Long build.. Talisman 1

[Talisman]

A wee bit of an update..

Hi all,
Over the weekend i managed to get the hull and windows painted. (pic 7)

A bit of work on the Paddle Wheels. Slowly there is an end in site - knowing what i know now Graupner paddles do look more attractive for the time they save. 

The wheels are taking a lot longer than i expected.

Despite my best efforts at keeping the measurements and drawings as accurate as i could a little human error has crept in, not that it matters to much to their operation but annoying given the amount of time i spent.

A little about the pics

Pic 1

Turning the boss and drilling the hole for the shaft. 10mm Silver steel rod should arrive by the end of the week. Fingers crossed.

Pic 2
Tapping for a retaining bolt.
I will use an m6 screw to hold the paddle on to the shaft no particular reason other than that was a size of tap and bolt i had to hand.

Pic 3

One rim bolted onto the boss using A2 stainless nyloc & bolts.  (m2.5) 
M3 rods were attached and checked for alignment the the second rim mounted, marked , drilled the attached.

Pic 4

Shows floats mounted on M3 rod. Washers/ spacers were cut from Silicon fuel line.
The rod further inside the wheel is M2 threaded rod and is used to keep the spacing and add strength. I could probably managed without this further strength but the holes were drilled and the materials purchased. A very footery job.

Pic 5

Shows the wheel nearly complete only needing the remainder of the m2 rods positioned and m3 rods trimmed.

Pic 6

Shows the eccentric wheel drilled and mounter on a nice piece of shaped brass. ( mirror mount from B&Q)
This will be bent at right angles along the base to allow mounting on the paddle boxes.
Again silicon washers cut from fuel line will be used.
To connect the floats to the eccentric disc i will use m2 threaded rod and bolts with a 'blob' of solder on the ends. They should look OK as the paint will probably cover the thread. I can live with that after considering buying rod and only taping the ends. The price of a small enough rod, nuts & a die sorted that decision for me.




Next....
I need to finish the paddle boxes  and mount.
Cut the 1m of Silver steel rod to length.
mount the shaft bushes.
Then a trial fit of the paddle wheels Then i can measure and cut the push rods.

Trusting all the above works then i can enclose the paddle boxes.

[Talisman]

Hi All,
Moving on with the paddle wheels after a motivation block...
I have rough fitted the eccentric wheel & rods and would be very gratefull if you would have a look at them and give me your thoughts on wether they are suitable or not.

I seem to have a fair bit of friction but should be able to remove that by opening holes a little & adjusting the silicon bushes.

How i put it all together...

First the eccentric wheel was centred on the drive axle centre of the paddle wheel. All rods were cut an fitted to the centred wheel. (2mm Threaded rod, Z bend at the float end, bent and retaining nut at eccentric end. All have been rough fitted and need trimmed.)

Once assembled the eccentric was moved to a position where the best alignment of the blades was achieved.
Not an exact engineering method but the best my patience would allow at the moment. 


My main concern is if they will actually work as they should. I have photographed the wheel on top of the plan for reference. The other pic is of my method for the fixed rod.
Any thoughts / opinions would be great.
Thanks
Kim

[Eddy Matthews]

I think that's one for the engineering bods to ponder on Kim..... Hopefully they can come up with a solution?

But my uneducated two-penneth worth is that the eccentric rods may be a bit small - At only 2mm diameter, they are probably bending slightly and causing the mechanism to bind..... I could be totally wrong, but that would be the first area I would look at.

Regards
Eddy

[Eddy Matthews]

Kim,

I'd also take a very close look at the bends in the rods, you will never get a HARD right angle bend (like that in a letter L) you will always get a soft right angle (Like the bottom of a letter J), so they don;t need to move very much to cause binding....

Regards
Eddy

[Talisman]

Many thanks Eddy right now I could do with all the help i can get. The wife doesn't seem to be of much help and i thought she was good with black art stuff

My thinking with the 2mm rod was to allow for bending rather than major strain on other areas.
If I'm wrong i could allways go up in size??

Its all a bit confusing at the moment and will be very happy when this part is behind me. All this just to stick them in a box and under the water

[Eddy Matthews]

My mother-in-law is pretty good at working her magic with these things, so I could always ask her for some advice........ But right now she's gone off for a ride on her broomstick

Eddy

[amdaylight]

My mother-in-law is pretty good at working her magic with these things, so I could always ask her for some advice........ But right now she's gone off for a ride on her broomstick

Eddy

If she is what you said than she will know what you said and then you will be in lots of hot water because once SWMBO finds out what you said about her mother she will hit you with her broomstick. 

Andre

[djcf]

The wheels & floats look the buisness, Kim, a lot of work there, keep in at it, will be worth it in the end  
Looking at your eccentric rods, can I suggest the following... and I haven't constructed my own wheels yet..so its just a thought...
As Eddy says maybe the rod is to small a diameter & the right angle problem...
The "fixed" driver rod (at about 10 o clock in your photo) in my opinion would have to be pretty solid & with no "flexing", for the whole mechanism to work smoothly as its that rod that drives all the gear on the wheel, so it may have the most strain on it??? On my pre bought wheels (Mike Mayhew) the star centre and the driver arm are one piece (will post pic tomorrow if it helps)
Again just an opinion with no experience to back it up yet  

Clark

[djcf]

Another thought I have had for eccentric rods (as I have no intention of buying another set of wheels when I have used the set I have!) (again I dont know if it will work in real life!!)..  is to use suitable dia brass rod with a slice of tubing soldered to the ends to make a bush to bolt through..a jig could be made to ensure they are all the same size...just an idea   

[Talisman]

Report form the Layman and Brute force engineering dept....

Thanks Guys for your replies..

Eddy you are right about the bendy right angles - proposed solution open out the holes a little to allow free movement.

As much as I'd like to have a near perfect set of wheels i have to be honest and admit my skill and patience isn't really up to it. At the end of the day the boat is for use on the water not for a museum.

Regarding the 2mm rods i have carried out a set of very non scientific tests...

I have tried over exaggerating the eccentric wheel's movements - All OK

I have tried revolving the eccentric disk with considerable force  - Yes there was a bit of a bend put into the rods but the amount of pressure it took would surely be enough to stall the motor or at least have the drive clutch start slipping ( more on my drive clutch system when the blasted silver steel supplier gets his act together and gets the stuff to me   )

So in short - I'm happy to leave the rods as they are after alteration to the hole sizes.

The real question is have i measured up my rods correctly and is my method of finding the correct  ( or as near as dam it ) offset a working solution.

Or

If anyone can see any mistake i have made that needs sorting before i start to build them into the paddle boxes I'd really appreciate hearing them.




I found this little piece of video on YT, the rods look very thin.

http://www.youtube.com/watch?v=K3ouAwBTyFo

Thanks All
Kim

[Eddy Matthews]

Hi Kim,

Rather than enlarging the holes, which will probably cause even more slop and therefore binding, what about simply countersinking the holes on the side that the bend is on? That should allow the "J" bend to move freely?

Looking at the video, yes the rods are very thin, but bear in mind the problems of scale...... A 3" diameter rod on the real boat won't really behave in the same way as a 2mm diameter rod on the model - The loadings on the model are HUGE compared to the real boat....

Again, please bear in mind that I'm certainly not an engineer, these are just my assumptions which may be way off the mark!

Eddy

[Talisman]

Hi Kim,

Rather than enlarging the holes, which will probably cause even more slop and therefore binding, what about simply countersinking the holes on the side that the bend is on? That should allow the "J" bend to move freely?

Good thinking - will give it a go.

Looking at the video, yes the rods are very thin, but bear in mind the problems of scale...... A 3" diameter rod on the real boat won't really behave in the same way as a 2mm diameter rod on the model - The loadings on the model are HUGE compared to the real boat....

Unless I'm overlooking something Eddy (which is very possible) it looks to me as if the majority of the force goes down the length of the rod - (Where is Mr Badger when you need him )

Again, please bear in mind that I'm certainly not an engineer, these are just my assumptions which may be way off the mark!?

I really do appreciate them Eddy as i didn't think to question the thickness of the rods till you mentioned them.

Eddy
[/quote]

[Talisman]

Another thought I have had for eccentric rods (as I have no intention of buying another set of wheels when I have used the set I have!) (again I dont know if it will work in real life!!)..  is to use suitable dia brass rod with a slice of tubing soldered to the ends to make a bush to bolt through..a jig could be made to ensure they are all the same size...just an idea   

Good thinking, but my soldering skills and balding head aren't up to that level of work

Q. why wouldn't you buy wheels again??

[djcf]

If I stick to 1:48 scale, its just a matter of £ however if I made something that graupner wheels would go in without hassle i'd try them
The wheels I have in stock have 9 floats & some of my intended subjects have 7 or 8 floats plus I just want to have a go..... I can see it now, lots of  and 
 Im no engineer either but if you do have probs i'd try a more rigid driving rod, are you going to try them in the hull? I think its just a case of experimenting with the position of the star centre. if they work as good as they look you'll be fine! I think you'll always have a bit of snagging with things like paddle wheels..

[Stuart Badger]

Here's my advice kim for what it's worth!

Don't worry about the diameter of the rotating actuating rods - the forces acting on them are in tension and compression so there shouldn't be any bending PROVIDED you solidly attached driven rod is stout enough.

I gather that you probably don't have any 'machine tools' and reading your posts you seem a bit unsure about your 'skill' level? Pshaw! get a grip man we are here to help!! .

I would suggest that you make another (new) solid fixed rod from flat strip with a hole at one end that will fit over the eccentric shaft and put a small BA nut and bolt through the strip to secure it to the rim of the eccentric disk. This method will ensure that the fixed rod CANNOT bend, flex or break free.
At the paddle end - again I would use small BA nuts and bolts for the pivot (12 or 14) to the paddle float, and use epoxy or thread lock to prevent it undoing. I know the engineers out ther will start muttering about bearings etc, but it WORKS - and that's all that matters.

For the other 'free' eccentric rods, can I suggest that you again use small BA nuts and bolts around the rim of the eccentric and make new rods from brass tube, flatten the ends and drill a hole that is a nice free fit over the bolts and again use epoxy or locktite on the retaining nuts. Do the same at the paddle float end. You can make a very simple jig to ensure all the holes are the same distance apart simply by gluing 2 lengths of stripwood to a board set the width of your tube apart and the exact length of the distance between the holes. If you put your rod into this and use it as a guide for your drill you should have no problem.

I can't do you  a sketch at the moment cos it's 3 in the morning here! But if you would like me to just ask. In the meantime have a look at my very old post that I did for the Old Trafford paddle wheels and see if it helps.
http://www.paddleducks.co.uk/smf/index.php?topic=757.msg2553#msg2553
all the best

Stuart