Brutus

[Bob Abell 2Participant @bobabell2]

Thank you, chaps for your comments

I'm looking forward to taking the ballast out, anyway

If I can keep the water out, I'll try anything

Although, It does sail in a decent fashion, already

Bob

[Dave MilbournParticipant @davemilbourn48782]

Apropos of 'adding lightness' I suddenly remembered a letter which was published in Model Aircraft magazine – so long ago that Cain was fighting Abel for the tube of Britfix Balsa cement and David Boddington was in short trousers –

"Dear Sir,

As lead is so heavy why don't aeromodellers use aluminium for nose-weights?"

DM

[Bob Abell 2Participant @bobabell2]

Right chaps, here is Peter Duckie Teal`s latest video production

Paul Thomason`s…….Brutus fitted with twin brushless motors……The latest development modification

**LINK**

Bob

[Bob Abell 2Participant @bobabell2]

Got a bit of a mystery here, chaps

Brutus has two Brushless motors, independently controlled

Two Brushless Speed Controllers……..Each with an On/Off switch

One receiver

We ran the boat, as shown on the above video……..But only one ESC was switched on!

Does this mean, both motors were being powered by one ESC?

Sort that one out!

Bob

[mike farrellParticipant @mikefarrell21522]

Hi Bob impressed with performance ,seems to have smooth exelleration Like it Michael

[Dave MilbournParticipant @davemilbourn48782]

Bob

The switch controls only the onward supply of power from the battery to the receiver (via the BEC components in the speed controller). You seem to have done the right thing accidentally.
Please don't ask me to explain any further, because I'm sick to death of those three letters.

Dave M

[Bob Abell 2Participant @bobabell2]

So I seem to have done the right thing for once?…..Truly amazing!

Are you sure?

I haven't cut the proverbial wire!…..and don't intend too!

The proverbial wire seems to be a pile of four thirds Pie R cubed!

Bob

[Paul TParticipant @pault84577]

Bob

The new and improved Brutus would be an excellent boat to sail at Ellesmere Port next spring along with the VGC.

Paul

[Bob Abell 2Participant @bobabell2]

Would be nice, Paul

Here`s what I`ve done to keep the spray out….Brass baffle and the top cover, sealed in position

We`ve got another regatta to attend next week at Buxworth, Derbyshire………A Victorian canal basin

Straight line running…..Ideal

Bob

[Paul TParticipant @pault84577]

Both venues are ideal locations to let Brutus rip, the spray deflectors look the business and if your prototype set work I will add them to the main drawing.

[Bob Abell 2Participant @bobabell2]

For Bill H

Bob

[Bob Abell 2Participant @bobabell2]

Hi Paul

We called at Etherow yesterday and spotted a fast moving cruiser

It was an Ellie type of boat, but it was galloping around something chronic and it sounded like an IC engine

Went for a nosie later and discovered it was a new type of Brushless motor made by the Aero engine makers…….The famous OS company

It was powered by two 7.5v batteries in tandem and a water cooled ESC

Motor revs were about 30,000 rpm

The point of this post, is to mention the motor makers ……..OS………It was about the same size as my brushless

Bob

[Paul TParticipant @pault84577]

Hi Bob

This is the OS website **LINK** but the electric motors all seem to be for aircraft. Not being an expert in brushless I don't know if these will operate in reverse.

Paul

[Dave MilbournParticipant @davemilbourn48782]

As far as I know all brushless motors will run in 'reverse', simply because there's no 'forward'. If the thing runs the wrong way for you then you just swap over any two of the three wires.

That said, I'd have to save long and hard to buy any of those. The cheapest is over fifty quid.

Dave M

[Paul TParticipant @pault84577]

So will the correct size marine speed controller enable any brushless motor to run forwards and backwards?

[Andy CParticipant @andyc56856]

Hi Paul, as long as it is for brushless motors, mtronic do one, others are available too, but not cheap, then yes.

Andy

[Mark Jarvis 2Participant @markjarvis2]

Paul, you must make sure that the ESC has reverse on it, most are for aircraft use and are forward only

Mark

[Paul TParticipant @pault84577]

Thanks Mark

I know next to nothing about brushless motors but did know that aircraft motors only run in one direction. I wasn't sure if they were wound differently to marine versions.

Paul

[Diede van AbsParticipant @diedevanabs87670]

Hi Paul,

The direction of brushless motors is indifferent, the direction is dictated by the ESC and how you wire it to the motor.

Brushless motors by my knowing do not have a preferred direction.

[Paul TParticipant @pault84577]

Dear Reader

It seems like eons of time since Brutus was first conceived during a change in my medication and I cant believe that it was Christmas 2013 that brave Captain Bob sallied forth with my unusual and slightly barmy build.

Those of you who followed the story of build, which twisted and turned like an episode of Eastenders, might not have seen the videos of the sailings so here they are.

The first sailing link was a tentative affair as the boat was gently put through its paces.

The second sailing link was very different as Bob had upgraded the boat with brushless motors and a snazzy set of teeth. This video shows the design intention of the bow slicing through the water rather than rising above it but the video also revealed a problem with the lower bow design as the bow wave wasn't being moved far enough away from the hull at medium speed.

So what is next for Brutus

Bob has generously gifted the model to me (complete with motors and ESCs) and it now sits in the workshop getting ready for the next stage of its life which will include:

The addition of small spray rails at the bow to prevent splashing of the long foredeck and a change to the keel to improve lift,

Enclosing the rear deck access hatch (which in retrospect was a stupid design) a slight change to the power train to increase speed and a radical dazzle paint job.

Paul

 

 

Edited By Paul T on 18/04/2017 19:00:14

[Bob Abell 2Participant @bobabell2]

Hi Paul

Looking forward to your planned development changes and improvements with great interest

How are you getting on with those pesky Brushless Motors?

Nice to see you back in action

Bob

[Paul TParticipant @pault84577]

Bob

As you know I don't understand these brushless thingies but I am thinking of running them at 12v and changing the props to a pair of stainless racing props.

Paul

Edited By Paul T on 18/04/2017 19:22:42

[Dodgy Geezer 1Participant @dodgygeezer1]

….the video also revealed a problem with the lower bow design as the bow wave wasn't being moved far enough away from the hull at medium speed.………The addition of small spray rails at the bow to prevent splashing of the long foredeck and a change to the keel to improve lift…

I suspect you will find that Axe bows require a very long slim forepart to the hull (unless you are doing something specialised like an ULSTEIN X). The water has to be parted comparatively slowly – see **LINK**

The scale effect works against us at model sizes. It is not enough just to have the prow vertical, the whole bow has to be considerably lengthened if you want to avoid a high bow wave.

[Dave MilbournParticipant @davemilbourn48782]

Paul

As you know I don't understand these brushless thingies

I don't believe that for a minute but for the benefit and education of other readers I can recommend John Parker's excellent article in MB, reproduced on this website **LINK**

Since the time of writing, the low-speed control of brushless motors has been improved with more Fwd + Rev ESCs being available at sensible prices and lower kv motors. I'm now a firm convert.

Dave M

[Paul TParticipant @pault84577]

DG

Brutus started out as an exercise in geometry by taking the Axe concept and tweaking to suit a smaller and faster boat. As you rightly said one of the problems that I faced during the design period was the inability to scale the structure of water. So a hull shape that worked well on a full size ship would fail on a model and conversely a suitable shape for a model would not work when scaled up.

Brutus in its present form is a design compromise, a prototype, and was expected to have problems that would only be revealed when the model was built and sailed.

Bob did a wonderful job of construction & testing, his experiences and Duckies videos have provided an invaluable reference for the next stage.

Dave

John's article is a superb reference and should be read by everyone contemplating the change to brushless.

Paul

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