Misplaced Pages

#539460

84-546: The Airco DH.2 was a single-seat pusher biplane fighter aircraft which operated during the First World War . It was the second pusher design by aeronautical engineer Geoffrey de Havilland for Airco , based on his earlier DH.1 two-seater. The development of pusher configuration fighters, such as the DH.2 and the F.E.2b enabled forward firing armament before the development of synchronisation gears such as that fitted to

168-463: A DH. 2 was shot down by Manfred von Richthofen flying an Albatros D.II . No original DH.2s exist. In 1970, Walter M. Redfern from Seattle , Washington built a replica DH.2 called the Redfern DH-2 , powered by a Kinner 125–150 hp (93–112 kW) engine. Redfern subsequently sold plans to home builders, and several of these replicas are flying. Redfern's original replica is now displayed at

252-532: A crack extends to the edge of the panel then this would compromise the structural integrity of the windshield. Aircraft windshields are designed in such a way that even if a crack were to extend all the way across the panel, the structural integrity is maintained via multiple failsafe methods in both frame and the glass plies. A sacrificial outer layer that cracks rather than devitrifies is the first failsafe. Circular bullseyes, linear cracks, crack chips, dings, pits and star-shaped breaks can be repaired without removing

336-592: A few remained in service in Macedonia including "A" Flight of No. 47 Squadron and a joint R.F.C. / R.N.A.S. fighter squadron, and with "X" Flight, in Palestine until late 1917. By then, it was dangerously obsolete as a fighter. The DH.2 was then used as an advanced trainer and for other secondary tasks, with the last recorded use of a DH.2 being a single example flying at RAF Turnhouse in January 1919. Distinguished pilots of

420-698: A fixed twin-gun configuration. Furthermore, the original gun mounting was criticised for being loose and unstable, and it obstructed the stick when elevated. DH.2s were routinely flown with the guns fixed into position. The arrival at the front of more powerful German tractor biplane fighters such as the Halberstadt D.II and the Albatros D.I , in late 1916, meant that the DH.2 was outclassed in turn. It remained in first line service until June 1917 in France, until No. 24 and No. 32 Squadron RFC reequipped with Airco DH.5s , and

504-516: A forward remote location, driving the propeller by drive shaft or belt: In canard designs a smaller wing is sited forward of the aircraft's main wing. This class mainly uses a direct drive, either single-engine axial propeller, or twin engines with a symmetrical layout, or an in line layout (push-pull) as the Rutan Voyager . In tailless aircraft such as Lippisch Delta 1 and Westland-Hill Pterodactyl types I and IV, horizontal stabilizers at

588-532: A lot of drag. Well before the beginning of the First World War , this drag was recognized as just one of the factors that would ensure that a Farman-style pusher would have an inferior performance to an otherwise similar tractor type . The U.S. Army banned pusher aircraft in late 1914 after several pilots died in crashes of aircraft of this type, so from about 1912 onwards, the great majority of new U.S. landplane designs were tractor biplanes, with pushers of all types becoming regarded as old-fashioned on both sides of

672-407: A low-wing pusher layout may suffer power-change-induced pitch changes, also known as pitch/power coupling. Pusher seaplanes with especially high thrust lines and tailwheels may find the vertical tail masked from the airflow, severely reducing control at low speeds, such as when taxiing. The absence of prop-wash over the wing reduces the lift and increases takeoff roll length. Pusher engines mounted on

756-473: A means of reducing the asymmetric effects of an outboard engine failure, such as on the Farman F.222 , but at the cost of a severely reduced efficiency on the rear propellers, which were often smaller and attached to lower-powered engines as a result. By the late 1930s, the widespread adoption of all-metal stressed skin construction of aircraft meant, at least in theory, that the aerodynamic penalties that had limited

840-481: A nose-on impact, the engine momentum may carry the engine through the firewall and cabin, and might injure some cabin occupants. Spinning propellers are always a hazard on ground working, such as loading or embarking the airplane. The tractor configuration leaves the rear of the plane as relatively safe working area, while a pusher is dangerous to approach from behind, while a spinning propeller may suck in things and people nearby in front of it with fatal results to both

924-398: A pilot having to bail out of a pusher was liable to pass through the propeller arc. This meant that of all the types concerned, only the relatively conventional Swedish SAAB 21 of 1943 went into series production. Other problems related to the aerodynamics of canard layouts, which had been used on most of the pushers, proved more difficult to resolve. One of the world's first ejection seats

SECTION 10

#1733085134540

1008-411: A propeller behind the fuselage, because it re-energizes the boundary layer developed on the body, and reduces the form drag by keeping the flow attached to the fuselage. However, it is usually a minor gain compared to the airframe's detrimental effect on propeller efficiency. Wing profile drag may be reduced due to the absence of prop-wash over any section of the wing. The engine is mounted behind

1092-436: A propeller efficiency of 0.75 compared to 0.85 for a tractor configuration, a loss of 12%. Pusher props are noisy, and cabin noise may be higher than tractor equivalent ( Cessna XMC vs Cessna 152 ). Propeller noise may increase because the engine exhaust flows through the props. This effect may be particularly pronounced when using turboprop engines due to the large volume of exhaust they produce. Power-plant cooling design

1176-406: A pusher configuration. Other craft with pusher configurations run on flat surfaces, land, water, snow, or ice. Thrust is provided by propellers and ducted fans, located to the rear of the vehicle. These include: The drive shaft of a pusher engine is in compression in normal operation, which places less stress on it than being in tension in a tractor configuration. Placing the cockpit forward of

1260-509: A pusher propeller at the end of the fuselage is stabilizing. A pusher needs less stabilizing vertical tail area and hence presents less weathercock effect ; at takeoff roll, it is generally less sensitive to crosswind. When there is no tail within the slipstream, unlike a tractor, there is no rotating propwash around the fuselage inducing a side force to the fin. At takeoff, a canard pusher pilot does not have to apply rudder input to balance this moment. Efficiency can be gained by mounting

1344-502: A safe center of gravity (CG) position, there is a limit to how far aft an engine can be installed. The forward location of the crew may balance the engine weight and will help determine the CG. As the CG location must be kept within defined limits for safe operation load distribution must be evaluated before each flight. Due to a generally high thrust line needed for propeller ground clearance, negative (down) pitching moments, and in some cases

1428-726: A specific reason for using the arrangement. Both the British and French continued to use pusher-configured bombers, though there was no clear preference either way until 1917. Such aircraft included (apart from the products of the Farman company) the Voisin bombers (3,200 built), the Vickers F.B.5 "Gunbus", and the Royal Aircraft Factory F.E.2 ; however, even these found themselves being shunted into training roles before disappearing entirely. Possibly

1512-410: A windshield is necessary to ensure safety. Different counties have made different set of rule that all windshield manufacturers need to comply under Motor Vehicle Acts. Some of the most know certifications are US DOT, EU ECE, Chinese CCC, South African SABS and Indian BIS standards. These certification ensures safety, reliability and quality of a product as per respective legal requirements. According to

1596-486: A windshield. Sports or racing cars would sometimes have aero screens , which were small semi-circular or rectangular windshields. These were often mounted in pairs behind a foldable flat windshield. Aero screens are usually less than 20 cm (8 inches) in height. They are known as aero screens because they only deflect the wind. The twin aeroscreen setup (often called Brooklands ) was popular among older sports and modern cars in vintage style. A wiperless windshield

1680-410: Is a common outboard motor for a small boat. “Pusher configuration” describes the specific (propeller or ducted fan ) thrust device attached to a craft, either aerostats ( airship ) or aerodynes (aircraft, WIG , paramotor , rotorcraft ) or others types such as hovercraft , airboats , and propeller-driven snowmobiles . The rubber-powered "Planophore", designed by Alphonse Pénaud in 1871,

1764-487: Is a windshield that uses a mechanism other than wipers to remove snow and rain from the windshield. The concept car Acura TL features a wiperless windshield using a series of jet nozzles in the cowl to blow pressurized air onto the windshield. Also several glass manufacturers have experimented with nano type coatings designed to repel external contaminants with varying degrees of success but to date none of these have made it to commercial applications. Certification of

SECTION 20

#1733085134540

1848-418: Is also often used for unmanned aerial vehicles , due to requirements for a forward fuselage free of any engine interference. The Aero Dynamics Sparrow Hawk was another homebuilt aircraft constructed chiefly in the 1990s. Airships are the oldest type of pusher aircraft, going back to Frenchman Henri Giffard's pioneering airship of 1852. Pusher aircraft have been built in many different configurations. In

1932-446: Is implemented. A study by Surrey University and Pilkington Glass proposes that waste laminated glass be placed into a separating device such as a rolling mill where the glass is fragmented and the larger cullet is mechanically detached from the inner film. The application of heat then melts the laminating plastic, usually, polyvinyl butyral "PVB" enabling both the glass and the interior film to be recycled. The PVB recycling process

2016-419: Is more complex in pusher engines than for the tractor configuration, where the propeller forces air over the engine or radiator. Some aviation engines have experienced cooling problems when used as pushers. To counter this, auxiliary fans may be installed, adding additional weight. The engine of a pusher exhausts forward of the propeller, and in this case, the exhaust may contribute to corrosion or other damage to

2100-456: Is the front window , which provides visibility while protecting occupants from the elements. Modern windshields are generally made of laminated safety glass , a type of treated glass , which consists of, typically, two curved sheets of glass with a plastic layer laminated between them for safety, and bonded into the window frame. Motorcycle windshields are often made of high-impact polycarbonate or acrylic plastic. Windshields protect

2184-524: Is then cured with an ultraviolet light. When done properly, the damaged area’s strength is restored, as is 90–95% of the clarity. Windshields that cannot be repaired have to be replaced. Replacement of a windshield typically takes less than an hour. To ensure the vehicle is safe to drive, time values called the Safe Drive Away Time have been established. Windshields which have been replaced must cure or bond sufficiently until they are able to withstand

2268-568: Is used generally throughout the US and Canada. The term windscreen is the usual term in the British Isles and Australasia for all vehicles. In the US windscreen refers to the mesh or foam placed over a microphone to minimize wind noise , while a windshield refers to the front window of a car. In the UK, the terms are reversed, although generally, the foam screen is referred to as a microphone shield, and not

2352-742: The British Empire 's fourth-ranking ace of the war. German ace and tactician Oswald Boelcke was killed during a dogfight with No. 24 Squadron DH.2s due to a collision with one of his own wingmen. Fourteen aces scored five or more aerial victories using the DH.2 and many also went on to further success in later types. Eight pilots scored all of their victories in the DH-2, including Harry Wood , Sidney Cowan , Hubert Jones , William Curphey , Maxmillian Mare-Montembault , Patrick Anthony Langan-Byrne , Eric Pashley and Selden Long . Lanoe George Hawker V.C., D.S.O. , and commanding officer of No. 24 Squadron flying

2436-608: The Omaka Aviation Heritage Centre in Blenheim, New Zealand . Data from Warplanes of the First World War - Fighters Volume One , General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Related lists Pusher configuration Though the term is most commonly applied to aircraft, its most ubiquitous propeller example

2520-679: The runway and become a safety hazard. In many places, laws restrict the use of heavily tinted glass in vehicle windshields; generally, laws specify the maximum level of tint permitted. Some vehicles have noticeably more tint in the uppermost part of the windshield to block sunglare . In aircraft windshields, an electric current is applied through a conducting layer of tin(IV) oxide to generate heat to prevent icing . A similar system for automobile windshields, introduced on Ford vehicles as " Quickclear " in Europe ("InstaClear" in North America) in

2604-403: The "Farman type". Other early pusher configurations were variations on this theme. The classic "Farman" pusher had the propeller "mounted (just) behind the main lifting surface" with the engine fixed to the lower wing or between the wings, immediately forward of the propeller in a stub fuselage (that also contained the pilot) called a nacelle . The main difficulty with this type of pusher design

Airco DH.2 - Misplaced Pages Continue

2688-464: The 1980s and through the early 1990s, used this conductive metallic coating applied to the inboard side of the outer layer of glass. Other glass manufacturers utilize a grid of micro-thin wires to conduct the heat especially on the later European Ford Transit vans. These systems are more typically utilized by European auto manufacturers such as Jaguar and Porsche . The use of thermal glass prevents some navigation systems from functioning correctly, as

2772-630: The Atlantic. However, new pusher designs continued to be designed right up to the armistice, such as the Vickers Vampire , although few entered service after 1916. At least up to the end of 1916, however, pushers (such as the Airco DH.2 fighter) were still favored as gun-carrying aircraft by the British Royal Flying Corps , because a forward-firing gun could be used without being obstructed by

2856-460: The DH.2 included Victoria Cross recipient Lanoe Hawker (seven victories, though none in the DH.2), who was the first commander of No. 24 Squadron. The commander of No. 32 Squadron , Lionel Rees was awarded the Victoria Cross after flying the D.H.2 for a solo attack on a formation of ten German two-seaters on 1 July 1916, destroying two. James McCudden became an ace in DH.2s and would become

2940-415: The DH.2 was ordered into quantity manufacture. The production aircraft was generally similar to the prototype with the only major alterations being a fuel system and a revised gun mounting arrangement. Deliveries of the DH.2 commenced during the latter half of 1915 and a handful of aircraft were reportedly operating in France prior to the year's end. A total of 453 DH.2s were produced by Airco. The Airco DH.2

3024-562: The DH.2, and the first RFC squadron completely equipped with single-seat fighters, No. 24 Squadron RFC , arrived in France early February 1916. The DH.2 eventually equipped seven fighter squadrons on the Western Front and proved more than a match for the Fokker Eindecker and the first DH.2 victory over an Eindecker may have been on 2 April 1916. DH.2s were heavily involved in the Battle of

3108-585: The German Fokker Eindecker monoplane fighter. The prototype DH.2 made its first flight in July 1915, but it was lost during the following month, on its service trials on the Western Front . The DH.2 was introduced to frontline service in February 1916 and became the first effectively armed British single-seat fighter. It enabled Royal Flying Corps (RFC) pilots to counter the " Fokker Scourge " that had given

3192-574: The Germans the advantage during late 1915. It served in fighting and escort duties for almost two years, while numerous pilots became flying aces using the type. It became outclassed by newer German fighters, resulting in the DH.2's eventual withdrawal from first line service in France after RFC units completed the process of re-equipping with newer fighters, such as the Nieuport 17 and Airco DH.5 , in June 1917. By

3276-636: The Somme with No. 24 Squadron engaging in 774 combats and claiming 44 enemy machines. Service training for pilots in the RFC was poor, and the DH.2 initially had a high accident rate, supposedly gaining the nickname "The Spinning Incinerator", but as familiarity with the type improved, it was recognised as being maneuverable and relatively easy to fly. The limited ammunition supply of the original gun installation proved to be inadequate. Although officially discouraged, pilots experimented with different gun arrangements, including

3360-501: The US National Windshield Repair Association, many types of stone damage can be successfully repaired. Whether the windshield can be repaired always depends upon four factors: the size, type, depth and location of the damage. Repair of cracks up to 6.1 cm (2.4 inches) is within permissible limits; automobile glass with more severe damage needs to be replaced. However, this is dependent on local laws. If

3444-589: The UV-A is absorbed by the PVB bonding layer. On motorbikes their main function is to shield the rider from wind, though not as completely as in a car, whereas on sports and racing motorcycles the main function is reducing drag when the rider assumes the optimal aerodynamic configuration with their body in unison with the machine and does not shield the rider from wind when sitting upright. Early windshields were made of ordinary window glass, but that could lead to serious injuries in

Airco DH.2 - Misplaced Pages Continue

3528-444: The absence of prop-wash over the tail, a higher speed and a longer roll may be required for takeoff compared to tractor aircraft. The Rutan answer to this problem is to lower the nose of the aircraft at rest such that the empty center of gravity is then ahead of the main wheels. In autogyros , a high thrust line results in a control hazard known as power push-over . Due to the generally-high thrust line to ensure ground clearance,

3612-419: The arc of the propeller. With the successful introduction of Fokker 's mechanism for synchronizing the firing of a machine gun with the blades of a moving propeller , followed quickly by the widespread adoption of synchronization gears by all the combatants in 1916 and 1917, the tractor configuration became almost universally favored, and pushers were reduced to the tiny minority of new aircraft designs that had

3696-423: The clear windshield with smaller dots to minimize thermal stress in manufacturing. The same band of darkened dots is often expanded around the rearview mirror to act as a sunshade. On a rainy day, water refraction on aircraft windshields can mislead pilots into believing that they are flying at a higher altitude than they actually are due to the horizon appearing lower than it is. This can result in undershooting

3780-536: The crew and passenger compartments, so fuel oil and coolant leaks will vent behind the aircraft, and any engine fire will be directed behind the aircraft. Similarly, propeller failure is less likely to directly endanger the crew. A pusher ducted fan system offers a supplementary safety feature attributed to enclosing the rotating fan in the duct, therefore making it an attractive option for various advanced UAV configurations or for small/personal air vehicles or for aircraft models. A pusher design with an empennage behind

3864-438: The embedded metal blocks the satellite signal. The RF signal tends to flow along the metal wires or layer so very little radiation can pass. This can be resolved by using an external antenna. Mobile telephones can also have problems; thermal glass typically allows only 0.001 (1‰, or one per mille) of the signal to pass, whereas a concrete wall with rebars allows up to 0.100 (10%, or 100‰) of the signal to pass. The term windshield

3948-432: The engine behind the pilot to minimize the danger to the pilot's arms and legs. These two factors mean that this configuration was widely used for early combat aircraft, and remains popular today among ultralight aircraft , unmanned aerial vehicles (UAVs), and radio-controlled airplanes . A pusher may have a shorter fuselage and hence a reduction in both fuselage wetted area and weight. In contrast to tractor layout,

4032-490: The event of a crash. A series of crashes led up to the development of stronger windshields. The most notable example of this is the Pane vs. Ford case of 1917 that decided against Pane in that he was only injured through reckless driving . They were replaced with windshields made of toughened glass and were fitted in the frame using a rubber or neoprene seal . The hardened glass shattered into many mostly harmless fragments when

4116-404: The first being the Airco DH.1 , which followed a similar formula to that of the F.E.2. Early air combat over the Western Front indicated the need for a single-seat fighter with a forward-firing machine gun. At this point in time, there was no dominant approach to arming fighters, but a pusher configuration was one answer. As no means of firing forward through the propeller of a tractor aeroplane

4200-406: The forces of a crash. Knowing the minimum time needed to cure the glass bonding adhesives is therefore important. This safe drive away time (SDAT) or minimum drive away time (MDAT) refers to the time required until a windshield installation or glass replacement is considered safe to drive again. Criteria are specified in U.S. Federal Motor Vehicle Safety Standards 212/208 (see FMVSS ) to ensure

4284-431: The fuselage wake, wing wake, and other flight surface downwashes—moving asymmetrically through a disk of irregular airspeed. This reduces propeller efficiency and causes vibration inducing structural propeller fatigue and noise. Prop efficiency is usually at least 2–5% less and in some cases more than 15% less than an equivalent tractor installation. Full-scale wind tunnel investigation of the canard Rutan VariEze showed

SECTION 50

#1733085134540

4368-418: The glass, eliminating the risk of leaking or bonding problems sometimes associated with replacement. Some damages are very difficult to repair, or cannot be repaired: In cracked windshield repair, air is removed from the damaged area on the windshield with a specified vacuum injection pump. Then using the injection pump, the clear adhesive resin is injected to replace the air in the windshield crack. The resin

4452-490: The ground. When an airplane flies in icing conditions , ice can accumulate on the wings. If an airplane with wing-mounted pusher engines experiences icing, the props will ingest shredded chunks of ice, endangering the propeller blades and parts of the airframe that can be struck by ice violently redirected by the props. In early pusher combat aircraft, spent ammunition casings caused similar problems, and devices for collecting them had to be devised. The propeller passes through

4536-449: The ideal curing environment can increase the time needed for a sufficiently safe bond to form. Because of the variables and difficulties involved in mobile windshield replacement, many vehicle manufacturers do not recommend this method of installations. Waste disposal of laminated glass is no longer permitted in a landfill in most European countries as the End of Life Vehicles Directive (ELV)

4620-424: The last fighter to use the Farman pusher configuration was the 1931 Vickers Type 161 COW gun fighter. During the long eclipse of the configuration the use of pusher propellers continued in aircraft which derived a small benefit from the installation and could have been built as tractors. Biplane flying boats had for some time often been fitted with engines located above the fuselage to offer maximum clearance from

4704-446: The level of security achieved: 1) Example: Security exceeding FMVSS 212/208 belted 2) Example: Security exceeding FMVSS 212/208 unbelted With the advent of quick-cure adhesives, mobile windshield replacements have become more prevalent. Often the temperature and humidity cannot be controlled for mobile installations. For most common glass adhesives the ideal environment is 21 °C (70 °F) and 50% humidity . Variations from

4788-443: The outbreak of the First World War , aeronautical engineer Geoffrey de Havilland was already an experienced aircraft designer, having been responsible for the experimental Royal Aircraft Factory F.E.1 , Royal Aircraft Factory F.E.2 and Blériot Scout B.S.1 , the B.S.1 being the fastest British aircraft of its day. In June 1914, de Havilland left the Royal Aircraft Factory for Airco , where he continued work on his own designs,

4872-431: The performance of pushers (and indeed any unconventional layout) were reduced; however, any improvement that boosts pusher performance also boosts the performance of conventional aircraft, and they remained a rarity in operational service—so the gap was narrowed but was closed entirely. During World War II , experiments were conducted with pusher fighters by most of the major powers. Difficulties remained, particularly that

4956-507: The plane and the people sucked in. Even more hazardous are unloading operations, especially mid-air, such as dropping supplies on parachute or skydiving operations, which are next to impossible with a pusher configuration airplane, especially if propellers are mounted on fuselage or sponsons. Windshield The windshield ( American English and Canadian English ) or windscreen ( Commonwealth English ) of an aircraft , car , bus , motorbike , truck , train , boat or streetcar

5040-428: The propeller is structurally more complex than a similar tractor type. The increased weight and drag degrades performance compared with a similar tractor type. Modern aerodynamic knowledge and construction methods may reduce but never eliminate the difference. A remote or buried engine requires a drive shaft and associated bearings, supports, and torsional vibration control, and adds weight and complexity. To maintain

5124-475: The propeller to prevent the propeller from striking the ground, at an added cost in drag and weight. On tailless pushers such as the Rutan Long-EZ , the propeller arc is very close to the ground while flying nose-high during takeoff or landing. Objects on the ground kicked up by the wheels can pass through the propeller disc, causing damage or accelerated wear to the blades; in extreme cases, the blades may strike

SECTION 60

#1733085134540

5208-399: The propeller. This is usually minimal, and may be mainly visible in the form of soot stains on the blades. In case of propeller/tail proximity, a blade break can hit the tail or produce destructive vibrations, leading to a loss of control. Crew members risk striking the propeller while attempting to bail out of a single-engined airplane with a pusher prop. At least one early ejector seat

5292-503: The rear of the aircraft are absent. Flying wings like the Northrop YB-35 are tailless aircraft without a distinct fuselage. In these installations, the engines are either mounted in nacelles or the fuselage on tailless aircraft, or buried in the wing on flying wings, driving propellers behind the trailing edge of the wing, often by extension shaft. Almost without exception, flexwing aircraft , paramotors , and powered parachutes use

5376-630: The reliability of adhesive systems. Typically the SDAT is verified with crash tests as well as with high-speed laboratory test methods. Consumers may be unaware that the MDAT or SDAT time is focused on safety and not necessarily on the quality, durability, or warranty of the installation. Care must be taken not to drive the vehicle prior to the SDAT/MDAT. Airbags deploy at speeds up to 320 km/h (200 mph; 89 m/s) and in some cases exert tremendous force on

5460-461: The similarly configured but much improved 110 hp (82 kW) Le Rhône 9J engine. Some sources state that the Monosoupape was retained in the DH.2 design despite a tendency to shed cylinders midair and a single DH.2 was fitted experimentally with a Le Rhône 9J. In addition to the variety of engines used, the fuel system also differed between individual aircraft. Typically, a gravity-fed fuel tank

5544-518: The trailing edge of the wing, plus four jet engines. Although the vast majority of propeller-driven aircraft continue to use a tractor configuration, there has been in recent years something of a revival of interest in pusher designs: in light homebuilt aircraft such as Burt Rutan 's canard designs since 1975, ultralights such as the Quad City Challenger (1983), flexwings, paramotors , powered parachutes , and autogyros . The configuration

5628-422: The vast majority of fixed-wing aircraft, the propeller or propellers are still located just behind the trailing edge of the "main lifting surface", or below the wing (paramotors) with the engine being located behind the crew position. Conventional aircraft layout have a tail ( empennage ) for stabilization and control. The propeller may be close to the engine, as the usual direct drive: The engine may be buried in

5712-427: The vehicle's occupants from wind and flying debris such as dust, insects, and rocks, and provide an aerodynamically formed window towards the front. UV coating may be applied to screen out harmful ultraviolet radiation. However, this is usually unnecessary since most auto windshields are made from laminated safety glass . The majority of UV-B is absorbed by the glass itself, and any remaining UV-B together with most of

5796-418: The vehicle's rigidity, but the main force for innovation has historically been the need to prevent injury from sharp glass fragments. Almost all nations now require windshields to stay in one piece even if broken, except if pierced by a strong force. The urethane sealant is protected from UV in sunlight by a band of dark dots called a frit around the edge of the windshield. The darkened edge transitions to

5880-420: The water, often driving pusher propellers to avoid spray and the hazards involved by keeping them well clear of the cockpit. The Supermarine Walrus was a late example of this layout. The so-called push/pull layout , combining the tractor and pusher configurations—that is, with one or more propellers facing forward and one or more others facing back—was another idea that continues to be used from time to time as

5964-495: The windshield broke. These windshields, however, could shatter from a simple stone chip. "Triplex" glass laminating , however, had been available for windshields in France from 1911 and in Britain from 1912; it was adopted as an accessory by some high-end American auto manufacturers beginning in 1913, and from 1919 to 1929 Henry Ford ordered the use of laminated glass on all of his vehicles. Modern, glued-in windshields contribute to

6048-439: The windshield. Occupants can impact the airbag just 50  ms after initial deployment. Depending on vehicle design, airbag deployment and/or occupant impact into the airbag may increase forces on the windshield, dramatically in some cases. Forces of occupants on the airbags - and hence the potential forces on the windshield - are lower for belted occupants. As consequence, adhesive suppliers usually inform their customers about

6132-501: The wing may obstruct sections of the wing trailing edge , reducing the total width available for control surfaces such as flaps and ailerons. When a propeller is mounted in front of the tail, changes in engine power alter the airflow over the tail and can give strong pitch or yaw changes. Due to the pitch rotation at takeoff, the propeller diameter may have to be reduced (with a loss of efficiency ) and/or landing gear made longer and heavier. Many pushers have ventral fins or skids beneath

6216-475: The wing to balance the weight of the engine(s) aft improves visibility for the crew. In military aircraft, front armament could be used more easily on account of the gun not needing to synchronize itself with the propeller, although the risk that spent casings fly into the props at the back somewhat offset this advantage. Aircraft where the engine is carried by, or very close to, the pilot (such as paramotors, powered parachutes, autogyros, and flexwing trikes) place

6300-523: Was (per force) designed for this aircraft, which later re-emerged with a jet engine . The largest pusher aircraft to fly was the Convair B-36 "Peacemaker" of 1946, which was also the largest bomber ever operated by the United States . It had six 3,800 hp (2,800 kW) 28-cylinder Pratt & Whitney Wasp Major radial engines mounted in the wing, each driving a pusher propeller located behind

6384-405: Was a compact two-bay pusher biplane fighter aircraft. It had a wooden airframe, which was wire-braced and covered by fabric across most areas, except for the nacelle nose and upper decking. Both the upper and lower wings had ailerons fitted. The upper ailerons were spring-loaded to automatically return to a neutral position when the controls were released. The upper part of the nose of the nacelle

6468-666: Was an early successful model aircraft with a pusher propeller. Many early aircraft (especially biplanes) were "pushers", including the Wright Flyer (1903), the Santos-Dumont 14-bis (1906), the Voisin-Farman I (1907), and the Curtiss Model D used by Eugene Ely for the first ship landing on January 18, 1911. Henri Farman 's pusher Farman III and its successors were so influential in Britain that pushers in general became known as

6552-400: Was attaching the tail (empennage). This needed to be in the same general location as on a tractor aircraft, but its support structure had to avoid the propeller. The earliest examples of pushers relied on a canard but this has serious aerodynamic implications that the early designers were unable to resolve. Typically, mounting the tail was done with a complex wire-braced framework that created

6636-414: Was cut away so that a machine gun could be mounted there. Unusually, the windshield was mounted on the machine gun rather than to the airframe. The DH.2 was armed with a single .303 in (7.7 mm) Lewis gun which was mounted on a flexible mount. Once pilots learned that the best method of achieving a victory was to aim the aircraft rather than the gun, it was fixed to fire forward, although this

6720-410: Was designed specifically to counter this risk. Some modern light aircraft include a parachute system that saves the entire aircraft, thus averting the need to bail out. Engine location in the pusher configuration might endanger the aircraft's occupants in a crash or crash-landing in which engine momentum projects through the cabin. For example, with the engine placed directly behind the cabin, during

6804-500: Was met with skepticism by higher authorities until a quick-release clip was devised at the Squadron level. The clip was devised by Major Lanoe Hawker , who also improved the gunsights and added a ring sight and an "aiming off model" that helped the gunner allow for leading a target. The majority of DH.2s were powered by the 100 hp (75 kW) Gnôme Monosoupape nine-cylinder, air-cooled rotary engine , however later models received

6888-462: Was not specifically targeted at the type, having commenced prior to the Eindecker's arrival. The first prototype DH.2 performed its first flight in July 1915. Following the completion of its manufacturing trials, on 26 July 1915, the prototype was dispatched to France for operational evaluation, but was lost over the Western Front and was captured by the Germans. Despite the prototype's premature loss,

6972-456: Was used, but it could be located on the upper wing central section, or either above or below the port side upper wing. After evaluation at Hendon on 22 June 1915, the first DH.2 arrived in France for operational trials with No. 5 RFC Squadron but was shot down and its pilot killed during early August 1915. This aircraft was recovered and repaired by the Germans. The first squadron equipped with

7056-445: Was yet available to the British, Geoffrey de Havilland designed the DH.2 as a scaled-down, single-seat development of the earlier two-seat DH.1. Aviation author J.M Bruce speculated that, had adequate synchronisation gear been available, de Havilland may have been less likely to pursue a pusher configuration. While it is popularly viewed as a response to the emergence of Germany's Fokker Eindecker monoplane fighters, its development

#539460