Another 'Presto'

[Spankbucket]

Hi all

Here's where I'm at before I lose focus giving my wife priority for the next few days!

I have now fibreglassed and resin'ed the hull.

Three pictures:

1. I bought a length of fibreglass on eBay last year which has done 3 boats with still loads to spare.

2. I prefer to use Polyester resin rather than epoxy. It's cheaper, readily available and isn't mix-quantity critical. It does however give off nasty fumes and is inflammable so you have to be careful. I wear gloves and a face mask and work in my ventilated garage/workshop. The 'Fastglas' tin in the picture was bought for less than £10 in my local general store. This is the 3rd boat its done and there is plenty for the next project!

3. The hull is 'hardening off' whilst my attention is elsewhere.

I have decided to make the paddles from scratch using a very useful posting on here from 2005. I have both a circle cutter and a 'rose cutter'. The latter is a wood tool for cutting circular holes in spruce wood sound boards. It has a fairly large centre pilot shaft (maybe 8/10 mm) but may prove useful.

I may also use my CraftRobo as an aid ... although designed for cutting paper and thin card it may be feasible to use it to score outlines on styrene for subsequent pressing out.

I'll post on these experiments once I get round to them.

Cheers...Bernie

[Spankbucket]

Hi all

I'm working on the paddle wheels using styrene sheet.

Pictures:

1. My experiment using my CraftRobo were successful and I was able to scribe nice deep cuts onto .65mm sheet. Any geometric distortion is due to my clumsy handling of the design software...the centering went awry along the line somewhere.

2. Cutting of the frames was slow going but I used a technique that old musical instrument makers used on parchment...I punched the scribed outline using a sharp chisel-headed craft cutter giving a few gentle taps of a small hammer to each section. The waste pieces were then easy to push out.

3. I cemented pairs back to back to get 1.3 mm frames.

More anon. I am conscious of producing lots of detail...if this is too much please let me know.

Cheers...Bernie

[Spankbucket]

Hi All

Today I have made the paddles. I re-used the jig I made for the 'Josie Olsen' project although the printed 12 spoke guide was a bit confusing for 10 spokes!

Radials are 2mm square styrene rod.

The paddles themselves are re-salvaged Ferrero Roche box styrene which is about 4mm thick.

I have a Boehler modellers saw which I find invaluable in cutting repeat items from stock...like the paddles.

Those with sharp eyes may spot the one paddle fixed on the wrong way...now corrected.

I now have to trim the excess of the radials (too long due to a measurement error!) and I may add some details to suggest the feathering mechanism.

I'll spray with red primer when all done.

Here are some pictures:

Cheers.....Bernie

[Dave R.]

They're almost to pretty to paint.
What is the axle?
Dave

[Spankbucket]

Hi Dave

Thanks for you very nice compliment. I've just added some dummy feathering rods and I'll spray the final assemblies tomorrow and post some pictures.

The axle will be 4mm brass tube (necessary because the paddles are built around 6mm aluminium tube) with a core of lesser size brass tube/rod. Whatever I can cobble together from my stocks!

Have a nice day and or sleep tight!

Cheers...........Bernie

[marinemole]

Looking good.

Andy

[Spankbucket]

Hi all

End of the paddle saga:

Photo 1 shows the dummy feathering gear (highly simulated!) made from styrene rod.

Photo 2 is final result after spraying with red car primer.

Cheers....Bernie

[derekwarner_decoy]

Hi PD's........ ...an excellent job Bernie.........basically ....1/2 of each wheel will be covered by the paddle box  ...can a box be of round proportions?...... .... we know the answer... as also 1/4 of the wheel is immersed in the briney.......

So the feathering gear when stationary will look fine.........when underway....the feathering gear will also look fine....... .....& that red auto primer spray is universal & great for model building.........Derek 

[Spankbucket]

Hi all

Thanks for your positive comments Derek.

Derek is right on all counts....In my case I'm happy to have a 'representational' model that looks right rather than an engineering marvel ... for which I don't have the temperament or skills anyway!!

I have just applied a couple of spray coats of varnish to finish off.

Have given the hull a good wet'n'dry sanding and have just starting work on the sponsons.

Cheers......Bernie

[Tug--Kenny]

Well, your  'simulation'  fooled me. Ingenious. 


ken

[Spankbucket]

Hi All

I've been busy over the last couple of days and the attached pictures show the fruits of my labours. The hull is nearly there including the sponsons and paddleguards.

I am still debating in my mind as to precisely if and how I can comfortably fit 2 independent motors and drive controls. These would be Action electronic speed controllers and mixer.

I am going to go for 6v motors with a separate NiMh battery for them, distinct from the R/C etc. gear which will be 4.8V NiMH cells. Hopefully it all should fit. I have bought some Delrin gears and chain from an eBay seller and I'll see how I go with these. My intention is to use 1:42 simple worm reduction gearboxes which in turn will drive the cogs/chain. From various discussions here I believe the target is around 150 RPM on the paddles. I haven't measured my other paddler speed where a worm gear /cog drive the paddle mechanism directly but I guess it's about that under load in water.

Photos:

1:  The Hull/Sponson assemble red primer'ed.

2:  The paddle shaft in situ. This will of course be split in to two with further central axle boxes built but not in yet. This depends on the fit for 2 motors.

3:  I will cut the paddle box exteriors in styrene sheet using my CraftRobo. This picture shows an early pattern being tried in place.

4: These are the final paper patterns. There are 2 of each to allow for scrap/waste/errors...or even double layering. Once I'm happy I'll scribe/cut real plastic!

Next job is to fit the rudder. As the deck is extremely low in the transom, clearance for the steering horns below deck is effectively nonexistent. In Don's fabulous model he has installed the horn over the deck with linkages going through it. I'll probably flatter him by copying this method as 1:76 makes the challenge even greater!!


Cheers...Bernie

[derekwarner_decoy]

Hi PD's.......& progress is good Bernie....... ....just a question or suggestion....

Have you completed a floatation test to gauge displacement & draft yet?   ......plug the rudder connection holes.....scribe some temporary draft marks FWD & AFT  fill the bath with water.....

Method 1 place the hull in the water & progressively place all of the intended components whilst constantly checking the draft marks
Method 2 place the hull in the water & get a set of bathroom scales...press down on the scales until the desired draft is achieved........record the achieved kilograms .....then add/place all of the intended components on the scales...you also need to consider the weight of the decking & deck houses etc 

In most models we never achieve a perfect weight/displacement & may need to add some additional lead ballast strategically placed low in the hull to even out the trim.....

Good luck...keep us posted ....Derek

[Spankbucket]

Hi Derek

No I hadn't yet done a flotation test and your suggestion is timed just right.

I have really only just decided on the battery/motor/etc. combinations and some arn't here yet. I'll definitely do as you suggest when its all present and correct.

I like your scales idea which I haven't come across before. In order to do it I'll need to engage my wife as my physique is beyond the normal bathroom scale range lol!!!!!

I always used copious lead ballast in my other RC boats...except my recent paddler which didn't seem to need it because of the wide, flat bottom.

I spent many a happy hour cutting up scrap lead flashing sheet with tinsnips last year and have a useful stock of ballast 'chips'.

As decks and above will be made of light materials such as balsa, styrene, veneer etc. they will probably not amount to much additional weight. I suppose there might be on or two white metal fittings so I'll add a nominal 10%.

Thanks for your help.....Cheers......Bernie

[Spankbucket]

Hi All

Slower progress in the last few days.

Rudder now fitted.  The first picture shows this and the 2 inner paddle bearings before fitting.

I have cut the components of the paddle box covers from thin styrene sheet on my CraftRobo. The 4 pieces will be made into a 'sandwich'. Likewise with the sponson grills but just one layer.

Motor choice, positioning and drive method now finalised. Motors are cheapo Mabuchi type 380's in worm/gear drive mounts delivering 1:42 gearing. These, in turn, turn a separate Delrin sprocket and chain to each paddle with 8:24 gearing. I'm hoping this will deliver the target 0-200 rpm in water. Time will tell!

I have purchased an Action Electronics P94 Lite (10A version..no heat sinks) which is going to be a tight fit in the hull along with all the other stuff....in particular separate battery packs for the motor pair to the electronics. The former will be a 4-cell 4.8V NiMH box. The latter a small 6V 5-cell NiMH battery pack bought from Hong Kong (for a Tamiya car I think).

Next step is to do the bath flotation test with all this stuff packed in ... I'm going to give it a break for the next couple of days as the wife is going into hospital again soon.

Cheers......Bernie

[Spankbucket]

Hi All

Even slower progress in the last few days.......biggest challenge is to get everything to fit into the hull. In order to achieve this I have had to cut away a lot of the deck supports carefully designed into my original patterns! See Picture 1!

I have fitted the rudder servo and link. I have used a small eSky servo from my spares box as it's a good fit into the hull...hopefully it'll have enough power. See Picture 2.

I have cut the deck in one piece using 1/32" balsa. This will be covered later with 0.6mm veneer from my stocks. Either walnut or something exotic! Doing it this way means I can apply the veneer and then cut out the holes from the back using the balsa as a template. I am not sure if I'm going to bother with scribing planking yet. See picture 3.

I have spent a lot of time laying out the deck house components using the CraftRobo design software. I then cut them in paper, do a trial assemble and then trial fit. Picture 4 shows an example (with a few problems!!). When I'm satisfied the final cut will be in styrene sheet.

Because of the way I have laid out the drive sprockets/chains and their sizes I am going to have to take some liberties with the plan size of the central deck house. You can see the extra bits I have had to cut out in Picture 5. Once these measurements are finalised I'll go back to the designs and make the modifications and cut further paper tests.

All of this has taken a lot of my spare time, particularly the PC bits!!!

Cheers........Bernie