Transport: Big Stuff

While the National Automobile Show boomed luxuriantly in Grand Central Palace to near record sales, last week the National Motor Truck Show jammed Manhattan’s Commerce Hall with the greatest display of industrial vehicles ever staged.

Equipment ranging from sleek little package cars to 30-ton double-trailer trucks, 58-passenger busses, and mobile airport units, indicated the range of utility covered by the U. S. trucking industry, which gives employment to more than 3,000,000, pays special taxes of $417,500,000 ($89,000,000 more than the amount of all taxes that U. S. railroads pay). Truck manufacturers represented were Autocar, Baker-Raulang, Brockway, Diamond T, Divco-Twin, Dodge, Federal, Ford, Four Wheel Drive, Fruehauf Trailers, General Motors, International Harvester, Mack, Marmon-Herrington, Pak-Age-Car, Reo, Sterling, Studebaker, Truck-tor, Walker, Walter and White. Motor-makers were Aircooled Motors Corp., Buda, Continental, Cummins, Hercules, and Waukesha. Represented, too, were some 75 body, wheel, accessory and fuel companies.

Reason for brisk interest in the motor truck show was the refinement of Diesel power (hitherto a luxury of heavy duty trucking), for 1½ to 3-ton trucks. Main advantages of Diesel power are that it needs no carburetion, no spark plugs, no electric ignition system (sources of 90% of gasoline motor troubles), gets more power and mileage out of low-grade cheap fuel oil than gasoline motors get out of premium gasoline.

Most Diesel engines have high compression ratios of about 16-to-1. The upstroke of a Diesel piston compresses the air above it into one-sixteenth of its volume until its heat is something like 1,000° F. A drop of fuel is then sprayed into the cylinder head, and ignited by this heat. The resulting explosion forces the piston down in the power stroke.

Higher compression translates into more efficient operation because it gets greater power punch on less fuel. It also necessitates a stronger and heavier motor to absorb the increased shock. For this reason, and because Diesels have not yet reached the mass production stage, they are costly. A Ford truck gasoline motor, for example, costs about $150, a comparable Diesel about $900.

Attacks on this cost are evident this year in weight-paring and the use of lighter, stronger metals by Cummins, Buda and Hercules (which displayed a Ford V-8 truck replacement unit), and in the entrance into large-scale Diesel production of Mack, Dodge and General Motors.

Further weight reductions are indicated in General Motors’ development of a two-cycle Diesel, which completes the four stages of operation—intake, compression. combustion and exhaust—in each up-and-down stroke of the piston, thus making every piston stroke a power stroke whereas four-cycle motors waste a full, powerless stroke on exhaust and intake.