Does anyone here have a formula for paddle area per HP

[freedem]

I am researching building small paddlewheelers and
woundered if anyone here knew how to size the paddle area for
engines of a certin size?
thankyou
Jeffery

[Joe E Brown]

There is no consensus on the proper wheel size. Some argue for the
biggest wheel possible, while others use smaller wheels rather than
additional gearing. Some prefer deep dip for more force, others
believe in letting the wheel rev up. Neither races or shoving
contests prove one idea to be clearly better than another. One thing
common is the wheel diameter is often times the same dimension as the
width especially on smaller boats. only advice I can give on engines
is that it doesn't take much to push a paddle wheel. Most real boats
range from 80 to 150 hp.

[Paulrjordan]

Hi Jeffery:

This has been the topic of some interest in Paddleducks and if you go
to your Paddleducks home page and click on messages..take a look at
some of the previous postings about paddlewheels. As Joe suggested,
the jury is still out on a lot of this stuff. ONE thing is for
sure...you HAVE to get the wheel rotation approximately right...a
paddler with a mixmaster wheel speed looks really dumb! TJ has said
in the past that anywhere around 100 to 120 RPM's is okay for
sternwheelers but on sidewheeler models (which I build) I can
recommend that up to 180 rpm still looks OK. Remember, the
paddlewheels on a sidewheeler are hidden to a great extent either by
boxes or under water but on a Sternie you see EVERYTHING! Which type
of vessel are you contemplating? Because water is non scaleable,
chances are you have to run a little faster than prototype (unless you
cheat with oversize paddles!)

Float area? That depends if you are modeling a prototype which
actually existed in which case the plans can give you the area you
need to scale. However..sssshhhh...on sidewheelers I "exaggerate" the
float area as much as I can without altering the overall outside
dimensions of the paddle boxes.

So far as motor torque is concerned for models...I've found that very
small motors will adequately power side paddlers. In fact I just
"recycled" the TWO motors from an old CD ROM drive from an ancient 386
computer I found in the street. They are PERFECT for driving a little
"Alligator" warping paddler I'm reseaching (the original only had one
engine, but I'm going to cheat a little with dual engines which make
for incredible handling!). These engines only draw .04 Amps at 6V and
their stall current is still only .45 amps. (they actually run better
at 3 volts) They are tiny but yet still have the torque to turn
paddles adequately. I have always been of the opinion that most R/c
modellers put engines that are FAR too big in their boats. In fact
I've just replaced a $40.00 gearhead Graupner motor which was drawing
over an amp in a Club boat with a small .06 Amp motor I bought for $1
at a flea market. The boat achieves exactly the same speed but at far
less current draw and a quarter of the size of the big Graupner. The
weight saving also allows for extra battery cells.

My philosophy is to start with the smallest motors and work up.
There's quite a bit of experimentation and the bathtub becomes a
regular haunt in paddlewheeler modeling.

I'm sure there'll be more on this topic from others but what you're
actually talking about here is "THRUST" which is all dependant on
1) Float size and number (total area)
2) Float shape.
3) Float plunge (dip)
4) Float type (feathering or non feathering)
5) Rotation (wheel speed)
6) Wheel diameter

I still owe Derek in Australia a diatribe on Paddle wheel floats and
plunge or "dip" (which TJ alluded to) and as soon as I get a little
more time I'll follow through.

Meanwhile tell us a bit more about what you have in mind to build.

PJ

[freedem]

Hi PJ
I'm researching about small prototype size paddlewheelers that
a privet individual might build for himself , say 8 to 32 feet. (
though there is always a grander dream of a 72 footer with the
cabability to cruse to the 50th state haiiawi (sp)

this year likely will see a 16 to 24 foot catamarane test boat so I
can try different paddle types eventually am looking at a
houseboat / sternwheeler of around 32 feet. ( a wilder idea
would be a 12 foot long side wheeler with independant wheels
so that I can try smallish rivers that might be only 15 feet wide
and a foot deep
Jeffery
ps I tries a search under horsepower and nothing area brount
up a few things so I thought I'd ask if you had some other search
word ideas.
on the other hand there only about 500 messages here which
may make a nice evening read :-)

[Joe E Brown]

Try these links www.steamboats.com and www.steamboats.org