The LeTourneau Model B Tournapull

LeTourneau was the pioneer in motor scraper development in the late 1930s, nobody else came close to replicating his success.  With his Model A Tournapull already in production, this is the story of the second Tournapull to see the light of day, the Model B.  By Richard Campbell

Authors note: The story of LeTourneau’s early B Tournapulls is very involved and encompasses quite a few models so hang on tight, you’re in for a rough ride!

Designed in late 1937, the first of the B Tournapulls (B-Pulls as they came to be affectionately known), was introduced in 1938 to a somewhat muted response. This surprised LeTourneau somewhat as market research had revealed the need for smaller versions of the (by now) successful Model A Tournapull which was already in production.

Several prototypes and configurations of the B Tournapull had been tested with different engines, Carryalls and tractor unit layouts, but despite all the trials, LeTourneau couldn’t seem to settle on a finite version of the machine. To identify various iterations of the Tournapull from each other they were unofficially given the designation B1, B2, B3 etc. and it was not uncommon to see a whole lot of variations, some of which never saw mass production.  Testing of these various Tournapulls was carried out at LeTourneau’s Peoria plant, and also at the new assembly plants at Toccoa Georgia, Vicksburg Tennessee and Longview Texas where they were used in bulk earthmoving operations prior to fabrication of the buildings.

It wasn’t until late 1939 that LeTourneau settled on a semi-production configuration for the Model B Tournapull, these machines being known as the Model ‘B1’ and were powered by a 158 horsepower General Motors 6-71 diesel and trailed a Model SU Carryall rated at 14½ cubic yards struck and 18 cubic yards heaped. Weighing around 22 tons, approximately 10 of these machines were built before production moved on to the next semi-production version, the ‘B8’.

Also built in very conservative numbers, the Model B8 Tournapull was introduced in late 1940 and powered by a 200 horsepower Cummins HBISD600 diesel.  Normally equipped with one of LeTourneau’s 23 cubic yard heaped Model LU Carryalls, the B8 was the first of the B Tournapulls to be offered with the option of a Model B-30 Tournacrane (rated at a maximum lift of 30 tons) or a Model W-30 Tournatrailer, also with a 30 ton capacity. World War 2 put paid to any further development of the B Tournapull as all focus was directed to manufacturing existing equipment for the armed forces.

Enter the electric control B Tournapulls

Despite WWII taking up much of LeTourneau’s production capacity, it didn’t stop LeTourneau from figuring out new kinds of equipment and operating systems.  The simplicity, power and speed of electric control had long fascinated Mr. LeTourneau and so it was that in late 1945 the first electric controlled Model B Tournapull appeared, the B9. As to be expected with such a revolutionary control system, there were bugs that needed to be ironed out and the B9 was not put into production.

First of the post-war B Tournapulls to see series production was the Model B29 which appeared in 1946. This was mated to a 25 cubic yard E-25 Carryall scraper and powered by a 215 horsepower Hercules diesel engine. Although not a runaway success, the B29 spurred on rapid development of the next model, the B31.

The B31 Tournapull was a major redesign using information about what was good (and bad) about the previous two Tournapulls and appeared in 1947. LeTourneau chose to power the Model B31 with a 225 horsepower Buda 6DCS-844 diesel engine mated to one of LeTourneau’s own ‘Tournamatic’ powershift transmissions and hauling one of the new 30 cubic yard E-35 Carryall scrapers.  Unfortunately for LeTourneau, although the B31/E-35 combination had the highest production run of any of the B Tournapulls up to that date, operationally it was a disaster and resulted in many unhappy customers.

As an interim measure, the trouble-fraught B31 was hastily replaced by the Model B33 of which only 27 were built. The B33 continued to use the E-35 Carryall but had a new engine, the 240 horsepower, eight cylinder, Buda 8DC-1125.

In 1949 the B33 was replaced by the ‘improved’ Model B34 Tournapull which retained the powertrain and scraper of the previous Model B33 but had significant upgrades to the electrical system. This machine was a moderate success and several dozen were manufactured.

Produced in parallel was the Model B ‘Roadster’ Tournapull which differed from the B34 in having a Fuller 5-speed 5F1220 manual transmission.  The B Roadster was powered by either a 300 horsepower Cummins NHRBIS-600, 6-cylinder diesel or a 320 horsepower General Motors 6-110, 6-cylinder diesel engine. Standard scraper was the new Model B Carryall rated at 25 cubic yards heaped.

The last of the cable controlled B Tournapulls

Ultimate version of the cable-controlled B Tournapull was the Model B-70 which came out in 1956 and was the most successful of all the B Tournapulls.  It was also the first time that production of the B series was undertaken outside of the USA with units being built at LeTourneau’s plant in Rydalmere Australia, commencing 1959. The B-70 was quite a beast of a machine, incorporating years of acquired knowledge from the many electric control B-Pulls that had gone before it.

Originally using the same powertrain utilized in the B Roadster, in the early 1960s this was changed to a 455 horsepower GM 12V-71 with an Allison CLBT5960 6-speed powershift transmission. Changes were also incorporated into the scraper, standard version which was now a Model B ‘Fullpak’ rated at 32 cubic yards heaped. The B-70 could also be ordered with a Tournacrane, Tournarocker rear dump or one of the new 31 cubic yard Hancock 333A elevating scrapers which were beginning to make an impression in the contracting world.

Production of the B70 Tournapull ceased in the USA in 1965 but continued in Australia until 1969 when the last unit was delivered. The Model B Tournapull was replaced by the Wabco 300 series which were a quantum leap forward in design and operator comfort.


The New Zealand connection

No cable-controlled B series Tournapulls ever came to New Zealand.  The reasons behind this are probably twofold and dictated by the machine’s size and NZ contractors reluctance (pre-1955) to try out anything quite that technologically advanced.    Our contractors of the day preferred to go with what they knew – tractors with towed scrapers and the odd Model C Tournapull here and there.  This train of thought was to undergo a paradigm shift with the advent of the many hydro dams and opencast coal mining

For the model collector

Only one model exists of a B Tournapull, a tiny 1:80 scale miniature of a 1950s-era variant manufactured by Hubley in the USA.   Being so small it has very little detail and can’t easily be displayed in collections of larger scale earthmoving equipment.  It is, however, unmistakably a B Tournapull!  Now long out of production, an example will cost you anywhere between US$45 and US$60 on Ebay.


Brief Specifications – B1 Tournapull (the very first production model)

Engine:                        General Motors 6-71 inline 6-cylinder diesel rated at 158 flywheel  horsepower at 1750                                         horsepower at 1750 rpm

Clutch:                        17” manual, single plate, oil cooled

Transmission:            Fuller 4-speed forward, 1 reverse, constant mesh manual transmission

Top Speed:                  21.9 mph

Brakes:                        Contracting band brakes running in oil

Steering:                      Heavy duty cone clutch and contracting band brake. Turns beyond 90° to either side                                              to either side are possible with the risk of jacknifing.

Tyres:                          24.00 x 32 all round

Capacity:                     (Model SU Carryall scraper) 14½ cubic yards struck, 18 cubic yards heaped

Control:                       All cable via a LeTourneau Model T double drum PCU

Length:                        40’ 8”

Width:                         10’ 1”

Height:                        10’ 7”

Operating Weight:      22 tons (empty), 44 tons (loaded)



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