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Avia B-534

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The Avia B-534 is a Czechoslovak biplane fighter developed and manufactured by aviation company Avia . It was produced during the period between the First World War and the Second World War . The B-534 was perhaps one of the most well-known Czechoslovakian aircraft of the era.

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98-461: During 1932, work had commenced on the development of a new single-engined biplane fighter aircraft, the Avia B-34 , which had been designed by aeronautical engineer František Novotný . During its development, various alternative engines were considered and trialled before eventually settling upon the licence-built Hispano-Suiza 12Y engine. Other improvements during the prototype stage included

196-453: A radio set, oxygen provision, and an adjustable seat and cockpit cover. Early-built aircraft featured an open cockpit, while later-built examples were furnished with an enclosed cockpit. The B-534 was furnished with a monoplane tailplane, composed of steel and covered by fabric; similar construction methods were used for the fin and rudder . Both the rudder and the elevator were statically and aerodynamically balanced. The undercarriage

294-501: 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

392-414: 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

490-442: 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

588-474: 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

686-756: A B-534-IV replica is on display in the Prague Aviation Museum, Kbely , Czech Republic . A second replica (Bk-534), using (like the Kbely example) some original parts, is displayed at the Museum of Aviation at Košice International Airport , Slovakia . Data from Aircraft of the Third Reich Vol.1 General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Related lists Note: Official RLM designations had

784-515: A Bk-534 (HT Model Special). Jiri Vrany. Avia B-534 (MBI). 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 was also formerly called alighting gear by some manufacturers, such as the Glenn L. Martin Company . For aircraft, Stinton makes

882-564: A flight of six B-534s were involved in a brief melee with six German Bf 109s at low altitude. One B-534 was lost, but the Germans quickly broke off, wary of both the low altitude and the B-534's manoeuvrability. During 1937, a batch of 14 B-534s was supplied to Yugoslavia ; some of these aircraft were still in service when Germany launched the Invasion of Yugoslavia in early 1941. During 1937,

980-519: A flying exhibition. The aircraft was tested against the best in the world at the IV International Air Meeting at Zürich 's Dübendorf airport. The B-534 entered three of the competitions. The first of these tested climbing and diving. A German Bf 109 took first place and a Henschel Hs 123 pilot pushed his biplane to claim second. The B-534 took the next three positions. The 534 outflew every other fighter participating, bar

1078-476: 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

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1176-621: A handful of fighters were delivered from Czechoslovakia to Greece , additional Greek B-534s appear to have been acquired from Yugoslavia as well. During 1940–1941, these fighters were later used during the Greco-Italian War as part of efforts by Greece to resist the invading Axis forces. Following Germany's forced annexation of the remaining "Czech" part of Czechoslovakia as the Protectorate of Bohemia and Moravia on 15 March 1939, large numbers of captured B-534s were pressed into

1274-585: 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

1372-474: 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

1470-489: 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

1568-403: 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

1666-461: A mixture of bolts and rivets and braced together using streamline wires. The wing, which had a riveted steel structure and fabric covering, was attached to the fuselage using N struts ; similar struts were present in the outer section of the wings attaching the wings together. The forward section of the fuselage was covered with detachable metal panels, while the rear section had a fabric covering. Production aircraft were exclusively powered by

1764-537: 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

1862-550: A number of the captured B-534s to its allies, reportedly at 40 per cent of their original cost. Following the German occupation of Yugoslavia in 1941, the Axis-aligned Croatian Air Force was created and supplied with B-534s by Germany, as well as the integration of remaining examples from Yugoslavia's own B-534s ordered prior to the outbreak of the conflict. There are no real surviving airframes, but

1960-466: A preference for the established biplane configuration over the incoming generation of monoplane fighters that would soon prove to outperform them, the B-534 stayed in production for considerable time (1933-1939). During the late 1930s, Czechoslovakia sought to expand production of the type in response to German claims over the Sudetenland (the western border area of Czechoslovakia). Large numbers of

2058-668: A repaired B-534, downed a Junkers Ju 52 transport under Hungarian colours on its way to a base in occupied Poland . This was at once the first aerial victory for the Uprising and the last recorded biplane fighter air-to-air victory. As the Slovak National Uprising was desperate for available aircraft, Sergeant Cyprich was derided by his colonel for not trying to force the Junkers Ju 52 to land and be captured instead. The last pair of B-534s at Tri Duby were burned as

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2156-580: A result of accidents. On 1 September 1938, less than a month before the Munich Agreement would cause Czechoslovakia to lose 30 per cent of its territory and 34 per cent of its population, 328 B-534s and Bk-534s equipped 21 fighter squadrons of the Czechoslovak Air Force, while other aircraft were assigned to reserve and training squadrons, and deliveries continuing of the final batch of fighters. On 14 March 1939, Germany forced

2254-581: A role, three aircraft were equipped with tailhook and underwent structural strengthening before the commencement of a flight test programme; however, none of Germany's aircraft carriers , the Graf Zeppelin -class , were ever completed. The B-534 also featured in the German propaganda movie Kampfgeschwader Luetzow in which the type was used as a stand-in for Polish PZL P.11 , being painted in Polish Air Force markings. Germany also sold

2352-457: 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

2450-520: 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,

2548-557: 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

2646-412: 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

2744-517: Is likely that the others were retired from use rather than being used for training purposes. The remaining three B-34s were retained by the new Slovenské vzdušné zbrane (Slovakian Air Force). One, perhaps two of these were still being used for training at Tri Duby airfield (today called Sliač Airport ) in August 1944. They then effectively became part of the Kombinovaná letka (combined squadron) of

2842-465: 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

2940-541: The B-34.2 was fitted with an Avia Rr 29 radial engine but was never actually flown with it as the engine was not sufficiently developed. It was, however, offered to the Air Force under the redesignation B-234 . The second prototype was then fitted with an inline Hispano-Suiza 12Ybrs piston engine, and later redesignated B-534.1 . The twelve production B-34s entered service with the 37 Stíhací Letka (fighter squadron) of

3038-536: The B-534/III version serial numbers B-534: 148–173. Production took place in the second half of 1936. It entered service between March and April 1937. The III series had aerodynamic refinements which saw the streamlining of the front carburetor air intake. Mudguard spats were also often added at the factory to the main gear. The remainder of the second order from 534.174 to 534.193 were the IV series . With later orders

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3136-705: 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

3234-726: The Czechoslovak Air Force during the latter half of 1935, the B-534 was put to use in the interceptor role. Initially, the responsibility for pursuit and aerial combat was shared with several other aircraft, including the Avia BA-33L and the Letov Š-31 ; however, by 1938, the B-534 was the sole type of aircraft in Czech service to be tasked with this role. By 10 November 1938, a total of 370 B-534 and Bk-534 aircraft in service; additionally, 53 aircraft had been written off as

3332-490: The Czechoslovak Air Force , soon increasing to 147, was placed on 17 July 1934. At that time, the B-534 was well ahead of its contemporaries. The United Kingdom was still dependent on Hawker Furies , with the first Gloster Gladiators being produced at this time. The Soviet Union was placing its hope on its Polikarpov aircraft designs. The United States was still using descendants of the Curtiss Hawk series, with

3430-1002: The Czechoslovakian Air Force in September 1934. They were retired to training duties in 1937. Despite inferior overall performance and some unpopularity, the aircraft was robust. Until the end of the First Czechoslovak Republic in March 1939, only one aircraft was lost; B-34.4 crashed and was written off in April 1937. Eight of the B-34s were handed over to the German Luftwaffe when the Czechoslovakian state ceased to exist in March 1939. At least three were soon lost in crashes and it

3528-645: The German Invasion of Poland ; the nation held the aim of regaining territories which had been previously lost to Poland at Munich. A pair of squadrons of B-534s were assigned to support the invasion. In the theatre, these were typically used to escort Luftwaffe aircraft, such as the Junkers Ju 87 dive-bomber, on eight missions. On 6 September the Avias shot down Polish reconnaissance aircraft Lublin R.XIIID over Prešov , killing its two-men crew. One Avia

3626-511: The Hispano-Suiza 12Y 12-cylinder water-cooled engine, rated to produce a maximum of 850 hp, which was built under licence by Avia. The total fuel capacity was 70 gallons (320 litres); a combined cooler and oil tank was installed beneath the fuselage, while a water-based radiator was also set below the engine. Engine ignition was provided via the cockpit, along with automated fire-fighting equipment. Other cockpit equipment included

3724-416: The Hispano-Suiza 12Ydrs engine. This was a liquid-cooled V12 -cylinder engine with a capacity of 36.05 litres. On the ground its normal power rating was 650 hp, it could deliver 750 hp for two minutes. At an operational height of 3,000 m (9,842 ft), it could deliver 850 hp for 30 minutes. At an operational height of 4,000 m (13,123 ft), it could reach 860 hp. Total fuel

3822-460: The Luftwaffe . In German service, the type was heavily used as a fighter-trainer at several fighter pilot training schools; another major use was as a glider-tug and target tug , which involved those B-534s involved being outfitted with cables and release-gear. Germany was also interested in potentially using the B-534 as a carrier-based aircraft . In order to evaluate its suitability for such

3920-561: 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

4018-702: 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

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4116-623: The Seversky P-35 and Curtiss P-36 about to fly as prototypes. The B-534 was designed as a single- engine biplane fighter with a licence-built Hispano-Suiza inline powerplant, and fixed landing gear . The air forces of the 1930s were reluctant to abandon the manoeuvrability and climb rates of biplanes for the speed of monoplanes , even in the face of new and better technology. The success of Soviet pilots with biplanes may have contributed to this reluctance; they were known to strip their aircraft of sliding canopies , preferring to have

4214-833: The Slovak Insurgent Air Force during the Slovak National Uprising against the Germans in September 1944. There is no evidence of them being used in combat at this time and if they survived the uprising they were almost certainly among the aircraft destroyed by the Slovaks before they left the airfield after the failure of the uprising. B-34.1 First prototype, flew Feb 1932 B-34.2 Second prototype, redesignated B-234 with Avia Rr 29 engine, then again as B-34.2 with Hispano-Suiza 12Ybrs engine, redesignated Avia B-534 .1. B-34.3 to B-34.14 Production aircraft General characteristics Performance Armament P. Schumirast, J. Andal. Avia B-34, B-534

4312-470: 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

4410-403: The B-534.2, was completed in September 1933. It differed from the first prototype by having an enclosed cockpit and a revised tail and undercarriage. On 14 April 1934, the second prototype, while flown by test pilot Václav Kočí , successfully attained a Czechoslovak national speed record of 365.7 kilometres per hour (227.2 mph). More testing followed, and an initial order for 34 aircraft for

4508-512: The B.34/2 before it flew, fitting it with a Hispano-Suiza 12Ybrs V12 engine. The Avia B-34/2 made its maiden flight on 25 May 1933. The prototype was sent for testing in September and was redesignated as the B-534.1 . On 10 September, the B-534 was displayed to the public for the first time at an Army Air Day. It was to compete against the Praga E-44 and Letov Š-231 . A second prototype,

4606-558: The Bf 109 and Britain's leading models – the Hawker Hurricane and Supermarine Spitfire – were raising the bar of fighter/interceptor standards. The Slovenské vzdušné zbrane (Slovak Air Force) was organised out of the units of the Czechoslovak Air Force that were based in Slovakia at the time of partition, and inherited about 71 B-534s and Bk-534s. Slovakia had to quickly make use of its newly formed air force, weakened by

4704-541: The Czechoslovak Ministry of Defence placed an order for B-34s. A second prototype, the Avia B-34/2, was built, which was intended to be powered by a 450 kilowatts (600 hp) Avia Rr 29 radial engine instead of the Hispano-Suiza 12N V12 engine of the first prototype and the initial production series. This engine proved prone to overheating and vibration, however, and it was decided to re-engine

4802-533: The Messerschmitt Bf 109 – and even then, the Avia was only 11 km/h slower than the German aircraft. Allegedly, problems were encountered with the redesign effort to adapt to installation of a newly installed cannon. These were not resolved in the summer of 1938; by this point, Czechoslovakia, sensing rising political tension amongst German claims to Czech-held territory, was eager to get more aircraft in

4900-521: The adoption of an enclosed cockpit along with a revised tail and undercarriage arrangement. On 14 April 1934, the second prototype, while flown by test pilot Václav Kočí, successfully attained a Czechoslovak national speed record of 365.7 kilometres per hour (227.2 mph). Deliveries of aircraft to the Czechoslovak Air Force commenced in October 1935. Partially as a result of its impressive maneuvrability, as well as some operators continuing to maintain

4998-469: The air, Avia decided to use a third machine gun in the nose. Judging by the size of the gun magazine, the nose machine gun was matched with an increased supply of ammunition. For the nation, time was running out and drew to Munich Diktat, at which point Germany commenced its occupation of the Sudetenland (the western border area of Czechoslovakia). Two series Bk-534 were produced, cn's 501 – 554 (63, for Czechoslovak air force), and cn's 555 – 620. Only three of

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5096-518: 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 ,

5194-416: 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

5292-470: 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

5390-435: The base was evacuated on 25 October 1944. During 1939, Bulgaria opted to procure a batch of 78 B-534s, well after the enactment of the Czech partition, from Germany, who had captured a large number of the type. The last batch of these aircraft were delivered from Czechoslovakia during March 1942. On 1 August 1943, 48 of these aircraft were able to make two passes at American Consolidated B-24 Liberator bombers returning from

5488-404: The best of its contemporary biplanes. A common alteration to the IV series was the replacement of the tailskid with a tailwheel . Operational experiences had shown that the spat on the main landing gear could become clogged with mud on grassy airfields and cause takeoff and landing problems. The spats were then often removed. During 1937, the superb performance of the B-534 was demonstrated at

5586-455: The departure of many Czech pilots, to defend itself when neighbouring Hungary launched an invasion on 23 March 1939. During the ensuing combat, a pair of B-534s were shot down by Hungarian anti-aircraft fire while a further four were claimed to have been shot down by Hungarian Fiat CR.32 fighters. Another Avia was compelled to perform a forced landing behind Hungarian lines and was captured. During September 1939, Slovakia participated in

5684-410: 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

5782-401: The fourth series would occupy the serial numbers .174 and 445 and was therefore the most numerous of the types. The most important change to the earlier series was the enclosed cockpit. The IV series also enjoyed a metal light alloy Letov ( Hochfeld ) Hd-43 propeller. The various refinements allowed the IV series to have an increased speed of over 200 mph, and this placed it on par with

5880-418: 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

5978-424: 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

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6076-438: 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

6174-603: 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

6272-471: 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

6370-402: 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

6468-405: 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

6566-417: 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

6664-504: 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

6762-489: 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

6860-611: 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,

6958-479: The nose on either side of the engine in a similar manner to the Avia B-34 and two were fitted in the wings. At an early stage of production, it was however recognised that the wing-mounted guns were troublesome. Aircraft from serial number B-534.47 were completed without the wing guns, which were also removed from the earlier aircraft. The first to fourth series aircraft were fitted with the Avia licence-built version of

7056-412: The nose. However, there have been claims that the company had encountered substantial difficulties in adapting the aircraft to accommodate the additional weapon and these were not quickly resolved. Judging by the size of the gun magazine, the nose machine gun was matched with an increased supply of ammunition. Consequently, however, the fuel load was decreased Upon its introduction to squadron service with

7154-444: 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

7252-410: The others. The four 7.92 mm (0.312 in) machine guns were located on the sides of the fuselage , firing through the propeller . One very modern innovation was a bubble canopy ; this had been tested on a small number of the early series aircraft, although it certainly was not a standard fit. During 1936, a second order for 46 aircraft were issued by the government. The first 25 of these were

7350-722: 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

7448-434: The partition of Czechoslovakia, with Slovakia being declared as the nominally independent Slovak Republic with Germany annexing the remaining "Czech" part of Czechoslovakia as the Protectorate of Bohemia and Moravia the next day. The abrupt partition of Czechoslovakia during 1939 prevented any actual combat operations of the B-534 to be conducted by the nation that had produced it. By then, high performance monoplanes such as

7546-556: 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

7644-610: The prefix "8-", but this was usually dropped and replaced with the manufacturer's prefix. Avia B-34 The Avia B-34 was a biplane fighter aircraft built in Czechoslovakia in the early 1930s. It was the first design of František Novotný for the Avia company and although built only in small numbers, it paved the way for the Avia B-534 . The B-34 was an all-metal single-bay biplane of conventional configuration, with tailwheel undercarriage . The mainwheels of

7742-563: The prototype were fitted with large spats . The first prototype underwent testing from 2 February 1932, leading to a large number of modifications being made, in particular the tail and engine cowling designs were considerably revised. The resulting B-34.1 served as the prototype for the 12 production machines ordered by the Czechoslovakian Air Force. These had an even larger vertical tail, interplane struts of narrower chord, and no wheel spats. A second prototype,

7840-646: The raid on Ploieşti . Hits were scored but no B-24s were shot down and some of the B-534s that received damage in the combat, cracked up on landing. The B-534s saw little use as frontline aircraft as Bulgaria had also procured the more capable Bf 109E and the French-built Dewoitine D.520 monoplane fighters. After the anti-German coup of 9 September 1944 , Bulgaria switched sides overnight. As such its B-534s were quickly pressed into use to conduct ground attacks against German units. On 10 September 1944,

7938-513: 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

8036-538: 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

8134-471: The second batch were completed for the Czechoslovak air force, and the remaining 63 aeroplanes from this production block were finished for the Germans, after the German invasion of the remainder of Czechoslovakia on 15 March 1939. The Avia B-534 was a single-seat unequal-span biplane fighter aircraft. The fuselage used a rectangular structure composed of steel tubes, which were attached together using

8232-508: 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

8330-504: 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

8428-646: The trainer role and other secondary duties during 1943. The training role would have been the last operational service of the B-534s in Slovak colours if not for the Slovak National Uprising of September–October 1944. The rest of the Slovak air assets did not turn-coat as expected and the leaders of the uprising were faced with using a rag-tag collection of leftover aircraft, including several B-534s stationed at Tri Duby airfield. On 2 September 1944, Master Sergeant František Cyprich, just after testing

8526-550: The type saw combat with multiple nations during the course of the Second World War. While relatively ineffective in combat during the later stages of war due to its obsolescence, the type formed a sizeable proportion of several countries' military aviation components. During 1932, the Czechoslovak aircraft company Avia flew the first prototype of a single-engined fighter biplane , the Avia B-34 , designed by aeronautical engineer František Novotný . After modification,

8624-685: 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

8722-498: The wind in their faces. Aircraft with two fabric-covered wings and fixed landing gear were also less expensive to manufacture. First deliveries of the B-534 to the Czechoslovak air force began in October 1935, and 568 had been completed by 1939. The first 100 of these were of the first series. The second prototype was the blueprint for the I series , although it was built with an open cockpit. These early series aircraft were initially armed with four 7.92mm vz.28 guns. Two were located in

8820-499: 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

8918-424: 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

9016-490: Was 347 litres (76 gal) which was held in two fuselage fuel tanks of 90 and 257 litres. The II series completed the remainder of the first order from the Czechoslovak Government, These were 45 aircraft numbered B-534.102 to 147. Like the I series these carried four guns. However the solution to the problems with the wing-mounted guns was to move these guns, now upgraded to the vz.30 to the fuselage with

9114-445: 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

9212-417: Was designed to carry one 20 mm (0.79 in) Oerlikon FFS-20 cannon firing through the nose, along with a pair of 7.92 mm (0.312 in) machine guns to the sides of the fuselage. By the summer of 1938, Czechoslovakia, sensing rising political tension caused by German claims to Czechoslovak border territory, was eager to get more aircraft in the service, thus Avia decided to use a third machine gun in

9310-425: Was low and no significant victories were achieved during their deployment. During 1942, one of these squadrons was redeployed to Slovakia to conduct anti- partisan operations. Over time, a combination of obsolescence, the lack of spare components and the old Czechoslovak air force's proprietary fuel mixture ( BiBoLi , or some other mix of ethanol, benzol and petrol) finally relegated the surviving B-534s to performing

9408-407: Was of a split-type configuration, being oleo -sprung and equipped with Dunlop -built wheels. The wheels, which were housed within streamlined fairings, were fitted with brakes; for conducting operations under winter conditions, skis could also be fitted to the undercarriage. According to reports from pilots who flew the B-534, it possessed excellent handling characteristics for the era. The Bk-534

9506-399: Was shot down by Polish anti-aircraft cannons, the other one crashed on 9 September (a pilot was killed). Also the downing of Polish RWD-8 liaison aircraft fleeing to Hungary was reported. The same squadrons fought alongside the elements of the German military in the area of Ukraine during summer 1941. According to aviation author Josef Krybus, on this front, moral amongst the Slovak pilots

9604-467: 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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