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
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.
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