Brutus

[Bob Abell 2Participant @bobabell2]

Thank you, Trevor

Paul is really only winding Ashley up, as he likes to do occasionally

Your assessment of the Brutus performance seems ok to me

We are not ready for running at the moment, having a spot of trouble with some of the crimped conns

But there`s no mad panic to get it on the water

Bob

[Trevor HollowayParticipant @trevorholloway99134]

We do get a fair bit of winding up at the pond – a very jovial lot we are too.

Leg pulling and underperformance / not quite working out as expected is par for the course at Bushey Park and all taken good heartedly.

I had one of your Eureka moments yesterday with an underperforming coupling, a bit embarrasing but hopefully now sorted at zero cost.

[Paul TParticipant @pault84577]

Hi Trevor

If all goes as expected then quite a few people will have egg on their faces……… but if it crashes and burns I will be banished to the nether regions of Fairfax Rd (which I believe is somewhere in outer TW11 and is a fate worse than death…warm beer and chippies without gravy)

As you are all so interested in how Brutus will perform I invite you to look again at the computer generated predictions at four different speeds.

Paul

 

Edited By Paul T on 10/03/2014 17:42:01

[Trevor HollowayParticipant @trevorholloway99134]

Nothing wrong with warm beer, chips and egg.

I will put my hand up for trying out "odd" designs that don't work, mostly tested in the bath and never in such a public way.

[ashley needhamParticipant @ashleyneedham69188]

My brother went to school with someone who lived in Fairfax road!! it is just at the back of mu old Primary school. The house postcode I lived in as a small boy had a tw11 postcode…

No egg at all. One either voices an opinion or simply lurks, which is no good for such an interesting post/design such as this.

We are all very interested in how it will perform. There`s nothing like a good guessing game. We all have experience of getting it wildly wrong…

I for one would like to see the pointy end stay in the water at speed, to make use of the featured feature, the chisel bow. I would like to see Bobs verson ploughing, nay, Sything schiving cutting through the waves in the bay in the sea. Do you hear that Bob…THE SEA.. the only place to get decent big rollers to plough through.

The ponders think it will plane, and they would like to see it stay in the water at speed, that`s all.

Ashley

Blast.. I shall have death threats from the pond now, i have spilled the beans.

[Paul TParticipant @pault84577]

I will put my hand up for trying out "odd" designs that don't work, mostly tested in the bath and never in such a public way.

That's what makes Bob such a hero as there are not many who would be willing to be so open about their build or to take such a risk with their reputation.

Respect to the captain

Ashley

Brutus will plane.

If you look at the diagram you will see how the attitude of the hull changes as the power increases, the hull rotates around the mass of the motors / batteries and will go onto the plane whilst the bow is still under water.

Paul 

 

 

Edited By Paul T on 10/03/2014 19:08:54

[Bob Abell 2Participant @bobabell2]

Right then chaps!

All fittings are now fitted to the wires and about to connect up!

Is there a safe wiring sequence of connecting the wires?……….."Connect the battery last!"……Some one shouted………..Good idea………..Thanks……….Peel that man a grape!

Just checking the fuse size. The paper work says the ESC is 50 amps!………Who said we don`t need a big cooler?……….Was it you, Ashley?

With both motors running, that`s 100 amps!……We could make toast with that!

I`m beginning to suspect that all this power can`t possibly be true!……Am I missing something here?

Somebody mentioned at Ellesmere, that these motors are very efficient and run cool and we don`t need fan cooling………..Well, we`ll see!………100 amps?……..Geeeeeez!

At the moment, the motors are not glued in place, so for safety reasons, I`ll clamp one to the bench and see how things turn out……….Good idea, Bob

Here we go, boys!

Bob in a bunker, somewhere in England

[Bob Abell 2Participant @bobabell2]

Hello chaps!……..Back from the brink!…….Unscathed too!………Anti-climax really

Connected the wires up………Battery last of course

When the radio was switched on……..Flashing lights on the ESC PCB……Beep…….then more beeps……the ESC fan went into overdrive, up to very high revs….(10,000rpm?) and made a goodly draught!

Switched the ESC on and the motor ran as sweet as a nut!……Very smooth……Very quiet

Moved the Rc stick forward and the revs increased very smoothly and quickly…..And blew the fuse!

Don`t know what the fuse rating was, but it wasn`t 50 amps!……….Might have to use a nail next time!

Still!…..That was a good test and we can now carry on regardless

This calls for a tinnie and a stiff drink!

Cheers chaps……..Bob

Edited By Bob Abell on 10/03/2014 21:10:50

[ashley needhamParticipant @ashleyneedham69188]

Bob.

50A esc…..hmmm.. Your battery packs I think are rated at 35A max discharge?? (check spec) Perhaps a 35A fuse should be fitted as a starter. Just a thought.

My larger "boat" with an in-runner brushless motor makes my batteries very hot when on full throttle. You have lots of air circulation in the hull so fires meltdown overheating should not be an issue.

Lipo batteries can deliver way more current that Nimh batteries. A check at the pond side of current draw may be in order starting with your smaller choice of prop.

I am not being alarmist, but big numbers are being talked about here!! I dont suppose for one minute that your motors are going to draw this sort of current.

Ashley

[Bob Abell 2Participant @bobabell2]

Hello Ashley

Many thanks for your timely advice

The fuse system I'm using is out of the junk box and came complete with Tamiya plugs attached, so I'm assuming they can be used with a 25 amp fuse?

I was pleased to see how gentle the motor was at low revs, so the maiden voyage will not be a firework event after all

Just wondering if I need to explore the setup for maximum power shortly?

When the radio was switched on, the ESC mini fan stared and was surprised it was using the receiver battery for power!

All very exciting

Bob

[Bob Abell 2Participant @bobabell2]

Just had another motor run to test the running with a slightly out of true motor coupling

Using a 15amp fuse, all ran well. The motor zoomed up and down smoothly and nicely, but didn`t like the coupling, approaching top speed, as it was whirling. Will try it again in the boat shortly

The motor ran so smoothly, I reckon it would run on the bench without being clamped down!

Also discovered that the Rc battery is not required to run the ESC

Conclusion, using Brushless motors?……….Easy, simple and excellent!

Got to admit, I was a bit over cautious during the run up, but you know what they say?……..Better to be cautious than sorry!

I expect some comment from Head Office

Bob

[Paul TParticipant @pault84577]

I expect some comment from Head Office

Stop messing about and get on with it

[Bob Abell 2Participant @bobabell2]

Now then, Paul!

Being a non brushless modeller yourself, I would have thought you would be pleased to read the trials and tribulations of a first timer!

You`ve got all the info on a plate now!

Bob

[Paul TParticipant @pault84577]

Bob

I've only just got used to using brushed motors instead of IC, these new fangled brushless are the devils work.

Paul

[ashley needhamParticipant @ashleyneedham69188]

There`s no magic to these brushless things, it is just that there are so many of them there is no pigeon hole to put them in to say "oh yes, a speed 600 will do you" and so on.

Partly why I think I may have suggested using 600`s as per original drawing, to set a benchmark and then "upgrading" to brushless later. Or was that slo-mo??

Ashley

[Paul TParticipant @pault84577]

Ashley

Life was so much easier when all I had to do was throw a decent petrol engine in, plonk it in the water and push the stick to full volume.

Happy days

[Bob Abell 2Participant @bobabell2]

Latest work in progress report

The system is fully wired up

One motor runs nicely, but won't run in reverse…….Not that we will be running backwards!

Second motor is erratic, but will run in reverse!

According to the instructions, the system needs setting up……..Which looks tricky at first glance, using a tiny button on the ESC unit

At the moment the routine of starting up seems rather vague

The ESC's each have a minute on/off switch, which is impossible to tell whether they are on or off!

The motors appear to run, regardless of the little switch positions!…….As do the ESC high speed fans

Due to coupling eccentricity, max revs cannot be achieved……Will be phoning the makers today, to sort this out and purchase another Brushless set for SloMo

Not happy with the junk box fuse line…..Need to get a higher rated set up

On the brink of sailing, but delaying same until more confident with the electrics

Enjoying the mysteries of Brushless technology!

Bob

[ashley needhamParticipant @ashleyneedham69188]

Bob. Get a program card for the ESC`s.

The main cooling fans are separate to the motors, are they not?

I would imagine that the ESC fans run full tilt all the time.

Ashley

[Bob Abell 2Participant @bobabell2]

Thank you Ashley

The instructions say that you don't need a Prog card with NiHm batteries, but you do with the LiPo type!

It's a mystery at the moment, but I'll sort it out shortly

Need to visit the pond and ask questions

The motors seem to have settled down now?

First question…..Why have a switch, where you can't tell if it's on or off?

Ha!…..Will ask the retailer, right now!………That was obvious!

Bob

[Bob Abell 2Participant @bobabell2]

Latest story

Phoned the supplier and sorted out the various questions amicably

It seems that the ESC is man enough to withstand a total motor lockup!……..Weed or a plastic bag on the prop etc and a fuse is not required, but would be useful in the event of water getting to the ESC`s

This is a complete surprise to me!

Don`t need a Prog card. The ESC is already set up for 7.2 v

The little switches should switch the motor off and may not be fully pressed into the socket on the PCB

They are sending two FOC motor couplings to replace the faulty units

Hope you find this info of interest

Bob

[ashley needhamParticipant @ashleyneedham69188]

Bob. What about the issue of your battery only being able to deliver 35A against a possible total demand of 100 A !!!

Good news regarding the program card.

This experience is akin to buying a, say, digital camera. You can read all you like about the specs and so on, but its not until you buy and use it that you discover what it is that you really want, or need in a camera.

You are taking the first tentative steps into the magic that is brushless, and are learning whats what.

After you have used all this good gear you will of course be none the wiser as there are a million different brushless motors out there and a thousand brushless ESC, and then there is the LIPO thing…you know..the batteries the chaps turn up with in a fire proof bag and a steel ammo-tin !!

It is a right minefield!

Ashley

[Bob Abell 2Participant @bobabell2]

Thank you Ashley

I`m using two 7.2 batteries, which is the size recommended by the motor suppliers, so they should me OK?

I`ve got four 12v batteries……What may happen if I tried to use them?

Don`t fancy the Lipo option at the moment

Bob

[Bob Abell 2Participant @bobabell2]

Paul

One our members bought a well made Tamar Lifeboat from the Ellesmere Boat Show last weekend

It was fitted with two brushless motors and powered by two 7.2v batteries in series

It had two four blade brass props and the first sail was a disaster!

The performance was so poor he has changed the motors to two x 750BB and he is happy with the result

This is not good news, obviously

We hope to sail Brutus tomorrow

Bob

[Paul TParticipant @pault84577]

Bob

Having seen these brushless things in action I am expecting great things from Brutus, perhaps the Tamar hadn't been set up correctly.

Glad to hear you are sailing tomorrow… are you getting the coast film crew around for the event?

Paul

[Bob Abell 2Participant @bobabell2]

Hello Paul

The best I can do, is to use the kind services of good friend Duckie, for the video

Do you know, he has posted 85 videos on YouTube, so he's got the hang of it now!

The Lifeboat I referred to, had three show plaques, showing it had visited Etherow Lifeboat show in the past three years, so it must have been a goer?

Bob

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