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Liebherr R 9100 Mining Excavator   (Radio Control)

Maker:  HK-FunctionsModellbau
Model No:  HK2941
Scale:  1:50
Review Date:  August 2014

HK-Funktionsmodellbau Index
Mining Equipment Index

Cranes Etc Model Rating
Packaging   (max 10)9
Detail   (max 30)24
Features   (max 20)20
Quality   (max 25)23
Price   (max 15)9
Overall   (max 100)85%


Liebherr R 9100 Mining Excavator   (Radio Control) Video.  [Youku Video]
Various boxes make up the full kit.
Two printed manuals - English and German.
Metal platforms and handrails.
Crawler track frames have working rollers added.
Almost no RC wiring visible.
Cab has an operator inside.  The beacon light is an addition of the lights package.
One difference to the standard Conrad model are the track motor housings.
Large bucket is a nice casting.
Profile view is almost identical to the standard Conrad model.
Lights are very bright.
Comment on this model.

The Liebherr R 9100 is a mining excavator which has an operating weight of 108.5 tonnes in backhoe configuration.  It is optimised for loading trucks in the 50-100 tonne range and has a bucket capacity of 6.8m³.

This version of the standard Conrad model has been converted to full radio control (RC) by HK-FunktionsModellbau of Austria.

The model comes with the mechanical functions motorised, and optional factory-installed extras include a lighting package and a sound package.  The review model had both options fitted.

HK-Funktionsmodellbau provides a warranty on the model of 2 years.


The model set comes in number of boxes.  The model itself is the standard Liebherr branded box with a HK label attached.  Also included are the battery charger for the model and the Spektrum DX10t transmitter.

The review model had no defects or missing parts.

Two instruction manuals are provided, one in German and one in English.  The manual is comprehensive covering all the functions and operation for the model. 

The only assembly required is that for the standard Conrad model which is adding a mirror and ladder, and any necessary charging of the batteries.


In terms of appearance and detail the model is almost identical to the standard Conrad version.

The metal tracks are strong and have bolt heads just visible on the pads.  They are mounted on track frames which are a good representation of the real machine and an addition on this version there are working rollers and metal drive sprockets and idlers which presumably are needed to assist smooth crawler track operation.  There are other differences underneath where the body has a recharging point and an on/off button.

The operator's cab has darkly tinted windows however some interior details are still visible, including an operator which is included to provide a more realistic appearance when the model is under RC control.  The main windscreen wiper consists of applied graphics and there are lights on the front but no local mirrors.  On top of the cab is a beacon light which is an addition on this version of the model.  Outside the cab there is a nice mesh walkway with realistic metal handrails.  A plastic access ladder fits to the side which is different to the ladder arrangement usually seen on the real machine.

The body casting is good with some very nice grilles on each side and the graphics are very sharp.  A couple of video cameras are modelled in plastic.  The inside of the body looks good with a mesh platform and plastic hydraulics equipment, with just a hint of electrical wiring for the RC functions.  Hoses run to the boom foot, and there are hoses and pipes on the main boom rams.  Lifting eye shapes are modelled on the counterweight but without holes.

The gooseneck boom has some very good hydraulics consisting of plastic pipe arrays and hoses but the lifting eyes are not modelled.  It has lights and as they are working on this version of the model there is some extremely thin wiring running to them and the standard of the workmanship is very good.  The short stick is modelled well and includes lifting eye shapes, but without holes.

The bucket is large and is a detailed single casting.  The teeth are good.


All of the functions of the model have been motorised and it will typically run for well over 1 hour on a full charge.  It is switched on by pressing the button underneath, and on the review model it sometimes gives an initial small twitch of movement, although this will be eliminated on the next software release.

The Spektrum transmitter is impressive offering lots of potential functionality, and it can be loaded with profiles of different models, so one transmitter can controller can operate different models, saving on the expense.

The track movement is controlled by a pair of levers on the transmitter or they can be assigned to one of the joysticks.  Each track is controlled independently and a degree of fine movement can be obtained.  The limiting factor is really the grip between the track shoes and the surface they are running on, as under test, the model was able to track up a slope of 30º so the motors are certainly powerful enough.

Rotation of the body is controlled by joystick and the proportional control allows the speed to be varied.  Rotation is completely free in that the model is not constrained to turn in only so many turns in one direction or the other.

Movement of the boom, stick and bucket has a good range of movement and the powered functionality is again proportional so fine control of the movement is possible.  The hydraulic rams are motor driven with screw threads inside the rams and they are powerful.  The model can easily be tilted up under power.

The model can be used to accurately replicate loading and digging operations, but it is best to use a softer material such as cork shreds rather than real sand or stones.  This avoids dust getting into the mechanism and prevents the paint finish getting worn and scratched.

The model takes skill and practice to drive properly and that reflects how well the RC package has been implemented.

The lighting package provides a light in the cab as an indicator that the model is switched on.  Also the floodlights can be separately switched on or off, and they are very bright so it looks impressive in eth dark.  The beacon light flashes when the tracks move.

The sound module can be switched on or off.  It consists of a horn and engine sounds recorded from a real machine, and the sound varies depending on the movement of the machine.  There is an idling sound when stationary, and the engine revs up when movement is engaged.  Also there is a movement horn which sounds when the tracks move.  Overall the sound package is very good.  It disguises the sound of the internal motors and aligns well to the machine movements.  It is also quite loud, and the volume is not adjustable.

A last feature is that as on the Conrad version of the model the access ladder slides up and down.


As expected the base model from Conrad is very solid with a high metal content.

The paintwork is good, and the applied graphics are very sharp.

The implementation of the radio control is to a very high standard with nothing detracting from the overall appearance of the model.


As a precision-engineered radio controlled model it cannot be expected to be cheap, and the price will be beyond the reach of many people who would be interested in it.


On one hand this model looks the same as the standard Conrad version of the model.  However in a way that reflects the true achievement of the model which is to fit all the electronics and motors required to provide full functionality within a 1:50 sized scale model.  The engineering is excellent and provides for a remarkable working model.


It was first available in July 2014.  This model was awarded Innovation of the Year for 2014 in the Cranes Etc Review of the Year.
Standard Conrad Liebherr box with HK label.
The Spektrum controller.
Model appears almost identical to the static version.
Nice grilles and graphics.
Underneath the switch and recharging point are visible on the body.
Extremely fine and well concealed wiring to the light on the boom.
Complex electronics and motors inside the body.  Here the battery is removed.
Posed loading an off-highway truck.  Here the model is posed with real stones but these are not recommended for RC use because of dust and wear.