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Author Topic: Norwegian Tjeld class MTB  (Read 44049 times)

SinWin

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Re: Norwegian Tjeld class MTB
« Reply #50 on: November 29, 2009, 10:28:08 PM »

Looks interesting, as long as it can be remotely controlled in some way - I want to be able to switch it on and off from the transmitter, and I figured a premodified servo would be the simplest solution; just plug into the reciever and you're ready to go. I know these servos exist, but I'm unable to find a suitable and reliable (in other words a web shop I can trust) seller for these servos that ships internationally. Either they don't exist, or my google-skills are way below par...
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Perkasaman2

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Re: Norwegian Tjeld class MTB
« Reply #51 on: November 30, 2009, 12:13:14 AM »

Hi Sinwin,  :-)
'Robbe' sell modelkits and parts.......... They also 'sell mini geared motors' in many ratios - 100:1, 250:1, 500:1 and 1000:1 which run at 6volts. I bought one of these tiny 6v units ( model No. 4124 - 500:1 ) from a model shop in the UK to rotate  the radar on my Perkasa. I never used it, but these are the units which are perfect  for spinning radar. This unit is available/sells for £25 here in UK and should be easy to buy in Norway. My model shop sold me the 500:1 type but you can check that this ratio choice will give the speed you want from a supplier before you buy.  ok2
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #52 on: November 30, 2009, 10:45:44 PM »

Thank you all for your help. I found a Norwegian supplier of Robbe-parts who were willing to help me, and have now ordered two on/off-switches for my reciever (to power on/off the lights and radar), and one mini geared motor - possibly a too slow, but we'll se (1000:1). I'm looking forward to seeing how well it works.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #53 on: December 05, 2009, 01:49:36 PM »

I've just tested the small motor, and it spins too slowly, however, that was a perfect excuse for buying the 500:1 motor as well, so I've now ordered that one.

However, I did get two on/off-relays which can be used for switching on and off lights and such. I did not know those things existed prebuilt, so I'm happy I asked the shop if they had something like that before I ordered.
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Perkasaman2

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Re: Norwegian Tjeld class MTB
« Reply #54 on: December 05, 2009, 08:23:26 PM »

I would like to have the  Robbe + Graupner catalogues to find out exactly what other gizmos/fittings etc. are available - the items I have bought  were expensive but good quality.   :-) 
The twin Napier Deltic diesel engines fitted to the Tjeld were amazing engines - 2 stroke/36 pistons/triple crankshafts - each!  :o

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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #55 on: December 05, 2009, 10:19:23 PM »

Indeed. When you think that those engines powered large locomotives designed to haul heavy loads on track, and you place two of those engines in a small, wooden hull - fit some torpedoes and a few guns - and there you have a powerful, fast and agile military vessel. I was not aware that the Hellenic Navy actually still uses four Tjeld-boats as patrol craft, but they do! Some links: http://www.hellenicnavy.gr/andromeda_p196.asp
http://www.hellenicnavy.gr/kyknos_p198.asp
http://www.hellenicnavy.gr/pigasos_p199.asp
http://www.hellenicnavy.gr/toksotis_p228.asp#a1

The design of the deltic engines are special - the triangle setup had me scratch my ear for some time to figure out how it could work.

I have always thought that one of the Tjeld-boats were preserved at the Norwegian Naval Museum, but my brother visited the museum the other day, and called me: no Tjeld-class were there. So, where is it? He was told the boat is somewhere here in Bergen (the Naval Museum is located in the eastern part of Norway, near Horten, as opposed to Bergen on the western coast), but I can't think of anywhere else it could be in Bergen but the Haakonsvern Naval base - off limits to civilians, of course...


I have today tried and tested a solution for an automatic bilge pump, but it did not work. It seems I just have to fit the pump, and make a switch for it so that I can easily operate the pump when I bring the boat up on dry land. I'm curious about the 500:1 engine. It's expensive, that is true. I hope it has the right speed for turning the radar, so I don't need to buy yet another motor :p
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derekwarner

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Re: Norwegian Tjeld class MTB
« Reply #56 on: December 06, 2009, 12:36:53 AM »

Perkasaman says.... "The twin Napier Deltic diesel engines fitted to the Tjeld were amazing engines - 2 stroke/36 pistons/triple crankshafts - each!"   

 >>:-( <*< <:(...amazingly complicated may be a better description  %% %% %%...however never designed for maintenance @ sea....... %) .......Derek

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Derek Warner

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Pale Horse

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Re: Norwegian Tjeld class MTB
« Reply #57 on: December 07, 2009, 08:37:52 AM »

I have always thought that one of the Tjeld-boats were preserved at the Norwegian Naval Museum, but my brother visited the museum the other day, and called me: no Tjeld-class were there. So, where is it? He was told the boat is somewhere here in Bergen (the Naval Museum is located in the eastern part of Norway, near Horten, as opposed to Bergen on the western coast), but I can't think of anywhere else it could be in Bergen but the Haakonsvern Naval base - off limits to civilians, of course...

i found some info about the remaining Tjelds:

There are three norwegian Tjeld-class boats left.  One is owned by the naval museum in Horten and will be displayed in the museum (on land), one is in Fredrikstad and will be fixed up and running as a floating museum, and the last one is used as parts for the one that will be running. 

more info (in norwegian) and some pictures can be found here: http://www.tmbk.no/delf1no.htm

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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #58 on: December 10, 2009, 04:23:07 PM »

I hope they'll get it out for display soon, I wonder where it is for the time being. A good thing, though, that three of them are preserved!


I'm currently investigating (with a lot of help) ways of making an automatic bilge pump for the boat. I have the pump, and was planning on just placing it in the hull with a simple switch for on/off operation on land when the boat should be emptied of any water, but it would be great if I managed to have it work automatically. It's not my top priority, though.

It was my last day at work before Christmas today, at last there will be time for some building!
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Perkasaman2

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Re: Norwegian Tjeld class MTB
« Reply #59 on: December 11, 2009, 01:25:04 AM »

Hi Sindre ,A car windsreen washer pump may be used - they are small and light BUT usually run on 12v??? - An inlet tube could remove water from water collected at the stern and pumped out through a side outlet fitting - when planing (bow lifts) water collects/flows there. A multi channel radio could operate the pump.................. or a pressure switch can be installed which is only pressed/activated by one of the rudder arm at full arc/swing- during either a full left or right turn - use during high speed run (when bow is lifted). Simple solutions are usually the best if possible. Your main batteries are 12v for pump power supply? good luck :-))
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #60 on: December 11, 2009, 09:00:01 PM »

A windscreen washer pump is exactly what I have bought =) It runs on 12 V, and I use one in my model of Smit Nederland, where I run it at six volts. It works very well, and makes it easy to drain the hull after use.

I have the possibility to use one of the channels on my sender to activate the pump, but I would also very much like it to be automatic! I'm therefore thinking of some way of building a small scale controller to activate the pump at a certain level of water, and deactivate it when the water level sinks below a certain level. It would be fun, but it is not my top priority. The main point is to hot have it go constantly on and off, which I'm worried would be the result of for example having the pump being activated by the rudder at full swing etc. My main problem is that I'm no electric engineer...

The plan is to use the internal 12V batteries, yes. I'm installing the pump anyway, with a simple switch for use when the boat is taken up on dry land. Priority number one, though, is to make the boat as watertight as possible.
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derekwarner

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Re: Norwegian Tjeld class MTB
« Reply #61 on: December 12, 2009, 12:25:02 AM »

Sinwin.....I must agree....."Priority number one, though, is to make the boat as watertight as possible"

Also remember there are two types of windscreen washer pumps...one is a gear pump [positive displacement] the other is an impellor type...although either would be OK in this application...have you considered using the pump as a fire monitor?

Sorry.......but I don't understand why your Smit Nederland would also take in water...... %%..............Derek
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Derek Warner

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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #62 on: December 12, 2009, 09:02:29 AM »

I think the one I've bought is of the impellor type. It is very cheap and not of the best quality, but it works.
My Smit Nederland is the first boat I built, and I have a feeling that some parts of the assembly manual were missing. A few drops of water enters through the shafts, but most of the water enters the hull via the cuts in the deck. Of course, that only happens when the boat is riding in «heavy» seas, but still.
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derekwarner

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Re: Norwegian Tjeld class MTB
« Reply #63 on: December 12, 2009, 12:51:16 PM »

You mean like this?.......... :-)) these .jpgs are just normal life in our Sydney harbour........& not @ sea......
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Derek Warner

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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #64 on: December 12, 2009, 01:51:16 PM »

Something like that - on a much smaller scale, of course :p I run it on small lakes and ponds, as well as in seawater; the latter of which offers somewhat larger waves and rough water.

So that is just in the harbour? Looks rough..


Does anyone know of a method of slowing down servos? I was thinking of slowing the one which are going to turn the 40 mm gun down. The gun was turned by hand on these boats, so I don't need a very quick servo. Would it work just fitting a resistor to one of the cables (that is, + or - and not the third "control"-cable)?
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derekwarner

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Re: Norwegian Tjeld class MTB
« Reply #65 on: December 12, 2009, 02:34:31 PM »

SinWin ....there are purpose designed "electronic servo slowdown" components available............... suggest you contact [Action Electronics].......... FLJ here on Mayhem ...

With respect to the water conditions .....yes the .jpgs as shown are certailny a heavy water .....but can occur at any time of year in Sydney harbour when crossing between the North head & South head of Sydney harbour........


For the squimish........stay @ home.....for the lovers :-)).....get a return ticket & stay on board all day    O0   {-) Derek
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Derek Warner

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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #66 on: December 16, 2009, 10:29:10 PM »

That's an idea. I will have to see how much I'm going to fiddle with the servo for the 40 mm.


Today I finally made some progress again: with help from my brother (who is far more accurate and clever than me) we cut out a piece of the deck. It is so big there's no problem accessing the batteries, motors and servo, and yet I think it will be possible to make it fit very well. The cut has been made behind the superstructure, and in a place where it will be somewhat hidden by the two aft torpedo tubes.



I've also revised the rudder servo placement. Earlier, it rested in the bilge, making it vulnerable to water damage. I've lifted it up, using the longest bar from the meccano set.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #67 on: December 18, 2009, 04:49:48 PM »

A short video showing the radar: http://www.youtube.com/watch?v=FR0QtwMup_I
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Perkasaman2

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Re: Norwegian Tjeld class MTB
« Reply #68 on: December 18, 2009, 05:46:36 PM »

Very impressive  ok2
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John W E

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Re: Norwegian Tjeld class MTB
« Reply #69 on: December 19, 2009, 05:47:38 PM »

Hi ya there SinWin

Having a look at your last two photographs and I noticed that around the edge of your hull, at deck level, you havent any support or a flange.   Is this done purposely - do you have a mating flange which sits inside the hull on the underside of the deck?   Because, with the thinness of the hull its giving you a very small cross-section contact area to seal on the underside of your deck.

It may pay you, if you wish, to have the whole deck removable all of the time, to fit some form of flange around the inside, and use a silicon sealer on the top.   You have possibly already thought of this, but, it was just a thought whilst looking at your photographs.

aye
john
bluebird
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #70 on: December 31, 2009, 03:06:18 PM »

Thank you both for your comments. I haven't had the time to update the thread for a while, but some progress has been made. 40 cm of snow and lovely weather means most of the time is spent outdoors, though. It is not possible to ski here on the coast every year, but this winter has given us lots of snow and near perfect conditions. Last time people skied out here, I am told, was the winter of 1978/-79.

I would like to be able to remove the whole deck, but I have tried to make the seal watertight, and have not succeeded. After weeks of thinking, I decided to make a cut in the deck behind the superstructure, to give me access to batteries and electronics. The main part of the deck will be glued on to the hull with araldite, and a seal of silicone on the outside. The pictures above were taken just after the cut had been made: these next images will show the supports I have made underneath. It is aluminium, and gives me about one cm of support on each side of what is now the hatch. On top of these, I have placed a weather strip, which will have to be modified a little bit in order to fit well.

The longer aluminium bars are fastened by four screws, and the two smaller ones with two. In addition, all four bars have been rubbed with sandpaper, and glued with araldite.




This last image also shows one of what is to become the torpedo tubes.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #71 on: January 01, 2010, 07:57:25 PM »

In addition to the progress under deck, my contractor for the 40 mm gun has been working hard this Christmas. Here's what he has come up with these last weeks:

   

I must emphasize that I am not the person building this gun. This is a build from the same person who paints wristwatches on 1:87-scale people, and brass buttons on their jackets. I'm glad he agreed to build the gun for me. And no, it is not quite finished yet  ok2
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #72 on: January 21, 2010, 08:07:26 PM »

The last thing I did before the holidays ended, was fastening the deck to the hull, and sealing the gap with silicone. I let it harden for a week before touching it at all, and it seems the silicone holds rather well. Perhaps it'll crack when I run the boat: after all, there are some vibration in the hull. The silicone is supposed to withstand changes in gaps up to 25 %, but: changes combined with vibrations. I wonder.

For the time being all open water apart from the sea is covered with ice and snow. It's beautiful, so I'm not complaining. Bad conditions for a test-run of model boats, though.


Not much open water on the little pond near our house.

Over to the boat:


And yes: the silicone is black. It was the only thing they had in the shop I visited. Bad. Perhaps I'll try and paint over it, but I'm not sure that's a good idea.
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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #73 on: April 18, 2010, 09:52:05 AM »

A long time since my last update here!

These past months I have mainly worked, studied and worked - though, alas, not on the boat in question.

However, some small improvements, or shall we say progress, has been made.

As mentioned earlier, I have sealed the gap between the deck and hull with silicone. I have not had the chance to test how good, or bad, this would work before now, simply because all small ponds have been covered with ice! When the ice finally melted, it rained - but a week ago, the weather was fair, and I charged my batteries, and went to the nearest pond to test the boat. Having fitted the batteries, turned on the transmitter and the receivers, I lifted the boat into the water - and just as I did that, I heard the sound of the transmitter telling me it had run out of battery. Argh!



Oh, well, at least the boat still floats...


Yesterday, I tried once again. It rained, but I HAD to test. This time, I made sure I had charged both the lead acid batteries AND the transmitter batteries, before taking the boat down to the pond - and guess what, it worked! I ran the boat for half a minute on near-full power, and then sailed in to shore to chech if there had been any ingress of water. Before sealing with silicone, it would have been lots of water in the boat, but now it was perfectly dry! Success! No use for the pump I installed.

I then proceeded to sail the boat out on the water, but after a few seconds, only one engine would run - and only backwards, at a very, very slow speed. I finally got the boat inshore, and found that the 30 A fuse on the starboard engine (I have mounted a fuse between the motor and the speed controller) had blown. 30 A! I mounted a new fuse, but after a few seconds, this blew as well. I mounted yet another fuse, but after a few seconds, not the fuse, but apparently the speed controller blew! It now refuses to drive the engine anything but backwards.

What a blow: after all, it worked perfectly well before (just look at the videos I have posted), so what on earth has happened now?! I suspect that the starboard engine has a short somewhere - that might explain my earlier trouble with the first set of speed controllers (?). One other thing that I came to think of, is that my engines is held in place with steel bars which is connected to each other: this means that the caps of the engines are connected to each other, electrically speaking: however, I have seen many model boats where this is the case, so should this really be a problem?

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SinWin

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Re: Norwegian Tjeld class MTB
« Reply #74 on: June 20, 2010, 12:15:10 PM »

After much effort, I have mounted a new speed controller to replace the one that melted on the starboard side. 

Also, I spoke with the dealer, and he asked if I had cut the power supplied from the battery eliminator circuit from one of the speed controllers, so that only one controller supplied the receiver with power. From what I understood, he meant that if two speed controllers supplied the receiver with power, this could be the source of the problem. I really can't understand why, but did what he said: I cut the red cable running from one of the controllers to the receiver.

Having done all that, I went for a test run. 25 A fuses were mounted between the speed controllers and the engines: and guess what, the starboard fuse blew, AGAIN! And again, the port engine stopped working properly when the fuse for the other engine blew: the port engine would just run backwards, at a very limited speed.

A new speed controller obviously did not help, and cutting the BEC-power supply from one of the controllers did not help either.

Now I really wonder what is wrong!
Could it be something wrong with the engine itself? After all, it is just the starboard engine that, when under load (i.e. with the propeller under water), blows the fuse.

Below is a sketch of my electronics layout - I can't see that I've made any errors here?

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