article_snippet.sent: Scroll down for video .
article_snippet.sent: Depending on the weather, the aerial refuelling demonstrations are due to last throughout the weekend.
article_snippet.sent: The goal of each of the refuelling demonstrations is to transfer 3,000lbs of fuel in five minutes.
article_snippet.sent: But this is the final test of the historic X-47B, which will now be donated to museums despite, according to Foxtrot Alpha, only having 20 per cent of their flight hours used up.