Hi Derek
Sorry about the delay in replying - had a few computer glitches - all better
now. I have uploaded 3 photos to the photos section of the progress so far
which is basically the fitting of the sponson outer beams and the start of
the sponson decking. I am getting just a little nervous - although I am
keeping the sponsons as light as possible commensurate with adequate
strength I have this feeling that Eddy's description of the 'crew' reeling
from side to side as the ship turns may turn out to be true! Never mind,
there is no way to make them any lighter unless I come up with a method of
injecting wood with Helium! The section of sponson in front of the paddle
wheels carrying the eccentric mounting will be removable to enable me to
take the paddle wheels off for maintainance. Having read your post about the
shaft bearings outside the hull I have made two scale 'dummy' bearings -
well - seemed a shame to leave them off :-))
I will of course keep you updated on the power plant. At the moment I cannot
decide whether to go with my original thoughts of 2 engines with 2 boilers
(more complicated but with a nice low centre of gravity) or 2 engines and
one boiler (much simpler but higher C of G as the boiler has to be twice the
size to give adequate steam capacity).
As to the rotational speed of the paddle wheeels I am not too worried. One
of the BIG advantages of steam power is that steam engines give maximum
tourqe at zero revolutions. Provided the wheels are geared down so that the
resistance to rotation is not more than the power of the engine (I will be
using a 4 to 1 reduction) then the speed of the wheels can be simply
regulated by the throttle. The engines I have chosen use one channel of the
radio for speed control and forward and reverse - neutral on the radio stick
being 'off'.
I expect the paddle wheels to turn at ABOUT 50 rpm. One of the main reasons
for instability on paddler models (sidewheelers) is that they are simply
travelling too fast! So I think about 50rpm is the maximum I would want them
to turn. I am hoping that as the model is fairly large she should be a good
deal less tender than a smaller model. The 26inch model I built some years
ago of the same boat was fairly worrying on the water - but if you were
gentle, then quite controllable and safe.
I have sourced some sub-miniature roller chain and sprockets from the info
that Randal Largent sent me (thanks again!) so that sorts out the drive
chain (no pun intended!).
So now its back to getting glue on my fingers and wood dust up the
nostrils!!
Stuart
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