People across Cornwall have been posting on social media about low-flying, noisy helicopters in recent weeks. Many have asked what they are doing and why they have been so visible.
The aircraft are Chinooks, the RAF's heavy-lift helicopters. They have twin rotors, two powerful engines and can carry up to 55 troops or around 10 tonnes of freight. The RAF uses them to move troops and equipment, and for casualty evacuation, search and rescue and emergency support.
Their sound is just as distinctive. The deep, rhythmic 'wokka wokka' noise of the twin rotors is one of the aircraft's most recognisable features. The RAF Museum describes it as the result of how the rotors and their gearboxes operate.
RAF St Mawgan, near Newquay, has confirmed what has been happening. Last week the Royal Air Force station said it had been an exciting time for aviation enthusiasts as it hosted a pair of CH-47 Chinooks from No. 28 (AC) Squadron, RAF Benson.
The aircraft were on exercise for a few days. While they were there, the crew invited cadets from the current Air Cadets summer camp to tour the aircraft on the pan, before taking a group of station personnel on a training sortie down the Cornish coast.
"It was a brilliant opportunity for those who hadn't worked with the Chinook force before and fantastic to hear that distinctive sound in the local skies," said a spokesperson, sharing what had been going on to Facebook.
"We know many of you were out capturing these aircraft in action". The station also mentioned flights from a Spitfire and a P51 Mustang, numerous training sorties from its own A400's and a quick visit from a Belgian Air Force A400M.
RAF Explains Recent Chinook Sightings Over Cornwall