Prinoth Leitwolf with Power Functions (2007)
After the completion of the first Prinoth Leitwolf Lego^® model based on the 'old' technic treads (#3873) it became clear that this model has some serious disadvantages. The old technic treads are to fragile, the electro motors (#71427) are not really powerful enough to drive the groomer and the undercarriage lift mechanism could be improved. With the launch of a new track system and (remote) power functions of The Lego^® Company this year, it was logical that the groomer would be upgraded.

This upgrade started on Monday the 20th of August, when I bought the bulldozer set 8275 at the Lego Shop in Oberhausen - Germany. The project is called Prinoth Leitwolf NT (New Treads) and took me about 3 months to complete.

But the result is here! The model looks more realistic, is fully remote controlled (tracks and tillers) and is powerful in driving. The undercarriage lift mechanism is now based on 2 pneumatic cylinders. 'Unfortunately' the undercarriage can only be raised / lowered at the front side; the back side is fully occupied with the new power XL motors and demands for a proper construction (otherwise the model is pushed apart by the force of the XL motors). The V6 engine is still inside and working. The battery box is placed behind the chairs of the cabin and can be easily removed. The infrared receivers are placed just under the roof of the cabin. Last but not least, the tracks do have a tension mechanism by using shock absorbers (6.5L).
An improvement after testing the model in real snow was the mounting of snow bars on the tracks, which gives the groomer much more grip and makes the two parallel tracks 'act as one track'. However, for just 'home play-ability' this is not necessary.

On You-Tube, a short video can be seen of the Prinoth Leitwolf snow groomer:

Notice that the model can be build in 2 designs:
* with loading platform only
* with drum winch equipment (just 'click on and lock')

The technic specifications of the 'Prinoth Leitwolf NT' model are:
* Independent track movement, powered by 2 power functions  XL motors
* Remote controlled via infrared (power functions)
* Front blade & rear tiller powered by 2 power functions medium motors
* Working V6 engine
* Undercarriage height adjustment (front side) based on pneumatic
* Track tension mechanism based on shock absorbers
* 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
* Easy access to battery box
* 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 NT (with drum winch) are:
* Length: 55 cm
* Width: 23 cm
* Height with lowered undercarriage: 21 cm
* Height with raised undercarriage: 22 cm
* Height adjustment: 2 cm (measured at the front side of cabin)
* Weight: 2,5 kg (including batteries)

* Number of parts:
     * with loading platform: 2656
     * with drum winch: 2926
     * crawler tracks: 192 treads, 16 yellow sprockets, 8 black sprockets
     * snow bars on tracks: 384 (288 Technic pin 1/2, 96 Technic liftarm 1 x 7)

* Development time for the upgrade: ~125 hours
* MLcad time: ~50 hours

Challenges in this project:
The power XL motors are very very strong!! Therefore, it took a while to develop a driving gear which will not end up with 'jumping gears, bricks and axles' when more friction comes into account by driving 'up-hill', or by 'steering' to left/right with just 1 running track. Due to the powerful motors, it was not possible anymore to have a loosely coupled undercarriage at the rear side for raising/lowering.

A couple of functions are 'packed together' in the same area of the model:
1) The 2 pneumatic cylinders to raise / lower the front part of the groomer.
2) The medium motor to operate the front tiller (between the 2 pneumatic cylinders).
3) The only place of the battery box was behind the driver seat and as low as possible (because of the weight of the battery box, and the fact that the infrared receivers must be able to fit above the battery box). And important, the battery box should be able to remove easily for switching batteries. This can be done by flipping the seats to the front.
4) The V6 engine, which is above the 2 pneumatic cylinders.

Another challenge was the construction of the undercarriage, the first model did bent to much when lifting the groomer. This was solved by making the undercarriage in such a way that the weight of the groomer is applied 'between' the 2 parallel tracks on each side.

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.

Ability to select 3 driving speeds!:
It is possible to change the driving speed of the Prinoth Leitwolf NT snow groomer by applying another set of gears within the 'driving train'. This must be done when building the model, and is not easily possible afterwards.

Standard the 'slowest' driving speed is used within the MLcad files, because this gearing delivers the most power to the tracks for crawling steep slopes. But you can change this according to the picture at the right.

Possibilities are:

- Slow (and powerful). Standard within the MLcad files.

- Moderate.

- Fast.

MLcad files:
The Prinoth Leitwolf NT is made up of several sub models within just one mpd file, except for the drum winch which has it's own mpd file.

    MLcad files zipped with WINrar

The following MLcad files are used:
* Prinoth Leitwolf NT.mpd                                            
        Assembly main model.ldr
        Battery box.ldr
        Cabin front.ldr
        Cabin side bars.ldr
        Cabin side window.ldr
        Cabin window and roof.ldr
        Chairs.ldr
        Chassis front.ldr
        Chassis middle.ldr
        Chassis pf motors.ldr
        Chassis rear.ldr
        Cylinder.ldr
        Engine frame.ldr
        Engine grill side.ldr
        Engine grille.ldr
        Engine roof.ldr
        Engine V6.ldr
        Exhaust pipe.ldr
        Flash and backlights.ldr
        Front blade.ldr
        IR receivers.ldr
        Mirrors.ldr
        Panel left.ldr
        Panel right.ldr
        Platform fence.ldr
        Pneumatic pump frame.ldr
        Rear tiller.ldr
        Snow flap.ldr
        Tracks.ldr
                Tread snow bar.ldr
        Tread guards.ldr
        Tread wings.ldr
        Undercarriage mounting unit.ldr
        Undercarriage.ldr
* Drum winch.mpd
        Drum winch assembly.ldr
        Drum frame.ldr
        Drum boom and hook.ldr
        

MLcad unofficial part list
Please navigate to the 'MLCad parts library' page on this website if you having trouble with the correct reflection of the *.mpd and/or *.ldr files within MLCad or LDview.

Probably you do miss some (or all) unofficial parts I did use within the model.

Flexible part list
All the flexible parts used in MLcad were generated with the Lsynth tool. As you might know, flexible parts are generated of many small (none lego) parts. Therefore, the MLcad part list for the flexible parts is not correct. The following flexible parts are used within the Prinoth Leitwolf model.
* Pneumatic tubes
        Pump: 1x 7 cm black
        T-bar to pump: 1x 21cm gray
        T-bar to switches: 2x 5 cm gray         
* Flexible axle:
        Loading platform: 2x Technic flexible axle 11 black (# 32199)
* Ribbed hose:
        To rear tiller: 2x Technic ribbed hose 11L metallic silver (# 78)
        Between undercarriage and rear-chassis: 2x Technic ribbed hose 2L metallic silver (# 78)
* Electric power functions 9V IR remote control (# 58122) with 2x axle 3 with end stud
* Drum winch wire: 2,5 - 5 meter

Complete part list (including unofficial parts)
The complete part list of the Prinoth Leitwolf snow groomer can be found in the Excel part list inventory. Be aware that MLcad parts do not always have the same number compared to the Peeron inventory (parts catalog). Example: Technic liftarm 1x2 is known under item 169 or 41677.
The excel file contains four worksheets with inventories:

a) Prinoth Leitwolf NT = complete part list for the groomer without the drum winch
b) Prinoth Leitwolf NT DW = complete part list for the groomer, equipped with the drum winch
c) Drum winch = part list for drum winch only, can be used to upgrade the groomer later on with a drum winch
d) Tracks & blades = part list of the tracks equipped with the blades. Gives you information about the number of pins and lift arms used for the blades

Notice that you don't need the sub-model 'Platform fence.ldr' in the drum winch version of the model. This is already taken into account in the inventory list of the Prinoth Leitwolf NT DW.

Adobe PDF building instructions
The building instructions are also available in the Adobe PDF document format. Please consider that this download takes a while due to the size of the WINrar file (~38 Mbyte). 

MLcad building instructions:
The following information will help you to build the Prinoth Leitwolf model without to much trouble.

1) Technic models nowadays uses frequent 'mounting axles' which must be 'pushed' into a sub-model part which was build separate. Within the MLcad files, these mounting axles are already in 'pushed' position. Keep this in mind when you want to mount individual sub models (especially when connecting the undercarriage).

2) Start first with the 'export' of all the sub-models of the .mpd file into one directory. This gives you the opportunity to load every sub-model into the LDview program, so you can take a close look to the sub-model from every perspective.

3) Start to build all the sub-models BEFORE starting to build the 'Assembly main model.ldr' file. This file starts with the main chassis of the snow groomer, but acts as an assembly file for all the other sub-models as well.
The same procedure is applicable for the 'Drum winch assembly.ldr' file.

4) All the sub-models can be placed as 'one unit' on the snow groomer model.

5) Notice that the two axles 10L in the 'assembly main model.ldr' mounts the sub-models 'Cabin window and roof.ldr' and 'IR receivers.ldr'.

6) Connect all the pneumatic tubes directly to the pneumatic cylinders, switches and pump when you build or mount these parts. Otherwise you will not be able to connect them later on. REMARK: Notice carefully how the tubes are lead through the model (picture 1, picture 2).

7) Notice carefully how the electrical wires of the PF motors are lead through the model. Especially the wires of the two PF medium motors (see red arrows on picture 1). The wire of the front blade PF medium motor must be routed under the pneumatic tube and under the electrical wire of the PF XL motor. If not, then this wire will interfere with the pistons-axle of the V6 engine (and stalls the operation).
The wire of the rear tiller PF medium motor must be routed under the gray technic pin 3L double (# 32136).

8) Notice that the wires of the both PF XL motors must be at the top side of the sub-model 'Chassis pf motors.ldr'.

9) The building steps of the rear tiller mechanism in the sub-model 'Chassis rear.ldr' are difficult to see. Better is to use the special 'Chassis rear_instruction.ldr' file.

10) Connect the 'Engine grill side.ldr' sub-model(s) to the 'Panel left.ldr' and 'Panel right.ldr' sub-models, before connecting these sub-models to the snow groomer model.

11) In the 'Cabin window and roof.ldr', take a careful look when the four blue '1/2-pins' on the roof must be placed for connecting the lights later on. These pins do differ in direction (forwards, backwards). Notice as well that the most outside's black '1x2 lift arm' must be place between the 'axle joiner perpendicular double split'.

12) Please take attention to the following notes for building the 'undercarriage.ldr' file.
a) The undercarriage width is an equal number of studs!

b) Two tracks are placed in parallel on each side; therefore make sure that all parallel yellow sprocket wheels (40.4) do have there 'tooth' exactly in parallel. It's possible that the tracks will not proper operate because one sprocket is 90 degrees turned clockwise / counterclockwise on the same axle, resulting in not synchronized tooth's (and friction in the track driving)!

c) The 'rear' 12-axle with the yellow sprocket wheels (40.4) is already in 'mounting position' for the snow groomer model. To mount the undercarriage, these axles must be 'pushed' to the outside as far as possible, without 'loosing' the inner sprocket wheel.

d) Do not mount the pneumatic cylinders on the undercarriage! Mount the cylinders in the main groomer model and connect the undercarriage later on.

e) The picture at the right shows the order of connecting the undercarriage to the snow groomer (step 1 till 3).

f) In the last building step, 3 dark-stone beams 9 are placed. MOUNT THESE beams AFTER mounting the undercarriage to the main groomer model and after the 'undercarriage mounting unit.ldr' is placed! Otherwise it is not possible to connect the pneumatic cylinders and the 'undercarriage mounting unit.ldr' sub-model.

13) Take a close look to the drum winch file when you place the wire. On the frame, the wire should led - seen from the drum -  as follows: over the first 'center groove wheel', under the second center groove wheel. At the end of the boom, the wire must led between the center groove wheel and the 'gray technic pin long with friction'. As explained, the drum winch is mentioned to lock the snow groomer to a concrete block on steep slopes, and not for lifting. This means that the wire is in a 'vertical' position when in use.

14) The reason why the hook does have two yellow 'technic bush 1/2 smooth' is that in this case it is possible to attach the wire exactly in the middle of the hook.

15) The sub-model 'Tread snow bar.ldr' has to be build 96 times (!) and is used within the 'tracks.ldr' sub-model.

LDview:
Version 3.0 of LDview will give the correct 3D views of the Prinoth Leitwolf. Previous versions had problems with multiple ldr files loaded into one mpd file.