ZIL-135: engineering delights of Dr. Grachev

ZIL-135. Source: drive2.ru Photo by Ivan Savitsky

Beyond constructor

In the previous parts of the cycle, we talked about search layouts of future missile carriers and the first floating prototypes. The third section should start with the personality of the chief designer of the ZIL Special Design Bureau and the inspirer of the 135 series machines, Doctor of Technical Sciences, winner of two Stalin Prizes, Vitaly Andreyevich Grachev.

ZIL-135: engineering delights of Dr. Grachev
Vitaly Grachev and Yuri Gagarin. Source: gvtm.ru

The designer of the first magnitude, who laid the foundation for the further development of off-road technology in our country, did not receive a higher education. According to legend, for his non-proletarian origin he was expelled from the Tomsk Polytechnic School. Until 1931, Vitaly Andreevich, one might say, was looking for himself, that is, he worked as a loader, a cinema radio mechanic, a designer at the Yegorov plant, an aircraft mechanic in the army, and also managed to build a glider. But the future automotive designer did not work out with aviation. In December 1931, upon mobilization of the Lensovnarkhoz, Grachev was sent to the Nizhny Novgorod Automobile Plant under construction, the future GAZ. There was such a shortage of automotive equipment in the country that during the construction of the plant, the first T-27 tankettes assembled there were used as tractors. The young engineer was immediately assigned to the development of off-road vehicles in the development group of the NAZ-NATI-30 machine. Grachev supplemented the technique of a three-axle truck with a demultiplier, rear balance suspension, jet rods, a coupling device, and the car went into series under the name GAZ-AAA.

In the design career of Vitaly Andreevich, there was also a disgrace: in 1933 he was transferred to the position of an assembly master in one of the branches of the automobile plant. This was largely a consequence of Grachev’s intransigence on the fundamental issues of car design. He was not afraid to criticize seemingly incorrect layout mistakes. As a foreman, Grachev did not stay long and by 1936 he had built a three-axle GAZ-AAAA pickup truck according to the 6×4 scheme.

The designer not only knew how to handle the drawing board well in the design bureau, but also loved to “go out into the field”. So, in his pickup, he personally went on the most difficult test run to the Karakum Desert – in total, the designer drove 12,291 kilometers in his car. After that there was an almost serial GAZ-21 of the 1936 model (not to be confused with the legendary Volga GAZ-21). About a hundred copies of such cargo-passenger “three-axles” were collected.

Leading designer V.A.Grachev and chief designer of GAZ A.A. Lipgrad (right) near the first passenger car all-wheel drive GAZ-61-40. Source: rim3.ru

But it is one thing to develop cross-country vehicles, in which this cross-country ability was provided by simple docking of an additional axle at the rear, and it is another thing to create a car with a front steered driving axle. This was a very non-trivial task for the Soviet Union in the mid-1930s. Vitaly Grachev coped with it.

The main problem was in the design of the Weiss-type constant velocity joint, for which the country did not have a license. The firstborn was the GAZ-61-40, a two-axle passenger four-wheel drive vehicle, after the development of which real glory came to Grachev. The car entered small-scale production, in particular, the GAZ-61-73 sedan collected only 194 copies. Most of the series was used as VIP cars for the highest command personnel: K. Voroshilov, S. Timoshenko, G. Zhukov, K. Rokossovsky, I. Konev, S. Budyonny and others.

In early 1941, People’s Commissar Malyshev actually ordered Grachev to create a domestic analogue of the American “Bantam”: the army desperately needed an inexpensive and simple all-terrain vehicle. This is how the GAZ-64 appears, which in many respects surpasses its prototype, and in January 1942, on its basis, the designer builds a light machine-gun armored car BA-64. For this development of defensive significance, Grachev received his first Stalin Prize.

In the design biography of the protagonist in 1944, the Dnepropetrovsk Automobile Plant appears and work on the three-axle amphibian DAZ-485. The car was created under the influence of the Lendleigh floating GMC DUKW-353, and one of the most important achievements of the design team was the development of a centralized wheel inflation system. After that, pumping became the trademark of the entire line of automotive equipment of the Soviet Army. For the amphibious DAZ-438 Grachev in 1951 receives his second Stalin Prize. In the same year, the designer was transferred to Moscow to the ZIS, where, on the initiative of Georgy Zhukov, a Special Design Bureau for the development of “medium” format military equipment was created. Vitaly Grachev is appointed head of the SKB. The main profile of the bureau’s work is becoming artillery tractors and missile carriers. At this place, the designer worked until his death in 1978.

In addition to numerous books and memoirs, the film “Outlandish Designer” from the series “Secrets of Forgotten Victories” was made about the famous Grachev. In particular, in this film the name of Vitaly Grachev is put on a par with such automobile designers as Henry Ford, Henry Leland (founder of Cadillac) and Ferdinand Porsche.

Design headquarters of the SKB on testing the ZIL-135 modification L. Source: gvtm.ru

For ZIL, the presence of SKB throughout its existence was frankly burdensome. In fact, Grachev’s office was defended only by the patronage of the military and the space industry. At the same time, the engineers and designers of SKB had the right to attract the forces of the main plant to fulfill especially important orders. The management of the plant often responded to this by attracting engineers and employees of the special bureau to work at ZIL. Grachev, naturally, resisted this as best he could, which caused antipathy with the management of the enterprise. In many ways, the whole situation was the result of a chronic shortage of workers at the main plant. According to Vladimir Piskunov, one of the SKB engineers, and later the deputy chief designer of ZIL refrigerators, the hard work, strict discipline of a secure enterprise and low wages compared to similar work at the enterprises of the defense complex forced people to leave the plant. We had to fill vacancies with workers from all over the Soviet Union, who worked successfully, received Moscow apartments and … left the factory. And so over and over again over the years. When orders from the military for SKB seriously decreased, the ZIL management began to demand one of the bureau’s employees on the main conveyor every month. This happened after the death of Grachev in the early 80s. It got to the point that the acting chief designer Vladimir Shestopalov, not finding volunteers in the SKB for the next “corvee”, went to work as an assembler on the conveyor belt himself.

But these were the years of decline of the Grachevsky SKB, and in the golden era of the domestic automotive industry, such a unique one as ZIL-135 appeared.

The brainchild of the “Grachevskaya firm”

Most of the off-road vehicles developed at SKB were distinguished by special engineering refinements, many of which found their place in the ZIL-135. First of all, these are tires of the maximum possible size in terms of layout, low-layer, with developed lugs, as well as a large ground clearance with a flat bottom of the car and a front inclined “entry” sheet. All this required the use of off-center or two-shaft wheel gears, which make it possible to simplify the supply of air to tires and brake fluid to sealed brakes. On 8×8 machines, to which the ZIL-135 belongs, a non-differential drive is used with the drive of the wheels of each side by a separate motor. To go to reduce the number of differentials to zero, Grachev was prompted by unsuccessful tests of early prototype units on prototypes No. 1 and No. 2 ZIS-E134, ZIL-134 and ZIL-157R. On these machines, worm-screw differentials of the Walther type with adjustable friction clutches of the Thornton Power-Lock type and freewheeling differentials of the Nou-Spin type were mounted. All of them were rejected at various stages of technology testing.

ZIL-135E with the S-123A launcher under test. Source: “Equipment and weapons”

The next characteristic “signature” of SKB equipment was the symmetrical wheel arrangement 1 – 2 – 1 for 8×8 vehicles. The front and rear wheels were made swivel. In addition to the fact that this unconventional technique increased maneuverability and cross-country ability (the wheels moved along the same track), it allowed the wheels to turn only 15-17 degrees. And this is the ability to accommodate large wheels, and the greater reliability of the hinges of equal angular velocities. A distinctive feature of SKB machines is the widespread use of filled fiberglass in the manufacture of cabins, gas tanks, amphibious hulls, wheel rims, torsion bars and honeycomb frames. For floating machines, submerged units were invented to pressurize air under pressure through an aircraft pressure reducing valve. Grachev was very skeptical about the winches on his equipment. The argument was simple – the permeability of the technique was so high that there was no need for it. And if suddenly some all-terrain vehicle does get bogged down, then no winch will save you. This principle follows, perhaps, from the main credo of the entire SKB Grachev – the fight against depriving the weight of equipment by any available means. Even if for this it is necessary to increase the cost of the structure with aluminum, magnesium or titanium. The chief designer demanded not to put an excessive margin of safety into the equipment – everything should work to the maximum without unnecessary overloading. “The reserve is pulling your pocket,” Grachev said about this. It is difficult to judge how justified this was, but SKB’s equipment cannot be called unsurpassed in terms of reliability.

ZIL-135E. Source: “Equipment and weapons”

The first car of the 135th series with the familiar characteristic appearance of the cab was the ZIL-135E model of 1960. The car was devoid of a suspension, which did not particularly bother the missilemen, for whom the all-terrain vehicle was intended. The fact is that they did not expect to travel a lot on roads with hard surfaces, but the lateral stability of the car increased – this was important when loading missiles. The connection of the wheels to the frame was carried out through a rigid bracket made of magnesium alloy – appreciate the degree of technical elegance of Vitaly Grachev’s design school. Naturally, these brackets were mercilessly broken during the tests and they had to be cast from steel grade 30 on the steered wheels. Also, in comparison with prototypes, the SKB increased the spacing of the base of the outer wheels. This made it possible to place on the ZIL-135E the 2P21 launcher of the Luna tactical missile system with an oblique launch. Also, under the requirements of the missilemen, the gas tanks were moved forward and the middle and rear parts of the frame were freed in order to improve the exhaust of gases of the starting winged product. The plastic of the cabin, which was mentioned above, appeared on the car not because of the fight against weight, but to counteract the gas rocket jet. The steel cockpit was irreversibly deformed, but the polyester resin filled with fiberglass returned to its original shape after launching the weapon. The cockpit had no metal frame at all and consisted of eleven large plastic parts fastened together with epoxy. Such are the high military technologies. In addition to the cab, gas tanks and the tail of the car were made of plastic.

Fighting vehicle 9P140 from the 9K57 Uragan MLRS. Source: autowp.ru

Launcher 9P113 from the OTRK 9K52 “Luna-M”. Source: autowp.ru

By the spring of 1961, two manufactured cars had passed the entire cycle of the necessary tests and, it would seem, were ready to go into series. The passability of the ZIL-135E was impressive. The car confidently took 27-degree ascents, overcame swamps of a meter depth, and the eight-wheeled missile carrier walked along broken country roads at speeds significantly higher than those of analogues with a spring suspension. But everything was spoiled by the lack of suspension. Since there is no suspension, then there are no shock absorbers to damp vibrations. At speeds of 22-28 km / h, the first wave of dangerous resonant vibrations came, the second came when it reached 50 km / h. And if the car “successfully” hit a special road profile, then the vibrations turned into sensitive shocks, requiring seat belts for three crew members. “Galloping” loaded with a ZIL-135E rocket on undulating asphalt began already at 40 km / h with a frequency of 120 units per minute. It was possible to stop such dangerous habits of a 16-ton missile carrier by abrupt braking with a decrease in speed by 30-50%, as well as a decrease in tire pressure to one atmosphere. In addition, the military did not like the low reliability of individual components of the machine (hello to the design principles of Grachev) and the excessive fuel consumption in the region of 134 l / 100 km. Each convoy of such missile carriers required the same convoy of fuel tankers.

As a result, it was decided to abandon the prototypes of the ZIL-135E in order to develop a modified ZIL-135L by the spring of 1961, which became a truly massive development of the “Grachev firm”.

To be continued…

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