic freedom, education.
It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many other countries. Canada's long and complex relationship with the United States has had a significant impact on its economy and culture. A developed country, Canada has the sixteenth-highest nominal per capita income globally as well as the twelfth-highest ranking in the Human Development Index, its advanced economy is the tenth-largest in the world, relying chiefly upon its abundant natural resources and well-developed international trade networks. Canada is part of several major international and intergovernmental institutions or groupings including the United Nations, the North Atlantic Treaty Organization, the G7, the Group of Ten, the G20, the North American Free Trade Agreement and the Asia-Pacific Economic Cooperation forum. While a variety of theories have been postulated for the etymological origins of Canada, the name is now accepted as coming from the St. Lawrence Iroquoian word kanata, meaning "village" or "settlement".
In 1535, indigenous inhabitants of the present-day Quebec City region used the word to direct French explorer Jacques Cartier to the village of Stadacona. Cartier used the word Canada to refer not only to that particular village but to the entire area subject to Donnacona. From the 16th to the early 18th century "Canada" referred to the part of New France that lay along the Saint Lawrence River. In 1791, the area became two British colonies called Upper Canada and Lower Canada collectively named the Canadas. Upon Confederation in 1867, Canada was adopted as the legal name for the new country at the London Conference, the word Dominion was conferred as the country's title. By the 1950s, the term Dominion of Canada was no longer used by the United Kingdom, which considered Canada a "Realm of the Commonwealth"; the government of Louis St. Laurent ended the practice of using'Dominion' in the Statutes of Canada in 1951. In 1982, the passage of the Canada Act, bringing the Constitution of Canada under Canadian control, referred only to Canada, that year the name of the national holiday was changed from Dominion Day to Canada Day.
The term Dominion was used to distinguish the federal government from the provinces, though after the Second World War the term federal had replaced dominion. Indigenous peoples in present-day Canada include the First Nations, Métis, the last being a mixed-blood people who originated in the mid-17th century when First Nations and Inuit people married European settlers; the term "Aboriginal" as a collective noun is a specific term of art used in some legal documents, including the Constitution Act 1982. The first inhabitants of North America are hypothesized to have migrated from Siberia by way of the Bering land bridge and arrived at least 14,000 years ago; the Paleo-Indian archeological sites at Old Crow Flats and Bluefish Caves are two of the oldest sites of human habitation in Canada. The characteristics of Canadian indigenous societies included permanent settlements, complex societal hierarchies, trading networks; some of these cultures had collapsed by the time European explorers arrived in the late 15th and early 16th centuries and have only been discovered through archeological investigations.
The indigenous population at the time of the first European settlements is estimated to have been between 200,000
A turboprop engine is a turbine engine that drives an aircraft propeller. In its simplest form a turboprop consists of an intake, combustor, a propelling nozzle. Air is compressed by the compressor. Fuel is added to the compressed air in the combustor, where the fuel-air mixture combusts; the hot combustion gases expand through the turbine. Some of the power generated by the turbine is used to drive the compressor; the rest is transmitted through the reduction gearing to the propeller. Further expansion of the gases occurs in the propelling nozzle, where the gases exhaust to atmospheric pressure; the propelling nozzle provides a small proportion of the thrust generated by a turboprop. In contrast to a turbojet, the engine's exhaust gases do not contain enough energy to create significant thrust, since all of the engine's power is used to drive the propeller. Exhaust thrust in a turboprop is sacrificed in favour of shaft power, obtained by extracting additional power from turbine expansion. Owing to the additional expansion in the turbine system, the residual energy in the exhaust jet is low.
The exhaust jet produces around or less than 10% of the total thrust. A higher proportion of the thrust comes from less at higher speeds. Turboprops can have bypass ratios up to 50-100 although the propulsion airflow is less defined for propellers than for fans; the propeller is coupled to the turbine through a reduction gear that converts the high RPM/low torque output to low RPM/high torque. The propeller itself is a constant speed type similar to that used with larger reciprocating aircraft engines. Unlike the small diameter fans used in turbofan jet engines, the propeller has a large diameter that lets it accelerate a large volume of air; this permits a lower airstream velocity for a given amount of thrust. As it is more efficient at low speeds to accelerate a large amount of air by a small degree than a small amount of air by a large degree, a low disc loading increases the aircraft's energy efficiency, this reduces the fuel use. Propellers lose efficiency as aircraft speed increases, so turboprops are not used on high-speed aircraft above Mach 0.6-0.7.
However, propfan engines, which are similar to turboprop engines, can cruise at flight speeds approaching Mach 0.75. To increase propeller efficiency, a mechanism can be used to alter their pitch relative to the airspeed. A variable-pitch propeller called a controllable-pitch propeller, can be used to generate negative thrust while decelerating on the runway. Additionally, in the event of an engine failure, the pitch can be adjusted to a vaning pitch, thus minimizing the drag of the non-functioning propeller. While most modern turbojet and turbofan engines use axial-flow compressors, turboprop engines contain at least one stage of centrifugal compression. Centrifugal compressors have the advantage of being simple and lightweight, at the expense of a streamlined shape. While the power turbine may be integral with the gas generator section, many turboprops today feature a free power turbine on a separate coaxial shaft; this enables the propeller to rotate independent of compressor speed. Residual thrust on a turboshaft is avoided by further expansion in the turbine system and/or truncating and turning the exhaust 180 degrees, to produce two opposing jets.
Apart from the above, there is little difference between a turboprop and a turboshaft. Alan Arnold Griffith had published a paper on turbine design in 1926. Subsequent work at the Royal Aircraft Establishment investigated axial turbine designs that could be used to supply power to a shaft and thence a propeller. From 1929, Frank Whittle began work on centrifugal turbine designs that would deliver pure jet thrust; the world's first turboprop was designed by the Hungarian mechanical engineer György Jendrassik. Jendrassik published a turboprop idea in 1928, on 12 March 1929 he patented his invention. In 1938, he built a small-scale experimental gas turbine; the larger Jendrassik Cs-1, with a predicted output of 1,000 bhp, was produced and tested at the Ganz Works in Budapest between 1937 and 1941. It was of axial-flow design with 15 compressor and 7 turbine stages, annular combustion chamber and many other modern features. First run in 1940, combustion problems limited its output to 400 bhp. In 1941,the engine was abandoned due to war, the factory was turned over to conventional engine production.
The world's first turboprop engine that went into mass production was designed by a German engineer, Max Adolf Mueller, in 1942. The first mention of turboprop engines in the general public press was in the February 1944 issue of the British aviation publication Flight, which included a detailed cutaway drawing of what a possible future turboprop engine could look like; the drawing was close to what the future Rolls-Royce Trent would look like. The first British turboprop engine was the Rolls-Royce RB.50 Trent, a converted Derwent II fitted with reduction gear and a Rotol 7 ft 11 in five-bladed propeller. Two Trents were fitted to Gloster Meteor EE227 — the sole "Trent-Meteor" — which thus became the world's first turboprop-powered aircraft, albeit a test-bed not intended for production, it first flew on 20 September 1945. From their experience with the Trent, Rolls-Royce developed the Rolls-Royce Clyde, the first turboprop engine to be type certificated for military and civil use, the Dart, which became one of the most reliable turboprop engines built.
Dart production continued for more than fifty years. The Dart-powered Vickers Vi
The turbofan or fanjet is a type of airbreathing jet engine, used in aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the turbo portion refers to a gas turbine engine which achieves mechanical energy from combustion, the fan, a ducted fan that uses the mechanical energy from the gas turbine to accelerate air rearwards. Thus, whereas all the air taken in by a turbojet passes through the turbine, in a turbofan some of that air bypasses the turbine. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust; the ratio of the mass-flow of air bypassing the engine core divided by the mass-flow of air passing through the core is referred to as the bypass ratio. The engine produces thrust through a combination of these two portions working together. Most commercial aviation jet engines in use today are of the high-bypass type, most modern military fighter engines are low-bypass. Afterburners are not used on high-bypass turbofan engines but may be used on either low-bypass turbofan or turbojet engines.
Modern turbofans have either a smaller fan with several stages. An early configuration combined a low-pressure fan in a single rear-mounted unit. Turbofans were invented to circumvent an awkward feature of turbojets, that they were inefficient for subsonic flight. To raise the efficiency of a turbojet, the obvious approach would be to increase the burner temperature, to give better Carnot efficiency and fit larger compressors and nozzles. However, while that does increase thrust somewhat, the exhaust jet leaves the engine with higher velocity, which at subsonic flight speeds, takes most of the extra energy with it, wasting fuel. Instead, a turbofan can be thought of as a turbojet being used to drive a ducted fan, with both of those contributing to the thrust. Whereas all the air taken in by a turbojet passes through the turbine, in a turbofan some of that air bypasses the turbine; because the turbine has to additionally drive the fan, the turbine is larger and has larger pressure and temperature drops, so the nozzles are smaller.
This means. The fan has lower exhaust velocity, giving much more thrust per unit energy; the overall effective exhaust velocity of the two exhaust jets can be made closer to a normal subsonic aircraft's flight speed. In effect, a turbofan emits a large amount of air more whereas a turbojet emits a smaller amount of air, a far less efficient way to generate the same thrust; the ratio of the mass-flow of air bypassing the engine core compared to the mass-flow of air passing through the core is referred to as the bypass ratio. The engine produces thrust through a combination of these two portions working together. Most commercial aviation jet engines in use today are of the high-bypass type, most modern military fighter engines are low-bypass. Afterburners are not used on high-bypass turbofan engines but may be used on either low-bypass turbofan or turbojet engines; the bypass ratio of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core.
A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core. Turbofan engines are described in terms of BPR, which together with overall pressure ratio, turbine inlet temperature and fan pressure ratio are important design parameters. In addition bpr is quoted for turboprop and unducted fan installations because their high propulsive efficiency gives them the overall efficiency characteristics of high bypass turbofans; this allows them to be shown together with turbofans on plots which show trends of reducing specific fuel consumption with increasing BPS. BPR can be quoted for lift fan installations where the fan airflow is remote from the engine and doesn't physically touch the engine core. Bypass provides a lower fuel consumption for the same thrust. If all the gas power from a gas turbine is converted to kinetic energy in a propelling nozzle, the aircraft is best suited to high supersonic speeds. If it is all transferred to a separate big mass of air with low kinetic energy, the aircraft is best suited to zero speed.
For speeds in between, the gas power is shared between a separate airstream and the gas turbine's own nozzle flow in a proportion which gives the aircraft performance required. The trade off between mass flow and velocity is seen with propellers and helicopter rotors by comparing disc loading and power loading. For example, the same helicopter weight can be supported by a high power engine and small diameter rotor or, for less fuel, a lower power engine and bigger rotor with lower velocity through the rotor. Bypass refers to transferring gas power from a gas turbine to a bypass stream of air to reduce fuel consumption and jet noise. Alternatively, there may be a requirement for an afterburning engine where the sole requirement for bypass is to provide cooling air; this sets the lower limit for bpr and these engines have been called "leaky" or continuous bleed turbojets and low bpr turbojets. Low bpr has bee