Member postings for Chris Fellows

Hi George, good to see you are making progress again.

I know exactly what you mean about building up some enthusiasm again. Having avoided Covid all this time I contracted it about 4 weeks ago when going with my mother to hospital. Didn't do anything for 3 weeks as I just couldn't be bothered! I obviously had the "man version" as my wife had milder symptoms and was over it in just over a week.

Just about over it though now and have started doing bits and pieces again.

Chris

Superb Richard. The weathering etc. and the nice little touches really make it look realistic.

Chris

Glad you mentioned that John. I've got messages from Dave and others I'd like to keep.

Chris

And another of my boats where the prop shaft isn't supported by the rudder. It still sticks out quite a long way because of the prop position. There are rudders with shorter brackets where props are further forward like yours.

If you do decide to replace the motors that will be the biggest challenge, getting ones of a size that will fit and be low enough to align with the existing shafts.

As for the rudder, with a fast boat one is enough and it has a small blade. Usually with this type of boat the rudder is mounted on the rear and so it comes down to practicalities - one in the middle is probably the best bet? Can you post a photo of the rear.

As I said before have a peruse of TFL Hobby rudders on Noahs Ark RC.

Here's a photo of the rudder on one of my boats. It sticks out a long way because it's carrying the prop as well. Yours doesn't need to so the rudder can be closer to the stern.

You could mount a rudder inside but that brings it's own problems; space, mounting, water ingress etc. Also, dependent on the position of the props the rudder might end up in front of them. It will steer but will probably be very twitchy and spin out a lot at higher speeds.

Ask as many questions as you like!

Chris

Edited By Chris Fellows on 26/09/2023 11:58:53

Welcome Chris

I note that you say that you don't have much of a budget. Trouble is with projects like this costs can soon escalate.

You could go brushless but to retain water-cooling which is common on this type of model, as being run at prolonged high speeds, then inrunners would be better as the outer casing doesn't turn. Coiled tube could be used but often matched water jackets are at more cost. You can get water-cooled motor mounts for outrunner though, but the existing motors are mounted low which might be a problem. It looks as though it has flexible drives? These will have to be adapted to the new motor shafts or new couplings obtained. If going brushless then an ESC will be needed for each motor and a water-cooled type.

Rudders for this type of craft are usually mounted on the stern. Noahs Ark RC do a range of different types.

As Ashley says, if using LiPo, then for safety, use a smart charger, Overlander batteries is another supplier.

Just trying to be realistic here. As the motors work and they are already mounted it might be better to stick with them, replace the other components and add a rudder?

Chris

I agree wholeheartedly with everything everyone else says. Do it because you want to but there ain't any money in it and you are likely to make a loss.

I've produced the drawings for seven models and currently building five and I wouldn't do it. Like David I tend to draw up enough to get started, albeit it in detail, and then additional drawings and freelance as I go along. The difference in producing drawings for ones own use and for others is great. Every last detail has to be drawn up and as others have said you've got to produce build instructions, build and test.

I have a background in design and drawing - drawing board and PC (not model boats though) and could do all the above but it wouldn't be easy and very time consuming as alluded to and I have no desire to! Paying someone else to do the drawing etc. just isn't viable for this type of thing.

Times have changed as well of course. Many years ago many plans were drawn up and some designers did make some money from them but that has all but disappeared. It's probably only the bootleggers who are making any money from plans and that's only for a limited number of popular designs.

And the emergence of 3D printing, but even there many folks provide the files for free.

If you can't do your own CAD quality drawings it's a non-starter really. As said, do it for your own satisfaction, but as for selling, no.

Chris

All valid points, but if it exists then it can be measured in metric. I surveyed many pre and post war properties, nearly all in metric. The only time you really had to worry about imperial was if you were trying to match bricks. For extensions though, this was usually disregarded though as bricks, unless reclaimed weren't available and so block bonding or wallplates were used to join new to old. In building sizes for materials unless manufactured are rarely as stated anyway, unlike engineering!

I still have my imperial scales, well all my drawing equipment and my 30foot/10metre tape as well as a laser measurer accurate to +/- a few mm over 100m. Bit better than what estate agents use!

Chris

When I first started work as an architectural technical I drew mainly at 1:48 and 1:96. When drawing in metric and carrying out building surveys I would estimate things at height I couldn't measure in feet and inches and convert to metric.

Over time though I found it easier to estimate in 100mm increments and unless I was working off old imperial drawings I rarely used imperial again. Mm and cm are just so much easier to work with rather than eighths and sixteenths etc!

I agree that imperial correlates with the most common modelling scales as many models pre-date our metric era but they are the same size in the end whether imperial or metric!

I still can't think in km or litres though!

Chris

You've answered my question as regards the battery as it was the current draw I was thinking about, as when operating at full throttle even a slight drop off will affect performance particularly when marginal.

Can you get plastic 3 blade props in the size you want. That would be the best for testing purposes before investing in the nice shiny ones, especially when you need 3!

I don't know much about brushed motors but looking/listening to the video reinforces my view that it's a lack of revs which is the problem. It could be argued that a coarser pitch could provide more speed but if the revs drop as a consequence no advantage is obtained.

Chris

Be interesting to see how you tackle the superstructure.

Chris

Only on full-size though!

Chris

In my view increasing from one prop and motor only has generally a negligible effect on speed. Reason being that the speed is governed by the revs. It might increase slightly as the load on each motor will be reduced and the motors are able to rev higher but it won't be significant.

The advantage for more than one motor is acceleration and more power which will increase the speed of a big heavy displacement hull pushing lots of water out of the way, to a point.

I think that when some folks, particularly with planing hulls, ask about twin motor set ups they think that the motors only need to be about half the size but that isn't the case. Maybe slightly smaller than a single motor set up but that's about it.

So I think when the third motor kicks in it initially takes load off the other two and they accelerate, hence the lunge, but then the top speed is then restricted by the max revs being achieved. And of course the third prop when not running is acting as a big brake which will then contribute to the lunge!

Increasing the voltage might help a bit but sounds as they it might be over-propped as well. Any reason why you used 5 bladed props and why you're considering 4 blade? Would have thought that 3 blade and maybe 50mm would be the best bet? I bet there is a fair amount of weight in that boat as well with three motors, prop shafts and rudders etc? What battery are you using?

Chris

Edited By Chris Fellows on 15/09/2023 13:03:38

Hi David

Sounds as though you have it covered. Personally I wouldn't bother with imperial as well as most builders are able to build from metric drawings.

I've worked in both professionally and find metric more convenient for model boat building. Well everything really!

Chris

Hi David

When you say the plan defines the dimensions do you mean that these are actually stated in mm? If so, that's great. The reference scales are good as well. Are they quite long as that provides more accuracy when printing/scaling up. To be honest the overall length and beam are more important especially if indicated by dimension lines as this clarifies where the dimensions relate e.g. inside or outside rubbing strips etc.

I produce my own drawings and don't always draw full size and so when printing at say 120% having reference points/distances is invaluable.

Chris

Edited By Chris Fellows on 13/09/2023 22:18:22

Whilst not wanting to criticise anyone who is going to the trouble of providing plans in these times I have to agree with Chris here. Not having the overall length on the drawings or even in the title is a serious omission, especially for a build aimed at beginners. This is such a basic requirement.

The magazine is almost worse here as you can't use the plan without enlarging it (unless you are happy with the size) as unless the builder can scan and enlarge it themselves then I doubt many will bother.

Chris

Edited By Chris Fellows on 13/09/2023 16:53:34

Not easy to get a cat to handle and perform well via RC. Looks really nice.

Chris

As another choice, our friend Harry from Tasmania, is a big fan of the Turnigy 3648 1450kv in boats around your size which go really well. I think he uses the Quicrun ESC as well. Nothing water-cooled and no problems.

I'd normally recommend 800 to 1200kv, or thereabouts, for a model like this, and this motor is at the top end, but Harry has a lot of experience with this motor and likes to run his boats fast!

Good thing with brushless, being so powerful is that different sizes and voltages will give you the performance you want.

Chris

You're welcome!!!

Yep, been through it!

Out for the day but if you have any other questions on batteries etc. then fire away.

Chris