Plot: Rachel and Jason head to a Birmingham BMX track to test the best in RC Motorbikes before putting the winner through its paces on a home built 'Loop da Loop' but will their bike and craftsmanship be enough to get them another place in the record books? Polly is on the east coast of America visiting twin brothers Geoff and Michael Howe, who have set up a business building military-grade armoured vehicles. After becoming the youngest duo ever to receive a military contract, and making the world’s fastest tank, they have clearly impressed the US Army