The Frog

Insane chain-driven swamp racer from Russia!

4y ago

My very first reaction to the Frog was pity. It was the first stage of the Ladoga Trophy a few years ago and as I listened to it rattle past it seemed such a shame that something serious had broken in the transmission so soon. But as it raced on another thought flashed in my mind… It passed quickly and was covered in mud, but my eyes had seen something that my brain had failed to register properly… it did have something between the wheels, didn’t it? They couldn’t have been moving without an axle, could they..?

The second sensation was wonderment!

The third, when I found out that each wheel is driven by chains that reach down four independent legs (catching a little inside the casings which is what creates that distinctive destroyed transmission noise), was pure astonishment and I remember struggling to find a word to describe it. Advanced didn’t quite fit, as it means ahead of its time, like the Range Rover was forty years ago, but in years to come I’m sure that the Challenge scene won’t be dominated by a plethora of axel-less creations. It’s not exactly high-technology either; that’s the realm of corporately sponsored R+D for ever more sophisticated sensor and electronic systems. The Frog is basically four welded together chainsaws and the only electrics are the starter and the lights … but there is one word that sums it up perfectly. Genius. Someone applied their mind to a difficult problem, that of building a competitive vehicle for the Russian bogs, and came up with a unique answer. If Leonardo Da Vinci had drawn the blueprints for the perfect off-roader, he would have come up with the Frog … so called because the swamp is it’s natural habitat.

Over the old railway tracks, past a fearsome looking guard dog we enter a rough compound of garages with graffiti all over the walls, oily stains on the floor and piles of gently rusting scrap piled up everywhere. It’s an innocuous place for one of the most impressive off-road creations I have ever seen. Sergei Volkov greets me with a greasy handshake and then with a proud smile leads me into his garage. The first vehicle we have to squeeze past is a Viking, a stunning half car, half boat on massive balloon tyres, but it’s what’s parked in the corner that I’ve come to see… yet once again I feel pity because seeing the two Frogs parked up together is a rather sad sight. The orange one hasn’t been cleaned since its last outing and in its last competition the green one tumbled back end over end three times so looked a bit worse for wear, a bit bashed in and sitting on three flat tyres.

For a long time the owners were very secretive of the technical details and would respond obliquely to any questions about its inner workings, but now they have another creation on its way, one that everyone is saying will be something very special … so now for the first time Sergei, the Frog’s builder, co-driver and Ladoga winner, is happy to tell me just how it works.

I peered inside the cab of the green one and my first thought was that someone had welded an upside-down bathtub between the two seats. The engine is set so far back that, a little reminiscent of a Hummer H1, the cover takes up a serious amount of interior space. The dashboard is a metal panel covered in rows of switches and fuses is and looks like something out of a WW2 vehicle; basic, but totally functional. Sport and war sometimes have similarities, but the battles that the Frog fights are those over mud, not blood. The gearbox of the orange one had broken and to get it out the interior had been stripped so it was easy to see the large 20cm diameter tube that ran across the cab about under where the driver’s knees are. Sergei patted it as he spoke and my friend Marina translated, “This is the chassis. It’s the key of the whole design, as absolutely everything in the car is centred on it.”

I asked if it was handmade or off something special, but he replied that it was just a standard pipe from a building suppliers, for use as heavy duty conduit or even for a sewer … But this piece of pipe definitely has a higher station in life than being filled with shit … it’s full of air! Hermetically sealed, it’s an air tank, but not for the difflocks though, as I said, the Frog has no diffs to lock … it’s for the CTIF. (Central Tyre Inflation System.) Either end of this tube is what the four legs, or levers as Sergei calls them, are attached to, which give the car its amazing break-over and articulation capabilities. “When you drive off the land into the river there is no chassis rail to catch on the bank. Just straight in and straight out!”

But before he divulged the main secret of its workings, first he wanted to explain all the minor details and so he led me to the front and opened the snub nosed bonnet, about 60cm long, to show me the shoehorned, de-turboed, 3 litre Toyota Supra engine. “And the gearbox is from an Audi A6,” he added. It seemed a rather odd combination to me and I questioned why he chose this particular combination. “Toyota is the best car, almost every component is very reliable and the gearbox … well … it’s because of the design of it, it has drive flanges mounted at the sides of it, near front, which transfer drive at 90 degrees …” But by the time Marina had translated he was already motioning us to the back. “Before we started construction the design for all the major components had to be exact … but then after that, for the ancillaries, we just went around the car shops looking for what fitted best, what would take the least amount of fabrication to get on,” he said, still with a proud smile … and the list of parts is a long one. He pointed at the rear-mounted radiator. “One from an Omega was the right size and fittings so we used that and found that cooling pipes from an Audi were right,” Marina kept translating as I scribbled my notes. The fuel tank is from a Mercedes 190, the pump from a Volga (which is a Russian made sedan that looks like the bastard child of a Mark 4 Cortina and a new 7-series BMW), the exhaust silencer, mounted vertically beside one of the back wheels, is from a Suzuki and the headlights come from a tank … not for the novelty value, they were fitted because they are bullet-proof (literally) as well as water-proof. The short suspension coils mounted close to the central pivot points were handmade as they could find nothing similar on any other type of vehicle, as are the massive damper struts on the front. “Maybe in America you could find something like this on those crazy rock crawling vehicles,” he said, “But in fact it was easier to machine them here ourselves in Russia.” The huge 150amp alternator is from some kind of HGV, but he couldn’t remember from which type. “And the steering pumps are from another Audi,” Marina said.

“Pump, not pumps,” I corrected, “there’s only one.”
“No,” he says there’s two,” she insisted and a rye smile spread over Sergei’s face at my confusion.
“The steering was the most complicated system to get working properly,” he explained. “On normal vehicles the front wheels are connected on the axle, so you just need a single ram to pull the steering bar between them, but on the Frog of course, the wheels are completely separate. What we had to do was design, install and calibrate two separate hydraulic systems, so as one ram extends on one wheel, the other contracts … one pushes the wheel out while the second pulls the other wheel in. We had to make the rams ourselves because nothing else fitted, but then after the first competitions we found that having just one ram on each wheel wasn’t strong enough … so we added another to each wheel … but installing and calibrating the system was one of the hardest things we had to do!”

As I squatted down to take a photo of how the rams were arranged he pointed to the short but thick driveshaft and told me it was modified from a Kamas truck and that they even had to make the wheels, with custom centres welded to UAZ rims. “But at least the tyres we could buy!” he laughed as he kicked one of the 40 inch Super Swampers.
But then he laid a plastic sheet on the floor, handed me a torch and beckoned for me to lie underneath…

I do have to admit to being embarrassedly excited about being so close to the Frog’s secret. I’m not particularly mechanically minded, nor am I that easy to impress, but there’s just something special about this vehicle. Maybe it has something to do with the select few people who have been out to do Ladoga coming back with such tales about it, but I couldn’t help feeling rather privileged as I shuffled under it. Everyone knows that it is driven by chains, but just how drive is transferred has always remained a mystery. In Ladoga if anyone had laid underneath all they’d have seen is the legs, which look a little like chassis rails, and the underbody armour plating, but now, along with the gearbox, all that was gone and so I could see everything. And like Howard Carter peering at the treasures in Tutankhamun’s tomb for the first time, I pointed my torch around.

Sergei drew my attention to the handmade brake disk mounted at the point where the two legs of one side met and pivoted from. Above was the central tube that he’d shown me before. “We made the disks ourselves, but the callipers are from a Vauxhall Vectra.” There’s only one calliper for each side of the vehicle, which is something I think that an SVA inspector might not be too impressed with if this was in Britain, although weighing in at less than 1500kg it doesn’t take all that much stopping. “The gearbox goes here,” he said motioning the space behind the exposed clutch plate, “And the main point of the car’s design is that the gearbox has drive flanges coming out of the side of it, just here,” he said as he motioned the short distance from where the side of the gearbox would be to the centre of the brake disk. “And inside here,” he said patting the point where the front and rear legs met behind the disk, “are four cogs that transfer drive to the chains, two to the front and two to the back … which turn the wheels! There’s no need for a transfer box as the cogs are geared just right to give us enough torque and speed.”

Somehow it all seemed so simple. There was no real mind blowing magic trick after all, but as I stood up again I reasoned that the Frog’s genius is in the concept of the design, not just its construction.
Sergei led us to the little kitchen above the workshop and as he put the kettle on he said, “The idea came in one moment and started with a piece of paper and a pencil, nothing else, because there was no precedent before it, nothing we could copy or compare our designs to. There were many, many calculations we had to do with all the geometry because it wasn’t based on another vehicle at all.”

But it wasn’t an awe-inspiring triumph for the Frog, trouncing all of its competition with ease as soon as it was unveiled a few years ago. During its year long build some people who had influence within the competition scene found out what was being built and terrified about competing with such a machine lobbied to get the rules changed … so before it was finished the regulations of the Russian Off-road Championship were altered to restrict tyres sizes to a maximum of 37 inches, instead of the previous 40. “Everything on the Frog was geared to run on 40s, so it just wasn’t competitive,” Sergei lamented. “But the Proto class at Ladoga still allowed 40s and we won there on our first attempt. But the problem with Ladoga is that it is stretched out over a 1000km … and a you know, there is nothing in the Frog designed to drive on tarmac, no compromise in any of the details for road conditions, so we used to collect it from the end of the stage on a trailer and take it to the next camp. But you know, just a little change in the rules can make a big difference and all those who didn’t want to drive against us just cried that you should have to drive the whole route without support … and well …” he shrugged philosophically.

After spending months bolting a pair of Laplander axles to a Land Rover chassis I can imagine it would be a pretty gut wrenching feeling turning up at the start line to find the Frog waiting for you, and if you know there’s no way of beating it in a fair fight I can imagine those not ready to rise up to the challenge of creating something to rival it would, no matter how underhanded it seems, seek to get it banned. Such is life, but Sergei is not bitter. “The Frog never saw its true potential, but even with the wrong sized tyres we still finished 4th in the Russian off-road championship and for me that was an amazing achievement. Each round is so hard that it makes Ladoga’s Proto class seem like a holiday, so I am very proud of that. But the Frog is the past now, we have a new car coming, a new project that makes the Frog look like a made-in-China toy in comparison!”

And did we get to see the new creation? Yes we did, all 330,000 euros of it. The story is coming soon!
ps. It’s not the car below. That’s the Lada Niva based amphibious Viking!

Photos: Robb Pritchard and Michael Lastochkin

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Comments (1)

  • Such a shame they changed the rules on them. Such a unique design deserves to stomp a few competitions, I should think.

      4 years ago