First of all, I'm sorry that things have been so slow around here. Literally, one post every few months? Oh, well...Anyway, a few months ago, I got this one great old Lego set....number 8466, the 4x4 Offroader. You can see it's original box's cover in the first picture (I hope that is is not illigal to take picture of Lego's boxes and put them online). Before I got it, I had already determined that I would try to "NXTize" it - Put NXT Motors and the NXT Intelligent Brick into it to make it mobile. This led me onto three attempts.
When I first built the set, I was disappointed - the drive train was very weak. I tried motorizing it anyway, and I put a Power Functions M motor on a worm and 24 tooth gear gear block. I put the whole thing on the pre-built drive train, and it moved, but with extremely low power and my Lego nemesis, gear slippage. So, I tried modifying the drive train. That didn't work either. Unfortunately, I don't have any picture of that first version, but it was a failure.
The second a
ttempt consisted of me building my own chassis, and putting some 4X4 Offroader parts on top of it. When I built the chassis, I had in mind that I didn't want any gear slippage, so I built it with those four tooth knob gears to transfer power ninety degrees to the front and rear differentials. I also put in a transmission. Then, I put 4X4 Offroader parts on top of it. However, I modified them to make them wider. When I tested it, something went wrong. If I tried to move it forward and steer for too long, it stopped driving - some pressure got too high, and the transmission would slip. If I moved it backwards and then steer after that, it would go just fine - but then the transmission would slip again. Also, the steering arms rubbed against the inside of the wheels when it steered too much. This version was also a failure. You can see it in the second picture.
And now, the third version! This one is really recent, and is still standing now. This time, I simply built the motors almost directly driving the differentials - no drive axle or transmission this time! I wanted to make it so that each differential would be driven by two eight tooth gears for the "slow" original model, the 4x4 Offroader, and one 24 tooth gear for the "fast" alternative model, the 4X4 Race Buggy. I managed to get the steering wheel to turn with the front wheels, and I tried to make the decoration "engine" pistons spin as well, and I rigged up a cool mechanism to do so, but it's gears slipped and it fell off. When I built the third version, I had to lengthen the wheel sets apart to to fit the drive motors, and therefore gives the finished model a kind of "stretched" look, but it's not too bad. After it was basically done, I tried it using the eight-tooth gears, but it slipped, so I replaced them with one 24 tooth gear. After that, it worked well, but I have not tested it fully. See it here in the last picture.Hopefully I'll get back here before too many months pass.
Nato
