In article .com,
Mathew Newton wrote:

As others have said, a flexible (ridged) hose impedes airflow, and
significantly so over long distances. If your ceiling void allows it
then smooth/rigid ducting will be far superior.

With the way the joists run, it looks like I will need a couple of sharp 90
degree bends unless I can think of another route.




In my case, being in similar circumstances to yourself, I bought a
Baumatic canopy hood from TLC
(http://www.tlc-direct.co.uk/Products/BMCAN54SS.html) which, at £100
for a 500m3/h freeflow is hard to beat. It has a 5" outlet and so I
bought a coupler (from BES?) to marry this to 6" ducting. The ducting
consisted of a 1.5m rise to the ceiling (void), a 90deg bend and a 3m
horizontal run to the outside wall. The exterior was finished with a
gravity flap as there is none such fitted to the extractor itself (and
thus would be draughty when not in use).


Interesting. The Beaumatic chimney hood is the one that caught my eye. Sadly
the white one is greatly more expensive than the stainless.

..and the final product at:

http://www.newtonnet.co.uk/house/200...s/IMG_4074.jpg
http://www.newtonnet.co.uk/house/200...s/IMG_4066.jpg

Very helpful and much appreciated.

--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk