The LWS-3 Mewa (" Seagull ") was a Polish observation and close reconnaissance aircraft , designed in the late-1930s by the LWS factory. It was ordered by the Polish Military Aviation , but did not manage to enter service before the outbreak of World War II.
78-549: The aircraft was designed as the successor to the obsolete Lublin R-XIII army cooperation plane . First sketches were drawn in 1936 by Zbysław Ciołkosz , the chief designer of the LWS factory ( Lubelska Wytwórnia Samolotów ). It was similar to the earlier light ambulance plane LWS-2 , which itself was inspired by the STOL plane RWD-9 wing design. After Ciołkosz had left LWS in 1937,
156-501: A ski-jump on take-off is subjected to loads of 0.5g which also last for much longer than a landing impact. Helicopters may have a deck-lock harpoon to anchor them to the deck. Some aircraft have a requirement to use the landing-gear as a speed brake. Flexible mounting of the stowed main landing-gear bogies on the Tupolev Tu-22 R raised the aircraft flutter speed to 550 kn (1,020 km/h). The bogies oscillated within
234-414: A "boat" hull/floats and retractable wheels, which allow it to operate from land or water. Beaching gear is detachable wheeled landing gear that allows a non-amphibious floatplane or flying boat to be maneuvered on land. It is used for aircraft maintenance and storage and is either carried in the aircraft or kept at a slipway. Beaching gear may consist of individual detachable wheels or a cradle that supports
312-442: A 10 in (25 cm) thick flexible asphalt pavement . The 210,000 lb (95 t) Boeing 727 -200 with four tires on two legs main landing gears required a 20 in (51 cm) thick pavement. The thickness rose to 25 in (64 cm) for a McDonnell Douglas DC-10 -10 with 443,000 lb (201 t) supported on eight wheels on two legs. The heavier, 558,000 lb (253 t), DC-10-30/40 were able to operate from
390-405: A 7.92 mm wz.37 machine gun in a rear station, covered by opening canopy. 14-cylinder air-cooled radial engine Gnome-Rhône 14M01 (prototypes) or 14M05 (serial) with 660 hp (490 kW) nominal power and 730 hp (540 kW) maximum power. Three-blade metal propeller (planned) or two-blade wooden propeller (installed on some aircraft). Fuel capacity about 380 L in wings. The aircraft
468-474: A 90° angle during the rearwards-retraction sequence to allow the main wheel to rest "flat" above the lower end of the main gear strut, or flush within the wing or engine nacelles, when fully retracted. Examples are the Curtiss P-40 , Vought F4U Corsair , Grumman F6F Hellcat , Messerschmitt Me 210 and Junkers Ju 88 . The Aero Commander family of twin-engined business aircraft also shares this feature on
546-606: A changed shape of a tail fin , became the first prototype of the army-cooperation plane, that eventually received a designation Lublin R-XIII . One more prototype was newly built (no. 56.1). On July 21, 1931, 50 aircraft R-XIII were ordered. The first couple of aircraft were designated R-XIIIA , and were distinguished by flat fuselage top. They were superseded by improved R-XIIIB variant, with oval fuselage top, newer machine gun ring mounting, and longer ailerons. R-XIIIA were later converted to R-XIIIB standard, and 49 were made in total (numbers 56.2 to 56.50). The first serial R-XIII
624-599: A crank mechanism to lower tailfin and rudder in order to increase angle of the rear machine gun fire, but as it proved impractical, the next prototype LWS-3/III from autumn 1938 again had a classic tailfin design. The third prototype, with some further changes, among others to the engine cover and canopy , was the pattern for serial production. The first prototype was exhibited at the 16th International Paris Aviation Salon in November 1938 (as " PZL Mewa"), where it met with interest. Official tests were satisfactory, and in 1938
702-558: A flight to Australia, however it was crashed in 1935 in Siam by Stanisław Karpiński. Several aircraft were converted to civilian sport ones, used in Polish Aero Clubs . 12 R-XIII's were converted to blind flying trainers R-XIIIt in 1934, with higher closed trainee cab. Some were converted to simple liaison aircraft , removing armament and mounting a windscreen in the second cab. Several R-XIII were used to tow gliders , using
780-476: A forward and aft position. The forward position was used for take-off to give a longer lever-arm for pitch control and greater nose-up attitude. The aft position was used to reduce landing bounce and reduce risk of tip-back during ground handling. The tandem or bicycle layout is used on the Hawker Siddeley Harrier, which has two main-wheels behind a single nose-wheel under the fuselage and
858-585: A higher sink-rate requirement because the aircraft are flown onto the deck with no landing flare . Other features are related to catapult take-off requirements for specific aircraft. For example, the Blackburn Buccaneer was pulled down onto its tail-skid to set the required nose-up attitude. The naval McDonnell Douglas F-4 Phantom II in UK service needed an extending nosewheel leg to set the wing attitude at launch. The landing gear for an aircraft using
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#1732782327048936-474: A higher sink-rate requirement if a carrier-type, no-flare landing technique has to be adopted to reduce touchdown scatter. For example, the Saab 37 Viggen , with landing gear designed for a 5m/sec impact, could use a carrier-type landing and HUD to reduce its scatter from 300 m to 100m. The de Havilland Canada DHC-4 Caribou used long-stroke legs to land from a steep approach with no float. A flying boat has
1014-489: A light aircraft, an emergency extension system is always available. This may be a manually operated crank or pump, or a mechanical free-fall mechanism which disengages the uplocks and allows the landing gear to fall under gravity. Aircraft landing gear includes wheels equipped with solid shock absorbers on light planes, and air/oil oleo struts on larger aircraft. As aircraft weights have increased more wheels have been added and runway thickness has increased to keep within
1092-403: A lower fuselage with the shape of a boat hull giving it buoyancy. Wing-mounted floats or stubby wing-like sponsons are added for stability. Sponsons are attached to the lower sides of the fuselage. A floatplane has two or three streamlined floats. Amphibious floats have retractable wheels for land operation. An amphibious aircraft or amphibian usually has two distinct landing gears, namely
1170-662: A machine gun ring mounting. The first R-XIIID was tested in February, 1933. All aircraft were given to the Air Force by March 2, 1935. During repairs, older models A, B and C were modified to R-XIIID standard as well. In 1933, Jerzy Rudlicki proposed a new design R-XXI, for a new contest for R-XIII successor, but it was not accepted (the contest was won by the RWD-14 Czapla ). However, some of R-XXI features, like higher and rounded in cross-section fuselage and changed shape of
1248-540: A night landing on Medyka airfield near Przemyśl on the same day, the other was burned on September 17, when it could not be evacuated. According to some sources, two other Mewas were assigned to the 23rd Observation Escadre on September 11, but this has not been confirmed. It is not clear whether any of these aircraft were armed. One of the aircraft was also seen during evacuation to Pinsk in mid-September. The rest of uncompleted aircraft were seized by Germans and scrapped. Contrary to its direct predecessor, RWD-14 Czapla ,
1326-537: A nosewheel) chassis. Landing is done on skids or similar simple devices (fixed or retractable). The SNCASE Baroudeur used this arrangement. Historical examples include the "dolly"-using Messerschmitt Me 163 Komet rocket fighter, the Messerschmitt Me 321 Gigant troop glider, and the first eight "trolley"-using prototypes of the Arado Ar 234 jet reconnaissance bomber. The main disadvantage to using
1404-457: A similar arrangement, except that the fore and aft gears each have two twin-wheel units side by side. Quadricycle gear is similar to bicycle but with two sets of wheels displaced laterally in the fore and aft positions. Raymer classifies the B-52 gear as quadricycle. The experimental Fairchild XC-120 Packplane had quadricycle gear located in the engine nacelles to allow unrestricted access beneath
1482-520: A smaller wheel near the tip of each wing. On second generation Harriers, the wing is extended past the outrigger wheels to allow greater wing-mounted munition loads to be carried, or to permit wing-tip extensions to be bolted on for ferry flights. A tandem layout was evaluated by Martin using a specially-modified Martin B-26 Marauder (the XB-26H) to evaluate its use on Martin's first jet bomber,
1560-419: A special frame with a hook, attached to a fuselage. The R-XIII prototype was converted in 1932 to an experimental variant R-XIX , with V-tail of Rudlicki's design, but it was not accepted by the authorities, despite it had better field of machine gun fire. In total, 15 R-XIV and 273 R-XIII were built, including 20 seaplanes. In the early 1930s the R-XIII was quite a successful plane for its purpose. It had
1638-528: A tail fin, were found in latest R-XIII variants. Single prototype of the R-XIIIE was built in 1934, fitted with a stronger 360 hp engine Gnome-Rhone 7 K Titan, but it was not produced. Another variant R-XIIIF introduced new, Polish-designed 340 hp engine Skoda G-1620A Mors-I. It had no Townend ring on cylinders of the radial engine. After one prototype (no. 56.101), a series of 50 R-XIIIF were ordered in 1934. After seven aircraft had been delivered,
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#17327823270481716-429: A tailwheel. Crew of two, sitting in tandem in a closed cockpit , with large transparent canopy surfaces. The crew had dual controls. Prototypes were armed with two forward-firing 7.92 mm machine guns fixed on the undercarriage covers, but it appeared, that their accuracy was low due to vibration, and (according to J. Cynk) production aircraft were intended to have twin machine guns on fuselage sides. The observer had
1794-557: A tricycle undercarriage to prevent damage to the underside of the fuselage if over-rotation occurs on take-off leading to a tail strike . Aircraft with tail-strike protection include the B-29 Superfortress , Boeing 727 trijet and Concorde . Some aircraft with retractable conventional landing gear have a fixed tailwheel. Hoerner estimated the drag of the Bf 109 fixed tailwheel and compared it with that of other protrusions such as
1872-514: A very short take-off (68 m for R-XIIIA) and landing, enabling it to operate from fields and meadows. However, only some of R-XIIIs were equipped with a radio and a camera , which lowered their usefulness. In 1932-1936 they were used in three-aircraft liaison platoons, being a basic Polish army-cooperation plane. In 1937 they were formed into army-cooperation escadres ( eskadra towarzysząca ), in 1939 reformed into observation escadres ( eskadra obserwacyjna ). Only in 1939, part of R-XIII were replaced by
1950-412: Is also unique in that all four pairs of main wheels can be steered. This allows the landing gear to line up with the runway and thus makes crosswind landings easier (using a technique called crab landing ). Since tandem aircraft cannot rotate for takeoff, the forward gear must be long enough to give the wings the correct angle of attack during takeoff. During landing, the forward gear must not touch
2028-608: Is not clear (possibly, it concerned the LWS-3B plans, in fact). The Bulgarian-built reconnaissance plane KB-11 Fazan bore some resemblance to Mewa. None of the aircraft entered service in the Polish Air Force before the outbreak of the World War II on September 1, 1939. The problem was with propellers, which had to be delivered from France. The first two aircraft were ready for delivery on September 2, but one of them
2106-465: Is required to reduce the impact with the surface of the water. A vee bottom parts the water and chines deflect the spray to prevent it damaging vulnerable parts of the aircraft. Additional spray control may be needed using spray strips or inverted gutters. A step is added to the hull, just behind the center of gravity, to stop water clinging to the afterbody so the aircraft can accelerate to flying speed. The step allows air, known as ventilation air, to break
2184-705: The Beriev A-40 Hydro flaps were used on the Martin Marlin and Martin SeaMaster . Hydroflaps, submerged at the rear of the afterbody, act as a speed brake or differentially as a rudder. A fixed fin, known as a skeg , has been used for directional stability. A skeg, was added to the second step on the Kawanishi H8K flying boat hull. High speed impacts in rough water between the hull and wave flanks may be reduced using hydro-skis which hold
2262-561: The Martin Marlin , the Martin M-270, was tested with a new hull with a greater length/beam ratio of 15 obtained by adding 6 feet to both the nose and tail. Rough-sea capability can be improved with lower take-off and landing speeds because impacts with waves are reduced. The Shin Meiwa US-1A is a STOL amphibian with blown flaps and all control surfaces. The ability to land and take-off at relatively low speeds of about 45 knots and
2340-702: The Martin XB-48 . This configuration proved so manoeuvrable that it was also selected for the B-47 Stratojet . It was also used on the U-2, Myasishchev M-4 , Yakovlev Yak-25 , Yak-28 and Sud Aviation Vautour . A variation of the multi tandem layout is also used on the B-52 Stratofortress which has four main wheel bogies (two forward and two aft) underneath the fuselage and a small outrigger wheel supporting each wing-tip. The B-52's landing gear
2418-687: The RWD-14b Czapla , which was not much more modern. A planned replacement was a modern LWS-3 Mewa , but it was not introduced due to war outbreak. On the eve of the Invasion of Poland in 1939, the Polish Air Force had about 150 R-XIII. Of them, 49 were in combat units, 30 in reserve, about 30 in training units and about 40 in repairs. In combat units, R-XIII were used in 7 observation escadres (out of 12): numbers 16, 26, 36, 43, 46, 56 and 66. Each escadre had 7 aircraft. The 16th Escadre
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2496-470: The maximum takeoff weight (MTOW) and 1.5 to 1.75% of the aircraft cost, but 20% of the airframe direct maintenance cost. A suitably-designed wheel can support 30 t (66,000 lb), tolerate a ground speed of 300 km/h and roll a distance of 500,000 km (310,000 mi) ; it has a 20,000 hours time between overhaul and a 60,000 hours or 20 year life time. Wheeled undercarriages normally come in two types: The taildragger arrangement
2574-473: The Air Force by 1938. However, only 26 of them were completed with Mors engines (and mostly used for training or staff liaison), while 32 had standard 220 hp Wright engines, lowering their performance to R-XIIID level. In 1931, one R-XIV was tested on floats, as a seaplane . Since tests came out well, the Polish Navy designated it R-XIII bis/hydro and ordered the next three (nos. 700-703). In 1933,
2652-668: The German aircraft or flak . During the campaign, 9 aircraft were given to observation escadres as replenishment. Some planes were also used in a wartime improvised units in air bases. About 10 combat aircraft and 7 from other units were withdrawn to Romania . A number of aircraft were bombed by the Germans in air bases or burned by withdrawing Poles. None have survived to today. In the Naval Air Squadron, 11 R-XIIIter and R-XIIIG floatplanes were used in 1939. The aircraft No. 714
2730-518: The Mewa was a modern close reconnaissance plane , comparable with leading foreign aircraft of that period, like Henschel Hs 126 or Westland Lysander . Its advantages were quite short take-off and landing, which enabled it to operate from short or unprepared remote fields. Mixed construction (steel and wood) monoplane, conventional in layout, with braced high wings, canvas and plywood covered. Wings folded rearwards. Conventional fixed landing gear , with
2808-588: The Navy ordered 10 R-XIII ter/hydro , which was a seaplane variant of R-XIIID (nos. 704-713). Finally, in 1934 the Navy bought 6 R-XIIIG seaplanes, differing in details from a previous variant - among others, a metal propeller (nos. 714-720). They were delivered by April 1935. All variants could also be easily converted to wheeled landing gear. In 1933, one R-XIIIB was converted to a long-distance sport plane R-XIIIDr , named Błękitny Ptak (the Blue Bird ), meant for
2886-416: The Polish Air Force ordered 200 aircraft of the production variant LWS-3A Mewa (or "Mewa A"). The production started in early 1939 , and first aircraft were to be ready in the summer. In August 1939, about 30 aircraft were almost completed (10 ready, but lacking propellers , 7 in painting and 10 in final assembly). LWS-3B Mewa variant powered with a Fiat R74 860 hp (640 kW) engine for Bulgaria
2964-609: The Polish aviation authorities refused to buy nearly completed further 18 aircraft, planning to nationalize all aviation industry in Poland. As a result, Plage i Laśkiewicz factory went bankrupt in late 1935, and it was next nationalized under a name LWS ( Lubelska Wytwórnia Samolotów - Lublin Aircraft Works). Then, 18 R-XIIIF, bought by scrap price, were completed, and next series of 32 was built. All R-XIIIF were delivered to
3042-550: The R-Xa, having the shortest take-off and landing, and good performance, but the factory was ordered to develop design further. At that time, Rudlicki was working upon an unarmed trainer aircraft R-XIV and an observation aircraft R-XV . Both were new designs, basing upon the R-X construction. Number XIII was initially omitted in designations as " unlucky ". In February 1930, the Polish Air Force ordered 15 of R-XIV. The first serial plane
3120-518: The aircraft and its design affects the weight, balance and performance. It often comprises three wheels, or wheel-sets, giving a tripod effect. Some unusual landing gear have been evaluated experimentally. These include: no landing gear (to save weight), made possible by operating from a catapult cradle and flexible landing deck: air cushion (to enable operation over a wide range of ground obstacles and water/snow/ice); tracked (to reduce runway loading). For launch vehicles and spacecraft landers ,
3198-416: The aircraft can be landed in a satisfactory manner in a range of failure scenarios. The Boeing 747 was given four separate and independent hydraulic systems (when previous airliners had two) and four main landing gear posts (when previous airliners had two). Safe landing would be possible if two main gear legs were torn off provided they were on opposite sides of the fuselage. In the case of power failure in
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3276-470: The airstream, it is called a semi-retractable gear. Most retractable gear is hydraulically operated, though some is electrically operated or even manually operated on very light aircraft. The landing gear is stowed in a compartment called a wheel well. Pilots confirming that their landing gear is down and locked refer to "three greens" or "three in the green.", a reference to the electrical indicator lights (or painted panels of mechanical indicator units) from
3354-617: The enemy. The PZL state factory proposed the PZL Ł-2 , built in a series of 25 aircraft, while private factory Plage i Laśkiewicz in Lublin proposed the Lublin R-X , designed by Jerzy Rudlicki . It was flown on February 1, 1929. Five aircraft were built for the Air Force as R-Xa , and one was built as a long-distance sports plane. The third competitor was the PWS-5t2 . The contest was won by
3432-410: The entire aircraft. In the former case, the beaching gear is manually attached or detached with the aircraft in the water; in the latter case, the aircraft is maneuvered onto the cradle. Helicopters are able to land on water using floats or a hull and floats. For take-off a step and planing bottom are required to lift from the floating position to planing on the surface. For landing a cleaving action
3510-418: The fuselage for attaching a large freight container. Helicopters use skids, pontoons or wheels depending on their size and role. To decrease drag in flight, undercarriages retract into the wings and/or fuselage with wheels flush with the surrounding surface, or concealed behind flush-mounted doors; this is called retractable gear. If the wheels do not retract completely but protrude partially exposed to
3588-424: The fuselage lower sides as retractable main gear units on modern designs—were first seen during World War II, on the experimental German Arado Ar 232 cargo aircraft, which used a row of eleven "twinned" fixed wheel sets directly under the fuselage centerline to handle heavier loads while on the ground. Many of today's large cargo aircraft use this arrangement for their retractable main gear setups, usually mounted on
3666-438: The fuselage, could be dropped in case of fire emergency (R-XIV - 135 liter tank). Data from Cynk, 1971 General characteristics Performance Armament Related development: Comparable aircraft: Landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing , takeoff or landing . For aircraft, it is generally needed for all three of these. It
3744-438: The fuselage. The 640 t (1,410,000 lb) Antonov An-225 , the largest cargo aircraft, had 4 wheels on the twin-strut nose gear units like the smaller Antonov An-124 , and 28 main gear wheels. The 97 t (214,000 lb) A321neo has a twin-wheel main gear inflated to 15.7 bar (228 psi), while the 280 t (620,000 lb) A350 -900 has a four-wheel main gear inflated to 17.1 bar (248 psi). STOL aircraft have
3822-603: The hull out of the water at higher speeds. Hydro skis replace the need for a boat hull and only require a plain fuselage which planes at the rear. Alternatively skis with wheels can be used for land-based aircraft which start and end their flight from a beach or floating barge. Hydro-skis with wheels were demonstrated as an all-purpose landing gear conversion of the Fairchild C-123 , known as the Panto-base Stroukoff YC-134 . A seaplane designed from
3900-471: The hydrodynamic features of the hull, long length/beam ratio and inverted spray gutter for example, allow operation in wave heights of 15 feet. The inverted gutters channel spray to the rear of the propeller discs. Low speed maneuvring is necessary between slipways and buoys and take-off and landing areas. Water rudders are used on seaplanes ranging in size from the Republic RC-3 Seabee to
3978-402: The landing gear usually consists of skis or a combination of wheels and skis. Some aircraft use wheels for takeoff and jettison them when airborne for improved streamlining without the complexity, weight and space requirements of a retraction mechanism. The wheels are sometimes mounted onto axles that are part of a separate "dolly" (for main wheels only) or "trolley" (for a three-wheel set with
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#17327823270484056-405: The landing gear usually only supports the vehicle on landing and during subsequent surface movement, and is not used for takeoff. Given their varied designs and applications, there exist dozens of specialized landing gear manufacturers. The three largest are Safran Landing Systems , Collins Aerospace (part of Raytheon Technologies ) and Héroux-Devtek . The landing gear represents 2.5 to 5% of
4134-417: The lower corners of the central fuselage structure. The prototype Convair XB-36 had most of its weight on two main wheels, which needed runways at least 22 in (56 cm) thick. Production aircraft used two four-wheel bogies, allowing the aircraft to use any airfield suitable for a B-29. A relatively light Lockheed JetStar business jet, with four wheels supporting 44,000 lb (20 t), needed
4212-504: The main gear struts lengthened as they were extended to give sufficient ground clearance for their large four-bladed propellers. One exception to the need for this complexity in many WW II fighter aircraft was Japan's famous Zero fighter, whose main gear stayed at a perpendicular angle to the centerline of the aircraft when extended, as seen from the side. The main wheels on the Vought F7U Cutlass could move 20 inches between
4290-489: The main gears, which retract aft into the ends of the engine nacelles . The rearward-retracting nosewheel strut on the Heinkel He 219 and the forward-retracting nose gear strut on the later Cessna Skymaster similarly rotated 90 degrees as they retracted. On most World War II single-engined fighter aircraft (and even one German heavy bomber design ) with sideways retracting main gear, the main gear that retracted into
4368-611: The nacelle under the control of dampers and springs as an anti-flutter device. Some experimental aircraft have used gear from existing aircraft to reduce program costs. The Martin-Marietta X-24 lifting body used the nose/main gear from the North American T-39 / Northrop T-38 and the Grumman X-29 from the Northrop F-5 / General Dynamics F-16 . When an airplane needs to land on surfaces covered by snow,
4446-444: The nosewheel/tailwheel and the two main gears. Blinking green lights or red lights indicate the gear is in transit and neither up and locked or down and locked. When the gear is fully stowed up with the up-locks secure, the lights often extinguish to follow the dark cockpit philosophy; some airplanes have gear up indicator lights. Redundant systems are used to operate the landing gear and redundant main gear legs may also be provided so
4524-722: The outset with hydro-skis was the Convair F2Y Sea Dart prototype fighter. The skis incorporated small wheels, with a third wheel on the fuselage, for ground handling. In the 1950s hydro-skis were envisaged as a ditching aid for large piston-engined aircraft. Water-tank tests done using models of the Lockheed Constellation , Douglas DC-4 and Lockheed Neptune concluded that chances of survival and rescue would be greatly enhanced by preventing critical damage associated with ditching. The landing gear on fixed-wing aircraft that land on aircraft carriers have
4602-556: The pilot's canopy. A third arrangement (known as tandem or bicycle) has the main and nose gear located fore and aft of the center of gravity (CG) under the fuselage with outriggers on the wings. This is used when there is no convenient location on either side of the fuselage to attach the main undercarriage or to store it when retracted. Examples include the Lockheed U-2 spy plane and the Harrier jump jet . The Boeing B-52 uses
4680-453: The project, named LWS-3 Mewa , was modified and further developed at the LWS bureau. In the same year, the Polish Air Force ordered three prototypes. The first prototype LWS-3/I was flown in November 1937 . It revealed some handling deficiencies, but otherwise a good performance. Following tests, the design of the aircraft was improved. In 1938 , the second prototype LWS-3/II was flown. It had
4758-513: The runway loading limit . The Zeppelin-Staaken R.VI , a large German World War I long-range bomber of 1916, used eighteen wheels for its undercarriage, split between two wheels on its nose gear struts, and sixteen wheels on its main gear units—split into four side-by-side quartets each, two quartets of wheels per side—under each tandem engine nacelle, to support its loaded weight of almost 12 t (26,000 lb). Multiple "tandem wheels" on an aircraft—particularly for cargo aircraft , mounted to
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#17327823270484836-538: The same thickness pavements with a third main leg for ten wheels, like the first Boeing 747 -100, weighing 700,000 lb (320 t) on four legs and 16 wheels. The similar-weight Lockheed C-5 , with 24 wheels, needs an 18 in (46 cm) pavement. The twin-wheel unit on the fuselage centerline of the McDonnell Douglas DC-10 -30/40 was retained on the MD-11 airliner and the same configuration
4914-508: The takeoff dolly/trolley and landing skid(s) system on German World War II aircraft—intended for a sizable number of late-war German jet and rocket-powered military aircraft designs—was that aircraft would likely be scattered all over a military airfield after they had landed from a mission, and would be unable to taxi on their own to an appropriately hidden "dispersal" location, which could easily leave them vulnerable to being shot up by attacking Allied fighters. A related contemporary example are
4992-685: The water suction on the afterbody. Two steps were used on the Kawanishi H8K . A step increases the drag in flight. The drag contribution from the step can be reduced with a fairing. A faired step was introduced on the Short Sunderland III. One goal of seaplane designers was the development of an open ocean seaplane capable of routine operation from very rough water. This led to changes in seaplane hull configuration. High length/beam ratio hulls and extended afterbodies improved rough water capabilities. A hull much longer than its width also reduced drag in flight. An experimental development of
5070-499: The wings was raked forward in the "down" position for better ground handling, with a retracted position that placed the main wheels at some distance aft of their position when downairframe—this led to a complex angular geometry for setting up the "pintle" angles at the top ends of the struts for the retraction mechanism's axis of rotation. with some aircraft, like the P-47 Thunderbolt and Grumman Bearcat , even mandating that
5148-424: The wingtip support wheels ("pogos") on the Lockheed U-2 reconnaissance aircraft, which fall away after take-off and drop to earth; the aircraft then relies on titanium skids on the wingtips for landing. Some main landing gear struts on World War II aircraft, in order to allow a single-leg main gear to more efficiently store the wheel within either the wing or an engine nacelle, rotated the single gear strut through
5226-743: Was also formerly called alighting gear by some manufacturers, such as the Glenn L. Martin Company . For aircraft, Stinton makes the terminology distinction undercarriage (British) = landing gear (US) . For aircraft, the landing gear supports the craft when it is not flying, allowing it to take off, land, and taxi without damage. Wheeled landing gear is the most common, with skis or floats needed to operate from snow/ice/water and skids for vertical operation on land. Retractable undercarriages fold away during flight, which reduces drag , allowing for faster airspeeds . Landing gear must be strong enough to support
5304-673: Was being developed as well as a floatplane LWS-3H (hydro) variant for the Polish naval aviation. None were produced due to the war outbreak. In 1939, the LWS-7 Mewa II was being developed at the LWS as the development of Mewa. Before the war, only a model for aerodynamics tests was made. Drawings of LWS-7 were evacuated in September 1939 to the Polish embassy in Romania by the LWS director Aleksander Sipowicz . Many publications claim that they were handed over to Bulgarians, but it
5382-569: Was built in June 1930, without an earlier prototype, and all were delivered by July 1931. The R-XIV was a two-seater, parasol wing aircraft, with a 220 hp radial engine and fixed landing gear . The crewman sat in open cabs in tandem . The R-XV was not ordered, but the Air Force demanded instead, that two R-XIV should be armed with an observer's machine gun , for testing. Thus armed, the R-XIV, fitted also with other minor modifications, most notably
5460-487: Was built on June 7, 1932. By March 11, 1933, all were given to the Air Force. In older sources, numbers of 30 R-XIIIA and 20 R-XIIIB could be found. In 1932, next 170 aircraft were ordered. 48 were built in R-XIIIC variant with minor modifications, then 95 were built in a most numerous R-XIIID variant. It introduced visible changes, like a Townend ring on a radial engine, and a new engine cowling. It also had new type of
5538-445: Was common during the early propeller era, as it allows more room for propeller clearance. Most modern aircraft have tricycle undercarriages. Taildraggers are considered harder to land and take off (because the arrangement is usually unstable , that is, a small deviation from straight-line travel will tend to increase rather than correct itself), and usually require special pilot training. A small tail wheel or skid/bumper may be added to
5616-484: Was damaged on the factory airfield in Lublin by German bombers. The fate of the other one is not clear. Following that, some of the almost finished aircraft were hidden in Lublin park and in a forest nearby. A couple were modified to use wooden propellers with a fixed pitch. Two such aircraft were evacuated to an airfield near Lwów , and given over to the 26th Observation Escadre on September 12. One of them crashed during
5694-613: Was fitted with radio and cameras. Data from Polish aircraft 1893-1939 General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Lublin R-XIII The Lublin R-XIII was the Polish army cooperation plane ( observation and liaison plane), designed in the early-1930s in the Plage i Laśkiewicz factory in Lublin . It
5772-542: Was in C-in-C reserve, while the others were distributed among the field Armies. The R-XIII was no match for any of the Luftwaffe fighters , bombers or even reconnaissance aircraft , being much slower, and armed with only one machine gun, but they were actively used for close reconnaissance and liaison tasks. About 40 R-XIII from combat units were destroyed during the campaign, but only part of those were shot down by
5850-617: Was metal covered). Conventional fixed landing gear , with a tailskid. Crew of two, sitting in tandem in an open cockpit , with twin controls. The observer had a 7.92 mm Vickers machine gun on a ring mounting (rarely, 2 machine guns). A 9-cylinder air-cooled radial engine Wright Whirlwind J-5 (produced in Poland) with 162 kW (220 hp) nominal power and 176 kW (240 hp) take-off power (on 22 aircraft R-XIIIF, 250 kW (340 hp) engine Skoda G-1620A Mors-I). Two-blade wooden or metal propeller . Fuel tank 200 liters in
5928-728: Was sent on September 7 at night to search for Schleswig-Holstein battleship in Danzig , but did not find it there. The crew claimed to have bombed civilian victory parade in Danzig, celebrating capturing of Westerplatte instead, but there has been no confirmation of such attack found in German sources. On September 8 all planes were bombed, while stationed on the sea near Hel on the Hel Peninsula . Mixed construction (steel and wood) monoplane, conventional in layout, with braced high wings, canvas and plywood covered (front part of fuselage
6006-512: Was the main army cooperation plane in the Invasion of Poland . Its variant Lublin R-XIV was a military trainer aircraft . In 1927, the Polish aviation authorities announced a contest for an army-cooperation plane (in Polish: samolot towarzyszący , literally: "accompanying plane"). In Polish doctrine it was a close reconnaissance, observation and liaison aircraft, operating from casual airfields, providing big Army land units with information about
6084-467: Was used on the initial 275 t (606,000 lb) Airbus A340 -200/300, which evolved in a complete four-wheel undercarriage bogie for the heavier 380 t (840,000 lb) Airbus A340-500/-600. The up to 775,000 lb (352 t) Boeing 777 has twelve main wheels on two three-axles bogies, like the later Airbus A350 . The 575 t (1,268,000 lb) Airbus A380 has a four-wheel bogie under each wing with two sets of six-wheel bogies under
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