A New “Flying Finn” for All Seasons

Something slightly different today on the Digger Man Blog as my Finnish friend and correspondent at Konepörssi magazine, Esa Suominen reports on an all new multi-purpose 4x4 designed for the military.

Finnish truck manufacturer Sisu has a long history of producing heavy duty vehicles for military purposes. The company first produced army vehicles as far back as the 1930s. But now the factory will join the competition producing slightly smaller specialist vehicles with the new Sisu GTP 4x4. The markets for this kind of multi-purpose armoured vehicle are global and Sisu is focusing on gaining market share. The GTP will be produced in Finland by way of serial production, but also allowing for customers special requirements.

The GTP is both an off-road and a highway vehicle, which is suitable to carry loads as well as troops. The pick-up version can carry load of five ton, so it is quite a powerful delivery pick-up, if needed.

The GTP is a modular constructed unit. This means the vehicle can easily be changed to suit a purpose out in the field. At the moment there are three different options for the upper construction; patrol cabin for 2+3 persons, crew cabin for 2+8 persons and so called “station wagon” version.

The manufacturer says that a full change of the upper construction can be made in around half an hour, on condition that the all the different cabs are nearby. The thinking behind the modular construction is that all the different cabs and chassis’ can be joined together in despite the different serial or chassis numbers. Routine servicing and maintenance is also very easy to carry out, with the help of modular construction. For instance, when the cabin is removed, there is easy access to the major drive line components.

The test drive vehicle was equipped with a patrol cabin. The total weight is 14 tons and dead weight nine tons. GTP can be registered as a road legal vehicle (Finland). 

Worldwide service network

One of the most important aspects of this GTP project was to provide a large service back up network. This is facilitated thanks to the use of many Daimler components. Engines are 6-cylinder diesel units from Mercedes-Benz Zetros Unimog, while the six-speed automatic gearbox comes from Allison.

 For the off-road work there is a reduction gearbox with electro hydraulic functions. Drive line is constant 4x4 and there are differential locks in every three differential gears. Every single wheel has separate steel spring suspension. Shock absorbers and springs can handle a wide range of movement.

According to Sisu, there is also a so called ”Mercedes-Benz component kit”, which includes besides the previously mentioned engines and gears, wiring harnesses and user interfaces in the cabin from MB. Even the bolt scheme of wheels is similar to MB heavy trucks. So GTP is strongly related to Daimler heavy duty trucks.

Finnish made

Despite of many Daimler parts, the Sisu GTP is a Finn made vehicle. The design and assembly of steel parts, including welding, is all done “in-house” in Finland. The steel material (armoured steel) is from Finnish steel producer SSAB.

Steel plate thicknesses were for obvious reasons, not disclosed, but they say that the cabin is assault rifle proofed, including the bulletproof glass. They are about 35–40 millimeters thick, from a visual inspection.

Sturdy construction can be seen in doors and in their mechanism. Hinges are heavy duty and the locking device is like in safe deposit box. In spite of that the handling of doors is easy and smooth. The locking device is designed to sustain a shock wave from a mine blast underneath the vehicle.

The chassis features a V-shape bottom which is designed to deflect away the effects of a mine blast below. GTP offers shelter also for fragmentation grenades. Sisu has vast experience in producing heavily armoured vehicles. This knowledge has been used in developing the GTP project.

Let´s drive

Even a long-legged bloke has to climb to get in to the GTP´s gabin. High mounted side steps are fitted with wire rope type footboards to help you into the cab. The dimensions of the armoured Sisu is a little different to normal cars, so you really have to think about which handle to grab first and how to slide in through the door opening. After couple of goes, entering the cabin becomes clearer and entrance is smooth as well as the exit.

Ground clearance is 400mm and wading depth is 850mm. In our test vehicle that number was even bigger, 1 200mm. Doorways seem to be quite small compared to the whole car. The size of the door is accurately designed to achieve the maximum explosive safety.

After getting inside the 2.5m wide cabin, you notice that it is very spacious. There is a huge area to travel in even in this patrol cabin (2+3). And in the back seat, there is no need to sit with your knees in your mouth!

Cabin interior is rather modest, but most of all, very practical and workmanlike. The dashboard is more like a working construction machine, but it’s ideal for the type of environment these trucks will work in. Most off the switches are from Hella, as used in a lot of heavy-duty machines. No fancy touchscreen to see in this vehicle. Gauges are from Mercedes-Bent component kit and the gear lever from Allison. All the controls require a certain amount of effort, forget the touch-sensitive switches.               

Good visibility

From outside, the windows look very tiny, but inside the cabin you don’t have that feeling. Visibility is excellent in every direction, except rear view. The test vehicle had an eagle eye camera system installed with an in-cabin monitor display. For example, in off-road situations the multi camera system sees rocks and stumps, which cannot be seen with the naked eye.

There is also a rear-view camera system with own display on the top of the windscreen, at the place where the rear-view mirror is normally.

On the highway ride the visibility is excellent. Even the sight to right hand side rear is better than in any van, because of the rear door window. Good visibility makes the drive easy and safe.

Engine power is 225kw, over 300hp. Engine start is made traditionally with an ignition key. The power plant rumbles away quietly hiding the power that lurks within. In-cabin noise levels are amazingly low in idle. And even when the engine rpm or speed increases, the noise level doesn’t change much. The massive car reaches highway speed easily and is as quick as normal cars.

Rough tyre tread and big tyre diameter (365/85 R20) don´t appear to make any problems to maintain highway speed. Manufacturer says that GTP reaches speed over 60 mph. This statement is easy to believe, because this huge lump of metal is accelerating without any trouble to legal road speeds.

Maybe it´s not keeping up with modern passenger cars, but the initial take off is quite fast anyway. And when the highway speed is reached, the ride is very enjoyable, stable and smooth. The general feeling inside is very safe when sitting tied in by the 4-point seat belts.

Braking is happening inconspicuously without any side movements or jumping, even on tarmac surface. Pneumatic disc brakes are equipped with ABS. Fuel tank capacity is 200 litres, which according the manufacturer gives easily over 400 miles range in highway.  

Let´s go off-road

Sisu’s GTP seems to be at home in every environment, in off-road as well as on the highway. My off-road session took place in a sand pit and this “beast” of a truck was unstoppable. With the help off the big tyres, the going was guaranteed even on sand desert.

The car is equipped with an electrical winch mounted on the front. Car has a 24 volt electrical system.

On the rocky bottom trails, this car really gave it´s best. A 6m total length with 3.8m wheelbase makes the crawling very easy on any lumpy terrain ride. With all the differential locks connected on (3 pcs), the vehicle is climbing up to places where a pedestrian can hardly get.

They say that the ship building steel is floating type. Sisu GTP is instead made of flying iron.

Video footage below show’s Sisu´s test driver Jere Alasimi slinging this monster up in the air and safely back on the ground. One of the most memorable things from the test drive is the sentence from Niko Vierimaa, “Push harder my man, this can´t be broken”. And Niko was right. He has had a lot of input into developing this furious GTP.      

For the authorities

Sisu GTP is a product under Finnish export control. The final export admission will be authorized by Finish Ministry of Defence. Theoretical the car is available for everyone (also for civilian sector), but the sale or export license is processed by Ministry.

According Sisu the potential customers are Defence Forces of different countries worldwide as well as different authorities and security operators.

List price is not available, because everything is based on customer´s equipment choices. The test car is so called demonstration unit to test manoeuvrability on the highway and on off-road.

Sisu GTP will be manufactured in Finland at the same production line where all the Sisu trucks are made. Every single unit will made according customer´s requirements.

According Jyri Ahonen, the export manager of Sisu Auto, the price will be very competitive in its category. International marketing has already started and the expectations are high.

The Digger Man Blog would like to thank Esa and Konepörssi for sharing the material contained within this blog post.