Thanks clf-gas,Agile & David937, I was thinking on lines of what David937 is doing but feel the comments by clf-gas & Agile may be right in the way the fins are designed, if I could find a long cylinder type fan with gentle flow similar to the NuAire PPV fan I have in loft that uses less than 16w I would give it a try but a normal fan would be to much and defeat the object, never mind my bright ideas keep my old rusty brain ticking over.
As for the Dyson we got the early DC01 when they first came out, it was an unwanted gift so new for £125, it has had a couple of bits replaced such as sole plate and hose mostly due to wife being a bit rough as she is with me but she loves it and it does a fair job just not got groove in base to clean to edge so have to use hose, we was filters and reuse several times, I have a spare in loft with pet type filter but costly to replace filters, I bought a Kirby Generation 4 full outfit like new for £100, an old lady bought it new but found it to much for a 1 bed flat so hardly used I got it off her son on eBay mainly for the shampoo job, we live in sandy area and picks up on shoes then into carpets but the Kirby really get the sand out from bottom of pile the way the picks up carpet and vibrates it, wife can't handle it so I run it over all carpets about 4 times a year to get sand out, they are well built but way over priced new and parts are costly but what can you get for £100 today. An engineer I got s/h Dyson spares off said newer models are fancy but poor compared to first few models.