Prinoth Leitwolf (2006 - 2007)
After finishing the 8421xl, I recognized a new challenge during a ski holiday in Söll (Austria), a snow groomer based on the Prinoth Leitwolf. The main reasons to build the snow groomer is based on the many technic functions, and the fact that I never saw a snow groomer in technic before.
The first model is constructed around the (now) 'old' technic tread (# 3873) and called therefore 'Prinoth Leitwolf OT' (Old Treads). These treads do have there limitations (strength, size) and I was happy The LEGO® Company launched a new tread recently (# 57518). A logical step was to improve the snow groomer with the new treads.

Web-page of the 'new treads and Power Functions' groomer:

Prinoth Leitwolf NT

At this moment, you will find on this page all the MLcad files to build the Prinoth Leitwolf model, based on the old treads. I hope you enjoy it.

Notice that the model can be build in 2 designs:
* with loading platform only
* with drum winch equipment 

 

 

 

 

 

 

 

 

 

 

 

 

 

The technic specifications of the 'Prinoth Leitwolf OT' model are:
* Independent track movement, powered by 2 electro motors
* Working V6 engine
* Undercarriage height adjustment (front & rear side)
* Pneumatic front blade & rear tiller
* Front blade rotation to the left & right
* Rotating cutter rollers in the rear tiller
* Drum winch with rope & hook

Other non-technic functions are:
* Cabin doors open & close
* Chair back rest movement to front & back (access to pneumatic switches)
* Engine roof open & close
* Front blade wings open & close
* Rear tiller front & side wings raised & down
* Drum winch boom rotates 360 degrees
* Drum winch equipment overturn to the rear side (access to engine room)

 

 

The dimensions of the Prinoth Leitwolf OT (with drum winch) are:
* Length: 51 cm
* Width: 24 cm
* Height with lowered undercarriage: 20 cm
* Height with raised undercarriage: 21 cm
* Height adjustment: 1 cm
* Weight: 1,7 kg    

* Number of parts:
     * with loading platform: 2324 (including crawler tracks)
     * with drum winch: 2580 (including crawler tracks)
     * crawler tracks: 360 treads

* Development time: 175 - 200 hours
* MLcad time: 50+ hours

 

 

 

Drum winch equipment:
Snow groomers do have occasionally a drum winch which is used to anchor the snow groomer on - for instance - a concrete block when crawling very steep slopes. The Prinoth Leitwolf can be equipped with a drum winch and is able to anchor itself over 850 meter distance.

The drum winch can be added after completing the loading platform model, because the mounting bricks are already added in this model.
Please take care when leading the wire over all the 'center groove wheels', especially the last center groove wheel before the hook. There, the wire must led between the center groove wheel and the '
gray technic pin long with friction'. As such the wire is locked in a 'vertical' position.

 

 

Undercarriage lift mechanism and tread drive shaft:
One of the first challenges to solve was the undercarriage lift mechanism. The Prinoth Leitwolf can lower of raise the middle undercarriage ('big gears'), depending on the circumstances (slope angle, snow conditions), which will result in more or less grip on the snow surface.

The mechanism is performed by driving two booms (front and rear) which 'pushes' the undercarriage down or 'pull' the undercarriage up. To make this possible, the undercarriage is 'loosely coupled' with the main body of the snow groomer.
The two booms are operated with the two black knobs at the roof of the cabin.


Another challenge which keeps me busy for hours was the tread drive shaft. The reasons were twofold:
1) I did want to place the electro motors a little high on the chassis to avoid contact with the snow (snow is wet and not very good for the motors).
2) The drive shaft must drive the rear small gears (like the original).

So, a special construction was developed with a worm gear and two universal joints to operated the tread drive shaft at the rear side of the groomer.

 

The small pictures show the different positions of snow groomer. Take a close look to the position of the small 24 tooth gears compared to the 40 tooth gears.

The pictures show (from left to right, up to down).
1) Front side raised
2) Rear side raised
3) Both sides raised
4) Both sides lowered

 


Pictures were taken in Les Arc2000, France.

 

 

Electro motors and V6 engine:
The original Prinoth Leitwolf does have a hydrostatic system powered by a V6 engine. The hydrostatic system is used to drive the crawler tracks and other equipment such as the front and rear tiller.

In the model, each track is powered by an individual electro motor. To prevent the electro motor from stalling, a 24 tooth gear clutch is used. Don't expect the snow groomer to crawl slopes, because the power of the electro motors (# 71427) is not sufficient. These motors will be replaced with the electro motors of the Bulldozer set (# 8275), which are expected to be more powerful.

The V6 engine is driven from the left electro motor, unfortunately there was no space left for a differential between the two electro motors.

 

 

 

 

 

 

 

 

 

 

 

 

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