 The Chinook aircraft , normally based at RAF Odiham , provides heavy @-@ lift support and transport across all branches of the British armed forces , and is supported by the smaller , medium @-@ lift helicopters such as the AgustaWestland Merlin HC.3 of the Royal Navy 's Commando Helicopter Force and the RAF 's Westland Puma HC.2 , based at RNAS Yeovilton and RAF Benson . 
