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[Patrick Henry]

Ye Gods...poor old Mr Bluecrisp only asked a perfectly sensible question, and look at the flak coming his way...

I just cannot understand why all the cr*p has to fly? By all means air your opinions, give your advice freely, but to start throwing all this sort of stuff about is plain ridiculous.

Mr Roadrunner...I suggest you think more carefully before hurling s*** about like you do, and are doing here. Can't we have a sensible discussion on the matter in Mr Bluecrisp's question without WW3 breaking out?

[Marks Model Bits]

Stavros, I'm surprised by your quoted amp draw, how did you test the current draw? A 55 mm prop will pull more than 5 amps if its spinning at more than about 2500 RPM regardless of the motor used.

Well we did a rough estimate on the current draw..... (didn't work it out too accurately, couldn't be bothered!!!)  4300Mah  NIMH batteries on 24v driving a 55mm 2 blade plastic prop run time 40 to 45 minutes. We estimated   just under 6 amps draw under normal operating load....

Mark.

[John W E]

Hi there
Mr Bluecrisp
 Is the Sea Queen model that you have dating from the 1960 or is it the modern day one from Jotika? if you want  the model to plane - the first thing to do is look at the weight in the model. The 1960 models are pretty heavy and looking at the new model on Jotika’s website that looks a pretty heavy build as well.   The thing to do I would have thought is to see what weight can be safely removed by thinning down bulkheads and opening up solid bulk heads to save weight, then when we have decreased the weight of the model but not jeopardised the strength of the model then look at the power requirement. less weight less power 

aye
john
 

[nick_75au]

Hi Mark,
 thanks for clarifying, I'm always quoting worst case I.e holding the boat steady while reading full throttle amps off a watt meter or amp meter.

Of course the average current is much lower, time for my guessing here but I ran the Axe bow for about 1/2 hour, the batteries are a pair of 5000 mAH, I started from storage voltage and put back to storage voltage at the end of the run 2500 mAH each battery
so 5 amps total consumed across 2 motors( If i ran for the full hour, I would have drawn 10 amps with an average current of 5 amps per motor)

From half throttle to full throttle the current almost quadruples according to my watt meter.

Cheers
Nick

[DickyD]

I see you've changed your silly little subtitle to 'temporarily inactive due to personal choice'. Good riddance.

Don't let the door hit you on the backside on your way out.

You are not alone lots of others feel the same as you crunchie.

[Bluechrisp]

We are just a little far south  but one was caught in the Logan river 100 odd  years ago. The lake drains into the Logan

Here is a quick Video of John Darkes brushed Perkassa, the motors are the ones Mr ACTion mentioned, it uses 55 mm props and draws about 20 amps per motor on 24 ish volts. About 1/2 hour runtime when not being quite so silly

http://www.youtube.com/watch?v=KRcDsCpqidY

Cheers
nick

Hello Nick,

Some great video's there, brought a smile or two. 

CP

[Bluechrisp]

Hi there
Mr Bluecrisp
 Is the Sea Queen model that you have dating from the 1960 or is it the modern day one from Jotika? if you want  the model to plane - the first thing to do is look at the weight in the model. The 1960 models are pretty heavy and looking at the new model on Jotika’s website that looks a pretty heavy build as well.   The thing to do I would have thought is to see what weight can be safely removed by thinning down bulkheads and opening up solid bulk heads to save weight, then when we have decreased the weight of the model but not jeopardised the strength of the model then look at the power requirement. less weight less power 

aye
john
 

Hello John,

It's a aerokits, I bought it a few years back, from another modeller who was retiring, I'm only now doing it up, as I am on sick leave, a few bits had water damage and needed replacing, now sanding down and repainting followed by this new engine arrangement yet to decide. I will be taking a few bits out ie the centre parts of the bulk heads, leaving the outside parts to support the hull. 

CP

[Paul S]

Hi Guys.

I can't help but remember offshore racing articles in Model Boats back in th 60's and 70's showing these 'Ladies' hammering along barely in the water, if memory serves me correctly they put a Taplin Twin in the Commander and a 15cc Gannet in the Queen.  I think things were a lot simpler in them days.

Cheers

Paul

[Subculture]

I think electric is a lot simpler and less troublesome than engines. It wasn't until the advent of true small scale electric flight that I got interested in flying.

[davidm1945]

Hi Folks,

Try this link - scroll about half way down, titled "Brushless Power"

http://philsworkbench.blogspot.com/search/label/model%20boat?updated-max=2011-03-02T01%3A14%3A00Z&max-results=20

Dave

[nhp651]

I see you've changed your silly little subtitle to 'temporarily inactive due to personal choice'. Good riddance.

Don't let the door hit you on the backside on your way out.

I thought personal comments like this were reprimandable and moderated, martin!!!!!!

could we please have a level playing field where ALL moderaters do the job uniformly, or the system breaks down

also from what I read on this and the other post it seems that road runner was right about his facts in the end.

Just don't like personal comments on air..........I learned my lesson a while ago...THE HARD WAY!!

[CF-FZG]

also from what I read on this and the other post it seems that road runner was right about his facts in the end.

The only 'fact' he got right was when he said he knew next to nothing about brushless motors!!

The rest was speculative rubbish that he also got wrong!

[Bluechrisp]

Hi Folks,

Try this link - scroll about half way down, titled "Brushless Power"

http://philsworkbench.blogspot.com/search/label/model%20boat?updated-max=2011-03-02T01%3A14%3A00Z&max-results=20

Dave

Hi Dave,

I loved the half in half out water shot of the lifeboat, with the smoke from the exhaust and radio comes. 


CP

[Dekan]

The Sea Queen is 46" long   The Sea Commander is 34"  

Why are "boaters" so anti  brushless motors...No self respecting "planeman" would give most of this ill informed piffle any credance

For the Sea Queen.... http://www.westbourne-model.co.uk/energ-c60-brushless-motor-6934-0.html  this suggests that maximum usefully current for this motor is probably in the region of 50A on 18 volts which means that the motor can be rated at 800W.

Ie 18v X 50A = 900W... no motor is a 100% efficient so say about 800W... then chose a prop to keep the maximium current to 50A..

Incidently its is S.O.P with a brushless motor to chose an ESC twice the maximium current you intend to use. This gives a good safety margin.

Duration ,as always, depend on how you drive the boat,the type of battery used and it's AmpHour rating

For Sea Commander IMO a 900Kv motor of 300-500W should do the job

As already pointed out a brushed motor set up would be a cheaper but slower solution...