… according to John Deere, which was previewing its new 36m carbon fibre boom technology on a pre-production 5,000-litre R4050i self-propelled at Cereals.  Claimed advantages of carbon fibre are that it’s five times stronger than steel, five times lighter than steel and even 1.9 times lighter than aluminium. On top of that, it’s reckoned to neither fatigue nor corrode, and is also easy to repair.  Other than the boom, many of the R4050i’s core features are shared with the existing 4,000-litre R4040i, although Deere says that more new components will be added by the time the bigger machine goes on full sale in 2018.