Lazarov Laz-14

 

During the 1950s it was clear that piston-engined aircraft were a thing of the past and the jet engine was the future.

At that decade, the Bulgarian aviation industry was already been cut off and made dependant of the Soviet. Most of Bulgarian aeronautical industry was reconverted to manufacture cars, electric pumps or even bee hives.

However, in Sofia, at the State Polytechnic there was still an faculty of Aeronautical Engineering and the people working there didn't want their work, carried over for more than 30 years, to fall into oblivion so ingloriously. They think that the dismantling of the Bulgarian aeronautical industry was a gross mistake and that the government should reactivate it.

Among that people was prof. Tsvetan Lazarov, dean of the faculty of Aeronautical Engineering. The father of designs like the DAR-6, DAR-6A, DAR-9, DAR-10 , Laz-7 , Laz-7M and Laz-12 thought about the future of the Bulgarian aeronautical industry and tried to revive it in the following years. So, in order to keep pace with the technological advances of the world aeronautical industry, specially regarding trainer aircraft, he started a project for a jet-powered trainer that could be used both by air forces and even flying clubs.

The copies of the designs that survived the Cold War, labelled as Laz-14, are dated 26th June 1958, meaning that work on the project began much earlier. 

Initial sketches were clearly inspired by the Czechoslovak Aero L-29 which was designed by Karel Tomasz and Zdenek Rublich, both colleagues of Lazarov. However, unlike the L-29 which flew for the first time in 1959 and was one of the main jet trainer aircraft of the Warsaw Pact and other countries, the Laz-14 couldn't pass the design stage. 

Laz-14 was designed as a two-seater, single-engined jet trainer for primary training and pilot training support. As it was expected to be armed too, it could've also performed some sort of ground support missions.

It was going to be made entirely out of metal, with trapezoidal-shaped low-wings with two spars and a strongly developed central section. Air intakes were to be located at the roots of the wings. It was also equipped with a tricycle retractable landing gear which retracted into the fuselage. The wings were to be equipped with ailerons with axial compensations and flaps for take-off and landing. They had spindle-shaped fairings at both ends to reduce inductive drag.

The power section of the fuselage was a steel pipe truss. It was going to be equipped with a fully-glazed cockpit with two seat arranged in a tandem configuration, with the student  sitting at the front and the instructor at the rear.

Lazarov wanted the Laz-14 to be powered by the French Turbomeca Marboré engine which could yield a thrust power of 400-480 kgf and was already powering some successful trainer aircraft like the Fouga Magister or the Morane-Saulnier Ms.760 Paris. However, considering the political situation of the time, it was more likely to be powered by the Czechoslovak Motorlet M-701, which powered the aforementioned Aero L-29. Anyway, the engine was going to be placed in the centre of the fuselage to avoid the loss of thrust power in the extension tube.

Tail planes' design were traditional. Elevator and rudders had aerodynamic compensation and trim tabs were going to be controlled from the cockpit. The horizontal stabilizer was going to have the ability of deviating 3 degrees up or down to facilitate aerobatics with either one or two pilots.

According to calculations, the Laz-14 was going to be extremely light, 700 kg (1.543 lbs) empty (for comparison, the mass of an empty L-29 is 2.280 kg - 5.026 lbs). Apparently, considering the expected numbers there is little doubt that, if the aircraft had been made, it would've been successful among Bulgarian pilots, as it would've fully met the requirements of the time.

Source:

http://www.airwar.ru/enc/other/laz14.html (translated and adapted)