Another Lulonga

[Tomas Krejci]

Part 1
Another Lulonga  - paddle Wheel
When building a model paddle steamer Lulonga I had to solve the design of the wheel, which would be as simple as possible and still meet my requirements for my simple production conditions.
I came to an interesting Russian sites SEATech , which designed the paddle steamers, but the wheel are specially shaped => this is also one in my post here on Paddleducks

http://wheelships.ru/

http://wheelships.ru/index.php/joomla-license

This idea appealed to me, so I decided to use it in the construction of the model  paddle wheels for  Lulonga model.

Here I would like to first point out that the wheel on some sternwheelers  used earlier or less similar regulate water flow driven by skew  blades so that the leaves were divided at halves in the middle of the big and broad wheel , flat and inclined against each other in the middle of a similar way.
This design was used among others in sternwheeler  tug Verity. * (Article Geo.M.Verity)
See also the contribution from> towboat joe <>  herringbone Wheel  <
      Aug 7/2007 to>  www.paddleducks.co.uk  <

similar shape of wheels  we found, however, for other ships.
reason as stated above, that should  reduce the noise level
But the most sophisticated use of such  structural element brings up Russian patent from SEATECH , mentioned above.
Paddle wheels for Lulonga- description, history of development and construction
For my first model steam sidewheeler Ned Kelly * ( in the download Paddleducks section), I chose simple design wheel to test the two-cylinder steam engine Wilesco.
  I had some cheap  pieces of  discarded    sheets  of fibreglass  laminated  by copper sheets(The board with copper on it is called "copper-clad laminate" too , primarily used for printed circuit board, or PCB technology, in this article “ CCL” ) . This material I used for  model wheel  blades .
The paddle wheel  skeleton was formed by full plywood disc Ø 140 mm    (plywood  thickness 4mm), into which was inserted 8  blades ,  glued by  epoxy(  "CCL" 50x40 mm)
The paddle wheel  skeleton was formed by full plywood disc Ø 140 mm    (plywood  thickness 4mm), into which was inserted 8  blades ,  glued by  epoxy(  "CCL" 50x40 mm).I glued everything on the  template -wood block that allowed me to check the squareness of blades  Next step was sticking wooden flange on the center of the disk, serving as a tenon for attachment to the wheel axis. the whole construction was then  painted with thin epoxy and polyurethane varnish.
                                >  3 > Ned kelly wheel <
practical implementation
>  Appendix figure   >  4  > Ned Kelly paddle <
                                >  5  > Ned Kelly from behind <
As you can see from the photos, the wheel was mounted on the axis of a broader part of shoulder blades toward the fuselage.

[Tomas Krejci]

…… Part 2
When driving this arrangement surprised me their efficiency. It probably contributed to the fact that the model side, along which the blades were moving was  practically straight and parallel to the longitudinal plane of the disc wheel, and formed a kind of plywood  tray(between disc and model side) in which the  blades were moving.  I think  it would enhance the effectiveness  of paddle propulsion..Steam engine rev were reduced  overall in the ratio of 6:1 (3:1 on the engine,  then 3:1  reduction from  chain drive to paddle wheel   shaft; total resultant speed of model was sufficient  even at minimal  engine revolutions (50-60 rev / min on a paddle wheels)but  at maximum speed (120 rev / min and above)  the speed of model  was unnaturaly  too fast when compared with an average speed of  original Australian steamers.

> Appendix foto 6> Ned Kelly > Engine room  <

this design of paddlewheel   I could not very well use for Lulonga, because I did not have a good waterproof plywood.In an effort to keep the design as simple as possible,  I was forced to think of somewhat better and more durable construction.

[Tomas Krejci]

……………….. part 3
 I needed a simple design producible at home without greater mechanization (milling cutter, lathe), which was also  my   case.
The main requirement was that I need two independently driven paddle wheels. Their design must allow for mounting and dismounting accessible on the driven shaft (steel rod Ø 4 mm), and especially their resultant  structure should be strong enough.
The material, for which I again decided  , were the  Fiberglass copper coated  thinner boards that I have used identically  for model Ned Kelly .. This would partly be used to construct  design both soldered and glued. I finally chose bonding by epoxy glue. In addition, the material is definitely stronger than the sheets of hardened polystyrene   recommended in  Lulonga drawings  . Of course,here  could be used directly thin fiberglass sheets, and reinforced structure by  small rivets.  The  use of Aircraf or waterproof  plywood  I did leave  due the  price  of such  stuff.
Here at Paddleducks, you will find many inspirations both in material and in its use .. just choose what suits you best.
 As a basis I used the wheel drawing   from  original drawing in the scale 1:32( in plan from David Metcalf,> Quarter-wheeler River Paddle Tug Lulonga <Magazine> Model Boats <), which I repainted separately on paper
> Annex image> 7>
the outside diameter of the  paddlewheels  is 140 mm
………………………………………

[Tomas Krejci]

Part 4
Mesasured  pieces of wheel  I cut  with  shears and filed  down with flat file. I cut the  notches into spokes  with a hacksaw with intent to    insert  at the end blades into notches   . I made spokes a bit wider, due to the strength, nevertheless the   greater  width of spokes does not hamper  movement  of the wheel in the water  . The wheel spokes I cut toward the center   of the wheel ,  as in figure 7B ( like the wheel structure sternwheeler Okahumkee -here at Paddleducks.
Side view of wheel I drew on paper which  I put into the transparent PE envelope..This envelope I   put to the surface of the hardboard . The PE envelope  allow individual parts directly glued  after attaching them together at the envelope surface.Individual parts I pinned up to the appropriate place according to the drawing. (through  drawing to hardboard pad) and glued with epoxy glue.
Each side of the wheel  had 8 spokes, glued again  on the middle part of CCL in which are  the pre-drilled holes Ø 6mm for false shaft . I had not circle cutter , so I cut the middle parts as squares.
After hardening of epoxy I have glued  the same part ( for strengthening   of  joints  ) to opposite  side, rotated by an angle of 45 ° .To maintain perpendicularity of siderails to the shaft   ,  I put  small  wooden flange at  the center of the wheel  , (to make flange joint ) and let harden it  in the simple  wooden jig. After preparing the template, I then glued 4 equal siderails this way.
As a  next and final  step I placed subsequently   these prepared parts  symmetrically ,(flanges inside),at  an auxiliary (false) shaft , made of  Cu pipe Ø 6 / 4, 2mm and set 40 mm pitch  between  siderails.
 
Now, after a moment's hesitation, I made an important decision - when I glued prepared "star" sides  to auxiliary shaft ,I turned  these against each other slightly about the width  of spoke   ( approximately by  10 ° here), likewise  to the aforementioned Russian patent.
When building wheels with angled blades, so dashed line in Figure 7  indicate position for the second wheel side   !!

 Here need to be careful .. if you also wanted to make such adjusted wheel  .. => Wheel are symmetrical and  mirrored ! So then here are  the left wheel and the right wheel, and these can not be (or..should not  in any case) interchanged.
                >  foto  8 >
                > foto  9 >
After the curing of the adhesive on the axes , followed by sticking blades, again on a  wooden  template jig,  for adjusting   the equal  lateral height of blades.
             > foto 10>
             >foto 11>

[Tomas Krejci]

part 15

The next step was to attach the side brass flanges (cuffs) to the copper tube at the inside of the wheels.. After inserting the flanges I marked the place where the  copper shaft is drilled and  with screw (grub screw ) M4 tightened on its own drive shaft, (consisting of a steel rod Ø 4mm.)

The drive shaft may be common to both wheels, but now I have it split, each wheel has its own drive( geared electric motor  DC 12V with ESC )
Drive shafts are each placed in two brass bearings, one on the inside of the paddle wheel box , the outer  at longitudinal  paddlebox   reinforcement.
On the inside of the shaft in the hull,  there are deployed flanges  of  toothed belt gears .

> Image 12 >
> Image 13 >
  Paddle wheels on the outside are covered with covers from GPPS  with mounting hole, allowing assembly and disassembly of paddle wheels .against orginal version of covers I made some improvements .
> Image 14 >
> Image 15 > ..

[Tomas Krejci]

At the end of this chapter I put photo of  my  live steam model Ned Kelly ..

I was convinced that here at Paddleducks   must be somewhere photos of  my model Ned Kelly too ,

                 nevertheless   somewhere over the rainbow ....

[Harold H. Duncan]

Very nice Tomas,
both models.
cheers
kiwi