Commodores Challenge

[Paul TParticipant @pault84577]

Captain Bob

You are one of life's real gentlemen and your experiences are an invaluable source of inspiration to both newbies and experienced model builders.

I still cant fathom how you wired up the four huge motors in the VJC that you built, according to the known laws of physics they shouldn't have run, and yet you impressed everyone at the Haydock show when you demonstrated the big four running in perfect harmony.

I still think that you invoked some kind black magic.

Paul

[Bob Abell 2Participant @bobabell2]

Hello Paul

Flattery will get you anywhere…….Thanks very much my mate

Regarding my three loaves and five fishes trick, even I am impressed! and so was Dave M

We had great fun at the Haydock show, charging the visitors, 10p to see the motors go round and round…All for your chosen Charity.

Picture to follow

Bob

[Paul TParticipant @pault84577]

Bob

What you don't know is that DM and myself tried to duplicate your four motor set up and DM even asked the electronics expert who helped him design the Action equipment.

The result of all this debate was that such a set up would either fail to work or more likely burst into flames, and yet your system worked, we were completely stumped and DM had a very healthy new respect for your abilities, as we know Daves respect was difficult to attain.

Paul

[Bob Abell 2Participant @bobabell2]

A few fotos

[ashley needhamParticipant @ashleyneedham69188]

Loved that engine setup. A masterpiece indeed, and that green and red is just right…sort of colour a steam engine would be painted!

Ashley

[Bob Abell 2Participant @bobabell2]

Many thanks. my mate

Bob

[Paul TParticipant @pault84577]

I still can't get my head around the setup, In the real world one motor would run at a different speed to its twin resulting in either one of the pair becoming a dynamo or the pair fighting against each other and stripping the rubber belts.

Not to mention the way that you wired everything up, as it should have put far to many amps through the system and cooked everything.

Amazing and completely stupefying they are still an enigma wrapped up in a Pandora's box of contradictions.

[Richard SimpsonParticipant @richardsimpson88330]

Surely, If I am reading the set up correctly and I might not be, any slight variation in free running speed between the motors, as there almost certainly will be with manufacturing imperfections, will manifest itself as a slight imbalance of load. They must all be running at the same speed as they are physically locked together so, in this case current would be slightly different for a constant voltage.

Assuming a total load of 100% if the motor speeds are not perfectly equal when not locked together then you might have one taking 23% of the total current, one taking 24% of the total current, one taking 26% of the total current and one taking 27% of the total current. As long as each motor is within its own capabilities there should not be a problem.

This is basically a similar set up to most marine generating plant whereby more than one generating set is connected to a common bus bar. They are similarly locked together electrically by the bus bar so have to be rotating at the same speed but the load of each engine can vary.

With Bobs arrangement you will only get one motor acting as a dynamo if the power to that motor is cut. Similarly with the ship's power generation should one of the diesel engines suddenly fail then that generator will immediately start to act as a motor and try to drive the engine. That is precisely why all such plant is fitted with reverse power trips. If you are watching the panel when a diesel engine fails then you will see the power go into reverse momentarily before it trips off the board. This is because say for instance the engine has shut down on lube oil pressure then the generator would start to drive the engine.

Bobs set up is pretty much the same with all four motors rather than generators sharing load but probably not perfectly.

 

Edited By Richard Simpson on 18/06/2021 19:42:43

[Bob Abell 2Participant @bobabell2]

Thank you Richard for the Technical explanation…..Very impressive stuff.

I realised at the time. that there could be possible snags, especially with the the idling motors etc but still went ahead, being curious to see what would happen

And it ran perfectly

I`ll dig out a lovely video shortly and is very impressive

Bob

[Bob Abell 2Participant @bobabell2]

"lady joyce model boat"

Hope this works?

Bob

PS……No it doesn`t, but the title is correct for YouTube

Bob

 

Edited By Bob Abell on 19/06/2021 09:28:47

[Bob Abell 2Participant @bobabell2]

I`m very mjuch surprised that there are no comments regarding such a very interesting video?

Just type …..".Lady Joyce model boat" in Youtube

Bob

[Richard SimpsonParticipant @richardsimpson88330]

How about this Bob:

Lady Joyce Video

 

Edited By Richard Simpson on 19/06/2021 16:47:01

[Richard SimpsonParticipant @richardsimpson88330]

Certainly an interesting video Bob, although I must admit to being a bit unsure myself now. I had thought that all four motors were physically connected together but it would appear that they are not.

Could you just explain the arrangement as regards what is connected to what, how many shafts and what drives them etc. I take it by the four speed controllers that all four motors are independently controlled from the transmitter?

Is there a build thread for this one somewhere?

 

Edited By Richard Simpson on 19/06/2021 16:56:30

[Bob Abell 2Participant @bobabell2]

Thank you, Richard for adding the Shortcut to the video, much obliged

I can normally do it myself, but at the time, I had a memory lapse

The model was built six years ago, so I`ll have to give it some thought on how I arranged the motor controls

I will dig out the original thread of the build and post a link

On the video, you won`t find any info regarding the method of operation, at the time I was having Fun and Games with our friend DM. He said it couldn`t be done and I kept it a secret!

The model was sold a few years ago, which I now regret

There is a nice video of the model sailing on the Etherow Lake, I will post a link shortly

Back soon

Bob

[Bob Abell 2Participant @bobabell2]

I have found the sailing video already

Once again, my Copy and Paste skills are lacking

Hi Richard, Post a link for me, please….Thank you

The title is…..Silver Mist and Lady Joyce

It`s a nice video, filmed by my mate, Peter `Duckie` Teal

Bob

[neil hpParticipant @neilhp]

Silver Mist & Lady Joyce – Bing video

is this what you are after, Bob.

[Bob Abell 2Participant @bobabell2]

Yes Neil, many thanks

Bob

[Bob Abell 2Participant @bobabell2]

Sorry Richard, can`t find the build thread with the multi motors etc at the moment

But will keep trying

I think the thread was Paul`s originally

Can you find it Paul or the title please?

Bob

[ashley needhamParticipant @ashleyneedham69188]

I think that the ganged together motor arrangement would not provide the best efficiency, but the difference between that and simply using four motors singly would be hard to measure and in any case, for a model such as this, really doesn’t matter.

if this were a container ship, then a 2% increase in efficiency would be worth chasing, but not on a model.

In any event, even a 20% drop in efficiency would be worth it just for the coolness of that look alone.

Ashley

[Bob Abell 2Participant @bobabell2]

Thank you, Ashley

The Quad motor drive idea was in my head for years before it became a reality

The Timing belt drives were nice to watch

It was a bit of a gamble too at the time

It was only 12 degrees at Etherow lake this morning

Bob

[Paul TParticipant @pault84577]

Hi Ashley

Apart from the technical brilliance I really liked the Victorian style of the casings, most people would have simply put the motors side by side on basic mounts, but not Bob Brunel, he went the extra mile and not only produced those excellent casings but detailed an engine room for them to sit in.

But these motors are nothing compared to his Great Eastern, the quantity of research that Bob did was staggering and I remember our discussion on how the ships launch failed.

Paul

[Bob Abell 2Participant @bobabell2]

Thank you Paul

Such distant memories,

Bob

[Paul TParticipant @pault84577]

Captain Bob

Even though they are distant memories the build threads that you produced on this forum are very relevant today as they are a great resource for newcomers to scratch building, you demonstrate the practical building skills that are fast disappearing which is especially important in our modern 'plug and play' society.

Your building techniques have influenced my model designs, in fact the 'pinched bow' and the form of the unique bow wave on the Lady Joyce directly owes its existence to your work on Brutus.

If you ever want to do another signature build then I would be proud to design it for you.

Paul

[redpmgParticipant @redpmg]

Great videos Bob – as Paul says you are truly a master builder like Brunel – the drive belts etc are fantastic and the rest of layout puts most of us to shame.

Are there any more videos of you boats out there Bob?

[Bob Abell 2Participant @bobabell2]

Thank you, Red

There are dozens of video`s of my boats on Youtube

For example, try these….

Just type……

Silver Mist and Lady Joyce

Lady Joyce

Jeanie Deans at Etherow

Great Eastern at Etherow

Slo Mo 2 at Etherow

GVC and Slo Mo2 at Etherow

Brutus at Etherow

That should keep you quiet for a while

Bob

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