The words “aerodynamic” and “speed” would never be used to describe my concept designs or professional work. Most of the machines I design have a top speed that just about any healthy human could outrun… But one of my clients, LMS International (an engineering firm) wanted a tractor trailer truck they could use for marketing purposes. So here’s my first stab at “speed” and “aerodynamics”. They didn’t want to pay for an interior, so no interior. But all the steps meet ISO human factors standards and the grab rails are accessible on the inside of the cab door when it’s open.
I always had an idea in my head for a cab over design where the cab sits on top of the engine instead of around it. This would allow for a cab over interior that you can truly stand up in. The elevated cab would give superior forward visibility and an air tunnel bellow the cab that would in theory help reduce the amount of air the tractor has to push out of the way at highway speeds. So this project was a good chance to see if I could put my concept on paper….
The rear of the cab is sculpted in on-center to the fifth wheel and the front of the trailer is formed out on-center of the fifth wheel. This allows the trailer to nest tight to the tractor cab (for better aerodynamics) while still allowing the trailer full rotation on the fifth wheel. This truck was designed primarily to operate on main highways. But while traveling on secondary roads, the fifth wheel can push back and lift up by using a series of hydraulic rams. This pushes the trailer away from the cab and lifts it off the rear tractor deck to allow the trailer to pivot up and down on the tractor's fifth wheel without interference with the tractor cab and chassis. This is necessary when approaching steep inclines and declines.