Always the innovative thinker when it came to earthmoving equipment, Robert LeTourneau came up with the idea of the Tournatractor in 1946. By RICHARD CAMPBELL
We examined one of the smaller Australian-produced versions of the Tournatractor, the LW12, in the September 2010 issue of Contractor, but the Model C was the grandaddy of them all!
LeTourneau was constantly thinking of ways to improve the earthmoving cycle, to speed up production, and to lower costs per yard.
Following his success with the Tournapull, the world’s first self-propelled scraper, LeTourneau began experimenting with rubber-tyred dozers to keep up with these new high speed haul units.
Conventional track type tractors of the period were good for about 7 miles per hour top speed but the rubber-tyred bulldozer offered speeds of up to 15 miles per hour.
It also meant that they could be better utilised on a jobsite, quickly travelling to where they were needed.
If public roads separated the jobs then it was no problem for the Tournadozer to travel there under its own power.
Of course there is no perfect tractor and the Tournadozer was not suitable for all jobs, particularly those where flotation was a problem.
However, one of the trickier underfoot conditions that the machine handled well was sand, and sand was a material that wore conventional tracks out very fast.
The first production Model C Tournadozer was introduced in 1947 and development of the type was continuous from then on until the machine was discontinued around 1972.
LeTourneau sold quite a lot of C Tournatractors to the military who saw the obvious mobility potential of the machine, and export orders were particularly strong, especially to India, North Africa and South America.
Westinghouse Air Brake bought out LeTourneau in 1953 and the Model C was carried over in production as the LeTourneau-Westinghouse Model C Tournatractor
The final version of the machine was the Model CH Tournatractor that featured a hydraulically operated blade – something Mr LeTourneau would have shuddered at as he had a known dislike for hydraulic systems.
It was not too long after the Tournatractor appeared that other manufacturers of earthmoving equipment began to develop their own rubber-tyred bulldozers, notably International-Hough, Michigan, M-R-S and Caterpillar.
Imitation they say, is the kindest form of flattery.
The Model C Tournatractor Described
The design of the Tournatractor was simplicity itself.
The entire chassis was a rectangular welded metal tub into (or onto) which all the necessary components were inserted or attached.
The underside of the ‘tub’ was completely smooth, and therefore safe from rocks and other projections.
The primary powerplant was a 186 horsepower GM Detroit Diesel 6-71 six-cylinder diesel, although a Cummins HBIS600 or Buda 6-DC844 diesel could be substituted at the customer’s request.
A LeTourneau designed and built 4-speed ‘Tournamatic’ powershift transmission with torque converter was bolted directly to the engines’ flywheel giving the machine a top speed of approximately 17 miles per hour in top gear.
Initially this transmission gave a fair bit of trouble as it had air-operated clutch packs that were prone to leakage. This usually resulted in more than one gear being selected at once with the inevitable catastrophic consequences.
Final drives were of the bull gear and pinion type, totally encased in box section side frames that kept everything nicely in alignment
Steering was essentially similar to today’s skid-steer loaders.
LeTourneau utilised a set of multiple plate disc brakes on each wheel with a central steering clutch for gradual or spot turns. The Tournatractor was effectively able to turn in its own length.
A wide range of tyre types could be fitted to suit operational requirements.
The operator sat very close to the front of the machine and had an excellent view of the blade and work area – so good in fact that on a windy day it was always a good idea to plan your work with the wind behind you lest you end up with half a yard of dirt in your lap!
Operating controls consisted of the standard LeTourneau instrument panel with electric switches for blade and attachment functions.
Two steering levers projected from the floor plate and the transmission shift quadrant was located to the operator’s right.
LeTourneau trialled a system of switches for transmission shifting early on but quickly went to a manual system when reliability of the switches was found very wanting.
Tournatractors were manufactured in the USA and at LeTourneau’s plant in Rydalmere, NSW, Australia.
A remarkable range of bits & pieces could be hung off the Tournatractor to equip it for its selected task.
The standard blade was a 12’ electrically activated, cable operated S blade. A similarly sized angle blade was also offered. This was reeved rather cleverly so that it could apply a measure of downforce if needed for ground penetration.
Push plates, rear mounted cable controls, towing winches, snow plows, rail wagon couplers, tree pushers and scrub rakes were all advertised as options for the Tournatractor making it potentially a very versatile machine.
A fully enclosed cab for the operator was also offered as an option.
The New Zealand Connection
From what the author can ascertain, at least eight Tournatractors were imported into New Zealand by franchise holders of the time, Earlo Tractor Co & Frederic W Smith Ltd.
It is known that two of these worked on the Wellington Airport job in 1956 (saw them with my own young eyes!) but records of who actually owned them no longer exist and even photos of them working in New Zealand are hard to track down.
It would be interesting to know if any are left in one piece.
For the Model Collector
Collectors with deep pockets may like to acquire one of the 1:50th scale Model C Tournadozers manufactured by EMD and available through Buffalo Road Imports, USA.
This represents a pre-1953 version of the Model C and is powered with a Cummins engine and has a cable operated dozer blade.
As alluded to, this is not a cheap model but it is very well made and a good representation of a Tournatractor.
At press time this is the only model available of one of these machines.
Brief Specifications: LeTourneau-Westinghouse Model C Tournatractor
Engine: General Motors 6-71 6-clinder, inline, naturally aspirated diesel rated at 186 flywheel horsepower @ 2000 rpm
Transmission: Tournamatic 4-speed air operated powershift transmission, 4-speeds forward, 2-speeds reverse
Top Speed: 17 mph
Steering: Combination of steering clutch and multiple disc brakes
Std.Tyres: 26.5×25 14-ply E3
Length: 18’ (with std.S blade)
Width: 12’ (with std.S blade)
Op.Weight: 17 tons (with std.S blade)