Hi ,Could anybody advise me as to what drive to use on the above,ie what revs to aim for ,to use a gearbox  or not .Basicly  I,m lost  Thanks John 

Hi John, basically you need to have the paddles turning at approx 90 to 120 rpm so a gearbox is a must. Have a look around on fleabay for motor /gearbox combinations, they are ex industrial motors and are usually well made, the only drawback is they need 12v but will be quite happy on 6 to 12. I connect mine up with chain drive but belt drives are also used. I try to avoid exposed gears as they tend to be quite noisy.
Have fun, Chris M.

While your'e fleabay have a look for Heng Long or Tamiya R/C tank gearboxes.  I bought a pair for around 10 quid complete with motors. 

Okay, so I was looking at these http://www.motionco.co.uk/motors-worm-gearbox-gearmotor-c-54_73.html as they have an rpm right in the middle of those range (couldn't find anything on fleabay) but the torque worries me. Any ideas as if these would be useful ? Or should I be looking at something with more torque, a planetary system perhaps ?

Thanks

John

Hi again, do a search on fleabay for 12v dc motors. About 1/3 the way down is a 12v 120rpm unit for less than £7 each delivered from China. I have used these types in previous models and have found them smooth and reliable.
Cheers Chris Monk.