Ikarus 451

{{Short description|Yugoslavian research aircraft family}}  {{Infobox aircraft | name = 451 | logo = | logo_size = | image = File:BAM-41-Ikarus 451 M.jpg | alt = | caption = The first Yugoslavian [[jet aircraft]] ''Ikarus S-451 M'' on display at the [[Aeronautical Museum Belgrade]]. | long_caption = | other_names = | aircraft_type = [[Research aircraft]] | aim = | outcome = | related = | national_origin = [[Yugoslavia]] | manufacturer = [[Ikarbus|Ikarus]] | design_group = | designer = | builder = | issuer = | status = | owners = | primary_user = | more_users = | service = | major_applications = | proposals = | prototypes = | number_built = | construction_number = | civil_registration = | military_serial = | radio_code = | requirement = | aircraft_carried = | flights = | total_hours = | total_distance = | construction_date = | introduction = | retired = | first_flight = 25 October 1952 (Type 451M) | initiated = | in_service = | last_flight = | expected = | developed_from = | variants = | developed_into = | preservation = | fate = | predecessors = | successors = | concluded = }} [[File:BAM-40-Ikarus 451.jpg|thumb|Ikarus S-451]]

The '''Ikarus 451''' is a family of [[research aircraft]] designs built in the former [[Yugoslavia]] in the 1950s by the [[Belgrade]]-based manufacturer Ikarus (now [[Ikarbus]]), all sharing the same basic [[airframe]], but differing in [[Aircraft engine|powerplants]] and [[cockpit]] arrangements. One member of the family '''Ikarus 451M''' became the first domestically-built [[jet aircraft]] to fly in Yugoslavia on 25 October 1952.<ref name=JAWA55-56>{{cite book |title=Jane's all the World's Aircraft 1955–56| last= Bridgman| first= Leonard| year= 1955| publisher=Jane's all the World's Aircraft Publishing Co. Ltd.| location= London}}</ref> It was succeeded by the [[Ikarus 452]].

==Design, development, and variants== To research [[prone pilot]] cockpit arrangements and controls, the Yugoslav Government Aircraft Factories developed the '''Ikarus 232 Pionir''', a small twin-engined [[low-wing]] [[monoplane]], powered by 2x {{convert|65|hp|kW|abbr=on|disp=flip}} [[Walter Mikron III]] [[piston engines]].<ref name=JAWA55-56/>

===Type 451=== An enlarged version of the Pionir was developed as the '''Type 451''', powered by 2x {{convert|160|hp|kW|abbr=on|disp=flip}} Walter Minor 6-III six-cylinder piston engines<ref name=JAWA55-56/> of {{convert|160|hp|kW|abbr=on|disp=flip}} each. The Type 451 had a 6.7 m (22 ft) [[wingspan]], a maximum speed of 335 km/h (182 [[knot (unit)|knots]]), and a [[ceiling (aeronautics)|ceiling]] of 4750 m (15,570 ft). It first flew in 1952.

It also accommodated the pilot in [[prone position]], but was an otherwise conventional low-wing monoplane with retractable [[tailwheel]] [[landing gear|undercarriage]], the main units of which retracted backwards into the engine [[nacelles]] mounted below the wings.

===451M Mlazni === By the end of 1952, the Type 451 was followed by the '''451M Mlazni''' ("Jet") which had conventional seating for the pilot. In place of the two Walter Minor 6-III inline engines of the original Ikarus 451, the 451M was fitted with [[Turbomeca Palas]] [[turbojets]].

In this version, the undercarriage retracted inwards. Provision was made to carry one 20 mm [[Hispano Suiza 404A]] [[autocannon|cannon]] under the fuselage, plus six [[RS rocket]]s under the wings. Further developments were aimed at developing a viable [[military aircraft]] from this basic design.

===S-451M Zolja=== The '''S-451M Zolja''' ("Wasp") that flew in 1954 featured a stretched [[fuselage]], [[folding wings]], and redesigned engine nacelles, now in the same plane as the wing rather than being hung under them. In 1960 a S-451M Zolja set an [[airspeed record]] with a [[takeoff weight]] from {{convert|1000|kg|abbr=on}} to {{convert|1750|kg|abbr=on}}, flying at 500.2 km/hour.

===J-451MM Stršljen === The S-451 Zola was developed into an armed version, the '''J-451MM Stršljen''' ("Hornet") intended for the [[close air support]] (''Jurisnik'') role, with [[Turbomeca Marbore]] engines boasting over twice the [[thrust]] of those used on earlier aircraft, and an armament increased to two HS.404 cannon carried under the fuselage. The J-451MM Stršljen also differed from preceding designs in having a [[tricycle undercarriage]].

===S-451MM Matica=== The J-451MM Stršljen configuration then formed the basis for the '''S-451MM Matica''' ("Queen bee") two-seat [[trainer (aircraft)|trainer]] that set an airspeed record for aircraft weighing between {{convert|1750|kg|abbr=on}} and {{convert|3000|kg|abbr=on}}, achieving 750.34 km/hour (466.24 mph) in 1957. It was also developed into the '''T-451MM Stršljen II''' single-seat [[aerobatics]] trainer.

No member of the family was produced in any number. The 451, 451M, and J-451MM are all preserved at the [[Aeronautical Museum Belgrade]].

==Variants summary==

=== 232 Pionir === (''Pionir'' – Pioneer) A small twin-engined prone-pilot research aircraft, powered by 2x {{convert|65|hp|kW|abbr=on|disp=flip}} Walter Mikron III piston engines. (1 built)

=== S-451 === A larger, more powerful version of the Pionir, powered by 2x {{convert|160|hp|kW|abbr=on|disp=flip}} Walter Minor 6-III piston engines and also incorporating a prone pilot cockpit. (1 built)

=== S-451M === (''Mlazni'' – Jet). Derived directly from the S-451 airframe, the S-451M substituted Turbomeca Palas turbojet engines for the piston engines, in underslung nacelles at the same positions on the wing and conventional cockpit.

=== S-451M Zolja === (''Zolja'' – Wasp). Flown in 1954, the S-451M Zolja featured a stretched fuselage, folding wings, and engine nacelles centred on the wing chordline. Powered by 2x {{convert|353|lbf|kN|abbr=on|disp=flip}} Turbomeca Palas 056A turbojet engines; set a world speed record in its class in 1960. [[File:BAM-42-T-451-MM Strsljen II.jpg|thumb|Ikarus J-451MM Stršljen II from 1956 (''J-451MM Hornet'') on display at the [[Aeronautical Museum Belgrade]]]]

=== J-451MM Stršljen === J – ''Jurisnik'' – (close air support) (''Stršljen'' – Hornet). The intended production close support version with tricycle undercarriage, Turbomeca Marbore engines and cannon armament. (1 built).

=== S-451MM Matica === (''Matica'' – Queen bee). Two-seat trainer version, used for a world speed record in 1957.

=== T-451MM Stršljen II === A single seat aerobatic trainer, fitted with more ammunition and maximum ordnance weight was slightly increased.

==Specifications (451M)== [[File:Ikarus 451m - Testing in Aeronautical Testing Center.jpg|thumb|Ikarus S-451M – Testing in [[Aeronautical Technical Institute|Aeronautical Testing Center]] in 1950s.]] {{Aircraft specs |prime units? = met |crew=One pilot |length m=7.45 |length ft=24 |length in=5 |span m=6.78 |span ft=22 |span in=3 |height m=2.32 |height ft=7 |height in=7 |wing area sqm=8.0 |wing area sqft=86 |empty weight kg=897 |empty weight lb=1,977 |gross weight kg=1,350 |gross weight lb=2,980 |eng1 number=2 |eng1 name=[[Turbomeca Palas]] 056A |eng1 kn=1.5 |eng1 lbf=330 |max speed kmh=470 |max speed mph=290 |range km=300 |range miles=190 |ceiling m=8,500 |ceiling ft=27,900 }}

==See also== {{Portal|Aviation}} * [[Ikarus 452]]

==References== {{Reflist}} * {{cite book |last= Taylor |first= Michael J. H. |title=Jane's Encyclopedia of Aviation |year=1989 |publisher=Studio Editions |location=London |pages=430 }}

==External links== {{Commons category}} * [https://translate.google.com/translate?hl=en&sl=ru&u=http://www.airwar.ru/enc/other/s451.html&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3Dhttp://www.airwar.ru/enc/other/s451.html%26hl%3Den%26sa%3DG Ikarus S-451M] (Specifications, photos, scheme...) * [https://web.archive.org/web/20110718020139/http://rides.webshots.com/photo/2884361950033538523mVoavK Ikarus T-451M Stršljen ("Hornet") photo] * [http://www.airliners.net/search/photo.search?aircraft_genericsearch=Ikarus%20S-451&distinct_entry=true Ikarus S-451, 451M & S-451MM Matica ("Queen bee") photos] * [http://www.airliners.net/search/photo.search?aircraft_genericsearch=Ikarus%20T-451MM%20Strsljen&distinct_entry=true Ikarus T-451M Stršljen ("Hornet") & T-451MM Stršljen II ("Hornet II") photos]

[[Category:Ikarus aircraft]] [[Category:1950s Yugoslav experimental aircraft]] [[Category:Prone pilot aircraft]] [[Category:Twinjets]] [[Category:Low-wing aircraft]] [[Category:Aircraft first flown in 1952]]