Fastest propeller-driven aircraft

From Wikipedia, the free encyclopedia

A number of aircraft have claimed to be the fastest propeller-driven aircraft. This article presents the current record holders for several sub-classes of propeller-driven aircraft that hold recognized, documented speed records. Fédération Aéronautique Internationale (FAI) records are the basis for this article.^[1] Other contenders and their claims are discussed, but only those made under controlled conditions and measured by outside observers. Pilots during World War II sometimes claimed to have reached supersonic speeds in propeller-driven fighters during emergency dives, but these speeds are not included as accepted records.

Contents

• 1 Propeller versus jet propulsion
• 2 Turboprops
• 3 Piston engines
• 4 Other claimants
• 5 See also
• 6 References

Propeller versus jet propulsion

Aircraft that use propellers as their prime propulsion device constitute a historically important subset of aircraft, despite inherent limitations to their speed. Aircraft powered by piston engines get virtually all of their thrust from the propeller driven by the engine. A few piston engined aircraft derive some thrust from the engine's exhaust gases, and there are certain hybrid types like the Motorjet that use a piston engine to drive the compressor of a jet engine, which supplies the primary thrust (although some types also have a propeller powered by the piston engine for low speed efficiency). All aircraft prior to World War II (except for a tiny number of early jet aircraft and rocket aircraft) used piston engines to drive propellers, so all Flight airspeed records prior to 1944 were necessarily set by propeller-driven aircraft. Rapid advances in jet engine technology during World War II meant that no propeller-driven aircraft would ever again hold an absolute air speed record. Shock wave formation in propeller-driven aircraft at speeds near sonic conditions, impose limits not encountered in jet aircraft.
Jet engines, particularly turbojets, are a type of gas turbine configured such that most of the work available results from the thrust of the hot exhaust gases. High bypass turbofans that are used in all modern commercial jetliners, and most modern military aircraft, get most of their thrust from the internal fan, which is powered by a gas turbine; turboprop engines are similar, but use an external propeller rather than an internal fan. The hot exhaust gas from a turboprop engine can give a small amount of thrust, but the propeller is the main source of thrust.

Turboprops

Tupolev Tu-114

The Tupolev Tu-114, a large aircraft with four turboprop engines, has a maximum speed of 870 km/h (540 mph, Mach 0.73).^[2] The 11,000 kW (15,000 hp) Kuznetsov NK-12 turboprop engines designed for the Tupolev Tu-95 (and used to power the derivative Tu-114) are the most powerful turboprops ever built and drive large contra-rotating propellers. This engine-propeller combination gives the Tu-114 the official distinction of being the fastest propeller-driven aircraft in the world, a record it has held since 1960.^[1][3]

McDonnell XF-88B experimental fighter

Probably the fastest aircraft ever fitted with an operating propeller was the experimental McDonnell XF-88B, which was made by installing an Allison T38 turboshaft engine in the nose of a pure jet-powered XF-88 Voodoo. This unusual aircraft was intended to explore the use of high-speed propellers and achieved supersonic speeds.^[4] This aircraft is not considered to be propeller-driven since most of the thrust was provided by two jet engines.

XF-84H "Thunderscreech"

An oft-cited contender for the fastest propeller-driven aircraft is the XF-84H Thunderscreech. This aircraft is named in Guinness World Records, 1997, as the fastest in this category with a speed of 1,002 km/h (623 mph, Mach 0.83).^[5] While it may have been designed as the fastest propeller-driven aircraft, this goal was not realized due to its inherent instability.^[6] This record speed is also inconsistent with data from the National Museum of the United States Air Force, which gives a top speed of 837 km/h (520 mph, Mach 0.70),^[7] slower than the Tu-114.

Piston engines

Rare Bear, world speed record holder

The more "traditional" class of propeller-driven aircraft are those powered by piston engines, which include nearly all aircraft from the Wright brothers up through World War II. Today piston engines are used almost exclusively on light, general aviation aircraft. The official speed record for a piston plane is held by a modified Grumman F8F Bearcat, the Rare Bear, with a speed of 850.24 km/h (528.31 mph) on 21 August 1989 at Las Vegas, Nevada, United States of America.^[8][9]
The FAI record for the fastest piston-powered aircraft over a long-distance circuit is the 2000-km record of 720.13 km/h (447.47 mph) set on 22 May 1948 by Jacqueline Cochran in a P-51C. (She also holds the 100-km record of 755.67 km/hr, set in December 1947.) Higher speed records exist; some are unofficial and some were officially-timed one-way trips aided by tailwinds. Examples of the latter: a B-29 averaged 725 km/hr from Burbank to Floyd Bennett Field (3957 km in 5.455 hours) on 11 December 1945, and Joe DeBona averaged 904 km/hr from Los Angeles LAX to New York Idlewild (3981 km in 4.405 hours) in a P-51 on 30 March 1954.

Other claimants

The 1903 Wright Flyer did 48 km/h (30 mph) during its first flight; the Bleriot XI reached 75 km/h (47 mph) in 1909. Fabric-covered biplanes of the World War I era and shortly after could do up to 320 km/h (200 mph). In 1925 U.S. Army Lt. Cyrus K. Bettis flying a Curtiss R3C won the Pulitzer Trophy Race with a speed of 400.6 km/h (248.9 mph).^[10]
Speeds of all-metal monoplanes of the 1930s jumped into the 700 km/h (430 mph) range with the Macchi M.C.72 reaching a top speed of 709 km/h (441 mph), still the record for piston-powered seaplanes.^[11] The Messerschmitt Me 209 V1 set a world speed record of almost 756 km/h (470 mph) on 26 April 1939,^[12] and the Republic XP-47J (a variant of the P-47 Thunderbolt) is claimed to have reached 813 km/h (505 mph) in testing^{[citation needed]}. A prototype of the successor to the Supermarine Spitfire, the Supermarine Spiteful F.16 (RB518), reached 494 mph (795 km/h). The fastest German propeller driven aircraft to see combat in WWII was the Dornier Do 335 "Pfeil" which had a top speed of 474 mph (763 km/h).^[13]
The record-shattering flight, on 2 October 1941, of one of the Messerschmitt Me 163 rocket fighter prototypes that reached a top speed of 624 mph (1,004 km/h), as well as development of jet-powered fighters by both the Allies and Axis powers during World War II, ensured that all new absolute air speed records would be held by jet or rocket-powered aircraft.

Republic P-47J reached 505 mph in testing

Convair XFY-1 "Pogo"

Lockheed XFV-1 "Salmon"

During the 1950s two unorthodox United States Navy fighter prototypes married turboprop engines with a "tailsitting design", the Convair XFY "Pogo" and the Lockheed XFV. Maximum design speeds of 980 km/h (610 mph) at 4,600 m (15,100 ft) and 930 km/h (580 mph) respectively have been quoted. The Lockheed XFV was fitted with a less powerful engine than it was designed for and had makeshift non-retractable landing gear for horizontal takeoff and landing;^[14] the Convair's landing gear supported it in a vertical position. It was usually flown with the cockpit open, since the ejection seat was thought unreliable.^[15] These aircraft had "compromised in-flight speed" because of the conflicting demands of vertical and horizontal flight.^[16]

See also

• List of vehicle speed records

Kuznetsov NK-12

From Wikipedia, the free encyclopedia

NK-12
NK-12M Turboprop engine on a Tu-95 at RIAT Fairford 1993
Type	Turboprop
National origin	Soviet Union
Manufacturer	Kuznetsov Design Bureau
Major applications	Antonov An-22 Tupolev Tu-95 Tupolev Tu-114

The exhaust ports of a NK-12 in an outboard nacelle on a TU-95

The Kuznetsov NK-12 is a Soviet turboprop engine of the 1950s, designed by the Kuznetsov design bureau. It drives huge eight-bladed (four per propeller) contra-rotating propellers 5.6 m (18ft 4.5in) in diameter (6.2 m (20ft 4.1in) in the NK-12MA and NK-12MV). It is the most powerful turboprop engine ever built.

Contents

• 1 Design and development
• 2 Applications
• 3 Specifications
  • 3.1 General characteristics
  • 3.2 Components
  • 3.3 Performance
• 4 See also
• 5 References
• 6 External links

Design and development

The design that eventually became the NK 12 turboprop was developed after World War II by a team of deported German engineers under Ferdinand Brandner, which had worked for Junkers before. Thus, the NK 12 design evolved from late war German turboprop studies. This started with the post-war development of the wartime Jumo 022 turboprop design that developed 6000 eshp in a 3000 kg engine. The effort continued with a 5000 ehp engine that weighed in at 1700 kg, completed by 1947. The evolution to the TV-12 12000 Ehp engine required extensive use of new Soviet-developed alloys and was completed in 1951.^[1]
The NK-12M developed 8,948 kW (12,000 ehp), uprated in the NK-12MV to 11,033 kW (14,795 ehp) and reaching 11,185 kW (15,000 ehp) in the NK-12MA. The NK-12 remains the most powerful turboprop engine ever built. Only recently the Progress D-27 and Europrop TP400 came somewhat close. It powered the Tupolev Tu-95 bomber and its descendants like the Tu-142 maritime patrol aircraft and the Tupolev Tu-114 airliner (with NK-12MV), which is still the world's fastest propeller-driven aircraft. It also powered the Antonov An-22 Antei (with NK-12MA), the world's largest aircraft at the time, and several types of amphibious assault craft, such as the A-90 Orlyonok "Ekranoplan" and the Zubr class LCAC.
The engine has a 14-stage axial-flow compressor, producing compression ratios between 9:1 to 13:1 depending on altitude, also controlled by variable inlet guide vanes and blow-off valves. The combustion system used is a cannular-type: each flame tube is centrally mounted on a down-stream injector that ends in an annular secondary region. The contra-rotating propellers and compressor are driven by the 5-stage axial turbine. Mass flow is 65 kg (143 lb) /sec.^[2]

Applications

• A-90 Orlyonok
• Zubr class LCAC
• Antonov An-22
• Tupolev Tu-95
• Tupolev Tu-142
• Tupolev Tu-114

Specifications

General characteristics

• Type: Turboprop
• Length: 4.8m^[2]
• Diameter: 1.2m^[2]
• Dry weight: 2,900kg (6393 lbs), for NK-12MV

Components

• Compressor: Axial flow, 14 stages^[2]
• Turbine: 5 stages^[2]

Performance

• Maximum power output: 11,033 kW (14,795 ehp), for NK-12MV
• Overall pressure ratio: 9.5^[2]
• Turbine inlet temperature: 1250K^[2]
• Specific fuel consumption: 0.360 lb/shp-hr ^[3] 0.219 kg/kW-hr for NK-12MA and NK-12MV
• Power-to-weight ratio: 3.7 kW/kg (2.3 hp/lb), for NK-12MV

See also

Related lists

• List of aircraft engines

Trident Iceni: the fast and the frugal

April 29, 2014 12:15 PM Relaxnews

The new Trident Iceni claims to be the world's fastest and most fuel efficient diesel-powered sportscar.

There's no debating that diesel technology has come on in leaps and bounds over recent years, but trying to convince avid well-heeled drivers to take a chance on an Iceni rather than its British compatriots, say a Jaguar XK or Aston Martin, might take some doing.

Luckily enough, as well as good looks, the Trident Iceni, officially launched Tuesday, has the stats to support its claim: a 0-62mph (0-100km/h) time of 3.7 seconds, a top speed in excess of 190mph (305km/h), 395bhp and an incredible 700lb ft of torque thanks to a 6.6-liter V8 turbodiesel engine.

Yet despite all of this performance, it is capable of traveling 2000 miles (3218km) on a single tank.
The key to this efficiency is torque manipulation technology, something that the company has been developing for a number of years.

Horsepower is one measure of power and it is usually at its peak as the engine revs towards its red line. But the more revs, the more fuel the engine is burning through.

V8 engines in general and diesels in particular are great at producing lots of torque -- the other measure of power -- at low revs, using less fuel and that's the key to the car's speed and efficiency.

View gallery

The Trident Iceni

Its automatic gearbox shifts up at 3000rpm, well within the engine's prime torque band, and when the car's cruising at 70mph (112km/h) it's at fewer than 1000rpm.

Manipulating the torque like this also means a combined fuel economy of around 68mpg -- that's better than a Toyota Prius.

Then there's the price. At £96,000 (€117,000/$160,000) for the standard car, it's cheaper than an Aston. And for customers looking for something even more special or personalized, there are a host of optional extras for setting the car up for greater luxury or greater track performance. The track pack offers carbon ceramic brakes and cranks the engine up to 660bhp and 1050 lb ft of torque.

Or for those that fancy filling up the tank and driving until it's completely empty 2000 miles later, a luxury pack including matching luggage, touchscreen entertainment system, extra leather trim and blinds for the smoked glass roof panels is also on offer. 

As well as the convertible Iceni, Trident is also offering the car as a coupé -- the Magna -- and as a two-door estate -- the Venturer.

AN-70 Pictures