reporting type variants jet fighter prototype designed manufactured shortly end world war derived different engines program canceled fighters powerful engines swept wings showed promise design development following limited success drastic changes introduced improve performance ease maintenance engine rated lbf thrust moved nose formed forward fuselage position thrust losses length intake allowed engine changed easily predecessor cockpit widened moved position mid set wings engine exhaust pilot seat armored protected armor plate fuel tanks positioned ahead cockpit total capacity kilograms fuel mid mounted wings different flow span wing single flaps retracted fuselage meant aircraft narrow ground track aircraft armed millimeter starboard aircraft nose port gun rounds ammunition flight december manufacturer trials completed june state acceptance trials commenced july prototype crashed eighth flight engine failed approach maximum speed attained crash kilometers hour mph decided improve performance late replacing engine powerful lbf thrust design work completed september construction began prototype shortly afterward engine ready testing project canceled significant difference cannon furnished rounds ammunition developing versions increase engine power successful model millimeters longer weighed additional kilograms original engine power increased additional lbf thrust engine designated bureau fitted aircraft prototype november initially designated changed aircraft following month addition powerful engine aircraft seat additional cockpit armor revised canopy importantly fitted new wings greater span surface area new designed delay area vertical increased prototypes built completed february flight march second prototype joined manufacturer trials later month aircraft participated august given reporting type additional power increased aircraft speed mph second prototype began state acceptance trials september demonstrated maximum speed mph altitude meters reach meters minutes aircraft rejected trials concluded january report said engine required work ready production aircraft problems longitudinal stability excessive stick forces elevators troublesome consequently canceled program experimental version built thin wing thin straight wing thickness believed flown world imported rolls engine rated lbf mounted nose cannon nose accommodate engine flown january speed mph sea level reached altitude meters minutes impressive gains inferior swept wing flown months earlier program canceled variants second airframe canceled delays engine originally known aircraft modified engine version thin wing version engine performance overshadowed lower powered aircraft development abandoned data early soviet general characteristics crew length wingspan wing area weight gross weight fuel capacity powerplant version lbf thrust dry lbf performance maximum speed mph range nmi service ceiling rate climb min wing loading armament guns rounds total
Lavochkin La-152