Paddlewheel issues - various

[Derek Warner]

I am slowly progressing with Decoys wheels and new proposed drive & still have a few issues

1) question for Mike [PS Waverley] - model paddle speed - some years back I think I posted
something like 'is the model paddle wheel RPM = to the real vessel shaft speed x the cube root
of the scale', but I got no real confirmation [only lots of things like we cannot scale H2O]

With PS Waverley, you naturally know the real vessel nominal shaft speed, so are you able to
confirm the scale & model [again say nominal] shaft speed? - I think this would most advantageous
to all PD's etc

2) Leighton [Spirit of Wakiato] provided some synthetic [non splitting, non rotting] blind slats for paddle
blades - I have sectioned and compared the rigidity between the plastic and real cedar and the cedar
has near twice the mechanical strength - so it looks like I have to be very careful of the underwater
cedar blades - regards Derek

[dragoncity]

Hi DEREK.
I recently saw a nice ADELAIDE ( about 1200mm long) and his
paddlewheels were completely fabricated out of rigid plastic
and they worked a treat!. I guess we modelers do tend to 'over
engineer' just 'cause we think we need to !! :-)

( also tends to make your scale m del aircraft unable to fly !!)

I'd stick with the plactic floats and not use wooden floats unless
you can really seal them, you could always glue thicker foam onto
them to give you the scale thickness.

Cheers,

[Leighton]

Hi Derek,
The cedar would be stronger because of the cell structure.
With regards to being in water did you consider pressure treating it?
Here in NZ we pressure treat Pinus Radiata by puting it in a kiln
and applying a vacum to take the moisture out of the timber then
pumping up the air pressure and introducing a liquid (preservative)
which fills the cell cavities. As the residue dries the cell walls
are coated and will not rot.
Perhaps a small version could be used just large enough to hold your
paddle wheels with the blades bolted on (this will eliminate the
need to fillet stack the blades). The "preservative" could be
polyurathane.
Leighton