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Author Topic: Norwegian Tjeld class MTB  (Read 44697 times)

Flying Sparks

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Re: Norwegian Tjeld class MTB
« Reply #100 on: August 27, 2010, 07:51:22 PM »

SinWin

You should really invest in Wattmeter or something similar to check how many Amps you are pulling, relying on the fuse blowing is very hit and miss. I few years ago I invested in Wattmeter and it has repaid itself many times over in not blowing up motors, batteries and controllers as I know how much current I'm putting through the system. Giant Cod and many other place sell cheap Wattmeters like this one http://www.giantcod.co.uk/neodynm-multif-watt-meter-p-403851.html

Another thought is are you sure that your lead acids are capeable of providing enough power without stressing them? You might want to try NiMhi or Lipo as they can supply much more power.

Your boat looks very impressive, keep up the hard work  :-))

Phil.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #101 on: August 27, 2010, 08:22:08 PM »

Thank you so much!

That looks like a neat little instrument, and not all that expensive either. Perhaps I'll give it a go. After all, I have wanted something like that for some time.

However, even if my engines draw 20 amps or slightly more than that, I can't understand why the speed controllers should fail in the way they do. Every single one of them, that has been broken, has failed in the same way - they just quit to give the engine current forwards. If the engine should draw more than 25 A, the fuse would blow: both the engine and the speed controllers should be able to handle that amount of current.

Perhaps my setup is all wrong, but I am really not able to tell what is wrong. I mean: it worked for several hours a week ago, and then, yesterday, it just quit after two minutes on the water.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #102 on: August 28, 2010, 11:06:56 AM »

I'm currently looking for new speed controllers - is there anything you out there would recommend? I am beginning to wonder if I should just cut out the luxury of controlling each engine separately, and just use one channel and one speed controller for it. Trouble is, as the engines draw so much power, I guess it will be difficult to find a speed controller that can handle the amount of current?

Should I buy some different style propellers? 4 blades? 5 blades? 2? Different pitch?

I also note that my receiver is placed rather close to the engines - this could be a problem, but I can't se why it should make the controllers fail?
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DickyD

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Re: Norwegian Tjeld class MTB
« Reply #103 on: August 28, 2010, 11:39:06 AM »

Hi SinWin contact Dave at ACTion Electronics he will help you out.

www.action-electronics.co.uk

He has designed many purpose made systems for boats.

He has just supplied Martin du in Australia with all the electrics for his very complicated 1:16 Brave Borderer.

http://www.modelboatmayhem.co.uk/forum/index.php?topic=9865.msg250599#msg250599
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Richard Solent Radio Controlled Model Boat Club http://www.srcmbc.org.uk

SinWin

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Re: Norwegian Tjeld class MTB
« Reply #104 on: August 28, 2010, 01:00:17 PM »

Thanks for the tip. If he is willing to help me even without me nessecarily needing to buy something from him, I'll be sure to send him an email!
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Flying Sparks

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Re: Norwegian Tjeld class MTB
« Reply #105 on: August 29, 2010, 09:41:37 AM »

SinWin

Before you buy any new speed controllers you still need to have an idea of how much current you are pulling, then you can order a ESC of the correct rating.

I have heard a lot of good reports of ACTion electronics but I have no personal experience of them. I do however own a couple of Mtoroniks controllers and are excellent brushed controllers. I had a problem with on of the controllers and it was probably my own fault, the controller was replaced promptly by Mtroniks, no questions asked.

Phil.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #106 on: August 29, 2010, 02:48:50 PM »

I have now ordered the wattmeter linked above. Looking forward to receiving it! I have also sent an email to action electronics, perhaps Dave is able to help me out.

It is strange, though, that four ESCs should fail from too much current (I can't se why else it should fail in the way they did?), even when I have fuses installed, and fuses rated well below the maximum current for the ESCs?

Well, when the instrument arrives, we will find out how many watts the motors are consuming. Thank you all for your suggestions!
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derekwarner

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Re: Norwegian Tjeld class MTB
« Reply #107 on: August 29, 2010, 09:14:45 PM »

SinWin ....some types of fuses are slow delay. >>:-(....& designed for robust applications...it is possible that a current spike could pass throught the fuse & destroy the electronic component  prior to the fuse blowing ......Derek
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Derek Warner

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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #108 on: August 29, 2010, 09:33:45 PM »

Oh, that is true. I did not think of that, stupid me. I have just bought some fuses made for cars, and I have no idea if they are slow or fast fuses. Most likely they are slow, if we are to judge by the amount of destroyed ESCs!
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derekwarner

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Re: Norwegian Tjeld class MTB
« Reply #109 on: August 30, 2010, 07:12:27 AM »

Sinwin...I have near ZERO electrical knowledge  {-) %% ....however even a new digital multimeter may not register a high amplidude ...short duration [milli/micro second] current spike...........

The popular reference here on Mayhem is to talk with FLJ..........I have ACTion components from the previous owner..... O0 ....& can only speak as a very satisfied customer........Derek
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Derek Warner

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FullLeatherJacket

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Re: Norwegian Tjeld class MTB
« Reply #110 on: August 30, 2010, 07:34:59 AM »

I have had an E-Mail about this thread (which I confess I haven't been following) and I've replied to SinWin with my suggestions. Let's hope he can now sort it.
BTW it doesn't involve a wholesale refit with our stuff; that would just be gratuitious, wouldn't it?  8)
FLJ
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #111 on: August 30, 2010, 09:24:54 AM »

I guess you can't follow every thread =)

However, to sum up the email i received, FLJ concludes that my model is too heavy, the lead acid batteries unsuited for the task, and the propellers perhaps a little too big. Oh, and, that BEC is not the best thing in the world. I am inclined to agree with this (though, on the BEC-think I have nothing to say). As I have noted before, my only model previously has been a tug (Smit Nederland), where I would say lead acid batteries works like a charm, and the ESC did not fail from too much current, but because of my clumsy installation which allowed for short circuits. I blew four ESCs in that model, before I found out what the problem was; in other words, ESCs and me does not go very well together!

Based on FLJs recommendations I will buy new batteries (two large NiMH-battery packs), a receiver battery, and I still need another ESC. It means, though, that I can continue to use my engines, and now I also know, thanks to FLJ, that having the engine cases connected to each other in the way I have, is no problem.

I must thank you for showing me Action Electronics, and a special thanks to FLJ for his quick and very useful response!
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #112 on: August 30, 2010, 10:43:22 PM »

I've now ordered the two battery packs, 12 V 5Ah, and a separate receiver battery pack. Also, the wattmeter is on its way.

Now I'm looking forward to a model that works!
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Flying Sparks

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Re: Norwegian Tjeld class MTB
« Reply #113 on: August 31, 2010, 12:52:17 PM »

SinWin

If you fit a separate receiver pack you will remember not to power the receiver by a BEC supply as well won't you  :-))

Phil.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #114 on: August 31, 2010, 02:52:53 PM »

Hehe, I will! Thanks for the reminder. I guess some red wires will suffer!
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #115 on: September 02, 2010, 05:43:21 PM »

Still waiting for all the new gear to arrive. I hope it arrives before Sunday!

I've also bought some lead, as I guess the 5 kg reduction in weight will make the boat ride too high in the water, and I want some weight in the middle, as low as possible. Not too much, though.
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FullLeatherJacket

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Re: Norwegian Tjeld class MTB
« Reply #116 on: September 02, 2010, 07:12:42 PM »

Still waiting for all the new gear to arrive. I hope it arrives before Sunday!
That's now very much in the hands of Norwegian Customs and Royal Mail. We waved goodbye to our little contribution to the cause on Tuesday.
As I said, you should concentrate more on getting the model to sit level in the water than ballasting it down to the waterline. I think you will be very surprised at the difference in performance.
FLJ
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #117 on: September 02, 2010, 10:36:47 PM »

Of course! I ment no offense, my point was not to complain in any way, I am just very eager to get all the things I've ordered, put it together and see that it works!

And yes - I want do do like you said, make it sit level on the water, but not much more. I have not ordered any new propellers yet, I hope to be able to maintain the 45 mm, but perhaps they should be smaller.

I watched an old Norwegian movie the other day, where the Tjeld class plays a part. Some of the scenes shows the boats at full speed, and the bow lifts noticably more than I've been able to replicate in my model. I wonder, though, how stable it will be in a turn when 5 kg of weight disappears!
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FullLeatherJacket

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Re: Norwegian Tjeld class MTB
« Reply #118 on: September 03, 2010, 08:33:36 AM »

Of course! I ment no offense, my point was not to complain in any way,
None taken, Sindre. It's like waiting for Christmas morning, isn't it  ok2
FLJ
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #119 on: September 03, 2010, 10:11:44 AM »

Glad to hear it.

And yes, it is a little bit like waiting for Christmas! After all the problems I've encountered with something that should be simple, I'm looking forward to a fully functional vessel.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #120 on: September 06, 2010, 06:43:30 PM »

I got my batteries today! And oh my, they are light! At least compared to the two lead acid batteries I have used. Now I just have to buy some male plugs so I can charge them.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #121 on: September 09, 2010, 01:17:14 PM »

Just checked the mailbox, and my fuse holder from Action Electronics are here as well! A neat little installation.

I was going to charge my two battery packs the other day, but unfortunately, my NiMH-charger can only charge 8 cells, and not 12. This means I have to buy a new charger as well. Bah.

Now I need a new ESC, a new charger, and some 12 V fans as well, to cool the ESCs, which I will place differently than they are today. Oh, well. Have to wait until 15 September to buy any more stuff, though; payday.
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steve pickstock

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Re: Norwegian Tjeld class MTB
« Reply #122 on: September 09, 2010, 02:11:29 PM »

Do you not have an old computer?

They're a good source of fans.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #123 on: September 09, 2010, 02:25:57 PM »

I don't, but I work in a place where used computer fans are all over the place, although not so many 40x40-size, which I would prefer - and my brother is an inexhaustible source of old computer components. If all fails, I would have to buy some.
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Perkasaman2

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Re: Norwegian Tjeld class MTB
« Reply #124 on: September 29, 2010, 04:49:53 PM »

Hi Sindre, Enjoy:

http://www.britishpathe.com/results.php?search=motor+torpedo+boat&o=20                     :-)
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