1930s high wing single seat fighter aircraft yugoslav design built designed french trained engineers saw developing home grown aircraft industry production models built aircraft time brought service time german led axis invasion yugoslavia april defeat yugoslavia remaining aircraft taken strength air force axis puppet state croatia survived war background late 1920s scheme promoted yugoslavia sent aspiring engineers france develop knowledge intended advanced training return yugoslavia offered specialist roles industry went program returned yugoslavia employed administrative work frustrated decided design replacement built fighter service working basement belgrade apartment devoted spare time secretly working design original concept low wing retractable contemporary thinking led modify initial design high wing armed hub firing cannon fuselage mounted machine guns wing design emphasised power characteristics design development aircraft designed french cylinder engine mounted cylinder banks engine firing propeller hub powerful shaft horsepower engine combined hub firing cannon mandated use metal fuselage armament consisted french machine guns mounted engine wing fuselage fixed conventional landing gear mounted wing fixed enclosed cockpit located wing horizontal rigid lower tied flying wires vertical bladed propeller manually pitch considerable work needed fully develop design early men moved project pre project basic aerodynamic evaluation stages including building wooden scale model took paris test built wind tunnel point men received outside help forced borrow family project going decided approach head technical department lieutenant colonel design surprised impressed work official report proposing build design presented september senior officers opposed concept captain acknowledged outstanding fighter tactics considered shp engine ultimate fighter design despite opposition support younger pilots meant concept approved prototype ordered factory near belgrade delivery end year prototype designated standing believed prototype complete september flight delayed concerns wing structure following month appointed test pilot prototype operate preparations maiden flight decided develop test program permission granted flight testing begin april conducted flight prototype april initial uneventful flight weapons installed light fuel load following day manoeuvres wing fabric observed official checked stated resolve fabric completely dried took aircraft test flight day involved aircraft shallow dive pulled abruptly high speed point wing fabric began tear rapidly extent seen ground aircraft dropped spin starboard safely crashed ground critics exploited accident undermine concept joining criticising aircraft flights considered sufficient verdict design debate future fierce placed significant pressure designers element aircraft design subsequently attacked eventually generally agreed aircraft designed needed testing point decided build second prototype evident hand fabric wing stood strain question second prototype took months build designers closely involved main difference wings covered metal leaving rear fuselage fabric covered new wing tested fabric metal covering request changes reduced size improved shape modified air making streamlined fuselage machine guns replaced machine guns second prototype delivered aircraft placed hands different test pilot 1st lieutenant conducted flight august worked closely designers construction static testing suggestions resulted improved cockpit layout strictly followed completely new test program installed testing equipment recorded characteristics aircraft gaining complete mastery aircraft conducted manoeuvres visit future turkish president included complete inverted loop mid october broke unofficial european air speed record aircraft fixed attaining speed mph yugoslav air speed record aircraft able achieve greater expected power altitudes completed testing program submitted report acceptance group pilots conducted mock service displayed overall superiority british built aircraft point declared continuing doubts aircraft challenged duel flying preferred aircraft fury won climbing competition race belgrade final forced better aircraft november submitted proposal order batch approved following month production version included additional improvements continued testing resulted delays aircraft entering service year time international consensus superiority low wing time delivered fighter units operational history production aircraft delivered 6th fighter regiment based early pilots subjected considerable additional testing entered normal service mid year remaining entered service remainder aircraft delivered radios armament fitted workshops october transferred licence built delivered transferred 5th fighter regiment end production concentrated consisted solely interim allocation squadron group equipped hurricanes soon equipped hurricanes 5th fighter regiment threat war overtook planned deployment march moved near command german led axis invasion yugoslavia commenced april damaged landing accident workshops repaired fourth machine badly damaged condition day patrolled bosnia contact enemy machines conducted combat air patrol airfield 8th bomber regiment pattern continued following day incident patrol duration coverage limited short range aircraft april patrol unsuccessfully gave chase lone german reconnaissance aircraft later day force landed leaving seven operational aircraft april german fighters observed heading nova landing patrol poor flying weather managed climbed meet unable complete landing extreme avoid attack total hurricanes meet germans following seven minutes furious ensued german aircraft claimed hurricanes lost german records indicate aircraft lost pilot survived survived loss badly wounded germans low fuel broke headed north following day force landed engine failure reducing number despite deteriorating weather conditions revolts yugoslav forces combat patrols continued april aircraft grounded weather april aircraft 4th fighter regiment took air chasing german reconnaissance aircraft record victories following day 4th fighter regiment continued carrying sorties commander 2nd ordered remaining aircraft destroyed personnel withdraw road end brief campaign air_force independent state croatia croatian surviving captured aircraft beginning service lacked spare parts later year operational observed airfield near october operating airfield north remained nearly year conducting missions end service end following year remained survived war development proposed development dual control fast reconnaissance ordered operators kingdom yugoslavia independent state croatia data general characteristics crew length wingspan height wing area weight gross weight fuel capacity powerplant liquid cooled engine shp propellers bladed pitch performance maximum speed mph cruising speed mph range nmi service ceiling time altitude minutes seconds wing loading armament cannon rounds spiral drum machine guns rounds gun
Ikarus IK-2