L-29 Delfin

The L-29 DELF�N two-seat jet aircraft made by Aero Vodochody was designed by Z. Rubli� and K. Tom�s as a replacement of piston-engined trainers used by Czechoslovak Air Force. The L-29 was the first jet aircraft ever designed in Czechoslovakia.

In the early 1960's the USSR was looking for a basic jet trainer. Designs were submitted from the various satellite countries. The release of the L-29 coincided with a competition conducted by socialist countries within the framework of the Council for Mutual Economic Assistance's initiative. The Czechoslovak plane outpaced both Polish jet trainer PZL TS-11 Iskra and the Soviet Union's Yak-30. The Poles proposed the TS-11 Iskra (still flying with the Polish A/F) Czechoslovakia the L-29 Delfin, and Russia the YAK 30. The Czechs won with the L-29. The first prototype of XL-29 flew on 5 April 1959. The first production aircraft was delivered in April 1963. In addition to the standard model, two others were produced in small numbers, the L-29R, available with nose cameras and underwing stores, and the L-29A, a single seat aerobatic version. Altogether, about 3,600 aircraft were completed by the time production at Aero's Vodochody plant near Prague, ceased in 1974. Approximately 3,000 were delivered to the Soviet Union; other customers included the Czech Air Force, the German Democratic Republic, Romania, Syria, Bulgaria, Hungary, Egypt, Indonesia, Nigeria, Uganda, Iraq.

The aircraft, which is intended for both initial and advanced training, has a robust air-frame; it can operate from rough grassy, sandy and muddy fields. It is designed so as to facilitate the pilots� transfer to combat aircraft.

Being of a totally new design, a tandem seating position was chosen with the best wing for subsonic flight, the straight wing. The wing has the ability to carry two of the following:- 150 lts drop tanks (normal use), 100 kg bombs, pods each containing four 67mm rockets or two pods of 7.62mm machine guns. The maximum speed with underwing stores is 0.7 mach and 0.75 without, while "G" limits being +8 -4 all this in an aircraft weighing just over 3,500 KGs.

The mid-wing all-metal aircraft is powered by M-701 jet engine with a radial-flow compressor and a single-stage turbine made by Motorlet with the maximum thrust of 8,72 kN (since 1960). The fuselage has a single engine with an air intake in each wing root. This is mounted about mid way and towards the rear of the wing. The Motorlet M-701c-500 turbojet rated is at 1,960 lbs. thrust. The M-701 is an early generation jet engine and features a single stage centrifugal compressor driven by a single stage axial flow turbine. 100% RPM is 15,300, this gives a whistling sound a bit like the fouger magister of similar vintage. There are 7 combustion chambers mounted around the engine.

The semi-monocoque structure of the air-frame is divided into three compartments which are screwed together. The first compartment is the nose with the aerial, the second is a pressurized cockpit, and the third part of the fuselage contains the engine. The wing is a self-supporting one-sparred all-metal structure. On wingtips are pylons for auxiliary fuel tanks or optional missiles. The aircraft has a retractable three-wheel landing gear. The pupil and the instructor are seated one after the other in synchronised ejection seats.

For training purposes the aircraft is arranged to carry light weaponry. L-29 DELF�N is equipped with a ASP-3MN/U weapons sight with a camera gun and it can carry two training or live bombs (2 x 100 kg), 8 air-to-surface rockets, or two 7.62 mm machine-guns.

The L-29 entered operational service in 1963; its production ended in 1974. It was exported into a number of countries; in many of them it is still in operation, including ACR Air Force. In 1965, the development of the L-29R light reconnaissance combat version was finalised. As different from the trainer, the L-29R had a special built-in pod with optical cameras in the fuselage under the cockpit. For an increased range capability, external fuel tanks were added on the wingtips. A small series of single-seat L-29 AKROBAT has been developed which is designed for aerobatics performances.

The aircraft was produced in Aero Vodochody and Let Kunovice from 1962 to 1973. Over 3500 were built. Besides service in Czechoslovakia, Delf�n was exported into 13 countries. The L-29 is being replaced by subsequent L-39 Albatros.