Lulshorta - My Build

[rpbidgood]

Author's Introduction

I haven't made many contributions to this site, but it has given me a lot of pleasure and inspiration. In order to give something back I have very reluctantly decided to offer an account of my latest build. I say reluctantly, because I would never claim to be a master builder - I have neither the patience or the ability to produce the masterpieces that some modellers achieve, and the best I can hope for is to produce something that is a sort of "Stand Way Off Scale", a more elegant phrase might be "Monet Scale" ie. it looks good from a distance.
   ps. Initially I intended to build the Lulonga, but when my wife saw the size of the plan she muttered something like "Gonna need a bigger house". So, I decided to simply reduce the size, so, the Lulonga became the Lushorta. Then I decided to make a completely freelance design, but by now the name had stuck, and anyway I liked the joke.
   So, without further ado, let's get started on the build :-

"Take my hand, I'm going to take you into some dark places - but, I think I know the way"

The Hull
(i)    The design had to be a quarter wheeler, like the Lulonga.
(ii)   The drive to the paddle wheels was going to utilize worm gears.
(iii)   I also do a lot of my sailing on fairly rough, windy water, so I didn't want a fair weather boat - the hull would need to be stable and not ship water easily.

It did occur to me that if the worm gear shafts run in brass tubes, this would make the stern a little more water tight than using a more conventional chain drive.

The hull has been made from balsa, and has been given a few coats of epoxy finishing resin. Disaster nearly struck when one of the coats refused to harden; even after several days of warmth and patience - I must have used insufficient hardener. It took a lot of sanding and not a little cursing to remove the offending coat - it was a hard, gooey consistency that clogged up the sandpaper easily. I was a good deal more careful with the measurements next time. The hull is now nice and smooth, and when given a few coats of paint should be waterproof and fairly durable. Interestingly enough, the modeller, William Mowll, whose builds have been a regular attraction in Model Boats, once said, that with the use of modern finishing materials it is possible to produce a glasslike finish on the hull, unlike anything on a real ship whose hull, especially below the water line is a mass of rust, barnacles, dents etc. With this in mind, he, (on  his model of the steamship, Sirius, if I remember correctly) deliberately brushed the resin coat just before full hardening to roughen up the surface and simulate reality. I enjoy using painting effects to simulate weathering, but deliberately "messing up" the finish is a step I have been unable to take. Perhaps next time.
See picture of my Fletcher to show paint weathering.
 

[rpbidgood]

I intended to include a photo of the hull, but it somehow disappeared into the ether, so I'm going to try again.

[rpbidgood]

The Paddle Wheels
I made the wheels a few months back on the school's Laser Cutter (I think I'm in love) when I had originally intended to build reduced size Lulonga, but the size is the same so it doesn't matter. The wheels are made from 1.5 mm hips (high impact polystyrene or something like that), and the individual parts, when cut out, have quite a flimsy feel, but when assembled, even as a dry fit, they become remarkably rigid. The first photo shows the unassembled parts. This paddle wheel is actually not for this model, but is a replacement (second picture) for the wooden paddle on one of my previous builds, The Santa Ana (3rd picture).
Back to the current build - the 4th picture shows the assembled but unpainted quarter wheeler paddles. The wheels are attached to the axles with collars that I turned from some bronze stock - you might just be able to make them out. There are 15 paddles to each wheel, and probably this is less efficient on a small model than a smaller number, but I am not really interested in efficiency as long as the boat moves quickly enough - but I do want to see the those paddles churning up the water. Incidentally, on the Lulonga the paddle wheels are largely covered, and this is one reason I changed my mind and went for a freelance design (I suppose I could have modified the design, but there we are.)
   Strangely enough, I read somewhere that the screw, a new and radical design at the time, on Brunel's Great Western protrudes out of the water, even when fully loaded. Now Brunel was too good an engineer to have made a mistake like this, could it be that he designed this error in simply to provide spectators with the magnificently awesome sight of the propellor churning up the water behind. I feel a strange kinship with the great man.

All for now, I hope I'm not boring you all.

Keith.

----------------------------------------------------------------------

All the world's great men are dead, and I'm not feeling too well myself.

[Eddy Matthews]

Looking good so far Keith - Keep the posts coming!

I'd give my right arm for a laser cutter - Well, okay I wouldn't, but you know what I mean!!

The name reminded me of my motorcycling days - Remember that articulated trucks used to have a yellow and orange board on the back that said "Long Vehicle", I used to have a Suzuki 250 with a topbox, and on that it said "Short Vehicle". Some dipstick still managed to run into the back of me when I stopped at a zebra crossing though!

Regards
Eddy

[rpbidgood]

One day the worm will turn
Checked through my box of gears, the meccano gears are just too big, but I find a small supply of plastic ,spur gears from a previous project that are a nice, tight fit on a 3mm silver steel bar, and some matching worm gears that fit nicely on a a 1.7mm shaft. This latter shaft is a nice fit on a brass tube, but the shaft and tube will need to be supported. The are about 30 teeth on the spur, so the gear ratio is just that, ie. 1:30 ish.
  The attachments show the tubes epoxied to their wooden supports. You can also see the duralumin axle bearings.
Note (i)  the worm gear is very nearly flush to the brass tube - this should minimise the chances of the worm gear wandering off the spur gear
Note (ii) The inner ends of the brass tube are a different length - there is not enough space between the 2 shafts to allow the motors to be mounted side by side - this is to allow the 2 drive motors to be staggered. This will be clearer later on when the paddle assembly is attached to the transom.
   The 4th attachment shows the paddle assembly epoxied to the transom, and the next photo shows the the staggering of the motor mounts. The penultimate photo shows the paddle wheels temporarily in position and the staggered mounting of the 2 motors ( a 12inch rule is included to give an idea of the scale). The green bits are homemade coupling, a similar pair, used on another model are shown in the last photo.
 ps. I have tried the motors on 6V and the paddle wheels are turning at a most undignified rate - much, much too fast. The motors are tiny, I don't want to try and find smaller ones. I'm going to reduce the voltage and see if there's enough torque available using 2 cells or possibly 3 cells - I understand Action Electronics make a speed controller that operates at 2V.

Keith.

"A bad bush is better than an open field."            Scottish Proverb (translation please?)

[steamboatmodel]

Hi Keith,
Looks like a great build. You state "I have tried the motors on 6V and the paddle wheels are turning at a most undignified rate - much, much too fast" have you tried them powering the hull, A good esc will allow you to chose the speed you want to run at. It is a good idea to have reserve power for those situations when you need to move the model faster than scale.
Regards,
Gerald.

[rpbidgood]

Hi Gerald,
              I haven't actually tried it in the water yet, but I will do that before I commit any money for speed controllers (two!), however, my gut feeling is that at 6V the ship will be up on the plane . I stuck an Ohmmeter on one of the motors and it returned a value of about 3 ohms, which I suppose means that the stall current at 6V would be about 2A. I suspect that under normal operating loads the current draw will be much less than 1A, even when the red mist has descended and I'm making an attempt at the WSR, or trying to escape a belligerent duck, - but I can stick it in the bath and measure this with an ammeter.

 Most of my experience of esc's and motors has come from the time that my son raced model cars and the average current draw during a 5 minute race is probably around 20A so, I am a little unfamiliar with the more sedate pace and demands of a paddler. When I finally switched back from model cars to model boats I transplanted an expensive car speed controller into the boat only to find that I had very little precision/control at the slow speeds. Since this latest project is a quarter wheeler and I will be controlling the steering and the speed via the speed controllers - I need to have good control of the motors. Will a speed controller that has a maximum current draw of say 10A give me the precision I need when the motors are probably going to be drawing less than 0.5A?

I want to be able to do doughnuts, but sedate, ladylike ones.

These are not problems, so much as challenges, which makes life interesting.


Thanks for you suggestions.

Keith.

ps. I like the look of the P78 Condor 2 from Action Electronics which has a maximum current  of 2A and a voltage range of 2V to 12V - the voltage range should give me plenty of scope for experimentation with different cell combinations.

-----------------------------------------------------------------------------------------------------------------------------------------------------------------

"As I hurtled through space, one thought kept crossing my mind - every part of this rocket was supplied by the lowest bidder!"        John Glenn

-----------------------------------------------------------------------------------------------------------------------------------------------------------------

[steamboatmodel]

Hi Keith,
Most of the speed controls I have use were less then 10A draw and did give precision at slow speed, but they were designed for scale models. I haven't used any of Action Electronics units, as I still have some of my older esc for my electric models and most of my current boats are live steam.
Regards,
Gerald

[rpbidgood]

Hi,
    Since the last post I have been experimenting with Laser Cutter's potential for cutting out the superstructure/marking planks etc. and I enclose a few pictures. It is very easy with this technology to make everything pristine and perfect, and to make it more realistic I have deliberately exaggerated the imperfections, drawing different width planks and making the nail runs uneven. The material used is 0.8 mm and 1.5 mm birch ply, the thinner gauge being used for the upper superstructure and the severe curves. Balsa etches nicely, with deep, dark lines, but is a little fragile for the delicate window structure of the cabin. I am still exploring the different combinations of speed and power on the machine and hope to produce darker, more pronounced lines on the ply. Also, I intend to apply some stain to the ply, this might add another dimension to the finish.
  I quite enjoy planking decks etc., but I thought it would be an interesting exercise to use the laser cutter - it doesn't take as long as you might think to add the detail - once a few planks, knots and grain have been drawn the rest are simply 'copied and pasted' - my youngest granddaughter helped with this mundane detail - they are all familiar with this sort of thing nowadays - she helped so much that I have decided to name the boat after her. Meet the PS RACHEL ERIN.

Keith.

-------------------------------------------------

Growing old is compulsory. Thankfully, growing up is optional.

-------------------------------------------------

[PeeWee]

I have never thought of using a laser cutter for scale markings,  a great idea i have to say.

[rpbidgood]

Sorry for the massive delay in posting, but personal circumstances. too boring to relate, stopped the build. The partially completed hull remained on a shelf for a few years filling me with guilt every time I looked at it until I could take it no longer. I didn't photograph the remaining build - the main interest for me was the use of the worm drive, the rest was a pretty standard build - the funnel is rolled aluminium sheet and I plated the hull down to the waterline with embossed card.
   The first time I ran the motors (out of the water) the prop shafts screamed like banshees in the brass stern tubes and I thought that the exercise was a dismal failure. In desperation I filled the bath up and tried again, this time the resistance of the water slowed the paddles and ship was quiet! If I repeated the exercise I would use a thicker brass tube with bushes/bearings in the end.
  I have ballasted the ship in the bath and as a quarter wheeler she seems to steer quite well - the paddle wheels are however quite close together so it remains to be seen if she steers well in open/windy waters. In hindsight I could have moved the wheels a cm or so farther apart, this would have provided a greater turning moment, but its maiden voyage will be the proof of the pudding. I attach a photograph of the RACHEL ERIN showing her in a nearly completed state.
 

[derekwarner_decoy]

Hi PD's & congratulations on the build Keith  ....the rustic finish adds to her appearance......Derek