This is my second snow vehicle. It has some improvements compared to the previous one. Please read the review or watch the video. Comments are always welcome, maybe once an (improved) snow vehicle 3 will appear.
About this creation
-remote control driving (2x PF XL, gear ratio 2,5:1)
-remote control steering (PF m via linear actuator)
-rear and front are fully independent of each other, electric connection
I always like building strange, strong vehicles. Therefore I always build a snow vehicle when it is snow in Holland. It seems that this one is better than my previous one(1,2), because I've learned from the weaknesses of it. Firstly, the first one(winter 2011-2012) sometimes went short of motor power (and its speed was miserable already...). So now I added 2 XL motors, doubling the motor power of the driveline. This proved to be a good decision: the MOC never stopped. Secondly, the previous one was not that flexible, because front and rear part couldn't move freely in vertical direction. This has again been a dilemma, because rubber tracks are limited. When you want good climbing abilities, a triangle form of the track is very handy. But that decreases the 'normal' footprint of the total track, when it is normally on the ground. So after a vertical hill, always a MOC with this triangle track form won't go back straight, but stay in its curved form. This is because the tracks have a small footprint: the MOC is then not driving on its 'footprints', but on the inclined part of the track, which is in a normal case handy to overcome big obstacles. This is a serious problem that always occurs when such a track form is used. In the previous version, I simply deleted the problem by preventing the MOC to turn vertically. But now, I used a different method. By stabilizing the MOC in a special way the frame will return in straight position in very short time. You can also see this in the movie. And now the large ball joint came in handy, which enables steering and vertical movent simultaneously. Another new option is that the MOC now also can turn longitudinally.
This picture shows how flexible it is. Enabling longitudinal motion proved to be essential for good behaviour in snow.
A third thing that has changed, is the colour. I have chosen for light bluish gray to show and to find out that it indeed is a surprising colour. One IR Reciever is used: keep it simple. Such vehicles only work with a minimum of weight, therefore I have not added PF lights.
A picture of the rear. The XL motor is placed as far as possible at the back for a balances 'cart'. I had no L-motor yet, so another option had to be thought out. What is stronger then a linear actuator? Unfortunately, it is a slow option. But in offroad, strong is often more important than slow. A parallel guided system is used to convert the motion of the linear actuator in a strong, sliding motion.
What is the biggest problem in every MOC? Right, the battery box. 250 gram of useless weight is added to the MOC. This asks for serious balancing of a model, certainly in a model like this. In fact, this MOC is balanced to balance in a bouncing snow world! Placing the battery box at the front of a MOC ensures good climbing abilities, while placing it at the rear enables very good descending abilities. This MOC has no center! I chose for the front because in snow climbing is most common, descending in snow is more skiing. When the battery box is removed, a box of 11x5x7 is left open.
This picture shows how flexible it actually is. A question that always exists: what is the influence of longitudinal turning on the steering. My answer: go build it. It proved to be very little.