Keeping in mind this is Tamiya's first try doing a tipper, the tipper body looks quite good, a 'universial' design. Bottom plate is sheet metal and the sides and front is plastic. Looking at the clearence between the rear wheels and the fenders, it seams like the suspension system is the same as the tractors -> little movement. Not quite suitable for a construction vehicle. But not too complicated to move the rear and front suspension to get more clearence, if wished.
The tipper system is kind of creative, but unnessecary complicated and expencive (300 USD?) Watching the videos, seams like it takes 40-50+ seconds to the top?? THAT is slow IMO. The 1:1 ones use about I've have found 15-20 seconds. The tipper system we make ourselves takes about 8-12 seconds, which is still slow to many of the more unpatient RC truckers
