That absolute block of a Dodge semi truck in yesterday’s video reminded me how much aerodynamics had once been important in the trucking industry—beyond just the styling—and then was totally abandoned before being embraced so vitally in more recent decades. This 1935 Studebaker sleeper semi truck and trailer show that to good effect. That sloping trailer front contributed substantially to its aerodynamics, just like the big sloping fairings on modern semi tractors.
I’m referring to the Dodge LNT like this one, but that space-saving boxy style was almost universal at the time, given the very cheap diesel fuel, which commonly cost less than half of the price of gasoline.
One of the more interesting early approaches to improving aerodynamic efficiency after the energy crisis was the GMC Aero Astro, which had a fairing that could be raised or lowered according to the size trailer it was hauling. Apparently it did not catch on. But then the switch to conventional tractors was under way, and they utilized fairings a bit differently.
Apparently the Kenworth T680 is the most aerodynamic truck in current production, but I suspect the differences with its competition are minimal.
That will undoubtedly change when the Tesla Semi arrives. It is going into limited production later this year, as it will utilize the new larger format 4680 cells. Range was projected at either 300 or 500 miles, depending on battery pack size, but in November of 2020, Musk said it may be as much as 621 miles.
Aerodynamics went out the window when overall length laws and the desire for maximum load brought the block box look. Cab-over-engine models and short-nose conventionals emerged. Short-nose conventionals were not so common in the West where overall lengths were longer. Lucky drivers east of the Mississippi endured the short-nose conventional. Engines were partway into the cab which made for excessive noise (destroys hearing), heat (wonderful on a hot day) and lessened usable cab space. Once overall length limits allowed conventional tractors and 53-foot trailers, we reverted to designing fuel-efficient aerodynamic tractors. Love the photo of the Studey.
I always assumed the flat front tractors were also less safe too.
“I always assumed the flat front tractors were also less safe too.”
Who cares, drivers are cheap to hire .
Signed, management .
The flat fronted cabs were great on short wheel based tractors in the yards, hence the name “Yard Goat” .
Another factor concerning the change to the square front of the trailer was the standardization of the shipping pallet and the standardized cardboard boxes that fit onto a pallet. These boxes allowed 100% utilization of cubic pallet space.
That wonderful front of the trailer behind the ’35 Studebaker meant the trailer had to be manually loaded in order to fill it with maximum space utilization. Once the major shippers changed over to using pallets and forklifts to load trailers, it meant the trailers had to have squared corners. Shipping companies realized that while the trucks suffered a slight loss in fuel economy, those costs were offset by the higher income a square container offered for full load trailers. For many years these rounded front trailers were relegated to LTL use, where trailers were never operated at a full load.
Plus, using forklifts with pre-loaded pallets meant a rapid changeover in loading and unloading of trailers. What used to take hours, to unload and load a trailer by hand, took only minutes, using forklifts with loaded & wrapped pallets. There are videos showing 2 really good forklift drivers unload a 53″ trailer in under 4 minutes!
If you watch old videos of how freight trucks were loaded, there were still a lot of them that were loaded manually with hand trucks, especially the common carrier freight haulers, that hauled all sorts of sized packages.
Non-square semi trailers were still very common in the 1950s. The transition happened slowly over some time.
Regardless of how they are packed, a trailer with a rectangular front will hold more volume than one that is rounded off, so would seem better for the shipping companies.
Were the rounded fronts strictly for aerodynamics, or was that done to allow the space between the front of the trailer and the rear of the cab to be tighter, making for an overall shorter vehicle when length limits were stricter?
Also of note: Even when I enlarged the photo of the Studebaker, I was unable to find a small rear view door mirror, much less twin mirrors. Because that cab is far narrower than the trailer, it needs mirrors on stalks at least 30″ long. I see no mirrors at all. How the hell is he going to back that trailer up to the loading dock?
rear view camera? 🙂
Even on the one with the Santa Fe trailer, the mirrors are very small, and it would seem that those long, single stalks would vibrate quite a bit.
Were truck drivers just better back in the day, before they were spoiled by all them comfort and safety features that plague modern vehicles?
Also, the trailer in the lead photo doesn’t appear to have supports to hold it up when it is off the truck. Perhaps the driver, after backing it in blind, stacked wooden blocks under it.
I like the “wheels” on the supports of the Santa Fe trailer. I understand that the flat ones on modern trailers are better, but I have always liked the round ones.
I checked out the picture of the white Tesla truck/trailer combo. What I don’t see is the hinge point between the truck and the trailer. It appears to be seamless. With 5 axles that’s impossible.
It’s CGI; a computer generated image.
Here’s a real photo:
Will be nice to have trucks that out accelerate many of the cars around them.
In Europe where due to maximum length restrictions the cabover rules.
In the eighties you could buy a Scania Streamline, where the cab was adapted to improve aerodynamics and a lot of makers tried to offer roof spoilers and side skirt sets.
The game really changed when Renault started to offer the AE series aka the Magnum.
The whole concept was based on improved aerodynamics by installing a very high cab to keep the trailer out of the wind.
Although the tractor looks boxy and square, it is full of small features to cheat the wind.
And successfully, all major truck manufacturars have taken over the concept from Renault, which has also hugely improved the living quarters of the truck.
The MAN TGX I occasionslly drive, can be driven wearing a tophat, while in its pre-decessors there was hardly room to wear a baseball cap so to speak.
By my layman’s understanding of aerodynamics, I believe that the front shape of a vehicle is less important than the rear. Air compresses easily. Though that does consume energy, it takes much more to create a vacuum. With airplanes, the low-pressure above the wings is powerful enough to lift the plane against it’s weight. The low-pressure area behind a square-cornered box is a worst-case scenario for drag. And kind of tapering at the rear will help, and we’re seeing that with folding panels by the rear doors.