Development of Russian ejection systems was initiated largely by the findings of a German report which concluded that 40 percent of emergency escapes, during the late 30s and early 40s, resulted in fatalities. This led to concern by the acceptance authority for the MiG-9, which identified lack of equipment for a forced evacuation of the aircraft in case of emergency, as a serious fault.

Following ground rig testing, the first airborne live ejection in the USSR was carried out by GA Kondraschow, from a modified Petlaykov Pe-2, on June 24, 1947. This seat, designed by the Mikoyan OKB, was subsequently fitted to MiG-9s and on January 16, 1948, a live ejection was carried out from the front seat of a M1G-9UTI at 412kts (764km/h). The seat was cleared for operation at speeds of up to 378kts (700km/h) and heights above 820ft (250m) and installed in MiG-15s, MiG-17s and the 1-320.

Developments continued, including armour protection, face blind initiation, leg restraint and aerodynamic seat stabilisation. All were incorporated into a seat designed for use in high speed and research aircraft, such as the later series MiG-17, MiG-19, Yak-25 and Yak-27. Although the maximum speed was increased to 486kts (900km/h), the minimum height remained the same.

In 1962, the Mikoyan OKB designed a novel system, which protected the pilot against wind blast by coupling a portion of the cockpit canopy to the seat. This was installed in the MiG-21 (F-13, P and PF) and had an operating envelope of 594kts (l,100km/h) at heights above 360ft (110m).

At the beginning of the 80s, efforts were made to standardise all types of technology in Russia. As a result the OKBs stopped their own ejection seat development work and Soviet combat aircraft adopted the K-36 seat, developed by the Zvezda bureau. The first Soviet zero-zero seat, it weighs 205kg (4501b) and is cleared to a maximum height of 82,000ft (25,000m) and speeds of Mach 2.5 and 700kts (l,296km/h). Unintentional demonstrations at both Le Bourget and Fairford have adequately demonstrated the efficiency of the seat.

Zvezda also produces the K-37, which is fitted to the Kamov Ka-50 Hokum attack helicopter. Upon initiation, explosive charges at the hub of the rotor shed the rotor blades, a rocket pack then ignites and the seat and pilot are pulled out of the cockpit by a cable attached to the rocket.


Another View


 

In total, more than 12,000 K-36 ejection seats have been produced to date and no less than 97% of the airmen who have used them in an emergency have been able to continue their flying careers-the highest percentage in the aviation world.

During the second half of the 1995, NPP Zvezda created a new generation of ejection seats based on the K-36. These were developed to meet the increasingly expanding flight envelopes; speed, height and g.

Satisfying these requirements necessitated comprehensive research in the fields of human physiology, ballistics and the aerodynamics of high-drag bodies. It sometimes also required unorthodox solutions in the field of both design and manufacturing technologies, something which called for the establishment of unique experimental facilities and development of design and testing methods.

The Russian economy has changed radically in the last decade. One of the effects of this has been to encourage NPP Zvezda and its partner companies to strengthen their position on the already crowded world market for crew escape systems. This is first and foremost in the interests of the new Russian Air Force.

According to reliable sources, the US Department of Defence intended to install Russian ejection seats in a next-generation American fighter Joint Strike Fighter) then under development. Thus, in 1993-95, NPP Zvezda held a number of joint demonstration tests with the K-36D ejection seat and associated KKO-15 oxygen equipment in the United States. The programme even included comparative tests of the Russian and US ejection seats.

Seventeen test firings of the K-36D were made at Russian and American research facilities, at speeds ranging from zero to 73okts (i,35okm/h) and Mach 2.5 and altitudes of 0 to 55,77oft (o to i7,ooom), as well as at high angles-of-attack (AoA) and sideslip. They were all successful; the performance figures for the Russian seats were fully confirmed and the experts were convinced that there would be advantages in using them. The Russian company's integrated approach to the development of crew escape systems, where system components possessing equal strength (the seat, protective helmet, oxygen mask etc) are created in the course of development and testing, also earned universal praise. The successful completion of the demonstration programme and the unequalled performance of the Russian ejection seats ensured the continuation of joint work in the area.

Nevertheless, it is primarily American companies and not the DoD which displays interest in contacts with Zvezda. In 1996, NPP Zvezda pledged to its American partners that it would demonstrate the possibility of adapting the K-36D ejection seat to US requirements. In particular, the seat had to be suitable for both men and women. Structural weight had to be reduced (the K-36D is noticeably heavier than the USAF's standard ACES II ejection seat); finally, the minimum safe ejection altitude was to be equal to, or lower than, that of the ACES II seat. By then, the company had developed the K-36D-3.5 seat for the Russian Air Force. This was part of the SKS-20OO integrated life support and crew rescue system designed for next-generation Russian combat aircraft. Building on the know-how which had gone into the K-36D-3-5, NPP Zvezda promised to adapt the seat to American requirements within two years and to conduct demonstration tests at Holloman AFB, New Mexico, in the first half of 1998. The result of this effort was the K-3&D-3-5A, an 'Americanised' version of the seat. Six prototype seats built to fill an order by the Boeing Company were shipped to the US.

Design requirements

In developing the K-36D-3.5A, NPP Zvezda paid special attention to finding solutions which would allow qualitatively new performance levels to be achieved without making the design excessively complicated. This included ensuring safe ejection at extremely low altitudes, during violent manoeuvres and extreme bank angles, or inverted. Structural weight had to be cut considerably. Finally, the seat had to be cheap to produce and maintain - no small consideration, considering Russia's prolonged economic difficulties in preceding years. Much attention was paid to the seat's ergonomics with a view to its use by both male and female aircrew. Analysis of K-36 ejections showed that 80% were performed at speeds below 350kts (650km/h) and 3% at speeds in excess of 540kts (1,000km/h). Two ejections occurred at 700 to 730kts (1,300 to 1,350km/h), two more at Mach 2.6 and 55,77oft (17,000m). Importantly, many of the ejections were made during vigorous manoeuvres, particularly at large bank angles.

The above statistics, and experience with the operation of K-36 seats in various aircraft types including vertical take-off and landing (VTOL) aircraft (the Yakovlev Yak-38 Forger and Yak-141 Freestyle shipboard fighters), enabled the engineers at NPP Zvezda to formulate the basic requirements for a new-generation escape system. These include an integrated approach to the design and construction of the escape system (compatibility and equal strength of the integrated life support system components and the ejection seat), the suitability of the seats for pilots over the entire anthropometric range; including the use of a lightweight flying suit, comfort, improved visibility, and safe ejection in horizontal flight from zero to 760 kts (0 to 1,400km/h) and 0 to 65,620ft  (0 to 20,000m), as well as speeds up to Mach 2.5. Also, ejection should be possible during manoeuvres with -2/+4g at speeds not exceeding 0.8 of the aircraft's maximum speed.

The state-of-the-art technologies developed by NPP Zvezda have made it possible to create a family of ejection seats meeting the above requirements. For instance, the K-36D-3.5 and K-360-3.sA seats retain all the safety features embodied in the original K-36D. They also have an increased range of vertical travel (31/2in [85mm] for the K-36D-3-5 and 3 3/4in [95mm]for the K-36D-3.5A).

Both seats feature a two-position reclining seat back which improves the seat's ergonomic qualities (pilot comfort, upward and rearward view).

A new system of thrusters for lateral manoeuvring has been evolved for controlling the seat's lateral motion. The seat also features a multi-programme electronic command system connected to the aircraft's data exchange system. This optimizes the seat's trajectory, taking into account factors such as pitch and bank angles and rates, airspeed height and sink rate. It was the first model of K-36 to incorporate an automatic system to adjust the ejection kinematics to suit the occupant's weight, so reducing the risk of injury.

To reduce the minimum altitude required for safe ejection, NPP Zvezda has provided operation modes in which parachute deployment is accelerated and the rocket motor cuts out immediately after separation from the aircraft in the event of ejection at large bank angles.

 

Extreme attitudes

The multi-programme electronic system's computer is produced in Russia and has been specially developed by the Ramenskoye Avionics Design Bureau (RPKB) to meet NPP Zvezda specifications. When the seat is ejected at extreme bank angles, for example, the automatic control system adjusts the seat's trajectory in the transverse plane. This allows the seat to gain additional height, ensuring parachute deployment. In cases of ejection in inverted flight, the main rocket motor is not ignited and the parachute is deployed immediately after the seat's separation from the aircraft, considerably reducing the minimum safe ejection altitude.

In designing the new seat, the specialists at NPP Zvezda faced an extremely complex task. Along with the introduction of the electronic command system, they had to drastically revise the design and strength philosophy used in the previous-generation K-36D seat. After more than five years of painstaking design work, they succeeded in reducing both the seat's weight (by 55lb [25kg]) and the overall dimensions (by between 5/8in to 3/4in [15mm to 20mm).

It should be noted that safe ejection at low altitude is largely dependent upon pilot reaction time. The time for the seat system to operate (including canopy jettison or franging and (canopy deployment) is just one element of the equation. Hence the key to ensuring safe ejection at low altitude, both for VTOL aircraft and conventional aircraft, is to equip the aircraft with an automatic ejection system which fires the seat if bank or AoA exceed certain limits. Years earlier, the effectiveness of such a system on the experimental Yak-36 Freehand VTOL aircraft and the production variant of the Yak-38 shipboard attack aircraft had exceeded all expectations: 100% of the pilots who had ejected in take-off and landing accidents were saved!

Sideslip is generally regarded as one of the critical factors during ejection. At high angles of sideslip (around 20) and at fairly high speeds (380kts [70okm/h]) there is a high risk of injury through the pilot's limbs flailing. The pilot's neck may be subjected to excessive loads, and seat stabilisation is difficult to achieve. All these problems have been minimised on the K-36D-3.5 and K-36-3.5A seats, which incorporate mechanical stabilising booms rather than drogue parachutes.

Thanks to the K-36D-3-5's modular design, it can serve as a basis for at least three derivatives, which can be tailored to the requirements of the Russian Air Force, the USAF or other foreign air arms. K-36L-3.5 is designed for attack aircraft and bombers. Ejection is possible from 0 to 595kts (0 to 1,100km/h) and 0 to 65,620ft  (0 to 20,000m). Seat weight (less oxygen equipment, survival kit and harness) is 156lb (71kg);

*The K-36V-3.5 for VTOL aircraft. The operating envelope is identical to the K-36L-3.5, and the weight (less oxygen equipment, survival kit and harness) is 165lb (75kg);

* K-36LT-3-5 lightweight seat for jet trainers. Ejection is possible from 0 to 510kts (0 to 950km/h) and 0 to 49,210ft (0 to 15,000m). Seat weight is 110lb (50kg).

 

Jet trainers

The first simplified version of the K-36LT-3-5 seat, designated K-93 by the manufacturer, has passed the manufacturer's and State acceptance (certification) trials programme. It is already fitted to two prototypes of the MiG-AT advanced trainer and will be standard equipment on the Russian variant of its Yakovlev/Aermacchi competitor, the Yak/AEM-130. The MiG-AT's system enables the crew to eject safely from inverted flight at altitudes above 164ft (50m). The ejection sequence takes no more than 0.9 seconds, the front seat occupant (student) is ejected first, followed by the instructor.

The basic K-36D-3-5 seat has also been tested successfully and will be fitted to the thrust-vectoring Su-3oMK aircraft (including the Su-3oMKK for China and the Su-3oMKI for India), as well as to the Su-27KUB multi-role shipboard aircraft. This seat has no other counterpart in the world, and at roughly the same weight as all the foreign models, it is superior to its competitors in basic performance. Thanks to its modular design and compactness, the K-36D-3.5 can be fitted to most combat aircraft. It was designed to meet new international requirements for just about any pilot - from a petite female weighing 9/lb (44kg) to a large-framed male of 244lb (111kg). These differences are allowed for by the computer, which introduces the necessary corrections into the operation of the firing device and the rocket motor.

The new seat provides more comfortable conditions for the pilot to work in than its predecessors and the rearward and upward view has been improved by reducing the size of the headrest. To improve g-tolerance during air combat manoeuvres, the seat's bearing surfaces have been enlarged and the seat has been designed to achieve a substantial reduction in maintenance costs during its service life. An excellent example is the fact that the solid rocket propellant used in the K-36 design has a 'shelf life" of 20 to 25 years.

General aviation seat

In recent years, considerable attention has been paid in Russia to the problem of safe emergency escape from sports and training aircraft, and the Sukhoi Design Bureau has pioneered the use of ejection seats in competition acrobatic aircraft. In June 1991, the Bureau issued a specification to NPP Zvezda for the development of an ultra-light crew escape system for sports aircraft. It took four years of painstaking work to create, and was designated SKS-94 (sverkhlyohkaya katapool'tnaya sistyema -ultra-light ejection system).

This system can be fitted to single-seat and multi-seat training, aerobatic and sports aircraft and to other general aircraft. The SKS-94 includes a

telescopic ejection gun, harness tightening device, an ejection control system, seat, headrest (in which the parachute and its deployment system are stowed), and the parachute itself with its harness. When ejection is initiated, the parachute actuating device ejects the headrest from which the parachute emerges, and the pilot is extracted from the cockpit by the ejection gun by means of a suspension system (the seat remains in the aircraft) before separating from the ejection gun and descending by parachute.

Manufacturer and certification tests of the SKS-94 system were conducted - for the first time in Russia - on a modified sports aircraft, a purpose-built Su-29KS test-bed (02 Black/RA-oi48s). Before that, a complete ground test programme was undertaken, including ejection tests with dummies -first on rigs and then in a wind tunnel. Part of the ground test was performed on a disused stretch of the old Ryazan highway. The cockpit section of a two-seat sports aircraft was mounted on a truck for simulating take-off runs: 50 firings were made in this manner, providing invaluable information on ejection at take-off.

The final stage of the manufacturer's tests was performed on the Su-29KS. Some of the trials employed a dummy and others a live parachutist, but the aircraft was invariably flown by Sukhoi test pilot Yevgeniy Frolov, Hero of Russia. Nearly 20 ejections were carried out, some during the State acceptance trials. They were performed at altitudes of 164ft to 6,s6oft (50m to 2,000m) and at speeds of 95kts to 216kts (180km/h to 400km/h). Trials were conducted with the aircraft in a variety of flight conditions including inverted flight at 64ft (50m). The minimum altitude for safe escape in inverted flight is 98ft (30m). There are no similar rescue systems for light aircraft anywhere else in the world.

The first man to demonstrate the operation of the ejection system on a ground rig was parachute tester Sergey Pereslavtsev, Hero of Russia. On April 12, 1995, parachute tester Vladimir Severin ejected in flight from the Su-2gKS and in so doing, earned the title 'Hero of Russia'.

In 1995, a prototype Su-3iM-i competition aerobatic aircraft equipped with the SKS-94 ejection system was shown at the Le Bourget air show, both statically and in flight. The Su-31M became the world's first quantity-produced sports aircraft equipped with an escape system. The first Su-31Ms have already been delivered to customers in Switzerland, Italy and Slovakia, and to the Central Aeroclub of the Russian paramilitary sports society ROSTO. (ROSTO = Rosseeyskoye oboronnoye sportivno-tekhneecheskoye obschchestvo - Russian Defence Sports and Technical Society. This is the successor of the Soviet-era DOSAAF (Dobrovol' noye obschchestvo sodeystviya armii, aviahtsiiiflotu-the Voluntary Society for the Support of the Army).

 

Helicopter seat

During the past decade, Russian designers have developed a rocket/parachute enforced escape system for combat helicopters. Designated K-37-800, the fully-automatic system is intended

for the Kamov Ka-so Black Shark attack helicopter (Hokum-A) and its two-seat version, the Ka-52 Alligator (Hokum-B). The pilot is extracted from the helicopter by means of a solid-propellant rocket motor attached to a strong, but light, cable, once the rotor blades have been jettisoned to facilitate unhindered egress. The pilot is also able to bail out of the helicopter manually.

The system consists of a seat, an on-board control module and the rocket-propelled towing device. The seat includes a life support system, a detachable seat back with a headrest, a suspension harness and operational systems which ensure safe escape from the helicopter. The seat pan houses a cushion containing the NAZ-/M survival kit (noseemy avareeny zapahs) and a dinghy, as well as the PS-3/A parachute system.

The seat pan's front wall houses the ejection control unit with actuating handles. On the right side of the seat pan (facing forward) is an override handle for disengaging the pilot's harness in the event of his deciding to abandon the helicopter manually without ejecting.

On production Ka-so helicopters now in service with Russian Army Aviation, the rocket/parachute escape system is used in combination with the ZSh-7V or ZSh-7VS special protective helmet, the KKO-VK-Ln oxygen system, and the KZO-Li 'Galoid' protective flying clothing.

So far, the K-37-8oo rescue system has not been used operationally, even though two examples of the Black Shark (including the first prototype) have been lost in crashes. On the second of these occasions, in Torzhok on July 17,1998, the upper and lower rotor blades of a production Ka-so collided during a high-g manoeuvre. The pilot, Major General Boris Vorob'yov, head of the Russian Army Aviation Combat and Conversion Training Centre, was killed. However, this was no fault of the rescue system - trying right up to the last moment to land the damaged helicopter, he did not attempt to use it.

Mention should also be made of two crashworthy seats developed for helicopters-the Pamir-K and the AK-20OO; produced by NPP Zvezda. Both models feature a cushion, a contoured seat back and a four-point harness with a quick-release central lock.

In the event of a crash landing, the shock is absorbed by a special damper consisting of a steel plunger and steel balls inside an aluminium alloy tube which de-forms at a controlled rate. In the case of the Pamir-K, the seat can reduce a 50g-impact force to between 14 and i6g. The Pamir-K seat moves on vertical guide rails, in contrast to the AK-20OO which has a levered suspension system.

In the opinion of many specialists (and not only Russians), the K-36 and other ejection seats developed by NPP Zvezda exhibit the highest performance capability in the world. The K-36 has saved the lives of hundreds of aircrew - both in peacetime and, more recently, during the second Chechen War where several aircraft have been shot down by shoulder-launched anti-aircraft missiles. Thanks to the seat's high reliability and to a fool-proof safety system eliminating the risk of injuries, the vast majority have been able to continue their professional activities. This is not only good from the standpoint of the value of human life, it is also economically beneficial because of the high cost of aircrew training.

 

 

 

(c) M J Gething 1994