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[tica]

Hi there

Just bought a M/S model of Drumbeat of Devon, complete with radio (2.4Ghz) battery ect. It's right now running with 2 Speed 900 motors direct connected to some Deutsch produced brass propellers, it's  run in series on a Electronize FR30HX ESC an a 12V 7.5Ah Gelcell. I do have another one which should be the best solution.

Just tried it in the bathtub and I'm not impressed by the Speed 900's performance (low speed and at 0 speed they are ticking, or is it the ESC or the combination ???

So the 100$ question is what is the ultimate motor / ESC solution for this model ??

Br
Carsten

[malcolmfrary]

If the motors will stand 12 volts, and the ESC will handle the resulting current, wire the motors in parallel.  At the moment, in series, they are effectively running on 6 volts each.  A lighter battery might well improve matters - less weight is easier to push around, to the extent that it is possible to get longer run times with better performance even though, on paper, there is less energy being stored.

[tica]

Thanks for the input.

Just tried it on the water yesterday and it's running fine but at a slow speed and very quietly, but it's very difficult to steer due to the lack of control of the motors.

Solution will be (for now at least).

One motor one ESC (there were an spar FR30HX ESC in the box)
I will add an mixer for combined rudder and esc control.

Long term solution will properly be an upgrade of the RC equipment to something that can be program so I can change between "rudder on one stick speed on one stick"
to 2 stick control of the engines for dock and harbour manoeuvring.

Br
Carsten

[john s 2]

Your speed controller is adjustable. Have you tried altering its settings? John.

[tica]

Hi John

The initial problem were that the motors was connected in series and as they are not 100% identical the chance that on will tick and misbehave is high. That is not possible to adjust.

Today I received a P40D mixer from Action, it's assembled and tested and now I just need to redo the cables and connect the other ESC, I do hope that the weather will behave so it can be tested on Sunday.

Drumbeat should look its best at Roskilde harbour June 9th and June 10 at Kronborg Castle.

[tica]

First run on the water and it was not a success 

I'm using a cheap 2 chanel Hobby King Rc unit that came with the boat and it cause a lot of problems with the mixer unit, I didn't have any rudder response what so ever when I enter the water.

I have now spend a good 2 hours in the work shop adjusting the whole thing including the ESC's from electroniz and it looks god now, it will be tested on of the next days, update to come !

Br
Carsten

[john s 2]

Have you tried running it direct from the battery? With no speed controllers? It should go right on to plane. If not then i do wonder about the battery or the motors. Good luck. John.

[Shipmate60]

tica,
What size are the props?

Are they these motors?

Graupner Speed 900BB Torque (6373)
Single ballraced, 12-pole armature.

Special high-performance motors with integral
suppressors. Characteristic high torque at low rotational speeds, therefore ideal for use in direct-drive model boat power systems with large
propellers.

Specification
Nominal voltage 12 V
Operating voltage range 6-40 V
No-load rpm 6500 min–1
No-load current drain 1,1 A
Current drain at max. efficiency 8 A
Current drain when stalled 54 A
Max. efficiency without gearbox 71 %
Length of case, excl. shaft 85 mm
Diameter 51.5 mm
Free shaft length 15 mm
Shaft diameter 6 mm
Weight 645 g

Bob

[tica]

Props: 48mm 4 blade brass.

Yes Speed 900BB No. 6373

I clocked the speed to 9Km/h by GPS.

It's like it max out at about 2/3 of full speed.

a video where the motors are in series. http://www.youtube.com/watch?v=2Zz7KM2P-_8

[Shipmate60]

How fast do you want her to go?
If the 900's on 12 volt aren't fast enough I would go for 2 x 550's on 6 volts with 35 mm 3 blade props.
550's will give about 9000 rpm on 6 volts so you are getting the speed you want.
If in doubt just change the motors and check if they get hot before changing props.
What I like about 550's is that they can run happily up to 12 volts or anywhere in between but on 12 volts they will be around 18000, a lot of revs for a scale boat.
Steve Tranter sells 550's  
CLICK

Bob

[tica]

I would say that the speed it does now is actually looking ok.

My initial problem were that the motors didn't stay still when they should they were ticking and turning on and of

I believe that the problem were related to the previous owner and his lack of skill regarding electronics (more or less his own words) It seems that I have managed to readjust and rewire the whole boat and everything is now working including the Action mixer.

Br
Carsten

[Stavros]

And If you really want more power you could use up to 24v with ease


Dave

[tica]

Due to my right arm doesn't works as it should = no modelbuilding or other physical work that include the use of this arm, I have worked a bit with this setup.

1: I replaced the 2 electronize ESC with 2 Grupner to see if it helped on the Mixer functionality and the ticking of the motors, and NO they perform as bad or wors 

2: I dumped the HK RC set and replaced it with a Grupner MX-12 and now every thing seems to be more stable, no ticking form the motors and the 4 settings of the mixer works as they are expected to.

The ultimate test will be tomorrow when we start the outdoor season in Vallensbæk Model Skibs Klub.