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[chas]

Sorry to ask a probably daft question. You are switching on the transmitter before the receiver etc when setting up? Plenty of us on here got the T shirt on that one.

[aln101boat]

Connectors unplugged, between brown and the Tamiya plug's black cable, what is the resistance?
Does the faulty V&A meter work outside of that installation?
It is just a hunch.

Ok.
0.6 ohms on both controllers.
The meter didn't work at all, but as it is just a shunt, I didn't think it would interfere with the drive supply, so fitted it temporarily till I got another.
I have tried both controllers with a 7.2v sixpack connected directly to the Tamiya plug anyway. No difference.
rgds, Alan

[aln101boat]

Man at Mtroniks didn't suggest anything after my description, so I guess there isn't anything to try. Said send them back for him to play with, so I'll go and find a jiffy bag.
Alan

[aln101boat]

Sorry to ask a probably daft question. You are switching on the transmitter before the receiver etc when setting up? Plenty of us on here got the T shirt on that one.

Even daft questions are worth asking if they jog the memory.
Yes, Tx first, to avoid the possibility of interference driving a servo silly.
Although nowadays its very quiet on 27, as the worlds all gone Gigga .
Alan

[Martin (Admin)]

Do those two channels work OK if you plug in a couple of servos?

[aln101boat]

Do those two channels work OK if you plug in a couple of servos?

Aye, and remember, Iv'e tried another Tx/Rx as well.
Alan

[HMS Invisible]

Ok.
0.6 ohms on both controllers.
The meter didn't work at all, but as it is just a shunt, I didn't think it would interfere with the drive supply, so fitted it temporarily till I got another.
I have tried both controllers with a 7.2v sixpack connected directly to the Tamiya plug anyway. No difference.
rgds, Alan

In this installation all of the heavy current negative connections, including crimped, are critical. If one comes loose it leaves only a back door route to battery through both escs and brown wires. The continuity test ruled out damage due to that potential fault current. That is some consolation.
Sleep tight.

[Martin (Admin)]

Aye, and remember, Iv'e tried another Tx/Rx as well.
Alan

A little percussive maintenance.... with a Glasgow screwdriver?!

[aln101boat]

A little percussive maintenance.... with a Glasgow screwdriver?!

I was getting close to putting them on the floor and jumping up and down on them!
That's them away back to Mtroniks, so we'll see what turns up.
rgds Alan

[aln101boat]

Well,
Mtroniks sent me two replacement 20s. They work fine, but scream to the point of unreasonable. A sound module would be a waste of time, as it would never drown out that racket
They didn't offer any explanation why I got two out of two duds, which doesn't really inspire much confidence in quality control. Just as well their customer service made up for it.
Alan

[Sub driver]

Hi
But at least you got 2 replacements 
Sub.

[aln101boat]

Hi.
I rather think its the motors  making the noise not the speedos....what amps do those pull on stall ?.
Imo they look rather large for 20 amp speedos...
But at least you got 2 replacements 
Sub.

I haven't got as far as trying them under load as I only gave them a quick test without the proper motor connectors fitted yet, but I'd be very surprised and unhappy if they drew much over 10amps.
I do see some crazy Amp figures mentioned at times, but assumed that was just the looney cruise missile mob
Stall amps? Probably 2 or 3 times normal. That's what the fuse is for.
Alan

[mudway]

, but I'd be very surprised and unhappy if they drew much over 10amps.

I have 2 x 700s in a Perkasa hull with 35mm 2 blade props and using 3S lipos. On start up, each motor pulls 12.5 amps.
What size props are you using?

[aln101boat]

, but I'd be very surprised and unhappy if they drew much over 10amps.

I have 2 x 700s in a Perkasa hull with 35mm 2 blade props and using 3S lipos. On start up, each motor pulls 12.5 amps.
What size props are you using?

This is good info, thanks.
If its the 4ft model, that's pretty much what I would have expected as two blade props are meant for much higher speeds. They usually have a very large pitch and will cause a considerable load at low speed. The amps should drop quite a bit once the boat is moving.
Iv'e got 45mm and 50mm nylon props available as the correct scale size would be about 47. I may find that it is a little over-propped, but that's an easy fix. The pitch may need adjusting in the kettle (when the better half is not around) .
Once Iv'e got some basic performance to work from, I intend to use NiCads and pick the best number of cells for a good scale speed. I'm fairly sure 12v will be too much and maybe end up around 9.6
Alan

[mudway]

That’s the one, an old Precedent.

My 785s come from John Darke over here and have a no load speed of  11,700 and in the water speed of 8,200 on 12 volts. John recommends props up to 40mm only on 12 volts.

If you want to use 50mm props, he recommends a 3:1 gearbox.

If I was you, I’d start on 6 volts and work up. You would have a no load speed of about 6,000rpm then.

[aln101boat]

That’s the one, an old Precedent.

My 785s come from John Darke over here and have a no load speed of  11,700 and in the water speed of 8,200 on 12 volts. John recommends props up to 40mm only on 12 volts.

If you want to use 50mm props, he recommends a 3:1 gearbox.

If I was you, I’d start on 6 volts and work up. You would have a no load speed of about 6,000rpm then.

I fitted the shafts with room for the 50mms. The 45mms look ok, but I don't think I want to go much smaller as they would be way underscale. Although it might be possible to get the same speed out of a smaller prop with a higher pitch or revving higher, the acceleration and low speed manouevering would probably be less realistic.
Iv'e got 6v cyclon, 7.2 NiCad, and 12v cyclone to try, so we'll see what shows up once its waterproof enough to put in the bath
Its a big boat, so props and volts are easy to change later, so I'll concentrate on getting it finished .
rgds Alan

[mudway]

What is the model? An RAF launch or PT boat?

[aln101boat]

What is the model? An RAF launch or PT boat?

I have read back through the posts and you are right. I didn't say what it was. To be honest I hadn't expected it to go this far.
Its a precedent Fairey Huntsman 31 aft cabin. The 48" version.
Alan

[mudway]

Very nice, I always liked the look of them. I'd simply put a pair of handed 35mm 2 blade props on them and see how she goes.

You could always take them off and replace them for displays. The Fairey page seems to indicate that they ran 16 3/4" D x 19 1/2 Pitch props which would be about 52mm in 1/8th scale.

[aln101boat]

Very nice, I always liked the look of them. I'd simply put a pair of handed 35mm 2 blade props on them and see how she goes.

You could always take them off and replace them for displays. The Fairey page seems to indicate that they ran 16 3/4" D x 19 1/2 Pitch props which would be about 52mm in 1/8th scale.

More good info, thanks.
I admit I used the 15 1/2" x 16 1/2" size off my own Huntsman 28 from a few years back as a guide.
rgds Alan