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70-498: Both Bell Aircraft Corporation and Curtiss-Wright Corporation had corporate headquarters, research & development (R&D), and manufacturing operations nearby in the middle of the twentieth century, and much of the material on display is from these two aviation companies. Among its many displays are many examples of early to mid-twentieth century piston, turbo-jet, turbo-shaft, and jet engines, as well as several static display aircraft including early Bell helicopters, an example of

140-464: A bent aluminium sheet for blades, thus creating an airfoil shape. They were heavily undercambered , and this plus the absence of lengthwise twist made them less efficient than the Wright propellers. Even so, this was perhaps the first use of aluminium in the construction of an airscrew. Originally, a rotating airfoil behind the aircraft, which pushes it, was called a propeller, while one which pulled from

210-473: A childhood fascination with the Chinese flying top, developed a model of feathers, similar to that of Launoy and Bienvenu, but powered by rubber bands. By the end of the century, he had progressed to using sheets of tin for rotor blades and springs for power. His writings on his experiments and models would become influential on future aviation pioneers. William Bland sent designs for his "Atmotic Airship" to

280-461: A craft that weighed 3.5 long tons (3.6 t), with a 110 ft (34 m) wingspan that was powered by two 360 hp (270 kW) steam engines driving two propellers. In 1894, his machine was tested with overhead rails to prevent it from rising. The test showed that it had enough lift to take off. One of Pénaud's toys, given as a gift by their father , inspired the Wright brothers to pursue

350-657: A factory near Marietta, Georgia , just northwest of Atlanta . Online by mid-1943, the new plant produced hundreds of Consolidated B-24 Liberators and Boeing B-29 Superfortress bombers. In mid-1944, the production of the B-24 was consolidated from several different companies (including some in Texas) to two large factories: Consolidated Vultee in San Diego and Ford Motor Company 's Willow Run factory near Detroit, Michigan , which had been specially designed to produce B-24s. For

420-416: A fixed-pitch prop once airborne. The spring-loaded "two-speed" VP prop is set to fine for takeoff, and then triggered to coarse once in cruise, the propeller remaining coarse for the remainder of the flight. After World War I , automatic propellers were developed to maintain an optimum angle of attack. This was done by balancing the centripetal twisting moment on the blades and a set of counterweights against

490-467: A large number of blades. A fan therefore produces a lot of thrust for a given diameter but the closeness of the blades means that each strongly affects the flow around the others. If the flow is supersonic, this interference can be beneficial if the flow can be compressed through a series of shock waves rather than one. By placing the fan within a shaped duct , specific flow patterns can be created depending on flight speed and engine performance. As air enters

560-528: A low- drag wing and as such are poor in operation when at other than their optimum angle of attack . Therefore, most propellers use a variable pitch mechanism to alter the blades' pitch angle as engine speed and aircraft velocity are changed. A further consideration is the number and the shape of the blades used. Increasing the aspect ratio of the blades reduces drag but the amount of thrust produced depends on blade area, so using high-aspect blades can result in an excessive propeller diameter. A further balance

630-415: A propeller efficiency of about 73.5% at cruise for a Cessna 172 . This is derived from his "Bootstrap approach" for analyzing the performance of light general aviation aircraft using fixed pitch or constant speed propellers. The efficiency of the propeller is influenced by the angle of attack (α). This is defined as α = Φ - θ, where θ is the helix angle (the angle between the resultant relative velocity and

700-453: A propeller suffers when transonic flow first appears on the tips of the blades. As the relative air speed at any section of a propeller is a vector sum of the aircraft speed and the tangential speed due to rotation, the flow over the blade tip will reach transonic speed well before the aircraft does. When the airflow over the tip of the blade reaches its critical speed , drag and torque resistance increase rapidly and shock waves form creating

770-454: A sharp increase in noise. Aircraft with conventional propellers, therefore, do not usually fly faster than Mach 0.6. There have been propeller aircraft which attained up to the Mach 0.8 range, but the low propeller efficiency at this speed makes such applications rare. The tip of a propeller blade travels faster than the hub. Therefore, it is necessary for the blade to be twisted so as to decrease

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840-759: A similar system was incorporated into the North American X-15 spaceplane. NASA selected Bell to develop and built the LLRV Lunar Landing Research Vehicle , three of which were built in the early 1960s to train the Apollo astronauts to land on the Moon. Bell also designed the rocket engine used in the Apollo LEM Ascent Propulsion System , which was responsible for getting NASA's astronauts off

910-583: A small coaxial modeled after the Chinese top but powered by a wound-up spring device and demonstrated it to the Russian Academy of Sciences . It was powered by a spring, and was suggested as a method to lift meteorological instruments. In 1783, Christian de Launoy , and his mechanic , Bienvenu, used a coaxial version of the Chinese top in a model consisting of contrarotating turkey flight feathers as rotor blades, and in 1784, demonstrated it to

980-417: A spring and the aerodynamic forces on the blade. Automatic props had the advantage of being simple, lightweight, and requiring no external control, but a particular propeller's performance was difficult to match with that of the aircraft's power plant. The most common variable pitch propeller is the constant-speed propeller . This is controlled by a hydraulic constant speed unit (CSU). It automatically adjusts

1050-698: A swirling slipstream which pushes the propeller forwards or backwards. It comprises a rotating power-driven hub, to which are attached several radial airfoil -section blades such that the whole assembly rotates about a longitudinal axis. The blade pitch may be fixed, manually variable to a few set positions, or of the automatically variable "constant-speed" type. The propeller attaches to the power source's driveshaft either directly or through reduction gearing . Propellers can be made from wood, metal or composite materials . Propellers are most suitable for use at subsonic airspeeds generally below about 480 mph (770 km/h), although supersonic speeds were achieved in

1120-470: Is a stub . You can help Misplaced Pages by expanding it . Bell Aircraft Corporation The Bell Aircraft Corporation was an American aircraft manufacturer , a builder of several types of fighter aircraft for World War II but most famous for the Bell X-1 , the first supersonic aircraft, and for the development and production of many important civilian and military helicopters . Bell also developed

1190-455: Is hydraulic, with engine oil serving as the hydraulic fluid. However, electrically controlled propellers were developed during World War II and saw extensive use on military aircraft, and have recently seen a revival in use on home-built aircraft. Another design is the V-Prop , which is self-powering and self-governing. On most variable-pitch propellers, the blades can be rotated parallel to

1260-479: Is suitable for airliners, but the noise generated is tremendous (see the Antonov An-70 and Tupolev Tu-95 for examples of such a design). Forces acting on the blades of an aircraft propeller include the following. Some of these forces can be arranged to counteract each other, reducing the overall mechanical stresses imposed. The purpose of varying pitch angle is to maintain an optimal angle of attack for

1330-409: Is that using a smaller number of blades reduces interference effects between the blades, but to have sufficient blade area to transmit the available power within a set diameter means a compromise is needed. Increasing the number of blades also decreases the amount of work each blade is required to perform, limiting the local Mach number – a significant performance limit on propellers. The performance of

1400-489: Is used to help slow the aircraft after landing and is particularly advantageous when landing on a wet runway as wheel braking suffers reduced effectiveness. In some cases reverse pitch allows the aircraft to taxi in reverse – this is particularly useful for getting floatplanes out of confined docks. Counter-rotating propellers are sometimes used on twin-engine and multi-engine aircraft with wing-mounted engines. These propellers turn in opposite directions from their counterpart on

1470-545: The French Academy of Sciences . A dirigible airship was described by Jean Baptiste Marie Meusnier presented in 1783. The drawings depict a 260-foot-long (79 m) streamlined envelope with internal ballonets that could be used for regulating lift. The airship was designed to be driven by three propellers. In 1784 Jean-Pierre Blanchard fitted a hand-powered propeller to a balloon, the first recorded means of propulsion carried aloft. Sir George Cayley , influenced by

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1540-578: The McDonnell XF-88B experimental propeller-equipped aircraft. Supersonic tip-speeds are used in some aircraft like the Tupolev Tu-95 , which can reach 575 mph (925 km/h). The earliest references for vertical flight came from China. Since around 400 BC, Chinese children have played with bamboo flying toys . This bamboo-copter is spun by rolling a stick attached to a rotor between one's hands. The spinning creates lift, and

1610-403: The Tupolev Tu-95 propel it at a speed exceeding the maximum once considered possible for a propeller-driven aircraft using an exceptionally coarse pitch. Early pitch control settings were pilot operated, either with a small number of preset positions or continuously variable. The simplest mechanism is the ground-adjustable propeller , which may be adjusted on the ground, but is effectively

1680-535: The Great Exhibition held in London in 1851, where a model was displayed. This was an elongated balloon with a steam engine driving twin propellers suspended underneath. Alphonse Pénaud developed coaxial rotor model helicopter toys in 1870, also powered by rubber bands. In 1872 Dupuy de Lome launched a large navigable balloon, which was driven by a large propeller turned by eight men. Hiram Maxim built

1750-482: The Moon. Société d'Étude et de Développement des Aéroglisseurs Marins (SEDAM) was a French-based unit of Bell founded in 1965 and builder of N500 Naviplane hovercraft, as well as N.300 Naviplane and Naviplane N102 . SEDAM ceased operations in 1982 and factory site re-developed for non-aviation usage. Propeller (aircraft) In aeronautics , an aircraft propeller , also called an airscrew , converts rotary motion from an engine or other power source into

1820-741: The P-39 was produced shortly before the end of World War II . Called the P-63 Kingcobra , this warplane addressed many of the shortcomings of the P-39, though it was produced too late in the war to make any significant contribution. 2,971 P-63's were built between 1943 and 1945, many delivered to the Soviet Union. Also, by that time, the Army Air Forces already had the superior P-47 Thunderbolt and P-38 Lightning fighter-bombers . In October 1942, The Bell-built twin-jet P-59 Airacomet

1890-507: The P-59 that was cancelled. The Bell XF-109 was a supersonic vertical takeoff fighter that was cancelled in 1961. Perhaps Bell Aircraft's most important contribution to the history of fixed-wing aircraft development would be the design and building of the experimental Bell X-1 rocket plane , the world's first airplane to break the sound barrier , and its follow-on, the Bell X-2 . Unlike

1960-737: The Reaction Control System for the Mercury Spacecraft, North American X-15 , and Bell Rocket Belt . The company was purchased in 1960 by Textron , and lives on as Bell Textron . As a pilot, Larry Bell saw his first plane at an air show, starting a lifelong fascination with aviation. Bell dropped out of high school in 1912 to join his brother in the burgeoning aircraft industry at the Glenn L. Martin Company , where by 1914 he had become shop superintendent. By 1920, Bell

2030-654: The World War II Bell P-39 Airacobra , and the Bell X-22 tilt-ducted-fan VSTOL aircraft. The museum appointed Lindsey Lauren Visser as the new Executive Director director in March 2024. 43°06′01″N 78°56′33″W  /  43.1002°N 78.9426°W  / 43.1002; -78.9426 This United States aerospace museum–related article is a stub . You can help Misplaced Pages by expanding it . This New York museum-related article

2100-399: The air in the propeller slipstream. Contra-rotation also increases the ability of a propeller to absorb power from a given engine, without increasing propeller diameter. However the added cost, complexity, weight and noise of the system rarely make it worthwhile and it is only used on high-performance types where ultimate performance is more important than efficiency. A fan is a propeller with

2170-428: The aircraft maintain speed and altitude with the operative engines. Feathering also prevents windmilling , the turning of engine components by the propeller rotation forced by the slipstream; windmilling can damage the engine, start a fire, or cause structural damage to the aircraft. Most feathering systems for reciprocating engines sense a drop in oil pressure and move the blades toward the feather position, and require

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2240-405: The airflow to stop rotation of the propeller and reduce drag when the engine fails or is deliberately shut down. This is called feathering , a term borrowed from rowing . On single-engined aircraft, whether a powered glider or turbine-powered aircraft, the effect is to increase the gliding distance. On a multi-engine aircraft, feathering the propeller on an inoperative engine reduces drag, and helps

2310-410: The angle of attack of the blade gradually and therefore produce uniform lift from the hub to the tip. The greatest angle of incidence, or the highest pitch, is at the hub while the smallest angle of incidence or smallest pitch is at the tip. A propeller blade designed with the same angle of incidence throughout its entire length would be inefficient because as airspeed increases in flight, the portion near

2380-407: The blade pitch in order to maintain a constant engine speed for any given power control setting. Constant-speed propellers allow the pilot to set a rotational speed according to the need for maximum engine power or maximum efficiency, and a propeller governor acts as a closed-loop controller to vary propeller pitch angle as required to maintain the selected engine speed. In most aircraft this system

2450-440: The blade rotation direction) and Φ is the blade pitch angle. Very small pitch and helix angles give a good performance against resistance but provide little thrust, while larger angles have the opposite effect. The best helix angle is when the blade is acting as a wing producing much more lift than drag. However, 'lift-and-drag' is only one way to express the aerodynamic force on the blades. To explain aircraft and engine performance

2520-403: The blade tips approach the speed of sound. The maximum relative velocity is kept as low as possible by careful control of pitch to allow the blades to have large helix angles. A large number of blades are used to reduce work per blade and so circulation strength. Contra-rotating propellers are used. The propellers designed are more efficient than turbo-fans and their cruising speed (Mach 0.7–0.85)

2590-606: The company was in financial difficulty. Textron purchased the Bell Aerospace division on 5 July 1960. Bell Aerospace was composed of three divisions of Bell Aircraft, including the helicopter division. Bell Aerospace Textron continued to play a significant role in NASA's mission to land men on the Moon in the 1960s. Bell designed and built the Reaction Control system for Project Mercury 's Redstone command module and

2660-467: The dream of flight. The twisted airfoil (aerofoil) shape of an aircraft propeller was pioneered by the Wright brothers. While some earlier engineers had attempted to model air propellers on marine propellers , the Wright Brothers realized that a propeller is essentially the same as a wing , and were able to use data from their earlier wind tunnel experiments on wings, introducing a twist along

2730-575: The duct, its speed is reduced while its pressure and temperature increase. If the aircraft is at a high subsonic speed this creates two advantages: the air enters the fan at a lower Mach speed; and the higher temperature increases the local speed of sound. While there is a loss in efficiency as the fan is drawing on a smaller area of the free stream and so using less air, this is balanced by the ducted fan retaining efficiency at higher speeds where conventional propeller efficiency would be poor. A ducted fan or propeller also has certain benefits at lower speeds but

2800-431: The feathering process or the feathering process may be automatic. Accidental feathering is dangerous and can result in an aerodynamic stall ; as seen for example with Yeti Airlines Flight 691 which crashed during approach due to accidental feathering. The propellers on some aircraft can operate with a negative blade pitch angle, and thus reverse the thrust from the propeller. This is known as Beta Pitch. Reverse thrust

2870-620: The first engine until March 1942. Also, General Henry "Hap" Arnold had forbidden use of wind tunnels to test and optimize the design, but later relented somewhat, only allowing the group to use the low-speed tunnel at Wright Field , Ohio . Bell engineers could only guess at the performance characteristics. Originally intended initially as a production aircraft, the P-59 nevertheless became an important experimental testbed for jet technology, providing invaluable data for development of later jet airplanes. During World War II, Bell also built heavy bombers under license from other aircraft companies at

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2940-411: The following year with the development of the single engine P-39 Airacobra, which 9,588 were built. Putting their previous experience with Allison engines to good use, the P-39 placed the engine in the center of the aircraft, with the propeller driven by a long shaft through which a 37mm cannon was also mounted, firing through the propeller's spinner. Due to persistent development and production problems,

3010-541: The former Consolidated plant at 2050 Elmwood Avenue in North Delaware area of Buffalo. Bell was the third major aircraft builder to occupy the site. The factory complex was originally built in 1916 for the Curtiss Aeroplane & Motor Company , and during World War I had been considered the largest airplane factory in the world. Bell's first military contract followed in 1937 with the development of

3080-463: The front was a tractor . Later the term 'pusher' became adopted for the rear-mounted device in contrast to the tractor configuration and both became referred to as 'propellers' or 'airscrews'. The understanding of low speed propeller aerodynamics was fairly complete by the 1920s, but later requirements to handle more power in a smaller diameter have made the problem more complex. Propeller research for National Advisory Committee for Aeronautics (NACA)

3150-574: The fuselage – clockwise on the left engine and counterclockwise on the right – however, there are exceptions (especially during World War II ) such as the P-38 Lightning which turned "outwards" (counterclockwise on the left engine and clockwise on the right) away from the fuselage from the WW II years, and the Airbus A400 whose inboard and outboard engines turn in opposite directions even on

3220-414: The hub would have a negative AOA while the blade tip would be stalled. There have been efforts to develop propellers and propfans for aircraft at high subsonic speeds. The 'fix' is similar to that of transonic wing design. Thin blade sections are used and the blades are swept back in a scimitar shape ( scimitar propeller ) in a manner similar to wing sweepback, so as to delay the onset of shockwaves as

3290-480: The ill-fated YFM-1 Airacuda , an unconventional bomber-destroyer powered by two Allison -powered pusher propellers . The YFM-1 incorporated groundbreaking technology for the time, with gyro stabilized weapons sighting and a thermionic fire control system. Including the prototype, just 13 Airacudas were produced, and these saw only limited service with the USAAC before being scrapped in 1942. Bell enjoyed much success

3360-400: The length of the blades. This was necessary to maintain a more uniform angle of attack of the blade along its length. Their original propeller blades had an efficiency of about 82%, compared to 90% for a modern (2010) small general aviation propeller, the 3-blade McCauley used on a Beechcraft Bonanza aircraft. Roper quotes 90% for a propeller for a human-powered aircraft. Mahogany was

3430-667: The only part of Bell Aircraft still producing aircraft when Bell was purchased by the Textron Corporation . That part of Textron is now known today as Bell Helicopter . After a series of successful helicopter designs, the UH-1 Iroquois became the most famous helicopter of the War in Vietnam , and Bell Helicopter still designs and manufactures helicopters today. Lawrence Bell died in 1956, and for several years afterwards

3500-561: The original turbosupercharger was deleted from production models, instead using a single-stage, single-speed supercharger, as was standard on all other Allison-powered products, with the exception of the P-38. The P-39 performed poorly at high altitudes compared to newer, late-war designs. Most Allied forces thought the Airacobra effective only for ground attack roles, as demonstrated by a few U.S. Army Air Forces units that flew P-39s, such as

3570-432: The other wing to balance out the torque and p-factor effects. They are sometimes referred to as "handed" propellers since there are left hand and right hand versions of each prop. Generally, the propellers on both engines of most conventional twin-engined aircraft spin clockwise (as viewed from the rear of the aircraft). To eliminate the critical engine problem, counter-rotating propellers usually turn "inwards" towards

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3640-417: The pilot to pull the propeller control back to disengage the high-pitch stop pins before the engine reaches idle RPM . Turboprop control systems usually use a negative torque sensor in the reduction gearbox, which moves the blades toward feather when the engine is no longer providing power to the propeller. Depending on design, the pilot may have to push a button to override the high-pitch stops and complete

3710-561: The propeller blades, giving maximum efficiency throughout the flight regime. This reduces fuel usage. Only by maximising propeller efficiency at high speeds can the highest possible speed be achieved. Effective angle of attack decreases as airspeed increases, so a coarser pitch is required at high airspeeds. The requirement for pitch variation is shown by the propeller performance during the Schneider Trophy competition in 1931. The Fairey Aviation Company fixed-pitch propeller used

3780-495: The property of the Lockheed Corporation , which has used it for producing C-130 Hercules , C-141 Starlifter , and C-5 Galaxy transport planes . Although Bell designed several more fighter plane designs during and after WW II, none of these ever entered mass-production. The XP-77 was a small fighter using non- strategic materials ; it was not successful. The XP-83 was a jet escort fighter similar in layout to

3850-588: The rest of the war, Bell's Marietta plant , under the management of Carl Cover and James V. Carmichael concentrated on producing B-29s, producing 668 of them by the time contract expired in the fall of 1945. Bell ranked 25th among United States corporations in the value of wartime production contracts. As the postwar defense industry downsized, Bell consolidated its operations at the Wheatfield plant, near Buffalo. The aircraft factory in Marietta later became

3920-411: The same force is expressed slightly differently in terms of thrust and torque since the required output of the propeller is thrust. Thrust and torque are the basis of the definition for the efficiency of the propeller as shown below. The advance ratio of a propeller is similar to the angle of attack of a wing. A propeller's efficiency is determined by Propellers are similar in aerofoil section to

3990-410: The same wing. A contra-rotating propeller or contra-prop places two counter-rotating propellers on concentric drive shafts so that one sits immediately 'downstream' of the other propeller. This provides the benefits of counter-rotating propellers for a single powerplant. The forward propeller provides the majority of the thrust, while the rear propeller also recovers energy lost in the swirling motion of

4060-602: The so-called Cactus Air Force on Guadalcanal in 1942–43. However, the Soviet Air Force used their Lend-Lease P-39s primarily in the air-to-air role, where they found it to excel as a front-line fighter against some of the best pilots and aircraft of the Luftwaffe . The Soviet-flown P-39s were the main reason that the aircraft is credited with highest number of individual kills attributed to any U.S. fighter type. A somewhat larger and more powerful version of

4130-530: The toy flies when released. The 4th-century AD Daoist book Baopuzi by Ge Hong (抱朴子 "Master who Embraces Simplicity") reportedly describes some of the ideas inherent to rotary wing aircraft. Designs similar to the Chinese helicopter toy appeared in Renaissance paintings and other works. It was not until the early 1480s, when Leonardo da Vinci created a design for a machine that could be described as an "aerial screw" , that any recorded advancement

4200-537: The usual designations for American aircraft, the X-1 models were successive (mostly identical) units of the X-1 program: the X-1, X-1A, X-1B, X-1C, X-1D, and X-1E. Bell went on to design and produce several different experimental aircraft during the 1950s. These helped the U.S. Air Force and the National Advisory Committee on Aeronautics (NACA) explore the boundaries of aircraft design, and paved

4270-528: The way for the founding of NASA and the exploration of outer space . The X-2 Starbuster achieved Mach 3 (2,100 mph) and a height of 126,000 ft in 1955, blazing a technological trail for the development of spacecraft. Bell played a crucial role in the development of rocket propulsion after WWII, spearheaded by the likes of some of the most brilliant minds in rocket science like Walter Dornberger (ex-commander of Nazi Germany Peenemünde Army Research Center ) and Wendell Moore. Bell developed and fielded

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4340-445: The wood preferred for propellers through World War I , but wartime shortages encouraged use of walnut , oak , cherry and ash . Alberto Santos Dumont was another early pioneer, having designed propellers before the Wright Brothers for his airships . He applied the knowledge he gained from experiences with airships to make a propeller with a steel shaft and aluminium blades for his 14 bis biplane in 1906. Some of his designs used

4410-571: The world's first nuclear-tipped Air-to-Surface cruise missile, the GAM-63 RASCAL in 1957. Wendell Moore developed the Bell rocket belt , utilizing peroxide monopropellant rocket engines. While the rocket belt failed to be commercially developed, the rocket technology proved invaluable in future Bell programs. Bell's crowning achievement in the realm of rocketry was the Agena rocket engine. The Agena

4480-537: Was a 12,000 lbf bi-propellant rocket that is considered to this day to be one of the most reliable rockets ever built. 360 units were produced starting in the late 1950s and it was responsible for inserting into orbit most of the satellites launched by the United States in the 1960s. Helicopter development began at Bell Aircraft in 1941 with the Bell Model 30 first flying in 1943. Bell Helicopter became

4550-562: Was booming, but he still wanted to run his own company. Although he could raise local capital, he knew he would not be able to compete with either Consolidated or Curtiss-Wright , the two major aircraft builders also based in Buffalo. Fortunately, in 1935 Fleet decided to move Consolidated Aircraft to San Diego , and Bell stayed behind to establish his own company, the Bell Aircraft Company, on 10 July 1935, headquartered in

4620-616: Was directed by William F. Durand from 1916. Parameters measured included propeller efficiency, thrust developed, and power absorbed. While a propeller may be tested in a wind tunnel , its performance in free-flight might differ. At the Langley Memorial Aeronautical Laboratory , E. P. Leslie used Vought VE-7s with Wright E-4 engines for data on free-flight, while Durand used reduced size, with similar shape, for wind tunnel data. Their results were published in 1926 as NACA report #220. Lowry quotes

4690-506: Was made towards vertical flight. His notes suggested that he built small flying models, but there were no indications for any provision to stop the rotor from making the craft rotate. As scientific knowledge increased and became more accepted, man continued to pursue the idea of vertical flight. Many of these later models and machines would more closely resemble the ancient bamboo flying top with spinning wings, rather than Leonardo's screw. In July 1754, Russian Mikhail Lomonosov had developed

4760-447: Was partially stalled on take-off and up to 160 mph (260 km/h) on its way up to a top speed of 407.5 mph (655.8 km/h). The very wide speed range was achieved because some of the usual requirements for aircraft performance did not apply. There was no compromise on top-speed efficiency, the take-off distance was not restricted to available runway length and there was no climb requirement. The variable pitch blades used on

4830-626: Was the first American jet aircraft to fly. Unfortunately, performance was below expectations, roughly on par with contemporaneous propeller-driven aircraft, an outcome generally attributed to the extremely short development timeframe required by the USAAF, as well as the intense secrecy imposed on the project. Design had begun in September 1941, during which time the Bell team was guided mostly by theory, as General Electric would not finish and begin testing

4900-573: Was vice president and general manager of Martin, then based in Cleveland . Feeling that he deserved part ownership, in late 1924, he presented Martin with an ultimatum. Mr. Martin refused, and Bell quit. Bell spent several years out of the aviation industry, but in 1928 was hired by Reuben H. Fleet at Consolidated Aircraft , in Buffalo, New York , where he was guaranteed an interest in the company. Before long, Bell became general manager and business

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