Noisy but effective, the Terex S-11E made its mark on New Zealand. By Richard Campbell
In 1964 Terex (then known as Euclid) entered the elevating scraper market with an adaptation of their S-7 scraper tractor connected to a bowl supplied by Hancock.
Initially known as the S-7/12E2 or simply “S-7/Hancock”, the designation was officially changed following a minor upgrade to S-12E in 1967.
This machine carried 12 cubic yards, and was very unusual in that it carried a separate General Motors model 2-71 diesel engine solely for the purpose of powering the elevator drive mechanism, via a long prop shaft.
While this machine worked quite well, it was not ideal, so investigations were begun for a suitable replacement.
As it turned out Terex didn’t have to look too far – it entered into negotiations with Clark-Michigan (who now owned Hancock), the manufacturer of the original S-7 elevating scraper, to build them a new machine.
This saved vast amounts of money in research and development costs – money which the GM Terex division didn’t have at the time – and resulted in a machine which Terex called the S-11E.
To all intents and purposes the S-11E was actually a Clark-Michigan 110-11 but with considerable cosmetic differences and a new transmission.
Terex introduced the S-11E to the contracting world in 1969 and waited for the orders to come rolling in.
Unfortunately, the 11 cubic yard elevating scraper market was well populated with other brands by this stage, many of which had been in the elevating scraper game considerably longer than Terex and offered comparable if not superior machines.
Principal competition came from the Wabco 111A, International Harvester E211 and Caterpillar 613. Other breeds vying for a slice of the market included the John Deere model 760A, and of course Clark-Michigan’s 110-11.
Sales of the Terex S-11E were moderate but sufficiently good enough for Terex to consider an upgrade of the type to keep pace with the competition. This took place in 1973 and the end result was known as the Terex S-11E series B.
Changes made to the basic S-11E included the addition of disc brakes, reinforcement of the elevator frame tower and the replacement of the original vane-driven elevator motor with an infinitely variable hydraulic elevator dive motor,
This permitted the S-11E series B to load far more aggressively that the former model as it could adapt on the go to changes in the material being loaded.
However, the most noticeable visual spotting difference was the bowl assembly, which was changed from a single plate outside braced design to one that was constructed of oblong box sections welded together with no external stiffeners, resulting in a very smooth look.
Unfortunately for Terex this machine also sold in unremarkable numbers and the S-11E series B had been dropped from its sales catalogue by 1978. Terex concentrated its sales efforts on the larger S-23E and S-35E elevating scrapers and has not offered a small elevating scraper since.
The Terex S-11E described
Terex chose the General Motors model 4-71N 4-cylinder naturally aspirated diesel to power the S-11E. Producing 144 flywheel horsepower in this application the engine was coupled to a Dana-Spicer 5-speed powershift transmission driving through an Eaton differential and Cark axles and planetaries.
This was a radical departure for Terex, which normally used axles of its own design and manufacture, and Allison powershift transmissions.
Brakes were air operated expanding shoe type (replaced by air/hydraulic disc on the S-11E series B).
Standard tyre was the 23.5×25 16 ply E2 but other options could be fitted.
Terex also stuck with Clark’s steering system, which consisted of two double acting hydraulic cylinders mounted high up on the scraper gooseneck and acting through torque multiplying linkages – a similar system to that used by Caterpillar.
The S-11E was one of the very few Terex machines to utilize this steering method, the other being the model S-23E.
By the time the S-11E was introduced, earthmoving equipment manufacturers had begun to give a lot more consideration to the operator and his work environment.
Consequently the S11E was a little more “user friendly” than previous Terex machines.
Terex located the operator over the left front wheel well and provided a Milsco air suspension seat as standard equipment. Gauges were split either side of the steering column with engine gauges on the left and transmission and hydraulics on the right.
If required, an all weather cab could be specified.
Rated at 11 cubic yards, the S-11E’s bowl was of standard Hancock layout with a fixed cutting edge base and retractable floor with bulldozer ejector. The fixed blade base gave the bowl considerable strength and held a four piece cutting edge which could be equipped with four removable teeth if required.
A 15 flight elevator, powered by a two-speed vane type hydraulic motor, operated the elevator.
Your author has had some ‘seat time’ on the S-11E and can confirm the claim that they are noisy little critters – ear protection was a necessity.
They enjoyed good visibility to the cutting edge but the view to the right was average at best.
Due to the fact that the S-11E had a reasonably heavy tare weight (16 tons) – heavier than most of their competitors – the ride was not as rough as it might have been.
Although only eight feet wide, this extra weight also meant permits were usually required to drive the machines between assignments.
The New Zealand connection
Remarkably the one country besides the United States where the Terex S-11E enjoyed good market penetration was New Zealand. This was probably due to the excellent reputation previous Euclid/Terex products had established and the capabilities of the distributor, Clyde Engineering.
Clyde imported 12 S-11Es and six S-11E series B machines over the course of their production. These were sold New Zealand wide to existing Euclid/Terex fleet operators and also to several owner operators.
Some users of the type included H Allen Mills, Pool Bros, Central Plateau Transport, Neil Construction, Greg Lamb and Aviemore Irrigation, who owned three of the little screamers.
S-11Es can still be found operating today some 40 years after the type was introduced.
For the modeller
If you want to add a model of the S-11E to your collection you will have to build one yourself, as currently there are none available in any scale.
As the S-11E (especially the series B) was relatively slab-sided in appearance this should not prove too difficult for the modeller with average scratch building skills.
Brief Specifications Terex S-11E 16UOT series (the most numerous type)
Engine: General Motors 4-71N, 4-cylinder, inline diesel with Roots blower rated at 144 flywheel horsepower
Transmission: Dana-Spicer P5-400 5-speed full powershift with Rockford torque converter
Top Speed: 29 mph
Brakes: Air operated expanding shoe type on all wheels.
Std.Tyres: 23.5×25 E2 16 ply
Steering: Full hydraulic , 90° each side
Turning Circle: 29’ 2”
Capacity: 11 cubic yards
Elevator Drive: Vane type hydraulic motor with gear reduction
Chain Speed: 63 rpm
No of Flights: 15
Length: 31’ 1”
Width: 8’ 2”
Height: 9’ 3”
Operating Weight: 16 tons (empty), 30 tons (loaded)