Hurtling through the Berkshire countryside, powered by nothing but nature, they were unlikely to break any speed records.
But the organisers of an annual race event are celebrating after a bumper year helped them cross the £100,000 mark for total donations.
The Cookham Dean Gravity Grand Prix, which celebrated its 10th edition in September, has handed over £14,962 to the Thames Valley Air Ambulance off the back of its last outing.
And more than £3,000 was also given to a range of other charities.
"It's a pretty impressive total," said Peter Bartlett, one of the organisers, when asked about the donation last year's record haul had allowed.
"And the thing I love about it is that it's such a Cookham Dean event.
"We don't really have to even advertise that we're doing it and the people we get are all locals - it's not like Notting Hill Carnival or something like that where people come from all over."
The latest gift to the airborne lifesavers means the race had contributed more than £100,000 to them since it was first held.
Preparations for the next one have already begun, with efforts led by Mr Bartlett and a team of about 10 others.
Between now and then they will need to recruit about 40 volunteers to help on the day and are also hoping to secure another main sponsor for the event to work alongside existing partner Lexus Reading.
Asked about the secret of the event's success, he added: "It's local and it's funny how you can recognise people you've seen in the village.
"There's nothing I enjoy more than going through the crowd and seeing people you haven't see for ages.
"And we've got the perfect village for it too - from one pub to the next and down hill all the way."
Visit www.gravitygrandprix.co.uk to find out more.
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