DCS: L-39 Albatros

Right Panel ..................................................................................................................... 125 Instruments ......................................................................................................................... 127 Flight and Navigation Instruments .................................................................................... 127 FLIGHT .................................................................................................................................... 163 L-39С Structural Limits ......................................................................................................... 163 Engine Start Preparation....................................................................................................... 165 Cold start ........................................................................................................................ 165 Perform Engine Start ............................................................................................................ 167 After Engine Start ................................................................................................................ 172 Preparing For Taxiing And Taxiing ......................................................................................... 174 Circle Pattern Flight .............................................................................................................. 175 Takeoff ........................................................................................................................... 175 Crosswind Takeoff And Landing ............................................................................................ 183 Engine Shutoff ..................................................................................................................... 183 Circle Pattern Flight .............................................................................................................. 184 Aerobatics ........................................................................................................................... 185 General Information ........................................................................................................ 185 DCS [L-39 ALBATROS] 4 HISTORY Behavior of the Airplane at Minimum Speeds .....................................................................186 Spin ................................................................................................................................186 Use of RSBN-5S (“ISKRA-K”) Equipment for Flight and Navigation ...........................................188 NAVIG (NAVIGATION) MODE ............................................................................................188 Initial Approach and Landing Using RSBN-5S (Iskra-K) Equipment ......................................190 Approaching Airfield Using RKL-41 .........................................................................................194 COMBAT EMPLOYMENT .............................................................................................................197 Aircraft Armament ................................................................................................................197 Bomb Armament ..............................................................................................................197 Unguided Weapon............................................................................................................198 Guided Missile Weapon.....................................................................................................199 Armament Controls and Signalization in Front Cockpit .............................................................201 Armament Controls and Signalization in Rear Cockpit ..............................................................202 Aiming and Photo Equipment ................................................................................................203 ESKR-46 Signal Flares ...........................................................................................................207 Ground Target Engagement Pre-flight Preparation ..................................................................209 Fictitious target base calculation .......................................................................................209 Вombs Delivery ....................................................................................................................209 Unguided Rockets Delivery ....................................................................................................213 Сombat Employment at Aerial Targets ...................................................................................217 L-39ZA .....................................................................................................................................221 Introduction .........................................................................................................................221 General description of the aircraft ..........................................................................................221 Operating Limitations ............................................................................................................224 Cockpit Equipment ................................................................................................................225 Front cockpit....................................................................................................................225 Rear Cockpit ....................................................................................................................231 Aircraft and Engine Systems ..................................................................................................232 Fuel system .....................................................................................................................232 PT-12 engine overheat control system ...............................................................................235 Aircraft equipment ...........................................................................................................235 [L-39 ALBATROS] DCS 5 Armament and Combat Employment ..................................................................................... 237 Aircraft Armament ........................................................................................................... 237 Bombing Armament ......................................................................................................... 237 Rocket Armament ............................................................................................................ 241 Missile armament ............................................................................................................ 242 GS-23L Gun .................................................................................................................... 244 PK-3 Machine-Gun Pod .................................................................................................... 246 Control and Indication Elements in the Front Cockpit ............................................................. 249 Armament panel .............................................................................................................. 249 Center Panel ................................................................................................................... 250 R-3S, R-60 and GS-23 Control Panel ................................................................................. 251 Annunciator Panels .......................................................................................................... 252 Bombs Delivery .................................................................................................................... 253 Rockets Firing ...................................................................................................................... 256 Air-to-Air Missiles ................................................................................................................. 259 Firing the GS-23 Gun on Ground Targets ............................................................................... 262 Firing the PK-3 Machine-Gun pods on Ground Targets ............................................................ 265 EMERGENCY PROCEDURES ....................................................................................................... 270 Engine Failure ...................................................................................................................... 270 Air Start of the Engine ..................................................................................................... 270 Spontaneous Changing or Holdup of Engine RPM .............................................................. 271 Engine Fire ..................................................................................................................... 273 Engine Surge .................................................................................................................. 273 Landing Gear Failure (Emergency Gear Extension) ................................................................. 274 ADI Failure .......................................................................................................................... 274 GMK-1AE Failure .................................................................................................................. 275 Flaps Non-Extension............................................................................................................. 275 Oil Pressure Drop at Engine .................................................................................................. 275 Pitot System Failure ............................................................................................................. 276 Bingo Fuel ........................................................................................................................... 277 Main Generator Failure ......................................................................................................... 277 DCS [L-39 ALBATROS] 6 HISTORY Primary and Backup Generators Failure ..................................................................................278 Canopy Destruction ..............................................................................................................278 Smoke in Cockpit – Cockpit Depressurization ..........................................................................278 Forced landing......................................................................................................................279 Flameout Landing .................................................................................................................280 Flameout Belly Landing .........................................................................................................281 FLIGHT CHARACTERISTICS .......................................................................................................283 Typical Speeds of Level Flight ................................................................................................284 Service Ceiling ......................................................................................................................285 Airplane Controllability ..........................................................................................................285 Pitch Balance in Level Flight ..................................................................................................285 SUPPLEMENTS ..........................................................................................................................288 Airdrome Data of Caucasus Map ............................................................................................288 Airdrome Data of NTTR Map..................................................................................................289 Sources ................................................................................................................................290 Eagle Dynamics ....................................................................................................................291 Management....................................................................................................................291 Programmers ...................................................................................................................291 Artists .............................................................................................................................292 Sound .............................................................................................................................292 Quality Assurance ............................................................................................................292 Science Support ...............................................................................................................293 IT and Customer Support .................................................................................................293 Localization......................................................................................................................293 Testers Staff ....................................................................................................................293 Special Thanks .................................................................................................................295 [L-39 ALBATROS] DCS 7 HISTORY DCS [L-39 ALBATROS] 8 HISTORY HISTORY L-39 Development Development and production of aircraft have always been one of the high priority tasks in those countries leading on the world stage. However, also several small countries developed airplanes, which took an honorable place in aviation history. One of those countries is Czechoslovakia. On January 1st, 1993, the country peacefully divided itself into the Czech Republic and Slovakia. One of the directions in the airplane industry was jet trainers. The L-39С “Albatros” became one of the most mass-produced jet trainers, taking 4th place in the world after the American T-33, the Soviet MiG-15UTI and its compatriot, the L-29 “Delfin” (English: dolphin). Figure 1: L-29 “Delfin” [L-39 ALBATROS] DCS EAGLE DYNAMICS 9 Developed in 1956, the L-29 “Delfin” won the Warsaw pact countries’ jet trainer competition. It marked a new era in pilot training, was very easy to pilot, robust and undemanding in service. At the same time, this airplane had several disadvantages and enhancement attempts showed that the L-29 had limited potential for modernization. Besides that, the fast evolution of aviation posed new requirements in young pilots’ training. Thus, there was a need for a new jet trainer. The Ministry of National Defense (MND) of Czechoslovakia officially ordered the airplane. MND started developing technical specifications in 1963. Work was ongoing in collaboration with the main customer – the Ministry of Defense of the Soviet Union. In particular, it was required to keep the positive qualities of the L-29, increase thrust-to-weight ratio and reliability in operations from unpaved runways. It was indicated that the maximum speed should not exceed 700 km/h. Special attention was paid to the trainee and trainer cockpits. They should be similar to the cockpits of combat airplanes. This task was delivered to the team, headed by the main constructor Jan Vlček from the Aeronautical Research Institute in Letňany (LVÚ, now the Aeronautical Research and Test Institute, a.s. – VZLÚ). Karel Dlouhý was the project’s chief designer. On July 15th, 1964, final specifications of the new jet trainer were ready and the name for the new airplane L-39С “Albatros” was approved. After 1,5 years of work, all design activities were transferred to Aero Vodochody, where Jan Vlček moved with his team. From the beginning, Jan Vlček decided on the classical cantilever low-wing scheme, three-point retractable gear and with trainer behind the trainee tandem cockpit. For the L-39C a trapezoidal wing was chosen. It was decided to equip the L-39С with a ruggedized landing gear, which is quite common for all jet trainers. To protect the engine from foreign objects, air intakes were located on both sides of the fuselage over the wing. To teach trainees how to employ weapons, two hardpoints could be installed. The ground maintenance of the airplane was well thought out; in particular, size and location of various inspection covers were chosen thoroughly to ease ground maintenance as much as possible. A lot of attention was paid to the selection of the power plant. From a reliability point of view, two engines were necessary, but this led to increased weight and fuel consumption. These disadvantages convinced the chief designer that one engine is enough, especially after taking into account increased jet engine reliability. Regarding engines, the plan was to install the Czech M-270 with thrust up to 2500 kgF, which Prague “Motorlet” factory was working on. The Soviet side was insisting on installation of the AI-25 with 1450 kgF thrust, which was in the final stage of development at the “Progress” design bureau (located in Zaporozhje), headed by A.G. Ivchenko. In the end, the AI-25 was chosen, because Prague’s engine was slightly too big for the light jet trainer. Besides that, after stand testing, it was obvious that operational development of this engine could not be finished fast enough. During 1964-66, models in scale 1:4, 1:5 and 1:25 were verified in the LVÚ’s wind tunnels. Based on these results, the form of the wing, the air intake configuration and several other components were finalized. In February 1967, a wooden model of the airplane was ready and a prototyping committee started working. In the same year, a model manufactured in Letňany was tested in “TsAGIs” (Central Aerohydrodynamic Institute) high-velocity and spin wind tunnels nearby Moscow. Similar testing continued in Czechoslovakia. By the end of 1968, all aerodynamic testing was finished. DCS [L-39 ALBATROS] 10 HISTORY Figure 2: L-39 model, 1:1 scale In the meantime, the “Motorlet” plant was preparing a licensed production of the Soviet engine, which received the local name AI-21W (W – “Walter”). In the beginning it was decided to produce only a small number of these engines. Several units from this lot were tested on stand in Prague and on the Il-28 flying lab at LVÚ. Due to the fact that the AI-25 initially could not produce sufficient thrust, Czech engineers started its modernization. Soon a decision was made, that all mass-produced airplanes would have the improved AI-25TL engine with 1720 kgF of thrust, delivered by the Zaporozhye Engine Plant (today the joint-stock company “Motor Sich”). The VS-1 ejection seat, developed at LVÚ by Jiří Matějček, was planned to be installed on the airplane. Apart from the ejection mechanism, the seat had to be equipped with a rocket booster, allowing ejection from the airplane on the ground. In 1967, designers manufactured several seat prototypes and started ground testing. The next year they manufactured several prototypes of VS-1B ejection seats. They had no rocket boosters, because development of this unit was delayed. At the same time, those seats were tested on the MiG-15UTI flying lab. Around 50 ejections were performed. They showed that pilots could safely leave the airplane from heights no less than 300 m, and it could be used on the first L-39С prototypes. Besides that, various L-39С systems were tested as well. For testing it was decided to build seven L-39С prototypes at once. Five of them (Х-02, Х-03, Х-05, Х- 06, Х-07) were intended for flight testing, while X-01 and X-04 were used for static and fatigue testing respectively. Aero Vodochody was the main factory. Here, the nose and fuselage midsections were produced and the final assembly was done. The “Let” plant in Kunovice produced the wings, and Prague “Rudý Letov” was responsible for the tail part and empennage. [L-39 ALBATROS] DCS EAGLE DYNAMICS 11 Figure 3: X-02 prototype In the spring of 1968, the airframe for the X-02 prototype was ready. By mid-autumn, all necessary equipment and systems were mounted on the X-02. Due to a delay in the AI-25TL engine delivery, the AI-25W was installed. On October 25th, 1968, the airplane was rolled out for the first time. Ground testing started at the factory airfield, where special attention was given to engine operation, landing gear, control system and wing mechanization. The tests were performed by Aero Vodochody chief pilot Rudolf Duchoň. On October 28th, 1968, the airplane on three occasions accelerated up to 175 km/h with nose gear lifting. The pilot noted good airplane behavior, brake efficiency and a surprisingly good view from the cockpit. After fixing several small issues, the L-39С was prepared for its first flight. The airplane had the civil registration OK-32 (later changed to OK-180) on the fuselage. On November 4th, 1968, Duchoň took off for the first time. The takeoff was performed without flaps. Flaps efficiency was evaluated at a height of 1000 m; the pilot estimated that with flaps extended, the airplane remained in the air at a speed of just 160 km/h. During the first flight, air brake functionality, landing gear extraction/retraction operation and engine behavior in various modes were tested. The airplane landed with flaps in takeoff position. The duration of the flight was 35 min. DCS [L-39 ALBATROS] 12 HISTORY Figure 4: X-02 prototype landing after the first test flight Literally 10 minutes after landing, Duchoň had to take off again. High level authorities arrived on the factory’s airfield and it was decided to arrange an air show with solo and group aerobatics for them. At first, accompanied by a single-seat L-29A, the X-02 flew at low altitude with extended air brakes and switched on landing lights. Later, high speed passes followed, which were finished by a spectacular climb and combat turn. The guests were quite impressed by this improvised air show. After these flights, X-02 was returned to the workshop, where a small operational development of the control system was completed. On December 2nd, 1968, the airplane was shown to the customer representatives. Figure 5: After the first official X-02 prototype test flight. From left to right: Jan Vlček, Rudolf Duchoň, Karel Dlouhý. [L-39 ALBATROS] DCS EAGLE DYNAMICS 13 In general, the testing followed a planned program. High angle of attack (AoA) flights, complex aerobatic maneuvers and several experimental flights to test the efficiency of the anti-spin parachute were performed. It turned out that such parachutes had a very low efficiency. Takeoffs and landings on the unpaved LVÚ runway in Letňany were conducted. During one of the days, the good handling of the L- 39С was proven, when the aircraft landed with crosswind gusts from 10 to 14 m/s. From time to time, the flights were interrupted for further operational development. For example, the cockpit air conditioning system started operating, and, by the spring of 1969, new wing root fairings were installed. By that time, engine operation became a growing concern. During one of those flights, several short engine surges happened and on March 19th, 1969, during a dive after exiting a spin, the engine spontaneously went out. Duchoň, using all his skills, managed to successfully land the airplane. The turbine blades were damaged. Despite this incident, the chief pilot wrote in his report that the overall impression of the plane was very good. First of all, he noted easy landing, great airplane handling and mentioned that, when operation development was finished, flight performance would be outstanding. Figure 6: Preparation of prototype X-03 for the test flight On May 4th, 1969, Duchoň took off in the X-03 prototype, which was equipped with the AI-25W engine. This airplane differed from previous ones in several aspects: The airplane had a different size of the wing root fairings, additional “windows” on the side of the air intakes and adjustable rudder trimmer. X- DCS [L-39 ALBATROS] 14 HISTORY 03 was then handed over to LVÚ to continue the test program. Another incident happened: During one of the flights, the rear cockpit canopy was torn off and barely missed the empennage. The same X-03 prototype was used for experimental flights in icing conditions and to verify operation of the VS-1BRI ejection seat. Figure 7: VS-1BRI ejection seat testing On September 23rd, 1969, the X-05 prototype, piloted by Duchoň, took off. The airplane was equipped with the same engine as its predecessors, but had different shaped intakes and wing root fairings as well as two hardpoints. During the first eight flights, special attention was paid to engine operation. Later, in October, the airplane was tested at minimum speeds and the engineers faced another engine surge. Figure 8: X-05 prototype [L-39 ALBATROS] DCS EAGLE DYNAMICS 15 In April 1970, X-05 was used to test airplane behavior during aerobatic figures. In one of the flights over-G occurred, resulting in deformation of the upper wing skin. The wing was sent to the manufacturer for repairs, and the old engine, which operated for 50 hours, was replaced with a new one. In July 1970, flights started again. The engine was changed once again at the end of August. At the end of October, beginning of November, 16 spin test flights were conducted. Having performed 78 spin turns in total, the pilots came to the conclusion, that the airplane exited spins easily and without any delays. During this program, the engine was changed twice, because of severe problems. By the end of 1970, X-05 had performed 159 flights. On April 28th, 1970, X-06 took to the air. The airplane had new air intakes and the auxiliary power unit (APU) “Saphir-5” (also “Safír-5” or “Sapphire-5”), produced by PBS Velká Bíteš under license from the French company “Turbomeca”. On July 1st, 1970, while performing a landing approach, the left landing gear did not extend as expected. Vlastimil David tried to retract and extend the landing gear leg several times, but ultimately did not succeed and had to perform an emergency belly landing. The investigation following the incident revealed a factory defect as the reason. Figure 9: X-06 prototype after emergency belly landing On December 15th, 1970, the X-07 prototype took off. “The seventh” was initially built to incorporate the AI-25TL engine, but the AI-25W was installed at first. On this airplane the shape of the root wing fairing was changed once again and fairings between wingtips and wing fuel tanks were installed. Some solutions used on other prototypes were not used on X-07, for example an adjustable stabilizer. In July 1971 the control system was modified. To reduce the effort needed to deflect the elevator to more than 28°, a special spring mechanism was installed and to reduce efforts on the pedals, the rudder servo compensator was lengthened by a quarter. This improved airplane handling during takeoff. At the end of summer – beginning of autumn 1971, X-05 and X-07 passed military tests, having a combined number of 115 flights together. The engineering staff worked 560 man-days during that time, which was equal to 39 man-hours per flight hour. Indeed, some say “Success in flight is forged on the ground!”. DCS [L-39 ALBATROS] 16 HISTORY During these tests, it was mentioned that due to increased weight of “the seventh”, some characteristics, compared to other prototypes, somewhat deteriorated, but in general remained on acceptable level. In the end of 1971, the long-awaited AI-25TL arrived from Zaporozhye. X-02 was the first prototype to receive this engine in the beginning of 1972. The airframe was strengthened and some other improvements were made. By the end of March 1972, the AI-25TL was installed on X-07 as well. Due to increased weight of the engine, the center of gravity of the machine was shifted. This led to changes in the layout of electrical equipment, in particular batteries were moved to the aircraft’s nose. After a short testing by factory pilots, the prototypes were transferred to military testing, which was completed in the beginning of 1973. Experimental flights showed that the thrust increase led to a significant improvement in flight performance. The new engine had better gas-dynamic stability as well. However, flight duration decreased slightly, but still remained at an acceptable level. On one full tank, the L-39 could perform fourteen 7-minute or eleven 9-minute flight circles or two 40-minute flights to the aerobatic area. Military pilots tested the X-07 on stall behavior. Their results differed very little from those obtained on the X-05 prototype. Before the stall warning, a shaking of the airplane with the stick jerking occurred, followed by a nose fall and a smooth slow roll. Figure 10: X-07 prototype Besides that, during 1972, the X-02 and X-07 were used for special testing. In particular, in the beginning of autumn, new air conditioning turbo-cooler operation was tested on “the second”. An extensive program for testing the electronic equipment was conducted on “the seventh”. In the beginning of 1973, X-07 was prepared to be sent to the USSR for a government test program at GK NII VVS (Soviet Air Forces Flight Research Institute). By that time, the airplane completely corresponded to the production modification L-39C (Cvičná - trainer). It was repainted, got red stars, the plane number № 07 and additional test equipment. Government testing started in May 1973. The Soviet pilots formed a favorable opinion about the airplane. They noted that the L-39С met all requirements for a training aircraft. Among the positive qualities of the airplane, special attention was paid to: the similarities with cockpits of combat aircraft for both the trainee and the trainer, a great view from both places, a robust emergency system, the possibility to start the aircraft without ground-based [L-39 ALBATROS] DCS EAGLE DYNAMICS 17 services, as well as basic combat training and MiG-21 landing approach simulation (with retracted flaps). There were also several disadvantages mentioned, including the lower-than-defined operational range, higher landing speeds and longer landing roll out. Soviet and Czech pilots had significantly different opinions regarding spin behavior. Spin tests, performed according to GK NII VVS test procedure, showed that spins in the L-39C had “unstable and uneven” characteristics and that the airplane usually exited the spin after its 3rd rotation. Despite the shortcomings found in the L-39С, it was recommended to put the airplane in service of the USSR Air Force and issue it to flight schools. After receiving the comments from the customer, the developer started to address them. Special attention was paid to the L-39C’s spin behavior. During 1974, work was performed on the X-02 and X- 07 prototypes. Several different design solutions were worked out, including special ridges on the nose sides for “the second”. Though tests showed that this measure improved airplane behavior, it was decided to not use this solution. In the end, angle of attack restrictions were introduced and more sophisticated spin exit methods were worked out. It was planned to start manufacturing the L-39С in 1971, but the implementation of this program faced several serious difficulties. First of all, the prototypes were still under testing and the final production configuration was not defined yet. In addition, initial delivery dates for the AI-25TL lagged behind schedule. As a result, it was decided in 1971 to build an initial production lot, consisting of 10 L-39Cs, equipped with the AI-25W, which had to be received by MND. On December 7th, 1971, the first airplane from this lot took off and on March 28th, 1972, five airplanes were transferred to the flight school in Košice. Figure 11: L-39V (Vlečná - tug) – single-seat KT-04 target tug DCS [L-39 ALBATROS] 18 HISTORY As planned, after the end of the AI-25W engine’s service life, the L-39Cs from the first lots were equipped with the AI-25TL. This was done in 1974. In the same year, L-39С went into mass production, which continued until 1999. In total, there were more than 2,950 airplanes built, without taking into account the first seven prototypes. The L-39С trainer became the most mass-produced modification, in the amount of 2,280 units. The USSR Air Forces received 2,080 airplanes (the latest one was received on January 25th, 1991). In 1970, prototyping of the X-08 L-39V (Vlečná - tug) – single-seat KT-04 target tug started. This airplane was requested by MND. In July 1972, the X-08 prototype was built. In the rear cockpit a towing winch was installed, which had up to 1700 meters of 5-mm steel cable wound. It was driven by an L-03 ram air turbine, located under the fuselage. This modification of the airplane had no air brakes. The KT- 04 target itself was created by the “Rudý Letov” factory under the guidance of Jan Franc. It was an all- metal airplane, weighing 110 kg, with a length of 4,9 m, a wingspan of 5,3 m and was intended for cannon fire practice by both pilots and ground based anti-air artillery crews. Before takeoff, the KT-04, installed on a trolley, was attached to the winch cable with a special grip. During takeoff, the distance between the tug and the target was 100 m. After reaching 230 km/h at a height of 5 m, the trolley separated from the KT-04. Operating heights of the target were between 500 – 2500 m. The standard towing speed was 500 km/h, the maximum speed was 600 km/h. The distance between the airplane and the target during shooting was about 1500 m. After the shooting exercise, the KT-04 separated itself from the cable, descended by parachute and landed on inflatable shock absorbers. After replacing the damaged parts, the target was again ready to use. X-08 factory tests started in October 1972 and comprised of 45 flights, including 30 flights with the target. Later, “the eighth” was used to study behavior of the airplane at lower speeds and to test the anti-icing system, equipped with the RIO-3 icing radioisotope probe. From July to September 1973, military testing of X-08 and KT-04 was conducted. By that time, the towing winch was equipped with a hydraulic cable cutter. A small lot of eight L-39Vs was produced in 1976. All of them were put in service with the Czech Air Force, but later two of them were transferred to the "Air Forces of the National People's Army", the air force of the German Democratic Republic. Several experimental airplanes were created on basis of the original L-39С. Czechoslovakia’s Air Forces used one of them during testing as recon airplane. The plane flew with locally developed recon containers on hardpoints, equipped with 4 AFA-39 cameras. This work did not receive further development. The airframe of another L-39С was subjected to strength tests, the results of which allowed increasing the estimated service life from 3000 to 4500 hours. In the Soviet Union one L-39С was used in LII (Flight research institute) of M.M. Gromov in 1981-85 as a flying lab for end airfoils testing. Results of this work were used during Il-96 and Tu-204 development. [L-39 ALBATROS] DCS EAGLE DYNAMICS 19 L-39 Further Development and Modernization L-39ZO X-09 In 1973, by order of the Libyan Air Force, development of the combat trainer L-39ZO (Zahraniční Obchod – armed, export variant) had begun. Figure 12: Libyan Air Force L-39ZO It was planned to use this airplane both for pilot training and as a light attack airplane. The aircraft had 4 hardpoints, which could carry a range of weapon systems. Each inner hardpoint was intended for 500 kg payloads, each external hardpoint for 250 kg, but in total the airplane could not lift more than 1100 kg. The new L-39ZO received strengthened wings and landing gear. The X-09 test flight started on June 25th, 1975, by Juraj Šouc. First of all, attention was paid to the airplane’s behavior when shooting rockets, the impact of rockets’ exhausted gases on engine operation and to the landing gear when working under excessive loads. In general, test flights gave very good results, though due to increased takeoff weight of L-39ZO, flight performances slightly deteriorated. The most serious problems during the X-09 test flight appeared after release of the 150-liter and 350-liter drop tanks. It was found, that after separation they began rotating about the transverse axis due to the incoming air flow. The speed and direction of rotation depended on aerodynamic forces and moments. There were several very unpleasant situations, when the drop tanks stayed “glued” to the wings, refusing to fall, and once even remained hanging on the pylon until the landing and fell off only during taxiing. The problem was solved by equipping the drop tanks with small horizontal surfaces, which created a dive moment. The test flights finished in June 1976. In total, 347 planes of this modification were built. DCS [L-39 ALBATROS] 20 HISTORY L-39ZА X-11 In 1974, MND ordered one more L-39 combat training modification, with the name “L-39ZA” (the meaning of this abbreviation is not mentioned in public sources). In contrast to its predecessor, this airplane was equipped with a 23 mm twin-barrel GSh-2-23 cannon, which was installed in the nose part of the fuselage under the cockpit and covered by fairings. Because of this, it was necessary to modify the fuselage, move several antennas, cover nose gear doors with stainless steel to protect them from hot propellant gases and once again equip gear with broader pneumatics. Figure 13: X-11 L-39ZA at Paris Air Show (Salon international de l'aéronautique et de l'espace, Paris-Le Bourget), June 1977. On May 16th, 1977, test pilot Juraj Šouc took the X-11 to the air. In the same year, this aircraft was painted in white-gray camouflage with civilian registration ОК-НХА and was sent to the Paris Air Show in Le-Bourget. It was shown without the cannon, with two 350-liter drop tanks on the inner pylons or with one drop tank and a PFK-5 reconnaissance container. The airplane was presented both on the ground and in the air, performing complex aerobatics. The X-11 passed military tests in Košice flight school. L-39ZA mass production started in 1980. [L-39 ALBATROS] DCS EAGLE DYNAMICS 21 Figure 14: Czech Air Force L-39ZA The company Aero Vodochody achieved a very modest success in sales of new L-39С modifications. Mainly this can be explained by a huge number of L-39s, which are still in service and have great modernization potential. Moreover, many owners are satisfied with increased airframe service life after traditional maintenance with minimum financial costs. As a result, several programs were introduced in many countries, which could extend the L-39С life cycle by many years. In the aircraft’s home country, the MND and Aero Vodochody in June 1999 signed an agreement on a major overhaul and modernization of eight L-39s from the latest lots for the Czech Air Force. Following this agreement, the nose and tail parts of the airframe, the wings and some other parts of the equipment and systems were replaced. The airframe’s service life was extended to 4500 hours. Similar work was conducted by Aero Vodochody on eight Hungarian airplanes, which were transferred to the customer on August 25th, 2005. Slovakian L-39s were modernized by the airplane repair plant in Trenčín. In 1996-97, the first stage of service life extension was performed on six L-39s from the 1st and 4th lots, produced during 1973 – 1975. The airplanes got new noses from unfinished machines. In 1999-2000, similar procedures were conducted on two L-39Vs. In the same year, all L-39s came to Trenčín for the second stage of modernization. This time, tails and wings were replaced. After that, the airplanes got new avionics and various other airplane equipment. Among them were TACAN AN/ARN-153(V) radio navigation system, Pro Line II ADF-462 radio compass and GPS receiver – all manufactured by Rockwell Collins. The upgraded airplanes were named L-39CM. The head airplane (marked 0111) flew on August 26th, 2003, piloted by J. Kello and R. Rosenberg. Russia developed a proprietary multi-stage program for modernization of the L-39С. It was planned to strengthen the airframe and extend its service life to 10.000 hours and to install four hardpoints, which would increase combat load from 250 to 900 kg. The plane had to be equipped with a K-93 ejection seat, new radio communication equipment and avionics, including the NK-39 navigation system, SVR- 39 video recording system and SOI-39 display. Spare parts had to be manufactured in Russian DCS [L-39 ALBATROS] 22 HISTORY factories. The new airplane got the name “L-39MT”, but this project was to remain on paper, because the Russian Air Force developed a program to replace the L-39С with the new Yak-130. L-39C Flying School Desk L-39 geography is very broad. It was mainly used for its intended purpose. Usually, Soviet and Czech pilots were in the instructor role. For example, 10 specialists from Czechoslovakia (pilots and engineers) worked in Libya from April 1978 to June 1981. The intensity of their work can be judged based on the total amount of flight hours of pilot-instructor Štefan Župko. During this time, he performed 1302 flights with a total duration of 511 h 25 min. The L-39, which operated in the harsh conditions of North Africa (high temperatures, sandstorms, etc.) showed unpretentiousness and survivability. Only one serious accident occurred during the mentioned period. On July 5th, 1979, an airplane with a Czech instructor and a Libyan cadet did not return from a training flight. The airplane was found the next day in a water- filled ground hole on the sea shore. According to witnesses, the airplane suddenly entered into a dive, from which it did not exit. Reasons for the accident and the question, why no one from the crew attempted to eject, were to remain unclear. Figure 15: L-39C in the Russian Air Force Soviet instructors participated in cadet training in Afghanistan. The first 12 L-39Cs appeared in Afghanistan on October 2nd, 1977. From September 23rd to October 2nd 1977, Czech pilots flew the route with a total length of 5042 km from Vodochody to Mazar-i-Sharif through Košice, Lviv (Sknilov), Kiev (Juliani), Donetsk, Krasnodar, Makhachkala, Krasnovodsk, Ashkhabad, Chardjou and Tashkent. Technical experts accompanied the team on an An-24. The flight went flawless, without a single incident [L-39 ALBATROS] DCS EAGLE DYNAMICS 23 and took 12 hours and 15 minutes of flight time. According to available information, it was the most distant L-39С group flight. The flight-technical school in Mazar-i-Sharif was created in 1957, but by the time of the L-39Cs arrival, only 22 cadet pilots studied there. They had to learn how to fly in the 393rd UAP (Aviation Training Regiment). One year later, the revolution government of Afghanistan transformed the school into the Air Force and Air Defense College. The lack of local trainers was compensated by a large number of Soviet specialists. Major V.A. Pehotin became the advisor of the 393rd UAP commander. It must be said that the training program for the Afghan pilots was significantly different from the one existing at that time in the Soviet Union. After three years of study, young pilots were graduated on the L-39С. Later, they were retrained on the MiG-17, which was considered as a transitional machine before the MiG-21. For that purpose, pilots were sent to the Soviet Union. Soviet officers proposed to learn the MiG-21 immediately after the L-39С, according to the methodology accepted in the Soviet Union. Afghans did not agree. Former military advisor to the deputy chief of the school, V.I. Ablazov, wrote that the DRA Air Force commander Mir Gausuddin, looking at a passing caravan of nomads, remembered this proposal and said: “Your children are being born listening to TV noise, unable to speak, they already know how to turn on the lights and tape recorder, twitch a car wheel. When they grow up, they do not have problems to release one control knob and take hold of another. Our children break away from the donkey or camel tail, from the mother hem and you want to put them right into the modern airplane cockpit? Take your time and do not rush”. It was hard not to agree with these arguments. Figure 16: L-39C in formation In the Soviet Union, the L-39С became one of the most popular military training airplanes. The machine quickly took root, “russified”. The Latin “L” in its type designation was immediately replaced by the DCS [L-39 ALBATROS] 24 HISTORY Cyrillic “Л”. The letter “С”, indicating the training intention, disappeared completely, because in the USSR only the training modification was used. Pilots used the proper name “Albatros” less often than its slang nickname “Elka”. The airplane arrived at the majority of flight schools: in Chernigov, Kachin and Kharkov, which specialized in preparing pilots for frontline fighter airplanes; in Armavir (air defense fighters); in Yeiskoe and Borisoglebsk (fighter-bombers); in Barnaul (frontline bombers); in Tambov (long-range aviation), in Krasnodar (prepared pilots for the Asian and African countries). The number of planes in training regiments was significantly higher than in combat ones. Some of them had over a hundred L-39Cs. L-39Cs were also in service at several combat training and pilot re-training centers and in the special training, flight testing regiment of the Cosmonaut Training Center of the USSR (airfield Chkalovskaya) and in GK NII VVS units. They were also used in several Su-25 regiments, where L-39Cs served as "twin-seaters", before the arrival of the Su-25UB trainers. In this role, several Soviet L-39Cs were used during the war in Afghanistan. Small numbers of L-39Cs were transferred to flying clubs and DOSAAF training centers. Also Flight Research Institute MAP (situated near Moscow Zhukovsky) had some L-39Cs. Their L-39Cs were used as flying laboratories, escort airplanes (for example during VKS Buran-analog flights) and in the test pilot school. In the Soviet Union, a pioneering role in L-39C adoption was given to the 105th UAP of Chernigov Higher Military Aviation School (ChVVAUL), headed by Colonel D.I. Boryakov and located on Konops’ airfield. On October 20th, 1973, a group consisting of 8 officers, headed by the regimental deputy commander, Major S.N. Shamsutdinov, left for Czechoslovakia to study the new machines. Czech pilots flew the airplanes to Ivano-Frankovsk and from there these machines flew to the 105th UAP base under regiment pilots’ control. The first L-39 was met in Konotop on April 29th, 1974. Among the first flight instructors, which were retrained on the L-39C, were P.A. Leontiev, N.S. Saponchik, A.P. Holupov, I.P. Fedorenko, and A.T. Filichkin. Among the first engineers were: V.I. Basco, V.P. Gardens, N.K. Panyuta, and A.I. Yakovina. Retraining was completed by the end of the year without accidents. The airplane surpassed its predecessor L-29 in all respects and quickly won sympathies of the flight and ground personnel. The new “Elka” offered an excellent view from the cockpit, comfortable seats, an excellent air conditioning system, nice liveries and comfortable ergonomics. [L-39 ALBATROS] DCS EAGLE DYNAMICS 25 L-39 In Local Conflicts The war in Afghanistan brought changes in the life of the 393rd UAP. Occasionally, L-39Cs, piloted by Afghan and Soviet trainers, were involved in combat missions. For example, from August 24th to 30th, 1979, they flew 11 combat missions to attack ground targets using rockets and bombs. Quite often, training flights were combined with Mazar-i-Sharif neighborhood reconnaissance. The first graduation of the pilots flying L-39Cs was held in August 1979. 15 pilots were graduated. The average flight time of every pilot was about 77 hours (22 hours without trainer) with 308 landings. Figure 17: Afghan Air Force L-39С Ethiopia had two L-39C wings, including the 16th training squadron, which was regularly involved in combat missions. At first they fought in Eritrea and after that took part in the civil war in Ethiopia. When in May 1991 rebels, fighting against the Mengistu Haile Mariam regime, approached Addis Ababa, L- 39C pilots defended the capital until it was defeated. After that, about 50 airplanes and helicopters flew into neighboring Djibouti. Among them was one L-39C. In 1993, Eritrea became an independent state and Ethiopia’s new authorities helped its former allies in the fight against the dictator regime, by training their pilots on the L-39C. But soon, in 1998, war between neighbors over territorial disputes began. L- 39Cs were not observed in these battles. However, during training flights, L-39s regularly were under own air defense fire, because ground observers confused them with Italian MB-339s, which were in use by Eritrea’s Air Force. One such incident occured on the 13th of November 1998 near Mekele airfield: An L-39C with Ethiopia’s captain Endegena Tadesse and a Russian trainer, whose name was not mentioned in the press release, was shot down. DCS [L-39 ALBATROS] 26 HISTORY Modern Time The L-39 remains in service in more than 30 countries across the world, including the Russian Air Force. In Krasnodar’s Military Aviation School, it is used as the primary jet trainer for basic flight training. Currently, the L-39C is being gradually replaced by the Yak-130. Figure 18: L-39C in the Russian Air Force A new phenomenon in the airplane’s history was the private ownership of L-39Сs. In the Czech Republic the first private L-39 took off on August 13th, 2004. The airplane was bought in Ukraine and was previously operated by Chernigov flight school. Hardpoints and various military systems were removed and equipment necessary to meet international airways requirements was installed. The airplane was painted black and received the civilian registration OK-JET on the fuselage. [L-39 ALBATROS] DCS EAGLE DYNAMICS 27 Figure 19: Private Czech L-39 DCS [L-39 ALBATROS] 28 HISTORY Aerobatic Teams Flying L-39C “Russ” is an aerobatic team, created at Viazemsky DOSAAF aviation training center (ДОСААФ) in 1987. The aerobatic team flies L-39С jet trainers. Figure 20: Russian aerobatic team “Russ” [L-39 ALBATROS] DCS EAGLE DYNAMICS 29 “Belaya Rus” is an aerobatic team of the Air Force and Air Defense Forces of the Republic of Belarus that is performing aerobatics with the combat training aircraft L-39С "Albatros". Figure 21: Belorussian aerobatic team “Belaya Rus” “Baltic Bees” is an aerobatic team from Latvia, based in Tucums city. Baltic Bees pilots fly L-39С jet trainers. DCS [L-39 ALBATROS] 30 HISTORY Figure 22: Latvian aerobatic team “Baltic Bees” “Patriots Jet team” is a private aerobatic team sponsored by Fry's Electronics. The team was organized by former United Airlines pilot Randy Howell. Figure 23: Patriots Jet Team “Breitling” is a private aerobatic team sponsored by the company Breitling, famous for its watches with the same name. [L-39 ALBATROS] DCS EAGLE DYNAMICS 31 Figure 24: Breitling Aerobatic Team The Breitling team is the largest civilian aerobatic team in Europe. The team is based on the military base in Dijon, France, and flies seven L-39С jet trainers. “Black Diamond Jet Team” is a private aerobatic team with five L-39С and one T-33, all planes are painted in distinctive arctic camouflage. They are piloted by former military fighter pilots from the US Navy and Air Force. DCS [L-39 ALBATROS] 32 HISTORY Figure 25: Black Diamond Jet Team [L-39 ALBATROS] DCS EAGLE DYNAMICS 33 Modifications L-39C is a standard modification of the jet trainer for basic and primary flight training. Usually, for standard modifications, the letter “C” in the name is omitted. Figure 26: L-39C L-39ZO is a modification of the airplane, which can be used as light attack airplane. For this purpose, it has 4 hardpoints. Figure 27: L-39ZO DCS [L-39 ALBATROS] 34 HISTORY L-39ZA is a further L-39ZO evolution with 23 mm twin-barrel automatic cannon installed. Figure 28: L-39ZA L-39V is a single-seat target tug version. Figure 29: L-39V L-39D is a modification with installed BUR “Test-1” instead of SARPP-12. Additionally, BUR “Test-1” performs audio information recording for 5 hours and is equipped with operational storage. [L-39 ALBATROS] DCS EAGLE DYNAMICS 35 L-39MS (L-59 Super Albatros) is a modification with the new modular DV-2 jet engine with 2200 kgF of thrust, “0-0” type ejection seats and new electronic equipment. It made its first flight in 1986. 80 airplanes were produced. Figure 30: L-39MS The L-39M1 is a Ukrainian L-39 modernization. The AI-25TL engine is replaced with the improved AI- 25TLSH (thrust increased from 1720 to 1850 kgF and engine response time reduced from 8-12 seconds to 5-6 seconds). It has an improved engine control system. Also a new onboard emergency and operational flight information recorder with additional sensors and devices was installed. Figure 31: L-39M1 DCS [L-39 ALBATROS] 36 HISTORY The Aero L-159 “ALCA” is a Czech jet trainer (light attack plane). The airplane is based on the L-59 and is a further evolution of the L-39 “Albatros”. Figure 32: L-159 ALCA The L-39 is in service in more than 30 countries. Many years of service proved that a very successful airplane was created. Thousands of pilots love the L-39, because, thanks to this airplane, they mastered basic flying skills and became pilots. It is rightly called “school desk”. The airplane has modernization potential. L-39 systems and engine are being constantly improved and this allows this airplane to stay in service in many countries for a long time. The history of the L-39 continues! [L-39 ALBATROS] DCS EAGLE DYNAMICS 37 AIRCRAFT OVERVIEW DCS [L-39 ALBATROS] 38 AIRCRAFT OVERVIEW AIRCRAFT OVERVIEW General Description of the L-39С The tandem seat combat trainer L-39С with the AI-25TL turbofan engine is designed for mastering pilot skills, air navigation in simple and adverse meteorological conditions during day and night, combat employment training, aiming and missile firing simulation at visually observed aerial targets, photo shooting at aerial targets, dive bombing (photo bombing) with 50-100 kg bombs, and the firing of S-5 rockets (photo shooting) at ground targets. In the L-39С module, firing the R-3S heat seeker missile at aerial targets under clear visual conditions is implemented. Dimensions of the L-39C: • Length: 12.13 m • Wingspan: 9.12 m • Height: 4.47 m • Main wheel track: 2.44 m [L-39 ALBATROS] DCS EAGLE DYNAMICS 39 Figure 33: L-39 drawings DCS [L-39 ALBATROS] 40 AIRCRAFT OVERVIEW Design The L-39С is a conventional low wing cantilever airplane with trapezoidal wings. The empennage consists of a trapezoidal vertical stabilizer with rudder and horizontal stabilizers with elevators. The airplane has a three-wheel landing gear configuration including nose gear. The main gear struts are retracted into the wings and the nose gear into the fuselage. The AI-25TL turbofan engine, developed under supervision of V.A Lotarev at the experimental design bureau, produces a maximum thrust of 1720 kgF and is mounted in the middle section of the fuselage. The fuel for the engine is located in seven tanks: five fuselage fuel tanks, located behind the rear cockpit, and two permanent wingtip tanks. There are two pressurized cockpits in the nose part of the fuselage. The cockpits are equipped with an environmental control system, which provides air conditioning and comfortable conditions at higher altitudes. It also allows the pilots to withstand allowed operational G-forces if special equipment is used. The VS1-BRI ejection seats, installed in both cockpits, allow the pilots to leave the airplane in case of an emergency. The canopy is sealed; its moving parts can be jettisoned by pyrotechnical systems in an emergency situation. The wing is attached to the bottom of the fuselage. Ailerons and extendable double-slotted flaps are installed on the wing. Various airplane equipment and avionics provide the possibility to fly during day and night in simple and adverse weather conditions. The airplane can carry missiles, rockets and bombs and is equipped with aiming and photo control equipment.