Combine - Development Approach

It would be very economical if the combine can b attached to the tractor instead of having a seperate power source for the combine. There are combines being manufactured in india where they are mounted on the tractor and when not in use the tractor is still used for other farm jobs. http://www.firstbtob.com/products/1143108/Wheat-Combine-Harvester-mounted-on-the-tractor.html http://www.indiamart.com/north-agro-industries/tractor-combine.html