Armed and Ad­vanced

Even while the L-39 trainer was be­ing de­signed, the de­vel­op­ment of ad­vanced ver­sions for other roles was be­ing dis­cussed. These dis­cus­sions would be­come re­al­ity in re­sponse to cus­tomer de­mand and would lead to a range of mod­els ca­pa­ble of op­er­at­ing in suc

Aviation Classics - - CONTENTS -

The new de­vel­op­ments of the L-39 led to one change for the air­craft al­ready in ser­vice, the des­ig­na­tion changed to L-39C, C stand­ing for Cvicná or trainer. Prior to this the air­craft had only ever been re­ferred to as the L-39. As L-39 pro­duc­tion in­creased at Vodochody, a num­ber of sup­port sys­tems were de­vel­oped to aid train­ing on the new type, in­clud­ing the TL-39 flight sim­u­la­tor, the NKTL-39 ejec­tion seat pro­ce­dures trainer and the KL-39 mo­bile ground di­ag­nos­tic sys­tem, these even­tu­ally be­ing supplied to cus­tomers world­wide. The first re­quest for a mod­i­fied ver­sion of the L-39 air­craft came about through the need for a new tar­get tow­ing air­craft from the Cze­choslo­vak Air Force.

L-39V

In 1972, the eighth pro­to­type of the L-39 emerged mod­i­fied to carry a ram air tur­bine

driven winch for tar­get tow­ing. The winch it­self was mounted in the rear cock­pit; the ram air tur­bine that drove it was in a pod un­der the for­ward fuse­lage. The now sin­gle seat cock­pit was un­pres­surised, since the open­ings re­quired by the ca­ble run for the winch and the drive sys­tem for the tur­bine could not be sealed. Along with Aero’s mod­i­fi­ca­tion of the L-39, which was des­ig­nated the L-39V, V stand­ing for Vlecná or tug, Le­tov had de­vel­oped a new towed tar­get, the KT-04, which re­sem­bled a small, tail­less straight winged air­craft. The KT-04 was mounted on a launch­ing dolly and the L-39V would take off with the KT-04 on a short length of tow ca­ble be­hind it. Once in the range area, the tar­get would be winched out to a safe dis­tance so stu­dents could prac­tice at­tacks on it. At the end of the sor­tie, the L-39V would re­lease the KT-04 over a safe area near its home base, the tar­get de­ploy­ing its own para­chute once re­leased. Un­der the KT-04’S cen­tre sec­tion, a land­ing bag would in­flate to en­sure a soft land­ing. The tar­get could then be re­cov­ered to be used again, the sim­ple shape be­ing made up of wings, fin and three-piece fuse­lage, all of which were easily re­placed in the event of dam­age. The test­ing of the mod­i­fied L-39 with the KT-04 and the de­vel­op­ment of their op­er­at­ing pro­ce­dures took the next four years, the first of eight L-39VS or­dered by the Cze­choslo­vak Air Force en­ter­ing ser­vice in 1976. The L-39VS proved pop­u­lar with pilots be­cause the lack of the cus­tom­ary gun­sight in the front cock­pit gave them a great view, de­spite the air­craft also lack­ing var­i­ous el­e­ments of the nav­i­ga­tion sys­tem. Later in their ca­reer, two of the L-39VS were trans­ferred to the East Ger­man Air Force who used them at Peen­e­mu­nde where they re­placed the Ilyushin IL-28 in the tar­get tow­ing role. One of these air­craft is pre­served to­day in the Luft­waf­fen­mu­seum at Ga­tow in Ber­lin.

ABOVE: The L-39 pro­duc­tion line at Aero Vodochody in full swing. Pavel Kucˇera

BE­LOW: Cze­choslo­vakian Air Force Aero L-39CS at Kosice in 1979. Pavel Kucˇera

ABOVE: The KT-04 tar­get was towed into the air be­hind the L-39V mounted on a take off dolly, the tar­get sim­ply fly­ing off it at the cor­rect speed. Pavel Kucˇera

ABOVE: The NKTL-39 ejec­tion seat trainer with the in­struc­tor’s con­trol po­si­tion. Aero RIGHT: A close up of the tur­bine drive for the winch un­der the for­ward fuse­lage of the L-39. Pavel Kucˇera

RIGHT: The sin­gle seat L-39V with the Le­tov KT-04 tar­get. Note the tur­bine drive sys­tem for the winch un­der the for­ward fuse­lage and the rear cock­pit that now con­tains the winch it­self. Pavel Kucˇera ABOVE: The TL-39 flight sim­u­la­tor seen from the in­struc­tor’s con­trol desk, be­yond which is the cock­pit mounted in front of a screen. Aero

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