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[essex2visuvesi]

Having an Issue with my boys white star.

It runs lovely BUT after about 4-5 seconds on Full Throttle the ESC cuts out

Speed controller is a Robbe Rookie 25
Motor is a Speed 400 6V
Battery pack is a Tamiya style 1700Mah stick pack separated into 2 sticks

The prop shaft is straight and true and well lubricated, runs freely with no binding

The motor seems to be OK (It runs fine on the bench) but Im not 100% certain so I want to fit an inline ammeter into the system so I can test it under load.  I found this one but it does not have a "Telltale" I want to be able to see the maximum current draw not the current one if you know what I mean
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8319

So anyone have any suggestions on where to find something suitable?

[john s 2]

This is only a guess but it could be your Esc shutting down then restarting. Would not a run in the Test Tank
(Bath) enable you to do a real time current test? If youve a spare Esc, its worth a swap to try.Could be
your r/c gear but less likely. Good luck we all have these problems at times. John.   

[essex2visuvesi]

Great Idea but sadly I dont have a bathtub :(

I have a swimming pool but its still in the shed lol

Going to try another motor as I have another S400 6V in the spares cupboard

[JB]

Great Idea but sadly I dont have a bathtub :(

I have a swimming pool but its still in the shed lol

Going to try another motor as I have another S400 6V in the spares cupboard

I don't know the answer to this Q as I only have a small amount of experience with electrics,
I'm hoping to see a friend today who has...I'm 'stealing'...! some of his motors and battery packs so I'll ask him what he thinks.

I'd like to know the answer myself.

J.

[Roadrunner]

I'm Surprised no ones asked you what size prop you have on the boat?

Reason i say this, is the prop may be to big for the motor size and what's really going on is the motor is unable to turn the prop under load, a club member has the same issue with his seaport once the motors under load it get very hot and stalls, due to overheating, the simple suggestion is to put either a smaller prop on, or put in a larger motor, since your using a 25A esc you should have no issues fitting at least a 480 size http://www.cornwallmodelboats.co.uk/acatalog/graupner_6304.html

As other suggestion run the boat up on the desk at full speed and see if it cuts out, i have a feeling its the motor, but it could be your wiring, battery, or ESC!

[essex2visuvesi]

I did some qick testing last night and I think you could well be right, the motor does get very hot, tho the ESC doesnt.

Im going to fit a brand new 400 tonight and test that see if it helps

Im not sure of the prop size as its not the prop that is shown in the instructions and its only a 2 blade. Ill check and get back to you

I do have a Tamiya sport tuned 540 size motor, would that be too much? lol

[Roadrunner]

The 540 should be fine with the esc, i used to run a 540 sport motor in my springer with a 27 turn ( 25amp) esc with no issues. however the run time will be seriously reduced to around 15-20 mins using the 7.2v 1700 pack, i would look to change the motor, perhaps water cool it if its hot, or fit a larger 480 size, as this will keep the run time up around the 45- 60 mins. The heats being generated by the load of the prop so maybe look to change it to a smaller prop 2 or 3 blades, other wise i think the new motor will have the same results, a bit of trial and error between the motor and prop i think.

[essex2visuvesi]

The prop is a 2 bladed 35mm 3mm Threaded prop Not sure how to work out the pitch tho. Looking at the plans it should be a 3 blade

http://www.cornwallmodelboats.co.uk/acatalog/billing_boats_white_star.html

If you look at the picture it has a 3 bladed prop

What would be a good staring point?

[JB]

Sorry I'll read from the beginning..again...

Is the pack 7.2v..?

Think I'm going (gone?) nutty..!

J.

[Roadrunner]

Try a 25mm 3 bladed prop (25mm M3 Threaded 3 Blade R/H Brass D-Type Propeller) http://www.cornwallmodelboats.co.uk/acatalog/R156-M3.html either LH or RH depending on your motor rotation, but you can change this on the motor wiring if needs be.

I've suggested 25mm 3 blade as this is the biggest prop i can find for an M3 threaded shaft without going into the £15-20 mark. £10 i think is a fair price.

Combine that with a 400 or a 460 motor using your 7.2 1700 battery you should now no longer have stall issues. 

[essex2visuvesi]

Spare parts ordered

Couple of different size M3 3 bladed props, only a couple of quid each so bought a selection from 25mm to 40mm
540 Aluminium motor mount (Just in Case) tho I may use it in the Girls Katja Im Building

[Roadrunner]

NO worries bud let us know how you get one, suggest starting with the smallest prop and working up until you get a happy medium with speed and motor endurance.

Let us know also how you got on with the Katja i'm interested in that little boat as a bit of a knock around my my daughter, she's gone off her tug and wants a speed boat now!

[essex2visuvesi]

NO worries bud let us know how you get one, suggest starting with the smallest prop and working up until you get a happy medium with speed and motor endurance.

Let us know also how you got on with the Katja i'm interested in that little boat as a bit of a knock around my my daughter, she's gone off her tug and wants a speed boat now!

I will do Its a learning experience for me and something I can put into practice when I get my Phantom finished

As for the Katja Its pretty a straight forward kit, no real suprises yet and yes I would reccomend it for the money you cant go wrong.
I think you could easily put one together for less than 100 including radio gear

So far I have started trimming the hull on the Katja and actually got around to using Unimat I got for Christmas lol

Im Going start a build log for it shortly

[Roadrunner]

I'll keep watch for that 

[essex2visuvesi]

Sorry for the delay in updating.... been a bit busy on other projects

After messing with some different props we finally settled on a Rasobech Type D 25mm prop as suggested... This gives a good balance on speed and duration with the 1700Mah nicad and speed 400 6V motor.

Still have to watch the reverse tho as she does like to dip her stern

[treeboa]

get a restrictor under the reverse side of the handset, i have the same problem with an e boat

[essex2visuvesi]

get a restrictor under the reverse side of the handset, i have the same problem with an e boat

We have sticky tape lol.... crude but effective.  The controller is used for his car as well so can't really do anything permanent as yet

[treeboa]

bit of lolly ice stick n some selotape