A vertical take-off and landing ( VTOL ) aircraft is one that can take off and land vertically without relying on a runway . This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-wing aircraft and other hybrid aircraft with powered rotors such as cyclogyros/cyclocopters and gyrodynes .
138-523: The Avro Canada VZ-9 Avrocar is a VTOL aircraft developed by Avro Canada as part of a secret U.S. military project carried out in the early years of the Cold War . The Avrocar intended to exploit the Coandă effect to provide lift and thrust from a single "turborotor" blowing exhaust out of the rim of the disk-shaped aircraft. In the air, it would have resembled a flying saucer . Originally designed as
276-429: A T-tail , but this proved to sit within the airflow of the turborotor and did not help. Frost's team considered two new designs, one with a large vertical tail and one with a wing with tip mounted verticals — "winglets". Both designs used two 2,700 lbf (12 kN) thrust General Electric J85 turbojets and increased the turborotor diameter from five to six ft. On 9 June 1961, a second USAF/NASA flight evaluation of
414-462: A fighter-like aircraft capable of very high speeds and altitudes, the project was repeatedly scaled back over time and the U.S. Air Force eventually abandoned it. Development was then taken up by the U.S. Army for a tactical combat aircraft requirement, a sort of high-performance helicopter . In flight testing, the Avrocar proved to have unresolved thrust and stability problems that limited it to
552-504: A turbofan in static or hovering conditions. Its efflux can be used for Upper Surface Blown architectures to boost the Lift Coefficient to values exceeding 8.0. Power-to-weight ratio Power-to-weight ratio ( PWR , also called specific power , or power-to-mass ratio ) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio
690-601: A "flying Jeep", and they became interested in Avro's concept as well. Frost pitched his smaller design both as a prototype of a vehicle suitable for the Army's needs, as well as an aerodynamic testbed for the WS-606. Initial performance requirements for the Avrocar were a ten-minute hover capability in ground effect and 25-mile (40 km) range with a 1,000 lb (450 kg) payload. The new plan appeared to make everybody happy, and
828-743: A "lift jet" version, but no further interest resulted from Canadian or other sources, to cap the end of this Special Projects Group program. In 1961, a number of later proposals, including the Avro P470 VTOL fighter concept derived from the Special Projects Group, were submitted to fulfill a NATO competition for a tactical strike fighter. These needs were filled by the Hawker Siddeley Harrier , but in more general terms, interest in VTOL faded as it became widely believed
966-555: A "pancake engine". The jet thrust exited from around the entire rim of the engine, and this presented problems trying to adapt the design to a typical aircraft. At the same time, the aircraft industry as a whole was becoming increasingly interested in VTOL aircraft. It was expected that any future European war would start with a nuclear exchange that would destroy most airbases, so aircraft would need to operate from limited airbases, roads or even unprepared fields. Considerable research effort
1104-624: A $ 2 million joint-services contract managed by the Air Force was awarded to Avro to build and test two Avrocars, which the Army referred to as the VZ-9-AV (with AV standing for "Avro", an unusual departure from normal U.S. Army nomenclature), the latest in a series of "VZ" aircraft. Army interest in the Avrocar program was apparently very high. Bernard Lindenbaum of the Air Force Flight Dynamics Laboratory recalls
1242-631: A VTOL (helicopter) show up in Leonardo da Vinci 's sketch book. Manned VTOL aircraft, in the form of primitive helicopters, first flew in 1907, but would take until after World War Two to be perfected. In addition to helicopter development, many approaches have been tried to develop practical aircraft with vertical take-off and landing capabilities, including Henry Berliner 's 1922–1925 experimental horizontal rotor fixed wing aircraft, and Nikola Tesla 's 1928 patent, and George Lehberger's 1930 patent for relatively impractical VTOL fixed wing airplanes with
1380-454: A Viper jet engine running wild, convinced Frost that a less dangerous test vehicle was necessary. To gather flight data on the basic concept while the engine development continued, in 1958 Frost proposed building a smaller "proof-of-concept" test vehicle he called the Avrocar . By this point, the U.S. Army was involved in a wide variety of experiments on smaller VTOL aircraft that would act as
1518-403: A continuous flow of electrolyte. Flow cells typically have the fuel dissolved in the electrolyte. Power-to-weight ratios for vehicles are usually calculated using curb weight (for cars) or wet weight (for motorcycles), that is, excluding weight of the driver and any cargo. This could be slightly misleading, especially with regard to motorcycles, where the driver might weigh 1/3 to 1/2 as much as
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#17327830133141656-543: A conventional wing and tilts the whole assembly to transition between vertical and horizontal flight. A tail-sitter sits vertically on its tail for takeoff and landing, then tilts the whole aircraft forward for horizontal flight. Thrust vectoring is a technique used for jet and rocket engines, where the direction of the engine exhaust is varied. In VTOL, the exhaust can be varied between vertical and horizontal thrust. Similar to tiltrotor concept, but with turbojet or turbofan engines instead of ones with propellers. A lift jet
1794-406: A cutoff voltage are typically specified for a battery by its manufacturer. The output voltage falls to the cutoff voltage when the battery becomes "discharged". The nominal output voltage is always less than the open-circuit voltage produced when the battery is "charged". The temperature of a battery can affect the power it can deliver, where lower temperatures reduce power. Total energy delivered from
1932-479: A degraded, low-performance flight envelope ; subsequently, the project was cancelled in September 1961. Through the history of the program, the project was referred to by a number of different names. Avro referred to the efforts as Project Y, with individual vehicles known as Spade and Omega. Project Y-2 was later funded by the U.S. Air Force, who referred to it as WS-606A, Project 1794 and Project Silver Bug. When
2070-408: A disk was the best solution. As he continued these experiments, he found that the same thrust-direction system he intended for VTOL operations worked just as well for forward flight. In this case the disk shape was not of itself a good lifting surface, as it was neutral in terms of lift direction – that is, it would fly sideways as readily as it would fly forward. However, by modifying the airflow with
2208-405: A disk-shaped aircraft with the same basic shape as a frisbee , the upper surface of the disk being fairly curved, and the bottom much less so. The disk was 18 feet (5.5 m) in diameter and 3.5 feet (1.1 m) thick. The main structural truss was a large equilateral triangle, to which the various components were attached. The 124-blade "turborotor" sat in the center of the triangle, with most of
2346-467: A fluid, or storage in a pressure vessel . A variety of effects can be harnessed to produce thermoelectricity , thermionic emission , pyroelectricity and piezoelectricity . Electrical resistance and ferromagnetism of materials can be harnessed to generate thermoacoustic energy from an electric current. All electrochemical cell batteries deliver a changing voltage as their chemistry changes from "charged" to "discharged". A nominal output voltage and
2484-419: A flying saucer, capable of flying at 1,500 miles per hour (2,400 km/h) and climbing vertically. Nevertheless, further funding was not forthcoming. While Project Y continued, Frost had meanwhile become interested in the Coandă effect , where fluid flows will follow strongly convex shapes, something that might be unexpected at first glance. Frost felt the effect could be used with his engine design to produce
2622-783: A followup story was part of the April 2006 issue that mentioned "the fuel-consumption and stability problems that plagued earlier plane/copter." Retired from the British Royal Navy in 2006, the Indian Navy continued to operate Sea Harriers until 2016, mainly from its aircraft carrier INS Viraat . The latest version of the Harrier, the BAE Harrier II , was retired in December 2010 after being operated by
2760-584: A helicopter, then transitions to fixed-wing lift in forward flight. Examples of this include the Bell Boeing V-22 Osprey A tiltrotor or proprotor tilts its propellers or rotors vertically for VTOL and then tilts them forwards for horizontal wing-borne flight, while the main wing remains fixed in place. Similar to tiltrotor concept, but with ducted fans . As it can be seen in the Bell X-22 . A tiltwing has its propellers or rotors fixed to
2898-439: A helicopter. The rotors would become stationary in mid-flight, and function as wings, providing lift in addition to the static wings. Boeing X-50 is a Canard Rotor/Wing prototype that utilizes a similar concept. A different British VTOL project was the gyrodyne , where a rotor is powered during take-off and landing but which then freewheels during flight, with separate propulsion engines providing forward thrust. Starting with
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#17327830133143036-563: A higher discharge current – and therefore higher power-to-weight ratio – but only with a lower energy capacity. Power-to-weight ratio for batteries is therefore less meaningful without reference to corresponding energy-to-weight ratio and cell temperature. This relationship is known as Peukert's law . Capacitors store electric charge onto two electrodes separated by an electric field semi-insulating ( dielectric ) medium. Electrostatic capacitors feature planar electrodes onto which electric charge accumulates. Electrolytic capacitors use
3174-406: A liquid electrolyte as one of the electrodes and the electric double layer effect upon the surface of the dielectric-electrolyte boundary to increase the amount of charge stored per unit volume. Electric double-layer capacitors extend both electrodes with a nanoporous material such as activated carbon to significantly increase the surface area upon which electric charge can accumulate, reducing
3312-419: A mechanical stability augmentation system that was independent of the pilot's controls. The turborotor had a fairly large angular momentum and was intended to act as a powerful gyroscope , providing a "normal" direction of flight. Control cables attached to the base of the rotor would be pulled when the craft moved in relation to the rotor, actuating the control surfaces to counteract the motion. The vehicle
3450-446: A misnomer, as it colloquially refers to mass. In a zero-gravity (weightless) environment, the power-to-weight ratio would not be considered infinite. A typical turbocharged V8 diesel engine might have an engine power of 250 kW (340 hp) and a mass of 380 kg (840 lb), giving it a power-to-weight ratio of 0.65 kW/kg (0.40 hp/lb). Examples of high power-to-weight ratios can often be found in turbines. This
3588-429: A more practical VTOL aircraft, the exhaust flowing outward over the upper surface of the aircraft and then being directed downward over a flap-like arrangement. This would produce a lift force around the entire edge of the aircraft, allowing it to land "flat". He produced a number of small experimental designs using compressed air in place of an engine in order to select a suitable airframe shape, and eventually decided that
3726-430: A nuclear first strike would not be used at the start of a European war. The second Avrocar had logged about 75 flight hours at the end of the flight testing. Judged by its performance, the Avrocar was an abject failure: it could not lift itself safely more than a few feet off the ground, and its bulbous design limiting high-speed performance accompanied by unbearable heat and screaming exhaust noise, made it impractical for
3864-647: A period of time is equal to the difference in its total energy over that period of time, so the rate at which work is done is equal to the rate of change of the kinetic energy (in the absence of potential energy changes). The work done from time t to time t + Δ t along the path C is defined as the line integral ∫ C F ⋅ d x = ∫ t t + Δ t F ⋅ v ( t ) d t {\displaystyle \int _{C}\mathbf {F} \cdot d\mathbf {x} =\int _{t}^{t+\Delta t}\mathbf {F} \cdot \mathbf {v} (t)dt} , so
4002-628: A power-to-weight ratio of 153 kW/kg (93 hp/lb). In classical mechanics , instantaneous power is the limiting value of the average work done per unit time as the time interval Δ t approaches zero (i.e. the derivative with respect to time of the work done). The typically used metric unit of the power-to-weight ratio is W kg {\displaystyle {\tfrac {\text{W}}{\text{kg}}}\;} which equals m 2 s 3 {\displaystyle {\tfrac {{\text{m}}^{2}}{{\text{s}}^{3}}}\;} . This fact allows one to express
4140-489: A proposal in 1948 for an aircraft capable of vertical takeoff and landing (VTOL) aboard platforms mounted on the afterdecks of conventional ships. Both Convair and Lockheed competed for the contract but in 1950, the requirement was revised, with a call for a research aircraft capable of eventually evolving into a VTOL ship-based convoy escort fighter. At the end of 1958, the French SNECMA Coléoptère ,
4278-473: A range of control problems. Before modifications could be achieved, funding ran out in March 1961. Frost's proposals for a modified design were not accepted, and the Avrocar and related WS-606A supersonic VTOL programs were officially cancelled in December 1961 by the U.S. military. Avro company executives encouraged additional VTOL research projects, exploring new configurations married to a disk platform and even
Avro Canada VZ-9 Avrocar - Misplaced Pages Continue
4416-483: A semblance of a normal wing. The resulting design would be tuned for high supersonic performance, have reasonable subsonic performance, and would also offer VTOL, all in a single design. In late 1953, a group of U.S. defence experts visited Avro Canada to view the new CF-100 fighter jet. Somewhere along the way, Frost co-opted the tour and rerouted it to the Special Projects area where he proceeded to show off
4554-467: A short time later. The Harrier is usually flown in STOVL mode, which enables it to carry a higher fuel or weapon load over a given distance. In V/STOL the VTOL aircraft moves horizontally along the runway before taking off using vertical thrust. This gives aerodynamic lift as well as thrust lift and permits taking off with heavier loads and is more efficient. When landing the aircraft is much lighter due to
4692-463: A single charge cycle is affected by both the battery temperature and the power it delivers. If the temperature lowers or the power demand increases, the total energy delivered at the point of "discharge" is also reduced. Battery discharge profiles are often described in terms of a factor of battery capacity . For example, a battery with a nominal capacity quoted in ampere-hours (Ah) at a C/10 rated discharge current (derived in amperes) may safely provide
4830-513: A solution to one of the most vexing problems of the era, designing an aircraft that was effective at subsonic and supersonic speeds. Subsonic lift is created by the airflow around the wing following streamlines , but supersonic lift is generated by shock waves at points of critical curvature. No single design could offer high performance for both regimes. The blown disk could attack this problem by being laid out for supersonic performance only, and then using jet thrust to modify subsonic airflow into
4968-401: A speed | v ( t ) | {\displaystyle |\mathbf {v} (t)|\;} and angle ϕ {\displaystyle \phi \;} with respect to the centre and radial of a gravitational field by an onboard powerplant , then the associated kinetic energy is where: The work–energy principle states that the work done to the object over
5106-543: A successful landing after boosting 11 commercial satellites to low Earth orbit on Falcon 9 Flight 20 . These demonstrations opened the way for substantial reductions in space flight costs. The helicopter's form of VTOL allows it to take off and land vertically, to hover, and to fly forwards, backwards, and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft would usually not be able to take off or land. The capability to efficiently hover for extended periods of time
5244-406: A tailsitter annular wing design, performed its maiden flight. However the sole prototype was destroyed on its ninth flight in 1959, and financing was never sourced for a second prototype. Another more influential early functional contribution to VTOL was Rolls-Royce 's Thrust Measuring Rig ("flying bedstead") of 1953. This led to the first VTOL engines as used in the first British VTOL aircraft,
5382-452: A thick delta wing . As the engine was disk-shaped, the triangular delta shape was pushed out near the front where it met the engine disk, producing a shape roughly like a spade on a playing card . The engine was disk shaped and its intake was positioned in the middle, which meant the engine air intakes had to be located near the middle of the wing. In the Ace design, these were located just to
5520-561: A tilting engines. In the late 1930s British aircraft designer Leslie Everett Baynes was issued a patent for the Baynes Heliplane , another tilt rotor aircraft. In 1941 German designer Heinrich Focke 's began work on the Focke-Achgelis Fa 269 , which had two rotors that tilted downward for vertical takeoff, but wartime bombing halted development. In May 1951, both Lockheed and Convair were awarded contracts in
5658-667: A train. As the coefficient of friction between steel wheels and rails seldom exceeds 0.25 in most cases, improving a locomotive's power-to-weight ratio is often counterproductive. However, the choice of power transmission system, such as variable-frequency drive versus direct-current drive , may support a higher power-to-weight ratio by better managing propulsion power. Most vehicles are designed to meet passenger comfort and cargo carrying requirements. Vehicle designs trade off power-to-weight ratio to increase comfort, cargo space, fuel economy , emissions control , energy security and endurance. Reduced drag and lower rolling resistance in
Avro Canada VZ-9 Avrocar - Misplaced Pages Continue
5796-460: A trip to Washington in the late 1950s to request additional funding for a study on helicopter drag reduction. Although the funding was approved, he overheard an Army General remark that the Huey would be the last helicopter the Army would buy since the helicopter would be replaced by the Avrocar. Additional Air Force funding of approximately $ 700,000 (unexpended from the 606A program) was also moved to
5934-522: A vehicle design can facilitate increased cargo space without increase in the (zero cargo) power-to-weight ratio. This increases the role flexibility of the vehicle. Energy security considerations can trade off power (typically decreased) and weight (typically increased), and therefore power-to-weight ratio, for fuel flexibility or drive-train hybridisation . Some utility and practical vehicle variants such as hot hatches and sports-utility vehicles reconfigure power (typically increased) and weight to provide
6072-433: A vertical take-off research aircraft issued in September 1953. The design was accepted by the ministry and a contract was placed for two aircraft (XG900 and XG905) to meet Specification ER.143D dated 15 October 1954. The SC.1 was also equipped with the first "fly-by-wire" control system for a VTOL aircraft. This permitted three modes of control of the aerodynamic surfaces or the nozzle controls. The Republic Aviation AP-100
6210-733: A work site. Initially ensconced in the "Penthouse", a derisive nickname for the executive wing of the Administration Building, the SPG was subsequently relocated to a Second World War -era structure across from the company headquarters, the Schaeffer Building, that was secured with security guards, locked doors and special pass cards. At times, the SPG also operated out of the Experimental Hangar where it shared space with other esoteric Avro project teams. At
6348-413: Is a calculation commonly applied to aircraft, cars, and vehicles in general, to enable the comparison of one vehicle's performance to another. Power-to-weight ratio is equal to thrust per unit mass multiplied by the velocity of any vehicle. The power-to-weight ratio (specific power) is defined as the power generated by the engine(s) divided by the mass. In this context, the term "weight" can be considered
6486-510: Is a measurement of actual performance of any engine or power source. It is also used as a measurement of performance of a vehicle as a whole, with the engine's power output being divided by the weight (or mass ) of the vehicle, to give a metric that is independent of the vehicle's size. Power-to-weight is often quoted by manufacturers at the peak value, but the actual value may vary in use and variations will affect performance. The inverse of power-to-weight, weight-to-power ratio (power loading)
6624-524: Is an auxiliary jet engine used to provide lift for VTOL operation, but may be shut down for normal wing-borne flight. The Yak-38 is the only production aircraft to employ lift jets. Lift fan is an aircraft configuration in which lifting fans are located in large holes in an otherwise conventional fixed wing or fuselage. It is used for V/STOL operation. The aircraft takes off using the fans to provide lift, then transitions to fixed-wing lift in forward flight. Several experimental craft have been flown, but only
6762-402: Is an important vehicle characteristic that affects the acceleration of sports vehicles. Propeller aircraft depend on high power-to-weight ratios to generate sufficient thrust to achieve sustained flight, and then for speed. Jet aircraft produce thrust directly . Power-to-weight ratio is important in cycling, since it determines acceleration and the speed during hill climbs . Since
6900-527: Is because of their ability to operate at very high speeds. For example, the Space Shuttle 's main engines used turbopumps (machines consisting of a pump driven by a turbine engine) to feed the propellants (liquid oxygen and liquid hydrogen ) into the engine's combustion chamber. The original liquid hydrogen turbopump is similar in size to an automobile engine (weighing approximately 352 kilograms (775 lb)) and produces 72,000 hp (54 MW) for
7038-417: Is conversely usually lower. Fuel cells and flow cells , although perhaps using similar chemistry to batteries, do not contain the energy storage medium or fuel . With a continuous flow of fuel and oxidant, available fuel cells and flow cells continue to convert the energy storage medium into electric energy and waste products. Fuel cells distinctly contain a fixed electrolyte whereas flow cells also require
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#17327830133147176-672: Is designed to perform missions like a conventional helicopter with the long-range, high-speed cruise performance of a turboprop aircraft. The FAA classifies the Osprey as a model of powered lift aircraft. Attempts were made in the 1960s to develop a commercial passenger aircraft with VTOL capability. The Hawker Siddeley Inter-City Vertical-Lift proposal had two rows of lifting fans on either side. However, none of these aircraft made it to production after they were dismissed as too heavy and expensive to operate. In 2018 Opener Aero demonstrated an electrically powered fixed-wing VTOL aircraft,
7314-527: Is due to the helicopter's relatively long, and hence efficient rotor blades, and allows a helicopter to accomplish tasks that fixed-wing aircraft and other forms of vertical takeoff and landing aircraft could not perform at least as well until 2011 . On the other hand, the long rotor blades restrict the maximum speed to about 250 miles per hour (400 km/h) of at least conventional helicopters, as retreating blade stall causes lateral instability. Autogyros are also known as gyroplanes or gyrocopters. The rotor
7452-499: Is only delivered if the powerplant is in motion, and is transmitted to cause the body to be in motion. It is typically assumed here that mechanical transmission allows the powerplant to operate at peak output power. This assumption allows engine tuning to trade power band width and engine mass for transmission complexity and mass. Electric motors do not suffer from this tradeoff, instead trading their high torque for traction at low speed. The power advantage or power-to-weight ratio
7590-405: Is then where: The useful power of an engine with shaft power output can be calculated using a dynamometer to measure torque and rotational speed , with maximum power reached when torque multiplied by rotational speed is a maximum. For jet engines the useful power is equal to the flight speed of the aircraft multiplied by the force, known as net thrust, required to make it go at that speed. It
7728-421: Is unpowered and rotates freely in the airflow as the craft travels forward, so the craft needs a conventional powerplant to provide thrust. An autogyro is not intrinsically capable of VTOL: for VTO the rotor must be spun up to speed by an auxiliary drive, and vertical landing requires precise control of rotor momentum and pitch. Gyrodynes are also known as compound helicopters or compound gyroplanes. A gyrodyne has
7866-455: Is used when calculating propulsive efficiency . Thermal energy is made up from molecular kinetic energy and latent phase energy. Heat engines are able to convert thermal energy in the form of a temperature gradient between a hot source and a cold sink into other desirable mechanical work . Heat pumps take mechanical work to regenerate thermal energy in a temperature gradient. Standard definitions should be used when interpreting how
8004-511: The Blackfly , which the manufacturer claims is the world's first ultralight fixed-wing, all-electric, vertical take-off and landing aircraft. In the 21st century, unmanned drones are becoming increasingly commonplace. Many of these have VTOL capability, especially the quadcopter type. In 1947, Ryan X-13 Vertijet , a tailsitter design, was ordered by the US Navy, who then further issued
8142-469: The F-35 Lightning II entered into production. Aircraft in which VTOL is achieved by exploiting the Coandă effect are capable of redirecting air much like thrust vectoring , but rather than routing airflow through a duct, the airflow is simply routed along an existing surface, which is usually the body of the craft allowing less material and weight. The Avro Canada VZ-9 Avrocar , or simply
8280-476: The Fairey Gyrodyne , this type of aircraft later evolved into the much larger twin-engined Fairey Rotodyne , that used tipjets to power the rotor on take-off and landing but which then used two Napier Eland turboprops driving conventional propellers mounted on substantial wings to provide propulsion, the wings serving to unload the rotor during horizontal flight. The Rotodyne was developed to combine
8418-645: The Focke-Achgelis Fa 269 of the mid-1940s and the Centro Técnico Aeroespacial "Convertiplano" of the 1950s reached testing or mock-up stages, the Bell-Boeing V-22 Osprey is considered the world's first production tiltrotor aircraft. It has one three-bladed proprotor , turboprop engine, and transmission nacelle mounted on each wingtip. The Osprey is a multi-mission aircraft with both a vertical takeoff and landing (VTOL) and short takeoff and landing capability ( STOL ). It
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#17327830133148556-623: The Hawker P.1127 , which became subsequently the Kestrel and then entered production as the Hawker Siddeley Harrier , though the supersonic Hawker Siddeley P.1154 was canceled in 1965. The French in competition with the P.1154 had developed a version of the Dassault Mirage III capable of attaining Mach 1. The Dassault Mirage IIIV achieved transition from vertical to horizontal flight in March 1966, reaching Mach 1.3 in level flight
8694-460: The Short SC.1 (1957), Short Brothers and Harland, Belfast which used four vertical lift engines with a horizontal one for forward thrust. The Short SC.1 was the first British fixed-wing VTOL aircraft. The SC.1 was designed to study the problems with VTOL flight and the transition to and from forward flight. The SC.1 was designed to meet a Ministry of Supply (MoS) request for tender (ER.143T) for
8832-401: The centrifugal compressor , pointed outwards like the spokes on a wheel. Power for the compressor was drawn from a new type of turbine similar to a centrifugal fan , as opposed to the more typical pinwheel-like design of conventional engines. The turbine drove the compressor using gearing, rather than a shaft. The resulting engine was arranged in the form of a large disk, which he referred to as
8970-468: The de Havilland Hornet , de Havilland Vampire jet fighter and the de Havilland Swallow aircraft, where he had been the chief designer on the supersonic research project. At Avro Canada, he had worked on the Avro CF-100 before creating a research team known as the "Special Projects Group" (SPG). Frost first surrounded himself with a collection of like-minded "maverick" engineers, then arranged for
9108-474: The fundamental theorem of calculus has that power is given by F ( t ) ⋅ v ( t ) = m a ( t ) ⋅ v ( t ) = τ ( t ) ⋅ ω ( t ) {\displaystyle \mathbf {F} (t)\cdot \mathbf {v} (t)=m\mathbf {a} (t)\cdot \mathbf {v} (t)=\mathbf {\tau } (t)\cdot \mathbf {\omega } (t)} . where: In propulsion , power
9246-529: The lunar module (LEM), which had to rely on a reaction engine to land on the Moon. The idea of using the same engine for vertical and horizontal flight by altering the path of the thrust was conceived by Michel Wibault . It led to the Bristol Siddeley Pegasus engine which used four rotating nozzles to direct thrust over a range of angles. This was developed side by side with an airframe,
9384-594: The "wind tunnel" test model at NASA Ames, where it remained in storage from 1961 until 1966, when it was donated to the National Air and Space Museum, in Suitland, Maryland . There it continued gathering dust for the next 40 years. The museum finally scheduled it for restoration and display at their newly constructed Steven F. Udvar-Hazy Center . Instead the Avrocar has been loaned to the National Museum of
9522-585: The 1960s and early 1970s, Germany planned three different VTOL aircraft. One used the Lockheed F-104 Starfighter as a basis for research for a V/STOL aircraft. Although two models (X1 and X2) were built, the project was canceled due to high costs and political problems as well as changed needs in the German Air Force and NATO. The EWR VJ 101 C did perform free VTOL take-offs and landings, as well as test flights beyond mach 1 in
9660-478: The Air Force added additional funding, and the aircraft became Weapons System 606A . A wide variety of designs were studied for a VTOL fighter aircraft, all revolved around the disk shape, leading to the Project 1794 involving a supersonic large disk fighter aircraft. The concept proceeded to wind tunnel testing with a variety of scale models. It featured a raised section in the middle over the engine that contained
9798-455: The Ames model and testing resumed in April 1961. The new design demonstrated much better control in hover and considerably improved lift. The vehicle was now able to travel at up to 100 knots (190 km/h), a great improvement over the 30 knots (56 km/h) previously reached. However, it remained unstable in pitch, and exhibited a strong nose-up trim. NASA engineers attempted to modify this with
9936-474: The Avro design. For testing purposes, a new engine consisting of six Armstrong Siddeley Viper jet engines blowing across the outer rim of an impeller was designed under the name PV-704, PV stood for Private Venture. The PV-704 was a stop-gap design built into a bunker-like building behind the Avro Experimental Test facility. It was intended to test various Project 1794 concepts and provide
10074-609: The Avro projects, recommended that the WS-606A and all related work (including the Avrocar) be cancelled. A "stop/go" work order came down and Frost was forced once more to try to rescue the project. In an elaborate effort, Frost made a resounding case for continuation of U.S. military funding. Late in May 1959, the USAF authorized Avro to continue the "flying saucer" programs. The Avrocar was
10212-489: The Avrocar project. In March 1959, an additional $ 1.77 million contract was received for a second prototype. At rollout, projected performance was far in excess of the requirement, with a 225 knots (417 km/h) maximum speed, 10,000 feet (3,000 m) ceiling, 130-mile (209 km) range with 1,000 lb (450 kg) payload, and hover out of ground effect with 2,428 lb (1,101 kg) payload. Maximum takeoff weight with transition to forward flight out of ground effect
10350-475: The Avrocar tethered to the ground. After the vehicle became airborne, an uncontrollable roll and pitch-coupled oscillation started that forced each of the three wheels into the ground in turn. The pilot, W. D. "Spud" Potocki, immediately shut down all engines. Changes were made to the stability system to provide more control authority, while new tethers were investigated to improve the ability to control these sorts of problems. As testing continued it became clear that
10488-414: The Avrocar was conducted on the similarly modified second prototype at the Avro facility. During these tests, the vehicle reached a maximum speed of 20 knots (37 km/h) and showed the ability to traverse a ditch six feet across and 18 inches (460 mm) deep. Flight above the critical altitude proved dangerous if not nearly impossible due to inherent instability. The flight test report further identified
10626-861: The Avrocar was prepared for the 2002 production, Avrocar: Saucer Secrets from the Past. It now resides as an exhibit at the Royal Aviation Museum of Western Canada , Winnipeg , Manitoba , Canada. Data from Avrocar: Canada's Flying Saucer... and The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters General characteristics Performance Aircraft of comparable role, configuration, and era VTOL Some VTOL aircraft can operate in other modes as well, such as CTOL (conventional take-off & landing), STOL (short take-off & landing), or STOVL (short take-off & vertical landing). Others, such as some helicopters, can only operate as VTOL, due to
10764-1262: The British Royal Air Force and Royal Navy. The United States Marine Corps and the Italian and Spanish navies all continue to use the AV-8B Harrier II , an American-British variant. Replacing the Harrier II/AV-8B in the air arms of the US and UK is the STOVL variant of the Lockheed Martin F-35 Lightning II , the F-35B. SpaceX developed several prototypes of Falcon 9 to validate various low-altitude, low-velocity engineering aspects of its reusable launch system development program . The first prototype, Grasshopper, made eight successful test flights in 2012–2013. It made its eighth, and final, test flight on October 7, 2013, flying to an altitude of 744 metres (2,441 ft) before making its eighth successful VTVL landing. This
10902-415: The Project Y mock-up and models and drawings (some never before seen by senior company officials) for a completely circular disk-shaped aircraft known as "Project Y-2". The USAF agreed to take over funding for Frost's Special Projects Group, and a contract for US$ 750,000 followed in 1955. By 1956, Avro management was interested enough to commit $ 2.5 million to build a "private venture" prototype. In March 1957,
11040-559: The Special Projects Group. However, three days following the announcement of the Arrow cancellation, many of the Special Projects employees were rehired. But it wasn't quite business as usual. The team now included people from the CF-100 and CF-105 teams and the Special Projects Group was moved into the main building, which was nearly empty. As well, company "brass" became more involved in the group's operations. The USAF Project Office devoted to
11178-506: The U.S. Army joined the efforts it took on its final name "Avrocar", and the designation "VZ-9", part of the U.S. Army's VTOL projects in the VZ series. The Avrocar was the ultimate result of a series of blue skies research projects by designer "Jack" Frost , who had joined Avro Canada in June 1947 after working for several British firms. He had been with de Havilland from 1942 and had worked on
11316-650: The U.S. military had paid for the work, they reverted to U.S. ownership at the end of the program. The second example, S/N 59-4975 , utilized for "flight" testing, returned to Canada briefly for display in Montreal at the Man and His World Exhibition (1968); after a lengthy period of outdoor display, it is now under restoration at the U.S. Army Transportation Museum in Fort Eustis, Virginia. The first Avrocar, S/N 58-7055 (marked AV-7055 ), after tethered testing, became
11454-602: The USAF with test data to show the viability of the concept. The original plan to initially test the Viper Engine Rig was to have continued into free flight testing. Unfortunately, testing was anything but smooth; the test model suffered from hazardous oil leaks, resulting in three fires. It eventually got to the point that staff were afraid of the machine, even when safely ensconced in a booth constructed of bullet-proof glass and quarter-inch-thick steel. A final, disastrous and nearly lethal engine test in 1956 which involved
11592-463: The USAF, as many groups were attempting to gain funding for their own pet projects, like nuclear powered bombers . In a repeat of the earlier Toronto Star release, in 1955 an extensive article appeared in Look magazine that, among other claims, speculated that current UFO sightings were Soviet-built saucers. The article went on to describe such an aircraft with diagrams that were clearly influenced by
11730-694: The United States Air Force in Dayton, Ohio , arriving in November 2007. After a full restoration, which included fabrication of both missing plexiglass bubbles, it was put on display in June 2008 in the museum's Cold War Gallery. It has since been moved to the Presidential Aircraft Gallery. In 2016, the Avrocar was moved to the museum's Research and Development Gallery in its new fourth hangar. A full-scale replica of
11868-549: The VTOL world. The Avro VZ-9 Avrocar was a "dead end" in VTOL design, according to Russell Lee, curator at the National Air and Space Museum , yet its technological innovations have intrigued other designers. One of the design elements it embodied, the use of ducted fans, led to other experimental programs. Dr. Paul Moller, a Canadian expatriate who had worked at Avro Canada as a young engineer, based an initial series of experimental VTOL vehicles on "saucer" technology utilizing
12006-520: The VZ-9, was a Canadian VTOL aircraft developed by Avro Aircraft Ltd. which utilizes this phenomenon by blowing air into a central area, then it is directed down over the top surface, which is parabolic and resembles a bowed flying saucer . Due to the Coandă effect, the airflow is attracted to the nearest surface and continues to move along that surface despite the change in the surface's direction away from
12144-627: The aircraft lacking landing gear that can handle taxiing . VTOL is a subset of V/STOL (vertical or short take-off & landing). Some lighter-than-air aircraft also qualify as VTOL aircraft, as they can hover, takeoff and land with vertical approach/departure profiles. Electric vertical takeoff and landing aircraft, or eVTOLs , are being developed along with more autonomous flight control technologies and mobility-as-a-service (MaaS) to enable advanced air mobility (AAM), that could include on-demand air taxi services, regional air mobility, freight delivery, and personal air vehicles (PAVs). Besides
12282-428: The aircraft was expected to sit pointed up, supported by long landing legs that extended out of the spine. Landing would be accomplished at a very high angle, making visibility during the approach very difficult. A number of other VTOL experiments of the era attempted various solutions to this problem, including rotating pilots seats and cockpits, but none proved very effective. Another problem with various VTOL experiments
12420-486: The aircraft. Frost's engine design used such a large number of nozzles that such an arrangement would not be too easy to build. In 1952, the design was advanced enough that the Canadian Defence Research Board funded the effort with a CAN$ 400,000 contract. By 1953, a wooden mock-up of Project Y was completed, of which only images remain. It appears the project was considered too costly within
12558-563: The airflow. The craft is designed to direct the airflow downward to provide lift. Jetoptera announced a proposed line of aircraft based on what it called fluidic propulsion that employs the Coandă effect. The company claims an Oswald efficiency number of 1.45 for its boxwing design. Other claims include increased efficiency, 30% lower weight, reduced complexity, as much as 25 dBA lower (and atonal) noise, shorter wings, and scalability. Jetoptera says its approach yields thrust augmentation ratios exceeding 2.0 and 50% fuel savings when compared to
12696-487: The airframe was made of aluminum with an empty weight of 3,000 pounds (1,400 kg). The undercarriage of the Avrocar was rudimentary with three small castering wheels mounted on "stub" shafts; a set of skids was substituted later in testing although they were not normally fitted. Pilot control was entirely through a single side-mounted control stick. Pitch and roll were controlled through conventional fore-aft and side-to-side motions, while yaw could be controlled by twisting
12834-407: The application of a small amount of jet thrust, the overall airflow over the craft could be dramatically altered, creating a sort of "virtual airfoil" of any needed configuration. For instance, by directing even a small amount of jet thrust down, a large mass of air would be pulled over the upper surface of the wing and dramatically augment the flow over the wing, creating lift. This appeared to offer
12972-627: The attempt to design, construct, and test two experimental VTOL fighters. Lockheed produced the XFV , and Convair producing the Convair XFY Pogo . Both experimental programs proceeded to flight status and completed test flights 1954–1955, when the contracts were cancelled. Similarly, the Ryan X-13 Vertijet flew a series of test flights between 1955 and 1957, but also suffered the same fate. The use of vertical fans driven by engines
13110-482: The buried ducted fan à la-Avrocar. The XM-2, the first of the series looked remarkably like a miniature flying saucer. After successful tether tests, the saucer designs also at one time publicized as "discojet" were abandoned and their latest project, the Moller Skycar , has a flying-car appearance. The Avrocar story did not end with the termination of the program. Only two Avrocars were ever produced and because
13248-420: The cockpit and a series of rectangular intakes that provided air to the engine during low-speed flight. For supersonic flight, the upper intakes were closed using louvers and air was instead provided from a separate supersonic intake along the front of the raised section. Frost's performance estimates for the concept were for a potential of Mach 3.5 at 100,000 ft (30,000 m) altitudes. As Project 1794
13386-709: The development of the Panavia Tornado . The Yakovlev Yak-38 was a Soviet Navy VTOL aircraft intended for use aboard their light carriers, cargoships, and capital ships. It was developed from the Yakovlev Yak-36 experimental aircraft in the 1970s. Before the Soviet Union broke up, a supersonic VTOL aircraft was developed as the Yak-38's successor, the Yak-141 , which never went into production. In
13524-458: The dielectric medium to nanopores and a very thin high permittivity separator. While capacitors tend not to be as temperature sensitive as batteries, they are significantly capacity constrained and without the strength of chemical bonds suffer from self-discharge. Power-to-weight ratio of capacitors is usually higher than batteries because charge transport units within the cell are smaller (electrons rather than ions), however energy-to-weight ratio
13662-495: The efficiency of a fixed-wing aircraft at cruise with the VTOL capability of a helicopter to provide short haul airliner service from city centres to airports. The CL-84 Dynavert was a Canadian V/STOL turbine tilt-wing monoplane designed and manufactured by Canadair between 1964 and 1972. The Canadian government ordered three updated CL-84s for military evaluation in 1968, designated the CL-84-1. From 1972 to 1974, this version
13800-403: The entire ring down, which would produce more airflow over its upper surface, which would then bend down over this surface toward the ground. Tilting the ring resulted in asymmetric thrust for directional control. It was discovered that the craft was inherently unstable in forward flight, as the aerodynamic center of pressure was well forward of the center of gravity . The Avrocar thus included
13938-418: The flap was positioned in order to provide control, the lift would be lowered on one side and raised on the other. Lift was indeed lowered on one side, but the lift did not improve on the other, so every control input resulted in a loss of altitude. After five flights, testing was temporarily halted on 5 December 1959, by which time the Avrocar had logged 18.5 hours of test time in total. A completely new design
14076-415: The front of the centre on the top and bottom of the aircraft. The cockpit was positioned over the main bearing, behind the intakes. A "spine" on the top and bottom ran from the cockpit area to the rear edge of the aircraft. Several other versions of the basic layout were also studied, including the "Omega" which was more disk-like as it cut away the rear portions of the delta wing as well. For VTOL operations
14214-421: The ground and re-establish the supporting air, while the other side would then be raised above this limit. This process would repeat itself, with the craft rolling from side to side. Modifications were carried out in order to try to solve the problem. Eventually a series of 52 holes were drilled in the bottom of the vehicle, located radially three feet from the center. These were to provide a central jet to stabilize
14352-400: The ground cushion. With these modifications complete and apparently working, the first completely free flight occurred on 12 November 1959. This test proved the nozzle control system unacceptable. The spoilers were intended to direct the air out over the top or bottom of the annular flap, out the bottom only during hover, but over the top and bottom during forward flight. The idea was that when
14490-406: The ground effect to 3,150 lb (1,430 kg), less than the empty weight of the aircraft at 4,285 lb (1,944 kg). This meant the aircraft would be incapable of hovering out of the ground effect. Following these tests, the vehicle was sent to NASA Ames for a wind tunnel testing. The second, # 59-4975 , was completed August 1959. On 29 September, the first attempt to hover was made with
14628-442: The ground effect, the air formed itself into a single narrow column, described by Frost as "tree trunking". At intermediate altitudes the craft would momentarily transition from one regime to the other, during which time one side of the vehicle would be entirely supported while the support was disappearing under the other. This led to a strong pitching motion towards the unsupported side. As soon as this occurred that side would approach
14766-418: The loss of propellant weight and a controlled vertical landing is possible. An important aspect of Harrier STOL operations aboard naval carriers is the "ski jump" raised forward deck, which gives the craft additional vertical momentum at takeoff. The March 1981 cover of Popular Science showed three illustrations for its "Tilt-engine V/STOL - speeds like a plane, lands like a copter" front-page feature story.;
14904-408: The main disk, shaped roughly like a rounded triangle with the flat surface on the "inside". Viewing the craft from the side, the control flap is almost invisible, appearing in its neutral position to blend into the profile. The pilot's controls moved the ring in relation to the rest of the craft, affecting the airflow moving outward from the center of the craft. Vertical lift could be increased by moving
15042-700: The mid- and late 60s. One of the test-aircraft is preserved in the Deutsches Museum in Munich, Germany, another outside Friedrichshafen Airport. The others were the VFW-Fokker VAK 191B light fighter and reconnaissance aircraft, and the Dornier Do 31 E-3 (troop) transport. The LLRV was a spacecraft simulator for the Apollo lunar lander. It was designed to mimic the flight characteristics of
15180-628: The military establishment, which was at the time involved in several extremely expensive air defense projects. On 11 February 1953, a story on the project was leaked to the Toronto Star along with images of the Omega design, apparently in order to gain further funding. Five days later, the Minister for Defence Production informed the House of Commons that Avro was indeed working on a "mock-up model" of
15318-577: The military. Although considered a technical failure, its design would be prophetic: it was a rubber skirt shy of being one of the world's first hovercraft , the Saunders Roe SR.N1 also taking off in 1959. Nevertheless, company designer John Frost applied for a number of patents in Canada, the UK and the U.S. that established the pivotal role that the Avrocar and related Avro experimental vehicles made in
15456-442: The perception of sports car like performance or for other psychological benefit . Increased engine performance is a consideration, but also other features associated with luxury vehicles . Longitudinal engines are common. Bodies vary from hot hatches , sedans (saloons) , coupés , convertibles and roadsters . Mid-range dual-sport and cruiser motorcycles tend to have similar power-to-weight ratios. Power-to-weight ratio
15594-431: The power-to-weight ratio purely by SI base units . A vehicle's power-to-weight ratio equals its acceleration times its velocity; so at twice the velocity, it experiences half the acceleration, all else being equal. If the work to be done is rectilinear motion of a body with constant mass m {\displaystyle m\;} , whose center of mass is to be accelerated along a (possibly non-straight) line to
15732-590: The powered rotor of a helicopter with a separate forward thrust system of an autogyro. Apart from take-off and landing the rotor may be unpowered and autorotate. Designs may also include stub wings for added lift. A cyclogyro or cyclocopter has a rotary wing whose axis and surfaces remain sideways across the airflow, as with a conventional wing. There are number of designs for achieving power lift, and some designs may use more than one. There are many experimental designs that have unique design features to achieve powered lift. A convertiplane takes off under rotor lift like
15870-406: The problem was inherent to the design, and the engineers started referring to the effect as "hubcapping", so-named as it appeared similar to a hubcap spun on the ground. Investigations into the effect revealed what was causing the problem. While in the ground effect, the high-pressure air under the craft was trapped, filling the entire area and thus providing a stable base. When the craft rose out of
16008-407: The propulsion and control system. Instead of the single annular triangular flap and spoilers, or the later ring control, the new system included two separate control systems for hover and forward flight, combined into a single nozzle. For hover, a series of "transition doors" were opened into the nozzles, blocking them off and re-directing the flow downward under the aircraft. Control during this regime
16146-701: The propulsive power of a jet or rocket engine is transferred to its vehicle. An electric motor uses electrical energy to provide mechanical work , usually through the interaction of a magnetic field and current-carrying conductors . By the interaction of mechanical work on an electrical conductor in a magnetic field, electrical energy can be generated . Fluids (liquid and gas) can be used to transmit and/or store energy using pressure and other fluid properties. Hydraulic (liquid) and pneumatic (gas) engines convert fluid pressure into other desirable mechanical or electrical work . Fluid pumps convert mechanical or electrical work into movement or pressure changes of
16284-433: The rotor's thrust directed straight down through an opening in the lower surface, but some was bled off to power the control system running along the outer rim of the disk. Power for the rotor was provided by three Continental J69-T-9 jet engines attached to the truss. Each engine had its own fuel and oil tanks and other support systems, although it was expected these would be interconnected in future models. The majority of
16422-408: The stick. No mechanical linkages were used, the stick instead controlled the flow of high pressure air around the craft, which either directly attached to various control surfaces, or indirectly through local cable linkages to replace controls that were intended to be cable-actuated (like throttle controls on the engines). The attitude/thrust control system consisted of a large ring situated outside of
16560-400: The time, Frost was particularly interested in jet engine design and ways to improve the efficiency of the compressor without sacrificing the simplicity of the turbine engine. He found Frank Whittle 's "reverse flow" design too complex and was interested in ways to clean up the layout. This led him to design a new type of engine layout with the flame cans lying directly outside the outer rim of
16698-768: The ubiquitous helicopters, there are currently two types of VTOL aircraft in military service: tiltrotor aircraft, such as the Bell Boeing V-22 Osprey , and thrust-vectoring airplanes, such as the Harrier family and new F-35B Lightning II Joint Strike Fighter (JSF). In the civilian sector currently only helicopters are in general use (some other types of commercial VTOL aircraft have been proposed and are under development as of 2017 ). Generally speaking, VTOL aircraft capable of STOVL use it wherever possible, since it typically significantly increases takeoff weight, range or payload compared to pure VTOL. The idea of vertical flight has been around for thousands of years, and sketches for
16836-516: The vehicle itself. In the sport of competitive cycling athlete's performance is increasingly being expressed in VAMs and thus as a power-to-weight ratio in W/kg. This can be measured through the use of a bicycle powermeter or calculated from measuring incline of a road climb and the rider's time to ascend it. A locomotive generally must be heavy in order to develop enough adhesion on the rails to start
16974-579: Was a prototype VTOL 6x General Electric J85 Turbojet engined nuclear capable strike fighter concept designed by Alexander Kartveli that had 3x ducted fans in the centre of its fuselage and tail as a possible contender for the TFX Program . Another design was the A400 AVS that used variable geometry wings but was found too complicated, however it led to the development of the AFVG which in turn helped
17112-490: Was calculated to be 5,650 lb (2,560 kg), maximum weight with a transition in ground effect (GETOL) was 6,970 lb (3,160 kg). Just as the first working test models were being manufactured, disaster struck. The Canadian government cancelled the Avro CF-105 Arrow program on "Black Friday", 20 February 1959. The ensuing result was the lay-off of almost all Avro Canada employees, including those with
17250-614: Was demonstrated and evaluated in the United States aboard the aircraft carriers USS Guam and USS Guadalcanal , and at various other centres. These trials involved military pilots from the United States, the United Kingdom and Canada. During testing, two of the CL-84s crashed due to mechanical failures, but no loss of life occurred as a result of these accidents. No production contracts resulted. Although tiltrotors such as
17388-587: Was developed, Avro Canada proposed a version of the "Project Y", the TS-140, to meet the United States Navy 's Specification TS-140 for a VTOL fighter aircraft in 1956; it was rejected by the Navy. The TS-140 was a canard type aircraft to be powered by four Bristol Orpheus jet engines; the Navy instead selected Bell Aircraft 's D-188A for its requirement. There was some debate about the concept within
17526-524: Was eventually able to demonstrate a "hands-off" flight. Nonetheless, Avro test pilot Peter Cope, USAF project pilot Walter J. Hodgson and NASA's Ames Research Center Chief Test Pilot Fred J. Drinkwater III, who all flew the Avrocar, considered it still a tricky vehicle to fly. Drinkwater likened a flight in it to "balancing on a beach ball". The first Avrocar, # 58-7055 , rolled out of the Avro Malton factory in May 1959. From 9 June to 7 October 1959, it
17664-405: Was how to use the annular thrust to drive the aircraft forward, as well as the problem of fitting the very large engine into a suitable airframe. Frost suggested using a series of ducts and vents to redirect the thrust flowing out of the front of the engine towards the rear. In order to keep the pipes as short as possible, the design ported the thrust out along the leading edge of what was essentially
17802-544: Was installed over the winter. The original spoilers were removed and replaced by a single ring below the annular flap. The ring shifted in relation to the craft under control input, "sealing off" the gap on one side while opening it on the other. Tests continued in January 1960, and appeared to work much better. However, while the new control system improved the hovering qualities, the craft now became unstable at higher speeds above 30 knots (56 km/h). The first Avrocar at Ames
17940-574: Was investigated in the 1950s. The US built an aircraft where the jet exhaust drove the fans , while British projects not built included fans driven by mechanical drives from the jet engines. NASA has flown other VTOL craft such as the Bell XV-15 research craft (1977), as have the Soviet Navy and Luftwaffe . Sikorsky tested an aircraft dubbed the X-Wing , which took off in the manner of
18078-423: Was manned by a crew of two, positioned in separate cockpits squeezed into empty areas in the airframe. In practice, only one pilot was usually on board during testing; a number of flights were made with an observer in the second cockpit. Until control problems were completely solved, the Avro test pilots acquired a "touch" for the extremely sensitive control inputs and Avro Aircraft Chief Development Test Pilot Potocki
18216-406: Was provided by moving the outer portion of the flap to "focus" the flow. At higher speeds, the doors were closed, allowing the air to flow out from the edge of the aircraft, where a series of simple flap-like controls were located. The new control system covered the rear 3/4's of the aircraft's outer circumference; the front section featured the hovering controls only. Modifications were completed on
18354-422: Was put into various solutions to securing a second-strike capability. Some of these solutions included rocket-launched aircraft like the zero-length launch concept, while many companies started work on VTOL aircraft as a more appropriate long-term solution. Frost felt the excellent performance of his new engine would be a natural fit for a VTOL aircraft due to its high expected power-to-weight ratio . The problem
18492-401: Was similarly modified, and, in April 1960, it was tested in their 40 ft × 80 ft (12 m × 24 m) wind tunnel. The problem became clear; the ring blocked so much of the overall engine thrust that the overall power was greatly reduced. As the craft sped up, the airflow on the underside reduced the recirculation, reducing the lift due to airflow over the upper surface. This
18630-413: Was somewhat unexpected; recirculation had been considered a "bad thing" due to the loss of engine thrust, and its positive effects on lift do not appear to have been appreciated. In the end, in order to maintain lift at higher forward speeds the craft had to be pitched to the end of its control capability. Avro was convinced that the concept was still workable, and proposed a new program for major rework of
18768-465: Was tested in a static hover rig. Unfortunately, hot gas from the exhaust was found to mix back into the intakes in hover, reducing engine thrust. In addition, the fan generated lift only from a small area of its surface, lowering overall thrust available. The ducts also proved to have higher losses than expected, and a series of modifications were not able to solve this problem to any large degree. These problems reduced maximum lift at higher altitudes out of
18906-399: Was that stability in a hover was difficult to arrange, although not entirely unexpected. A solution to this problem would require the thrust to be directed downward from a larger area, as it is in a helicopter, where the lift is supplied over the entire area of the rotor disk. Most designers turned to bleeding off air from the engine's compressor, and directing that through pipes arranged around
19044-655: Was the last scheduled test for the Grasshopper rig; next up will be low altitude tests of the Falcon 9 Reusable (F9R) development vehicle in Texas followed by high altitude testing in New Mexico. On November 23, 2015, Blue Origin 's New Shepard booster rocket made the first successful vertical landing following an uncrewed suborbital test flight that reached space. On December 21, 2015, SpaceX Falcon 9 first stage made
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