Robert E Lee

[k buck]

I am presently building a scale RC Robert E. Lee boat. This is my first attempt at doing a side-wheeler. I have built sternwheelers but no side-wheelers. Several of my RC buddies have told me these boats have a tendency to want to tip when turning. Has anyone had this problem, and how can it be corrected ? My finished model will be about 22" long and have 2 7/8" wheels. My thinking would be to have a sliding weight to move proportionally with the rudder. Any thoughts on this ?
"The Ol Boat Yard In Cincinnati"
Karl

[Paulrjordan]

Hi Carl:

Great project...but a 22" sidewheeler version of the ol' REL with all
that freeboard is quite a challenge and will need quite a bit of
careful planning. You should be commended for bravery!

Of course the first thing you'll have to do is to make sure the
superstructure is as LIGHT as possible and the COG is waaaay down low!
You might even consider "cheating" a little by giving her hull a bit
of extra draft... where do you plan on operating her? Inside or
outside? An indoor pool will be quite a different experience to
outside (unless there's little wind or surface turbulence). The big
challenge with a model this short and this high is stability and in
an outside pool, directional control (windage and drifting) is also a
major consideration..

Are you going to use scale size buckets (blades) or "overpower" them
a bit by increasing their surface area? You will definitely find the
ship will tend to "waddle" a bit, so venting of the paddle boxes
could be important. An REL at 22" will likely be "tippy" on the turns
and re-stabilizing her will be an issue as sidewheelers of this size
tend to get "stuck" one side down! Your thoughts of a sliding weight
track running athwartships is based on a solution to the same problem
in real British paddle tugs of the last Century where they also had a
tendency to flip (which a number did) especially when towing on a
turn. You'll need to build a good rudder activated bench model
first, but if you look carefully at your COG issues and test the hull
and mechanics first, you might not have to resort to a lateral
compensator.

May I suggest getting all the mechanics working IN the HULL before
you build the superstructure...getting the correct wheel plunge,
paddle thrust/RPM and COG is important...so you'll need to know
exactly where the model will "float" for maximum efficiency and how
much weight you have to play with once all your machinery and control
systems are in place...believe me on THIS one!!!

You'll find lots of info on the whole subject of COG and model
paddler propulsion in earlier archived posts. You might wish to
spend an evening going through them..they make fascinating reading.
I'm sure your fellow PD's will have other ideas for you, so please
keep us informed and don't hesitate to post when you need help.
We'll be watching your progress with great interest...and baited
breath!

Best regards

PJ
Victoria, BC Canada

[k buck]

Paul, Thanks for the information ! To give you a little more background of my progress so far.
The hull was made over a solid pine block, carved to the hull lines. This form was painted to a very high gloss,(auto finish ) I then applied several coats of wax, then applied a release agent on it. I covered it with three layers of 1/2 Oz fiberglass cloth. Removed the plug after final sanding and priming. Yes, I did increase the free board by 1/4". I adjusted the position of the wheels pillar blocks to compensate for this. The weight of the hull with blocks is 6-1/2 OZ. Presently I have been checking motors to determine their RPM to set up the gear drives. I am going to try to run the wheels at about 105 RPM at full speed. Each motor will have its own speed control to use the wheels to help compensate for the tipping along with the sliding weight. Presently I am working on Four boats, the Lee, the Creole Queen, Cape Girardeau and a Viking long boat which will be powered by 30 oars. I have built a Nova Scotian Dory which is powered by an articulated figurine using only oars. This boat does the six rowing strokes, all by radio control. This is done using 4 servos and a Micro chip (basic stamp).
"The Ol Boat Yard In Cincinnati"
Karl

[dragoncity]

As PJ already mentioned, small ships can have stability problems, however with
your twin speed controllers ( good idea !) pehaps you could consider linking
them through a model aircraft stabilizer? ( electronic gyro ).
I have not tried this, so it could depend upon your units abilities.

This 'should' remove the need for a moving weigth solution, which I think
could more trouble than its worth as you will need to figure out
a) how much weight is suitable,
b) how best to move the weight &
c) how far , in proportion to rudder movement, is required to get the best
effect. ( in fact you might find that the movement is outside your hull beam
!! :-)

Also note that paddle wheel speed sync is vital( they must be VERY close to
the same RPM,s - your speed controllers will help here, otherwise one paddle
will 'dig in' and the boat will become quickly unmanagable.

Also, dont' be surprised if your rudder is not very effective --its a problem
of scale effect. And differential motor control, via your twin speed
controllers will solve this problem nicely.

Good luck

[wsnowdon]

Hi there. The problem is not so much "heeling", all sidewheelers
heel in a turn, it is getting it to come upright. Fullsize
sidewheelers have their paddle boxes well ventilated as, when they
leen into a turn one paddle box gets very close to the water stopping
air entering the paddle box so that any water entering the box stays
there, unbalancing the ship. ventilating slits stop this, allowing
air to enter the SIDE of the box. This problem is many times worse in
a model, a box full of water meens a permanent list! I make sure
there are as many ventilating slits in the outer face of the box as
scale allows, and I also (On Occasions) make a couple of small holes
in the top of the box, so any vacuum caused by water logging
immediately clears. Also on very narrow hulled paddlers an external
ballast keel is not very noticeable and helps the model come upright
quickly. this also helps to resist windage on very tall "block of
flats" steamers. Hope this helps a little, Walter.

[gerald gardiner]

Hi Walter

Charles Larking in our club had the same problem with his Mt. Washington, It would lean to one side in a turn and then stick. The model almost ended up as a Static Display Model. Then He came up with the idea of mounting a servo on the centre line of the model with a weighted arm attached. This is connected to a extra Chanel which he can activate when the model turns. This has worked like a charm and unless you watch very close you don't know he is activating it. There are some pictures of his boat on the Metro Marine Modellers web site at metromarine.org hope this helps.

Gerald Toronto Canada

[wsnowdon]

Hi Gerald- the moving weight is not far remved from full size
practice in the past!. Early British paddle tugs with fixed float
paddles had a wheel barrow full of scrap iron on their decks which
was wheeled from one side to the other to trim tjhe tug whilr
altering couse. The more sohisticated had a small gauge railway line
running across the deck with awagon of scrap on it for the same
reason. Cheers, walter.