60-412: The Handley Page HPR.7 Dart Herald is a British turboprop passenger aircraft , designed in the 1950s as a DC-3 replacement, but only entering service in the 1960s by which time it faced stiff competition from Fokker ( F27 Friendship ) and Avro ( Avro/Hawker Siddeley HS748 ). Sales were disappointing, contributing in part to the demise of Handley Page in 1970. In the mid-1950s Handley Page developed
120-400: A Pratt & Whitney Canada PT6 , and an under-speed governor on a Honeywell TPE331 . The turboprop is also distinguished from other kinds of turbine engine in that the fuel control unit is connected to the governor to help dictate power. To make the engine more compact, reverse airflow can be used. On a reverse-flow turboprop engine, the compressor intake is at the aft of the engine, and
180-424: A propelling nozzle . Air enters the intake and is compressed by the compressor. Fuel is then added to the compressed air in the combustor, where the fuel-air mixture then combusts . The hot combustion gases expand through the turbine stages, generating power at the point of exhaust. Some of the power generated by the turbine is used to drive the compressor and electric generator . The gases are then exhausted from
240-520: A bombing raid. In 1941, the engine was abandoned due to war, and the factory converted to conventional engine production. 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 very close to what
300-442: A governor, and overspeed governor, and a fuel-topping governor. The governor works in much the same way a reciprocating engine propeller governor works, though a turboprop governor may incorporate beta control valve or beta lift rod for beta operation and is typically located in the 12 o'clock position. There are also other governors that are included in addition depending on the model, such as an overspeed and fuel topping governor on
360-692: A leased Series 100 on 16 May 1961, receiving the first of its own Series 200s in January 1962, while BEA began Herald operations in March 1962. The Herald attracted much early interest around the world because of its astonishing short field performance and excellent flight characteristics, but Handley Page failed to close many of the deals, as the F-27 and the Avro 748 /HS.748 had become rival offerings, both of which proved significantly more popular. A key design feature of
420-571: A merger with British Aircraft Corporation or Hawker Siddeley as part of the government's policy of consolidation of the British aircraft industry. As Hawker Siddeley offered less than half the valuation that Frederick Handley Page placed on the company, the merger did not occur, and the RAF's order went to the Avro 780, which became the Andover . The Herald Series 400 was a simpler tactical transport with
480-410: A mode typically consisting of zero to negative thrust, is used for all ground operations aside from takeoff. The Beta mode is further broken down into 2 additional modes, Beta for taxi and Beta plus power. Beta for taxi as the name implies is used for taxi operations and consists of all pitch ranges from the lowest alpha range pitch, all the way down to zero pitch, producing very little to zero-thrust and
540-515: A new fast short-range regional airliner , intended to replace the older Douglas DC-3 , particularly in third-world countries. The design, originally known as the HPR.3 Herald, emanated from the drawing office at Handley Page (Reading) Limited—the former Miles Aircraft factory site, which had developed an earlier airliner design, the Miles Marathon . The Herald was an extensive re-development of
600-581: A small amount of air by a large degree, a low disc loading (thrust per unit disc area) increases the aircraft's energy efficiency , and this reduces the fuel use. Propellers work well until the flight speed of the aircraft is high enough that the airflow past the blade tips reaches the speed of sound. Beyond that speed, the proportion of the power that drives the propeller that is converted to propeller thrust falls dramatically. For this reason turboprop engines are not commonly used on aircraft that fly faster than 0.6–0.7 Mach , with some exceptions such as
660-718: A strengthened cabin floor and side loading doors that could be opened in flight for dropping of supplies or paratroops. Eight were built for the Royal Malaysian Air Force . By 1965, almost all sales momentum had been lost, and Handley Page proposed the Series 700, powered by 2,320 ehp (1,730 kW) Dart 532s, with increased fuel and weights and was capable of seating up to 60 passengers. The Brazilian airline VASP placed an order for ten Series 700s, with plans made for production in Brazil, while further orders for
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#1732779600434720-591: 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 receive a type certificate for military and civil use, and the Dart , which became one of the most reliable turboprop engines ever built. Dart production continued for more than fifty years. The Dart-powered Vickers Viscount
780-489: Is coupled to the turbine through a reduction gear that converts the high RPM /low torque output to low RPM/high torque. This can be of two primary designs, free-turbine and fixed. A free-turbine turboshaft found on the Pratt & Whitney Canada PT6 , where the gas generator is not connected to the propeller. This allows for propeller strike or similar damage to occur without damaging the gas generator and allowing for only
840-407: Is that it can also be used to generate reverse thrust to reduce stopping distance on the runway. Additionally, in the event of an engine failure, the propeller can be feathered , thus minimizing the drag of the non-functioning propeller. 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
900-421: Is typically accessed by moving the power lever to a beta for taxi range. Beta plus power is a reverse range and produces negative thrust, often used for landing on short runways where the aircraft would need to rapidly slow down, as well as backing operations and is accessed by moving the power lever below the beta for taxi range. Due to the pilot not being able to see out of the rear of the aircraft for backing and
960-634: The P-3 Orion , and the C-130 Hercules military transport aircraft. The first turbine-powered, shaft-driven helicopter was the Kaman K-225 , a development of Charles Kaman 's K-125 synchropter , which used a Boeing T50 turboshaft engine to power it on 11 December 1951. December 1963 saw the first delivery of Pratt & Whitney Canada's PT6 turboprop engine for the then Beechcraft 87, soon to become Beechcraft King Air . 1964 saw
1020-841: The Piper Meridian , Socata TBM , Pilatus PC-12 , Piaggio P.180 Avanti , Beechcraft King Air and Super King Air . In April 2017, there were 14,311 business turboprops in the worldwide fleet. Between 2012 and 2016, the ATSB observed 417 events with turboprop aircraft, 83 per year, over 1.4 million flight hours: 2.2 per 10,000 hours. Three were "high risk" involving engine malfunction and unplanned landing in single‑engine Cessna 208 Caravans , four "medium risk" and 96% "low risk". Two occurrences resulted in minor injuries due to engine malfunction and terrain collision in agricultural aircraft and five accidents involved aerial work: four in agriculture and one in an air ambulance . Jane's All
1080-614: The Tupolev Tu-114 can reach 470 kn (870 km/h; 540 mph). Large military aircraft , like the Tupolev Tu-95 , and civil aircraft , such as the Lockheed L-188 Electra , were also turboprop powered. The Airbus A400M is powered by four Europrop TP400 engines, which are the second most powerful turboprop engines ever produced, after the 11 MW (15,000 hp) Kuznetsov NK-12 . In 2017,
1140-403: The Tupolev Tu-95 . However, propfan engines, which are very similar to turboprop engines, can cruise at flight speeds approaching 0.75 Mach. To maintain propeller efficiency across a wide range of airspeeds, turboprops use constant-speed (variable-pitch) propellers. The blades of a constant-speed propeller increase their pitch as aircraft speed increases. Another benefit of this type of propeller
1200-489: The 700 were placed by Swiss airline Globe Air and Taiwanese Far Eastern Air Transport , and production started on the new model. VASP cancelled its order, however, when it could not obtain financing from the Brazilian government, and Handley Page stopped work on the 700, scrapping six airframes on the production line. Production ended in 1968. Only 36 examples of the Series 200 production model were eventually built during
1260-566: The Friendship, which had entered service over six months previously, and to stimulate demand, Handley Page launched in 1960 a further improved version, the Series 200, which was lengthened by 42 in (107 cm), with corresponding increased weights, allowing up to 56 passengers to be carried, and attracted an order for six aircraft from Jersey Airlines . The second prototype was converted to Series 200 standard and first flew in that form on 8 April 1961. Jersey Airlines began operations with
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#17327796004341320-460: The Herald was the high-mounted wing, but with a noticeable dihedral. In addition, the Herald's vertical fin was covered with miniature airfoils, adding further to the Herald's excellent stability. Pilots reported that the Herald flew like a dream; very stable in the air, yet highly manoeuvrable even at slow speed. Ground handling was said to be the Herald's only vice due to an overlarge tailfin. While
1380-468: The Jetstream forcing its closure. Continuing support for the remaining Heralds in service was maintained by the setting up of a new company, Dart Herald (Support) Ltd, partly owned by Scottish Aviation . The Herald's last ever passenger flight was operated by British Air Ferries in 1987 doing subcharters for Ryanair. The type remained in use as a freighter, but by 1999 the only one remaining in service
1440-659: The Rolls-Royce Dart turboprop engine had shown proven success in the Vickers Viscount . Queensland Airlines and Australian National Airways cancelled their orders for Heralds in favour of turboprop-powered Friendships, while the Lloyd Aéreo Colombiano contract was stopped due to currency problems and Air Kruise's interest was ended when it was taken over by British Aviation Services . Before the second prototype had been completed, Handley Page
1500-449: The Rolls-Royce Dart. The revised aircraft, now designated the HPR.7 Dart Herald, was powered by 1,910 shp Dart 527 engines driving 12 ft 6 in (3.81 m) variable pitch four-blade Dowty Rotol propellers, and the fuselage was lengthened by 20 in (51 cm), while other improvements included increased fuel capacity. The first prototype was converted to Dart Herald standard, making its maiden flight on 11 March 1958, with
1560-479: The Series 200 was more commercially attractive, with no more Series 100 being ordered, sales were still slow. While the Herald was cheap compared to its major competitors, and in the 200 series had a roomy cabin, the Friendship could carry a larger payload and both the Friendship and the Avro 748 /HS.748 had better performance, resulting in superior long-term economics. By 1963, only 35 Heralds had been sold compared with over 240 Friendships. One hope of improving sales
1620-533: The Soviet Union had the technology to create the airframe for a jet-powered strategic bomber comparable to Boeing's B-52 Stratofortress , they instead produced the Tupolev Tu-95 Bear, powered with four Kuznetsov NK-12 turboprops, mated to eight contra-rotating propellers (two per nacelle) with supersonic tip speeds to achieve maximum cruise speeds in excess of 575 mph, faster than many of
1680-566: The World's Aircraft . 2005–2006. Dowty Rotol Dowty Propellers is a British engineering company based in Brockworth, Gloucestershire that specialises in the manufacture, repair and overhaul of propellers and propeller components for customers around the world. It is owned by GE Aerospace . The company was formed as Rotol Airscrews in 1937 by Rolls-Royce and Bristol Engines to take over both companies' propeller development,
1740-420: The additional expansion in the turbine system, the residual energy in the exhaust jet is low. Consequently, the exhaust jet produces about 10% of the total thrust. A higher proportion of the thrust comes from the propeller at low speeds and less at higher speeds. Turboprops have bypass ratios of 50–100, although the propulsion airflow is less clearly defined for propellers than for fans. The propeller
1800-414: The amount of debris reverse stirs up, manufacturers will often limit the speeds beta plus power may be used and restrict its use on unimproved runways. Feathering of these propellers is performed by the propeller control lever. The constant-speed propeller is distinguished from the reciprocating engine constant-speed propeller by the control system. The turboprop system consists of 3 propeller governors ,
1860-502: The company changed its name from Rotol Airscrews Limited to Rotol Limited , and in 1952 it acquired British Messier Limited, a specialist in landing gear and hydraulics. In 1958, Bristol Aeroplane and Rolls-Royce agreed to sell Rotol and British Messier to the Dowty Group . By 1959 Rotol and British Messier along with Dowty Equipment and Dowty Fuel Systems became part of the new Dowty Aviation Division based at Cheltenham. In 1968,
Handley Page Dart Herald - Misplaced Pages Continue
1920-517: The company introduced the first fibreglass propellers, which went on to see widespread use. Since then it has migrated to carbon fibre , and remains a leader in propeller design. Following a series of changes of ownership, the original Dowty Rotol facility at Staverton is now owned by the Safran Group, operating as part of its Messier-Bugatti-Dowty landing gear subsidiary (now known as Safran Landing Systems). Propeller design and manufacture
1980-407: The exhaust is situated forward, reducing the distance between the turbine and the propeller. Unlike the small-diameter fans used in turbofan 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. Since it is more efficient at low speeds to accelerate a large amount of air by a small degree than
2040-499: The first jet aircraft and comparable to jet cruising speeds for most missions. The Bear would serve as their most successful long-range combat and surveillance aircraft and symbol of Soviet power projection through to the end of the 20th century. The USA used turboprop engines with contra-rotating propellers, such as the Allison T40 , on some experimental aircraft during the 1950s. The T40-powered Convair R3Y Tradewind flying-boat
2100-564: The first deliveries of the Garrett AiResearch TPE331 , (now owned by Honeywell Aerospace ) on the Mitsubishi MU-2 , making it the fastest turboprop aircraft for that year. In contrast to turbofans , turboprops are most efficient at flight speeds below 725 km/h (450 mph; 390 knots) because the jet velocity of the propeller (and exhaust) is relatively low. Modern turboprop airliners operate at nearly
2160-573: The first production aircraft flying on 30 October 1959. The initial Series 100 version of the Dart Herald was certified in April 1958. The basic price in 1960 was around £185,000. The first order for the Dart Herald was in June 1959 from British European Airways for a lease of three aircraft for use on its Scottish Highlands and Islands routes. The Herald, had by this time, lost its initial lead over
2220-465: 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 (2.41 m) 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 to fly, albeit as
2280-542: The high wing of the Handley Page expected to give easier loading than the more expensive Avro. While short-field testing of the prototype Herald 200 at RAF Martlesham Heath in 1961 showed off the Herald's good handling and ability to operate from unprepared airstrips, other obstacles were more taxing. The Minister of Aviation , Peter Thorneycroft , refused to sign a contract for the HP.124 unless Handley Page would agree to
2340-492: The market being too small to support more than one company. The name is a contraction of "Rolls-Royce" and "Bristol". Rotol's propellers were always considered leading edge, its models equipping the Hawker Hurricane , Supermarine Spitfire , and many other Second World War -era aircraft. By the end of the war it had introduced the first five-bladed propeller to see widespread use, used on late-model Spitfires. In 1943
2400-671: The most widespread turboprop airliners in service were the ATR 42 / 72 (950 aircraft), Bombardier Q400 (506), De Havilland Canada Dash 8 -100/200/300 (374), Beechcraft 1900 (328), de Havilland Canada DHC-6 Twin Otter (270), Saab 340 (225). Less widespread and older airliners include the BAe Jetstream 31 , Embraer EMB 120 Brasilia , Fairchild Swearingen Metroliner , Dornier 328 , Saab 2000 , Xian MA60 , MA600 and MA700 , Fokker 27 and 50 . Turboprop business aircraft include
2460-568: The opposite choice for its competitor for the same market, choosing to power the F27 Friendship with two Rolls-Royce Darts . The HPR.3 could carry up to 44 passengers in its pressurised cabin , which could be quickly converted to allow the carrying of freight, with the aircraft's high wing, nosewheel undercarriage and large doors at the front and rear of the cabin making the loading of cargo relatively simple. Large flaps were fitted to give good short takeoff and landing characteristics. It
Handley Page Dart Herald - Misplaced Pages Continue
2520-486: The original concept of the Marathon, notable for its high mounted wing. Handley Page Reading succeeded in producing a modern design with excellent flight and performance characteristics. However, the company made a serious misjudgement which was, in the end, to cost the company dearly, and like some other classic British aircraft of the time, the Herald missed its chance. After extensive consultation with DC-3 operators, it
2580-493: The power section (turbine and gearbox) to be removed and replaced in such an event, and also allows for less stress on the start during engine ground starts. Whereas a fixed shaft has the gearbox and gas generator connected, such as on the Honeywell TPE331 . The propeller itself is normally a constant-speed (variable pitch) propeller type similar to that used with larger aircraft reciprocating engines , except that
2640-534: The propeller to rotate freely, independent of compressor speed. Alan Arnold Griffith had published a paper on compressor design in 1926. Subsequent work at the Royal Aircraft Establishment investigated axial compressor-based designs that would drive a propeller. From 1929, Frank Whittle began work on centrifugal compressor-based designs that would use all the gas power produced by the engine for jet thrust. The world's first turboprop
2700-403: The propeller-control requirements are very different. Due to the turbine engine's slow response to power inputs, particularly at low speeds, the propeller has a greater range of selected travel in order to make rapid thrust changes, notably for taxi, reverse, and other ground operations. The propeller has 2 modes, Alpha and Beta. Alpha is the mode for all flight operations including takeoff. Beta,
2760-577: The sales team had produced considerable interest from potential customers, and Handley Page had 29 orders for the Herald (from Queensland Airlines , Australian National Airways , and Lloyd Aéreo Colombiano ) by the time the first prototype made its maiden flight from Radlett on 25 August 1955, three months ahead of the first flight of the Friendship. Break-even was expected after the sale of 75 aircraft and Handley Page expected total sales of up to 300 Heralds, with first deliveries expected to British independent airline Air Kruise in 1958. By now, however,
2820-592: The same speed as small regional jet airliners but burn two-thirds of the fuel per passenger. Compared to piston engines, their greater power-to-weight ratio (which allows for shorter takeoffs) and reliability can offset their higher initial cost, maintenance and fuel consumption. As jet fuel can be easier to obtain than avgas in remote areas, turboprop-powered aircraft like the Cessna Caravan and Quest Kodiak are used as bush airplanes . Turboprop engines are generally used on small subsonic aircraft, but
2880-501: The six years of production, together with four Series 100s and eight Series 400s. The 50th, and last, Herald (a series 200 for Israel's Arkia ) was flown and delivered in August 1968, after which Herald production ceased, allowing Handley Page's attention to be fully focused on the HP.137 Jetstream . Handley Page went into voluntary liquidation in August 1969, the spiralling cost of developing
2940-415: The turbine. In contrast to a turbojet or turbofan , the engine's exhaust gases do not provide enough power to create significant thrust, since almost all of the engine's power is used to drive the propeller. Exhaust thrust in a turboprop is sacrificed in favor of shaft power, which is obtained by extracting additional power (beyond that necessary to drive the compressor) from turbine expansion. Owing to
3000-480: Was a series 401 G-BEYF with Channel Express ; it was retired at Bournemouth after its last flight on 9 April 1999. Data from Jane's All the World's Aircraft 1969-70 General characteristics Performance Aircraft of comparable role, configuration, and era Turboprop A turboprop is a turbine engine that drives an aircraft propeller . A turboprop consists of an intake , reduction gearbox , compressor , combustor , turbine , and
3060-480: Was decided to power the new airliner with piston engines , rather than turboprops , which were considered risky by the small airlines at which the HPR.3 was aimed. Handley Page preferred a four-engined design, which led to the new 870 hp (650 kW) Alvis Leonides Major 14-cylinder radial engine , driving three-bladed propellers being chosen for the HPR.3. At almost the same time, the Dutch company Fokker made
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#17327796004343120-573: Was designed by the Hungarian mechanical engineer György Jendrassik . Jendrassik published a turboprop idea in 1928, and on 12 March 1929 he patented his invention. In 1938, he built a small-scale (100 Hp; 74.6 kW) 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
3180-458: Was designed to cruise at a speed of 224 mph (360 km/h), had a range of 1,640 mi (2,640 km), could land and take off in a distance of less than 500 yards (460 m) and had an initial rate of climb of over 1,800 ft/min. At first, it seemed that Handley Page had made the right choices with the HPR.3, which was named "Herald" in August 1954, this being a name easily translatable into French and Spanish. Extensive work by
3240-404: Was faced with the fact that it had no orders for the Herald, and that the market had changed and wanted turboprops. There had already been a very substantial investment in the Herald project, such that the management held a meeting to discuss continuation. Handley Page decided to press ahead with the Herald project, in an effort to recover the investment; announcing a new uprated version powered by
3300-560: Was moved a few hundred metres down the road when the company was split into business units under its Dowty ownership in the early 1990s. On 16 January 2007, Dowty Propellers became part of GE Aviation Systems through GE buying Smiths Group ’s aerospace division. On 5 February 2015, a fire at Dowty's Staverton facility caused severe damage to 80% of the factory building, destroying the main production line. A facility at Vantage Point Business Village in Mitcheldean, Gloucestershire,
3360-467: Was of axial-flow design with 15 compressor and 7 turbine stages, annular combustion chamber. First run in 1940, combustion problems limited its output to 400 bhp. Two Jendrassik Cs-1s were the engines for the world's first turboprop aircraft – the Varga RMI-1 X/H . This was a Hungarian fighter-bomber of WWII which had one model completed, but before its first flight it was destroyed in
3420-714: Was operated by the U.S. Navy for a short time. The first American turboprop engine was the General Electric XT31 , first used in the experimental Consolidated Vultee XP-81 . The XP-81 first flew in December 1945, the first aircraft to use a combination of turboprop and turbojet power. The technology of Allison's earlier T38 design evolved into the Allison T56 , used to power the Lockheed Electra airliner, its military maritime patrol derivative
3480-682: Was selected for the company's interim propeller blade manufacturing. In late 2019, the company began moving its operations to an all-new purpose-built facility at Gloucester Business Park in Brockworth, on part of the site of the former aerodrome used by the Gloster Aircraft Company. Dowty propellers are used on many turboprop feederliners , including the Bombardier Dash 8 Q400, Saab 340 and Saab 2000 , and on turboprop transport aircraft such as later models of
3540-603: Was the first turboprop aircraft of any kind to go into production and sold in large numbers. It was also the first four-engined turboprop. Its first flight was on 16 July 1948. The world's first single engined turboprop aircraft was the Armstrong Siddeley Mamba -powered Boulton Paul Balliol , which first flew on 24 March 1948. The Soviet Union built on German World War II turboprop preliminary design work by Junkers Motorenwerke, while BMW, Heinkel-Hirth and Daimler-Benz also worked on projected designs. While
3600-402: Was to develop the Herald as a military transport. The Royal Air Force had a requirement for 45 tactical transports to replace piston-engined Vickers Valettas , and Handley Page began work in 1960 on the HP.124 to meet this need. This would have a new rear fuselage with a rear loading ramp under the raised tail. The HP.124 was considered favourite to beat Avro's 748 derivative, the Avro 780, with
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