Hi Les:
Alot depends on the kind of power plant you want to install.
Let me start off by saying, my experience is only with Sidewheelers
so when it comes to "Sternies" you need to have an expert like Joe or
someone else who has built them. Here are the most well known options:
SIDEWHEELERS
- ENGINES
1) ELECTRIVE DRIVE
a) Single engine driving both paddles (not recommended)
b) Dual engines driving individual paddles (recommended).
Remember many prototype paddlers had only ONE engine with a fairly
complex combination of reversers and clutches, but unless you are
trying to reproduce the model in EVERY detail, the dual engine set-up
is pretty efficient.
c) Conventional screw propeller(s) with "false" free
rotating wheels. I, personally, wouldn't do it..but some HAVE, and it
actually doesn't look THAT bad as the paddles are very much closer to
scale rotation although they don't kick up any WASH and that does
look as though "something's missing."
2) LIVE STEAM DRIVE - I have never built a true steamer...but I'd
LOVE to (50 years of steam locomotive passion). There's a "X" in the
equation here though..and that's the question of SPEED CONTROL and
REVERSING...it can be done successfully, but we need the LIVE STEAM
experts to advise you here. Although Edmar in Brazil is no longer
subscribed to Paddleducks, we maintain personal email contact and he
has kindly invited me to forward ANY technical questions to him.
- TRANSMISSION
OBSERVATION As far as I can tell, maximum prototypical paddle
wheel rotation was in the region of 60 rpm and may even have been
100, but I doubt that it could have been much higher as centrifugal
forces and water pressure would create enormous structural problems
in the wheel and paddles. (Please correct me if I'm wrong here!!).
We already discussed Model paddlewheel rotation and the Paddleducks
concensus seems to be max operating at 100 to 120 RPM, although David
Powell and I are trying for slightly higher rotations around 180
(Dave even higher) to have "power in reserve" in the event of windy
conditions. Remember if you rotate TOO fast the paddles will cavitate
or else you'll reach displacement hull speed beyond which additional
rotation is ineffective. Consequently, in models we are virtually
ALWAYS have to gear down the transmission, unless you can find a
slow RPM motor (my preference!)
1) GEAR DRIVES - Many combinations and gear arrangements exist
for this, so all you have to do is figure out your reduction, build a
gearbox (or two) and decide if you want brass or neoprene gears.
Remember, unless you really know what your doing, you can end up with
a noisy drive..and nothing kills the illusion of a graceful
paddlewheeler more than growling or chattering gear reduction.
2) BELT DRIVES - my own favourite method...quiet, forgiving,
easy to build and modify. I build my own pulley wheels (out of
styrene for weight reduction if ya don't mind)and for belts, I use
1/8" wide thick plumbers' pipe sealing washers of 1 1/4" and 1 1/2"
dia which, with gentle heating can be stretched to almost 2" dia if
necessary. Others use large O-rings on grooved brass pulleys and also
toothed rubber belts. (A good source of gearing and transmissions
for models is NorthWest Shortline in Seattle). However I find that
my little plumbers' belts are very stable, nice and sticky and have
never had a problem with belt slippage...theyr'e also incredibly
CHEAP at less than .50c each. The thing to remember on all belt
drives is you need to keep the belt tension absolutely precise....not
too tight and not too loose, and there is an optimum tension that you
can positively "feel, hear and see" when the motor and paddle wheel
"bed" into. The key here is to make engine mounts which are fully
adjustable (for and aft and vertical planes). I have a design for
fully adjustable "floating" engine mounts I build from styrneeand
which I'll put up sometime when I get a chance. So, in a nutshell, MY
OWN favourite combination - MATCHING low rev electric motors on
fully adjustable mounts with styrene pulleys and 1/8 wide belts).
Anyone who has seen my "Director" class sidewheeler performing is
astounded at her silent, smooth, transmission and incredible
maneuverability.
3) FRICTION DRIVES - this is something that REALLY interests me
and there has been some discussion on this at our "sister" group
Modelboats, and Mike (the moderator there and also a 'Paddleduck")
has some excellent ideas on this. I would love to pursue this a
little further with sidewheelers if anyone has any ideas.
Strongly suggest you all subscribe to Modelboats@yahoogroups.com
which covers ALL R/C BOAT subjects as you'll find a lot of crossover
up there. There is also an incredibly gifted lady up there called
Vikki Ford from the UK whose is building a fully operating model of
"Jules Verne's submarine "Nautilus" which has an amazing electronic
and onboard computer guidance system. She has a website and is VERY
helpful with information.
So finally, if you need more information of driving Sternwheelers, I
really do have to defer to our "experts" here... except to say....if
the paddler had one of those giant cranks and side arms visibly
turning the wheel..YOU really SHOULD reproduce it in the model...I've
seen quite a bit of "cheating" with Sternwheeler drives...
Hope this all helps and I invite LOTS of comments from you all. Pitch
in with just your thoughts and comments on what is probably one of
the KEY subjects in paddlewheeler modeling.
LES, thanks for opening the thread on this subject.
PJ
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