The 70s of the last century became for the automotive world, something like a starting point, the most productive time, when most of the different auto movements were launched and many different directions appeared. Most of the races took shape in what we now see, it was during that period, shows, competitions, tuning trends in the new and old world, as well as in Japan. In those distant years, Bob Chandler, a builder from a small American town, decided that bolting tractor wheels to a pickup truck was fun, to say the least. Everything, as usual, the enthusiast became the founder of an entire automotive subculture, which has become insanely popular on the American continent.
At first, Chandler's hobby was at the level of off-road racing through puddles and bumps, and he did not differ from other participants in the discipline in any way. Everyone had the same problems - old cars required constant repairs, there were no spare parts, tuned parts too.
He came up with the idea to equip an old Ford with 1.2 meter wheels, but the wheels no longer fit in the standard SUV arches and the thought process began. The challenge is accepted, either he will install them and the car will go, or he will finally break his old pickup truck. The process began, special spacers were installed under the frame (made by Bob himself), the suspension, chassis, transmission and engine were modernized. From afar, the car began to look like modern monster trucks. Chandler was pleased with his brainchild and hastened to demonstrate the creation to the world. He agreed with the organizer of the Nascar race that before the race he would arrange a small performance in his modernized car, the idea was accepted with a bang. The audience cheered. Bob began to modify his car in every possible way and perform at various shows and performances. One fine day, in a conversation with the organizer of car racing, he said that he was worried about the unreliability of such cars. After each show, they needed to be repaired, to which he was told that this comes from his "big paws". It was about huge wheels, which essentially tore the car's components apart. In English, big paws sound like bigfoot, hence the name of the vehicle.
Modern bigfoots are not those mass-produced cars that were put on huge wheels, they are a specially prepared vehicle with a monstrous engine located in the middle, a 4x4x4 wheel arrangement and a plastic body resembling an SUV. Cars with a capacity of more than 1500 hp, performing at colorful car shows, completely lost touch with the world of real cars, were called Monster-Truck.
Bob Chandler was the originator of not only the idea of a car on big wheels, but also the action that can be done with it. He thought it would be interesting to see how the huge wheels of his car could drive over several cars without leaving a wet spot on them. None of the spectators expected such a performance and the movement quickly began to gain momentum, turning demonstration performances into a whole sports discipline with its own rules, standards and records. In the USA, the shows became mega popular, cars improved, modernized and became more powerful. Great power needed a good strong transmission, a reliable frame (reinforced with railway rails), suspension, etc., all this made the already heavy structure heavier, the weight of the machines reached 10 tons. Such a mass, even with a powerful engine, did not allow Bigfoot to do breathtaking stunts, and Bob Chandler thought about a radical alteration of the car.
They decided to build a new truck on the principle of racing cars (minimum weight with maximum power). Instead of a standard pickup truck body, a light tubular frame was built, the engine migrated to the middle of the structure, a spring suspension was installed, and the appearance of the car was created by a plastic body stylized as an SUV. The lightweight design helped the monster to pirouette on the track and even do somersaults.
How to build a monster truck and how much does it cost
It all starts with a space frame made from 2"-2.5" diameter chromoly tubing. The frame design is designed on a computer with the calculation of the loads acting on each part. The dry weight of the frame is no more than 800 kg, which gives great opportunities for the future car. Next, wheels with a diameter of 1.7 meters and a weight of more than 500 kg are installed. These are standard tractor wheels that need to be adapted to Bigfoot. And this means that their weight should be reduced. This is achieved by replacing standard rims with lighter ones and trimming the tread. After all the manipulations, the wheels weigh about 350 kg. After creating the frame, they assemble the engine, which is based on the good old bigblock with a volume of 9-9.5 liters with mechanical superchargers from dredge cars. Similar internal combustion engines run on methanol, giving out 1500 hp and more. Bigfoot fuel consumption is measured in meters and is 20 liters per 100 meters.
Monster trucks use automatic three-speed transmissions with heavy duty components and a large torque converter. Coupled with a dreg engine, they allow the colossus to accelerate to 100 km / h in 4-5 seconds, jump over 60-meter obstacles, and also do somersaults. Jumping and stability are provided by dual shock absorbers filled with nitrogen and having remote oil reservoirs. To ensure the strength of the suspension and transmission mechanisms, good old axles with planetary gears are used, which reduce the load on the drive shafts and increase the ground clearance. Bigfoot has a 4x4x4 wheel formula, which means that the driver has full control over the wheels and therefore a unique steering. Standard off-road steering cannot handle such loads, so hydraulics are used to turn the wheels, and pressure is simply applied to the steering ramp. A fiberglass dummy is used as a body, repeating the silhouette of a standard pickup truck or station wagon.
From fuel consumption it is clear that participation in such a show is expensive and the construction of a car costs a pretty penny. To design a bigfoot, on average, you need from 150 to 200 thousand dollars. At least $ 500 thousand will be spent on annual maintenance.
The spatial frame of the monster is calculated on the computer. It must endure colossal loads, always protecting the rider. The frame is welded from two-inch thick-walled chrome-molybdenum pipes by helium arc welding.
The body is made of fiberglass, "glass" - from Lexan, to protect the pilot from accidental fragments. Thanks to these and other tricks, the total weight of the monster can be kept within 5-5.5 tons.
Engine
One thing that is not a problem in the United States is powerful motors. Recall that the 5.6-liter engine is called Small block there, and this is not irony. Under the hood of monster trucks is a Big block, i.e. classic, like a Colt pistol, a 9.4-liter engine, with a mechanical supercharger, powered by alcohol.
Such engines are simply bought from manufacturing companies like Merlin - they are usually put on dragsters. Typical power - 1500-2000 hp There are, however, more original specimens - for example, with aircraft engines. And in 2011, the appearance of the first alcohol-electric hybrid monster is scheduled! The Greens are here too!
However, it's long overdue. The fuel consumption of monsters is around 15-20 liters per ... one kilometer!
Transmission
A racing box with a giant margin of safety in America is also easy to get. Companies like Powerglide, Allison, or Lenco actually mass-produce gearboxes for dragsters and other weird American cars. This is, as a rule, the usual three-speed "automatic", only with a huge torque converter and other very strong components. There are, however, non-trivial solutions like “robots” with centrifugal clutch and pneumatic gear shifting.
The drive, of course, is permanent full, without any civil nonsense such as differentials. Bridges from school buses or other heavy equipment are sometimes taken as axles, but ordinary bridges for medium-sized pickups are more often used - their strength is enough for all acrobatics.
The load on the shafts is reduced due to the installation of planetary wheel gears. At the same time, this allows you to increase the clearance up to 120 cm. In the case of the Bigfoot, wheel gears with a gear ratio of 6.3: 1 are used, and the GP with a ratio of 2.6: 1. This adds up to a very "short" ratio of 16.5:1. The fact is that the monsters do not need to gain maximum speed, but powerful acceleration is what you need.
Suspension
The spring suspension of the first bigfoots could provide a travel of 10-15 cm. In modern monster trucks, the suspension travel reaches 70 cm! The circuit diagram is simple: trailing arms, springs, shock absorbers. Here are just the components themselves ... No Rancho or Bilstein produce such shock absorbers, so the teams make them on their own.
The body is steel or aluminum three-inch pipes. Steel is stronger, but aluminum is lighter - this is a matter of priority for the rider.
Nitrogen is pumped into the shock absorbers under a pressure of 30 atm. On landing, with full compression of the suspension, the pressure jumps to 150 atm!
The trailing arms attached to the axles and to the center of the frame are made from chrome-molybdenum tubing, which the teams heat up in a saline solution. After that, the pipes bend more strongly, further cushioning the landing.
wheels
For individual shows, monsters were built on wheels up to 12 feet (3.5 m), but the most common size is now 66 inches (170 cm). Rubber is taken from tractors or combines. But disks from agricultural machinery are not suitable for monster trucks - they are made of too thin iron that cannot withstand jumps.
So the designers make their own wheels out of 25-inch tubes, and then spend several weeks lightening and balancing the resulting 400-kilogram pieces. As a result, the weight of finished discs is no more than 200 kg.
Air is pumped into the wheels to a pressure of 12-14 atm. But all the same, when landing, the rubber is completely crushed - to the disk. Therefore, the disks are made narrower than expected, because. rubber sits on such better and does not fly off when in contact with the ground.
The cost of one set of wheels is USD 12,500. Not so much when compared with chrome-plated 26-inch Cadillac wheels.
Bigfoot Kastrytsky
First, let's visit the workshop of Aleksey Kastritsky from Chita, who has been working on his new and literally grandiose project - a bigfoot with a Chevrolet Suburban body.
But first, about something else: those of his cars that were built earlier - the trophy prototype of 2011 and the expeditionary "nurse" of 2012. The first is an original symbiosis using Japanese components and assemblies, as well as using wheel gearboxes (more on them later). In the second case, the name is only for the body, while the engine, axles and transmission as a whole are also from the "Japanese". Here they are, standing on the territory of the service "like alive", in full combat health. But the cars were by no means idle, but wound up the hardest kilometers of off-road competitions and independent trips. On their account, not just titles from exhibitions, but places of honor in cups and many-day raids into impassable places, in summer and winter, thousands of kilometers from the “base”. That is, these are by no means one-time projects for the show, but samples actually operating in extreme conditions.
These are Alexey's previous works: by no means only show cars for exhibitions, but actually working cars - winners of extreme competitions and participants in individual trophy raids.And here is a new project. It is completely different than the previous two works. Not for competition, of course. The concept of this machine is formulated as follows: for throwing a group of people into difficult terrain, including where they drive only on caterpillar conveyors. You can add - for a comfortable cast, since the entire interior arrangement of the Suburban with its three rows of comfortable seats remains in its original form. Moreover, even with the third row involved, there remains a quite large cargo compartment, which will still include enough luggage for such trips.
As Aleksey says, all the previous experience of long-distance extreme trips, including single ones, by itself formed the need for a large off-road vehicle for difficult conditions. Actually, for this purpose, on the occasion, a standard 1995 Suburban was purchased - large, roomy, comfortable in the cabin. But it was the body with its interior, the frame and some “little things” that went into “production”. So, the native frame of this American, in fact, a cargo category car, is quite impressive in terms of margin of safety. Yes, and rear leaf springs: they also inspire confidence in Suburban, so they went to work.
Otherwise, for the construction of the "expeditionary" bigfoot, it was necessary to look for products of a completely different origin. The 5.7-liter American V8 gasoline engine may be good in itself, but Alexei is used to dealing with simple Japanese-made atmospheric diesel engines. In addition, paired with a manual gearbox as an option, it is more reliable and unpretentious in the conditions in which you have to drive. One of the arguments in favor of the MCP is this: if water gets in, you can go, but you won’t go far with the AKP.
The search for a diesel engine was carried out among trucks of 4 and 6-cylinders, as a result, a compromise was found: the 5-cylinder Hino J07C with a volume of 6.6 liters is, in fact, a version of the more common six J08C “cut off” by one cylinder. Atmospheric, with simple in-line equipment, without electronics - that's what you need. Paired with his own 6-speed manual gearbox.
As for the bridges, the options were not considered - from the GAZ-66, but with the wheels, and primarily tires, it was not immediately decided. A variety of options were assumed, from "shishiga" to "Kraz-lappetzhnik", and even pneumatics were studied, but for one reason or another they were not satisfied.
As a result, wheels from agricultural machinery were chosen: with 10-ply tires Kama FD-14A 21.3 R24 on converted disks from a combine. The tires themselves will also be improved: according to the existing experience, grooves will be made in the solid crossbars of the tread - this will reduce the rigidity of the tires and to some extent increase grip. The mass of one such wheel came out under 150 kg! To “fit” them, it took a body lift of 25 cm relative to the frame and another suspension lift relative to the bridges of 10 cm.
Additional "cutting" of the tread crossbars has already been successfully tested on the previous trophy prototype of Alexei, the same will be done on the bigfoot.However, when a solution for joining the body and the chassis as a whole was found, the “highlight of the program” - the handout - remained in question. When they thought about this main transitional link, the native unit from Suburban "silently smoked on the sidelines" - lay indifferently in the corner of the workshop. Even from the GAZ-66, this unit looked incompetent - it would be rather weak. It was necessary to look for a suitable one at a completely different weight level.
According to measurements, the width of the bigfoot turned out to be 2.7 meters, the height is 2.75 meters, and the depth of the ford to be overcome is 2 meters. By the way, in connection with the latter circumstance, it was decided to refuse to install a snorkel.
Body lift relative to the frame through supports 25 cm high, plus a suspension lift of 10 cm.
What is the angle of the limiting transverse roll is unknown, but trial tests have shown that it is quite large.And the solutions led to the domestic product of a rare class - a razdatka from ZIL-157. It was suitable both in terms of configuration and characteristics: here both steps are lowering - one 1.16: 1, the other 2.27: 1. In addition, this transfer case, borrowed from the eminent 6X6 all-terrain vehicle with a separate (parallel) drive scheme for the rear axles, has a third output that can be usefully used. For example, to drive a water propulsion device, if the car is developed as an amphibian, this is being considered in the future.
Installed dieselhino J07 Cthe easiest way to see it is from the side in the wheel arch: from here the most convenient access to the injection pump is actually at chest level.
Front suspension springs - fromDodge Ram, for a test drive, native and “no” GAZ-66 brakes were used, and immediately after that they started installing third-party disc brakes (front and rear).
As the trailing arms of the front suspension, those fromLC80, but taking into account the specifics of the chassis layout, they “lay down” on the bridges upside down from above.
Like the body itself, the frame, rear springs and 170-liter fuel tank are fromSuburbanalso "fit" into the concept of building a bigfoot.
The ZIL-157 razdatka "sank" between the body and the frame so that it does not need additional protection. Its second exit back due to the absence of the third bridge will be idle for now, but in the future it is planned to use it to drive the water propulsion.The steering is combined, using a Suburban gearbox, the engine radiator is left from the same model - its parameters are quite sufficient. The fuel tank was also used from the "American" - its capacity of 170 liters does not yet make you think about an additional supply. But the fuel filter, as reliable and very efficient, is the native Khinovsky, but an additional one will be installed.
The hydropneumatic clutch, of course, is also native to Hino, besides, its compressor will later be used to install a remote wheel inflation system from the GAZ-66. In the cabin, except for the integration of new transmission controls into the space between the seats, everything will remain like that of the Suburban.
I happened to get acquainted with Bigfoot just on the day of his first test ride. Still with some shortcomings, but important parameters of the machine were established. For example, it quickly became clear that the "duty" brakes of the GAZ-66 were not suitable - as planned, suitable disc brakes would be installed.
But the main thing that I immediately understood was that the power connection turned out to be more than suitable. The Hino diesel engine with 170 horsepower at 2900 rpm, with a maximum thrust of 450 Nm at 1600 rpm, and the ZIL-157 transfer case surprised with their ability. Even on the “upper lowering” wheels, they seemed small to Alexei: there is plenty of traction, but the speed is low - you can’t really accelerate on the “track”. On the second lowering, bigfoot is completely similar to a tractor.
However, real off-road testing is yet to come, and after that the final verdict of the author on his big project will be. By the way, on public roads the car rolls elastically, but evenly and not hard - all the potholes “break” somewhere below, like waves on the tanker’s hull, without causing any concern to its “team”.
That's right, something is missing from the impressive cladding - yes, the car is still waiting for the installation of a suitable bumper and the 16000th winch.
