Chwannen Ddwr

Hello All

This is likely to be a slow build due to the fact that  am not exactly the fastest builder in the world. The model in question is the Chwannen Ddwr (Water flea) by Chris Brown. It is a small model at 16 inches long by 6 1/2 inch beam and is a semi-scale model of a small canal boat. Using the beam of the model as a gauge I would guesstimate it as being 1/12 scale and would give a full size vessel of 16 foot length and 6 1/2 foot beam.

At present I have the hull and drawings, electrical bits and bobs and have just modified a rudder to suite the hull. Pictures will follow in a couple of days time. I have to give Marks Model Bits a call and order a 1 1/4 inch propshaft and a coupling before building proper can start.

I hope to install a working spotlight and also working cabin interior lights switched by an Mtroniks micro switcher I have in my spares box.

Barriew very kindly sent me some accessories so I now have some cabin roof furniture to compliment the model.

Looking forward to your build & don't worry about speed ( I definitely don't 6 years + on one boat ), take your time, if you get stuck ask for advice, lots of knowledgeable people able to help.

RR

And so to playing with motors and battery combinations.

So far I have tried (on the bench) a 385 motor,380, 280 motor and a 400 motor. Also tried a small brushless outrunner just for jollies. What came out best was the outrunner: it consumes about 1 amp under load and has a 3 amp consumption when stalled. Maximum revs at 6 volts was 8400 and the throttling and slow speed running were excellent.

So the motor quandary continues to some extent except that the 385, 380 brushless motors have exactly the same mounting hole spacing's so I can try all 3 on the lake and decide that way. Lots of fun and interest so far playing with the electrics.

Hope to get the wood I need on Monday then fitting out the hull can commence.

Brushless motors will always be better then a brushed motor, there windings are much better and being 'AC' they run around 90% efficient 

Just  quick heads up on bruslhess.. if you want pure power and maximised RPM use an 'Inrunner' if you want to be be able to power a large prop with a decent pitch use an outrunner as they have better torque load ability's..

The calculation for starting with brushless is motors KV x battery voltage (7.2, 8.4,11,1 etc) = total RPM  so for example
 1500KV motor x 11.1V (lipo) = 16650 RPM.

Most of my more recent models are running outrunners so i can throw x45 & planing props, i only had one boat which was the delta force that ran an inrunner but that was for the fact electric mono 1 race series.

RR

Just had the definitive answer about motor selection from Chris Brown. A 280 motor is optimum and
any more power will just make it porpoise. So a 280 it is!

Prop shaft will be a 1 1/4 inch 2mm one - will give Mark's Model Bits a call tomorrow.

Got the wood on Monday and so have made a start. The wood at the bow and stern is 4 laminations of 1/16 balsa with 1/4 square balsa used amidships.

Been doing some work on the model: this is where I am at now.
Next job is to make up trays for the 6v gel cell and the RX battery pack. Missing from this picture are the fuse board, main power switch and rc power switch because I have not yet made the mounting for them.

Coming on nicely Emrys - its a good hull with plenty of room to work.

Barrie

Defiantly a great build, looks like your enjoying it, keep it up 

Looking good Emrys 

Thank you for your kind and encouraging words. It is an enjoyable build.
I have now decided to fit two fuses - one between the battery and the main power switch and the other between the ESC and the motor. Have just ordered the bits I need to make a circuit board that will hold the main power switch and a PCB mounting blade fuse holder. Might be slight overkill but better than frying an ESC should a problem arise while running the model.

Am also trying to work out how to make bow and stern rope fenders.

You can google ''how too's''  on making up fenders, but there's also a large range of fenders you can buy,  most tradition styles  although i do appreciate they may be unsuitable for your project. if you do get stuck send me a private message and we'll work something out on creating you some fenders ( i do decorative rope work at times )

See links here on a grafting technique I've written for the forum

https://www.thercmodelboatforum.com/t636-rope-work-part-1-simple-grafting?highlight=bell+rope

Had my idiot's hat on last night!
Made up a combined switch and fuse board using veroboard and once I had finished decided to read the specs for the veroboard and guess what - the max current for each strip is 1 amp - ah well.

Upshot is that I am going to use Action Electronics fuse boards.

Emrys

Two solutions - use two strips in parallel, or add a good layer of solder or brass rod to the strip. I actually doubt that your motor will draw a lot more than 1 amp anyway, but I have used both methods. It was my suggestion that had Action design the fuse boards, even though Dave didn't think there was a market!

Barrie

Thanks Barrie.

In the end I dropped the 'home brew' approach and have got a fuse board on the way from Action Electronics.

The deck is now fitted. Picture to follow.

Here is a pic of the fitted deck:

Here she is with electrical system in place:

Did some 'bath tub' testing last week and found that the boat draws just under 1 amp with a stall loading of 2 amps. The motor sounded strained and started to smell a little of cooked windings with a 5 cell nimh pack so I needed to drop the voltage. It was a lot happier on a 4 cell RX pack than ever it was on the 5 cell pack I had fitted. I decided to have a bit of rethink of the internal layout while I was at it and so have changed the servo mounting, fuse board mountings and well - everything else really.

Upshot is that the internals are now much easier to get at than before. I am going to try running the boat on 2 4 cell 2600mah RX packs wired in parallel. I don't think this will be a problem as the cells are capable of delivering 8 amps and the boat will be drawing about 1 amp under normal usage. Total battery capacity will be 5200mah so no shortage of capacity.

Here is a picture of the 'new' internal layout:

Far to tidy .. love it

Thanks Roadrunner.

Thinking back I don't know what possessed me to mount the servo on cross beams. I think the current layout is much better from a maintenance point of view.

Now I have to decide on the superstructure. At present I am leaning towards building it as a British Waterways tug/workboat.
Something like this:

A nifty little tug I like this superstructure.

Or perhaps this one................

The latter looks like the one I built using the same hull. Its come along nicely whilst I have been away.

Barrie

Just got hold of some 3mm Foamex with a view to using it to build the superstructure. It's my first time using Foamex and so far I am finding it very easy to cut and sand and it seems to glue well with polystyrene cement.

Slight change of plans: Superstructure is going to done as a Braunstone tunnel tug. It will be semi-scale rather than full on scale. I did not know that there was such a thing until I found an article on the web. These tugs/workboats were built to work in Braunstone tunnel with a requirement that they must be able to turn around within the confines of the tunnel:
 

Possibly the most boring picture ever posted on a model boat forum but here is the basic box superstructure made from Foamex:

Have just ordered some more Foamex as I am going to redo the superstructure and try and get it a little more to scale. This boat looks very much like it was based hull very similar to a tunnel tug:

Well - cracking on with superstructure mk2 at the moment. Will post a photo soon when I have made some more progress. The new cabin looks for more like a tunnel tug and far less like the ark! Foamex is great stuff to work with and I will be using it in future builds.

Superstructure mk2 is now well under way but is just too plain to warrant a photo. At the moment I am experimenting with using filler with Foamex to fill the odd imperfection. Best result so far has been with a filler made by dissolving small bits of Foamex in liquid poly cement.

emrys wrote:

. At the moment I am experimenting with using filler with Foamex to fill the odd imperfection. Best result so far has been with a filler made by dissolving small bits of Foamex in liquid poly cement.

I use that technique for plasticard - it work well for that material.

Barrie

Ah well - yet more boring superstructure photos. This time I hope it looks more like a tunnel tug!

You may think it's boring however it shows the rest of us progress. 

Here's a view of the stern. The hatches etc are square - I am a hopeless photographer and have managed somehow to cunningly position the camera in a way that makes everything look skewed.................

Don't sweat it mate it's only perspective from looking down to take the pic.
Happens to me all the time it's part of photography.

Looking great, and i'm liking the changes to the wheelhouse(S) maybe as a suggestion make a few different tops for the model, allowing you to have several boats on the same hull , don;t get to worried on things not looking right on photos, not the first time i've uploaded a photo and gone ''GAWD that looks like my 6 year old made it'' and look back and the model and go ''EH?!?! it don't look like dat!.. da fudge?!''