Sinclair C5 major consumer organisations published sceptical evaluations. The Automobile Association questioned many of Sinclair's claims in a report published at the start of May. It found that the range of the vehicle was typically only about 10 miles (16 km) rather than the promised by Sinclair, and reported that the C5's battery ran flat after only on a cold day. The C5's running speed was more usually around than the claimed , while its running costs compared unfavourably to that of a petrol-driven Honda PX50 moped. The stability, general roadworthiness, and especially the safety of the C5 were questioned, and the
F B swamp vehicle rubber floats attached to the track links in order to prevent the vehicle from sinking into the quagmire. The F B could also be used to transport men across water ways, powered by a drive propeller shaft. The S B swamp vehicle was the first prototype design built by the IJA for use as a military transport/personnel carrier for crossing swampy terrain and water ways. It was also designed to transport men across water ways, powered by a drive propeller shaft. Built in 1933, like the subsequent F B vehicle it had rubber floats attached to its track links to