From the Uckfield workshop in East Sussex (UK), numerous prototypes have come out, successfully treading the dirt roads of the Old Continent. Offroad Armory, has ventured into a new adventure: to make, first in Europe, an Ultra4 IFS Single Seater vehicle.
Pictures and text Paolo Baraldi
The name Butler, Rob Butler, is certainly not unknown to the many European fans who follow the Ultra4 Europe championships. Butler, as well as being a good and determined pilot and he is also an excellent builder of those tubular prototypes known as Ultra4. Since its workshop in Uckfield, in East Sussex (UK), numerous prototypes have come out and theyhave successfully in the dirt roads of Europe. This first series of Eurofighter vehicles has been brought to the forefront of European off-road scenes not only by Butler himself but also by Levi Shirley (USA), Jim Marsden (UK), Ferdinando Bartolucci (I) and Filipe Guimarães (PT). Moreover, in 2016, Rob Butler participated and finished in California at the King of the Hammers driving his Eurofighter. Closed this production chapter of Offroad Armory, for the season 2017 Rob Butler wanted to try a new adventure: to make, first in Europe, an Ultra4 IFS Single Seater rig. To be clear, the same type of prototype of Shannon Campbell. IFS it means Indipendent Front Suspension. The advantages of this type of suspension are known to all: better driveability at high speeds and greater accuracy in the insertion and travel of curves. In contrast, IFS are less advantaged, compared to the solid axles, in rock crawling sections and require more maintenance and attention because the transmission is more delicate. The choice instead of a Single Seater allows you to reduce the weight and size of the car but on the other hand requires special technical solutions especially for the gearbox and transfr case positioning .
After 8 months of hard work, Rob Butler made his debut at the King of France 2017 with his new Eurofighter IFS Sigle Seater. The tube structure of this vehicle is made of Cromoly 4130 and T45 steel tubes for a total weight of 2000 kg. The track is 90 inches, against the 88 of the other Ultra4, while the 114-inch wheelbase is in line with the standard of these prototypes. The body panels are made of aluminum and the flat bottom in HDPE (high density polyethylene). All this allowed to obtain a decidedly aggressive line with a very low center of gravity. For this single seater, Rob Butler decided to use a rear-mounted 6400 Chevrolet LS3 engine with GM Performance control unit that allows 525 hp. The gearbox is an Alders 4L80E (competition model) with a Coan Full Race 2600 torque converter and Worth Worth HERO 2.0 transfer case. As for the suspensions, the real gem is at the front, that of IFS to be clear. Butler's IFS is built by Off Road Armoury with RCV series 30 joints and ARB RD99CE differential locker. The hydraulic steering system is from Howe Trophy Truck.
It is amazing for how well it works! It keeps the wheels on the ground much better than a solid axle. The front wheels adapt perfectly to the ground even in the steps and in the rock, but it is especially in the fast sections, in the jumps and in the whoops that the front suspension with the shock absorbers from King Shocks give the best of themselves. If we combine this with the powerful engine and the excellent weight balance, we can say that we are facing an Ultra4 IFS that has nothing to envy to those made in US.
O.R.A – Off Road Armoury
Referente: Rob Butler (foto 20)