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Author Topic: Chinese 20 warships  (Read 15020 times)

djrobbo

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Re: Chinese 20 warships
« Reply #25 on: July 08, 2008, 07:23:50 PM »

Hi guys.....got one of these from howes to see what could be done with it..........straight out of the box the radio was crap , but no matter coz i didn't intend to keep it in anyway..........Stripping it all out was interesting , trying to find all the screws was fun , but hey ho onward and upward !
             Came to the conclusion that the best way forward with standard radio gear would be a single prop and standard rudder . It was strangely quite easy to remove all the revolvey leccie bits . i.e motors couplings shafts and tubes etc , and with not a great deal of modification and a suitably placed hole you can reuse one of the origional shafts and tubes and refit it in the centre of the hull and still leave plenty of room for a standard rudder.......haven't done anything since the weekend but will probably get back into it this weekend............we shall see how it all goes back in  :D O0

                 regards....bob.
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tobyker

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Re: Chinese 20 warships
« Reply #26 on: July 08, 2008, 10:33:44 PM »

It looks like we might have a little fleet of these. My destroyer sea trials today were unsuccessful as it didn't work at all, but maybe it was a bad battery connection as when I got it home and tested eveything, and put it on charge (again) for half an hour, it started working. I made up a charging lead to fit the Pro-peak and now I know the battery is fully charged, so we'll try again tomorrow. I can't wait to start stripping it but do want to see it running first. (The barge trials were a great success - now to rig it). How about some photos, Bob?
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DavieTait

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Re: Chinese 20 warships
« Reply #28 on: July 09, 2008, 12:41:37 AM »

Looks like they put the superstructure on back to front though , should be 2 main turrets fore end and one aft end not the other way around !!!!!
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Martin [Admin]

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Re: Chinese 20 warships
« Reply #29 on: July 09, 2008, 09:19:00 AM »

Maybe it's for navies that are not very confident...... 
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Edward Pinniger

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Re: Chinese 20 warships
« Reply #30 on: July 09, 2008, 02:56:27 PM »

This one (unlike the other boats in the range) is a complete freelance/fantasy design, it seems to be loosely based on the US Iowa-class (Missouri etc.) but re-uses a lot of parts from the "Challenger" Kiev-class carrier, including the Ka27 helicopter! The scale is more like 1/350, not 1/250 as the description says.
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Edward Pinniger

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Re: Chinese 20 warships
« Reply #31 on: July 09, 2008, 03:06:33 PM »

This one (unlike the other boats in the range) is a complete freelance/fantasy design, it seems to be loosely based on the US Iowa-class (Missouri etc.) but re-uses a lot of parts from the "Challenger" Kiev-class carrier, including the Ka27 helicopter! The scale is more like 1/350, not 1/250 as the description says.

If anyone's interested, I've added a "review" of the Bismarck to the "What's in the box" section.
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tobyker

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Re: Chinese 20 warships
« Reply #32 on: July 09, 2008, 04:56:06 PM »

Sea trials (in the sea) completed. Only way to get a decent turn is full fwd on one screw and full astern on t'other, Seems fairly seaworthy though.Couldn't do it at Largs as the lake was full of proper model boats with proper radios. Picture of superstructure and foredeck removed. Lots of the superstructure levels are held together with screws - scope for weight saving there if necessary. Interestingly, several of the jelly bungs seem to have reacted with the dark grey deck, softening it locally. To get this far you have to remove the missile tubes (I hot-knifed the legs) and the motor boats(brute force) The fore turret is not screwed, but sprung onto clips, off which it can be sprung by a a pair of screwdivers. The plastic does not seem to react to polysterene cement, so I think it'll be a superglue rebuild of the loose bits. Next to get the main deck off. Several of the screw holes seem to have hot glue inside.
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tobyker

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Re: Chinese 20 warships
« Reply #33 on: July 09, 2008, 06:19:17 PM »

Phew! Lots of careful levering with small screwdrivers, and the main deck off. Especially difficult where the chinese superglue has run off the liferafts on to the hull/deck join. I dunno how to get the words in among the pictures but you should see under the deck - the switch and charging pcb, the battery box and the radio box. In the hull are - a cylindrical steel weight, the cinder block weight under the black plastic cover, and the motors with another steel weight between them. aft of them, the white block is a piece of expanded polystyrene in a compartment vented to the sea, outside the sealed hull/deck assembly. Odd. All will now go quiet for a long time while I work out how and what to put together!
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tobyker

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Re: Chinese 20 warships
« Reply #34 on: July 12, 2008, 07:48:57 PM »

Just checked out the prop shafts - a brass collar with dogs is screwed on to the shaft, then the prop which is slotted to take the dogs, then a brass flat washer, a steel spring washer and finally a Nyloc (type) nut. Both shafts RH thread. Shaft 2.79mm dia, nut 5.41mm a/f. FLJ whom I have consulted about motor controls has advised me to ask SHG about more suitable props. However all is on hold until I've done an amp draw test on the present set-up, which may now be after my holiday. Incidentally, when I opened up the very well sealed radio box under the deck, I found a sachet of silica gel crystals inside. Somebody must have checked Mr Piece-work on that! I am thinking I will open up the deck over the radio box so I can get the new gear in, and build up a coffer dam inside the rear superstructure to stop the water getting in. This will give me access without having to strip the whole deck off. However the steering servo will probably have to sit behind, and be braced to, the shaft supports so that will be less accessible. Lots to think about while I'm away! Meanwhile, all suggestions welcome.
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Martin [Admin]

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Re: Chinese 20 warships
« Reply #35 on: July 12, 2008, 09:53:50 PM »


 How about wiring the 2 motors in parallel and using a long rudder, or a small rudder with a perspex enlarger?
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herrmill

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Re: Chinese 20 warships
« Reply #36 on: July 12, 2008, 11:23:53 PM »

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tobyker

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Re: Chinese 20 warships
« Reply #37 on: July 13, 2008, 01:54:20 AM »

One rudder? (As in "a handbag?") Get thee behind me Martin - the whole point is to work out how to do it elegantly, not easily.  If I can do it I want twin rudders and a mixer. Per ardua ad (dis)astra, or something. (Though I've never walked sideways, myself.)
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Edward Pinniger

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Re: Chinese 20 warships
« Reply #38 on: July 16, 2008, 02:00:35 PM »

I've started work on mine a few days ago (or rather resumed work... I repainted the hull and took off all the fittings + small bits last autumn, but it's sat on the shelf gathering dust ever since) - I'll post some more photos in a day or so. The hull, decks + superstructure are all repainted now, so it's looking much better already!
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tobyker

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Re: Chinese 20 warships
« Reply #39 on: August 05, 2008, 09:28:47 PM »

At last some activity on this one. I thought I'd better measure the wriggly amps so I can work out what to ask my electrical advisor and ESC supplier for. At the first try both motors wired in parallel were pulling 810mA, on the bench with no load. This seems like quite a lot to me - 4/5 of an amp just to turn the things over! The shafts felt fairly stiff so I thought I'd try a bit of running in, out of the water, with plenty of lubricant and checking for local heating quite often. After flattening the battery, I got 740mA on both motors, 370 on the port engine and 400 on the stbd. This still semed quite a lot - while I was investigating the shafts I discovered that there was no end float at all on the port, and only a smidgeon on the stbd one. I therefore stripped the motors out in turn, to show the UJs as pictured below. With the motors out, both shafts had a 1/4" or so end float, and the motors had about as much as motors usually seem to have. The socket part of the UJ is pushed right on the the motor shaft, so that the end of the ball is touching the end of it. I shaved a bit off the end of both balls with a scalpel, and reassembled things. Both shafts now had some end float and a bit more running gave me 600mA in parallel, 260 port and 290 stbd. So we seem to be making progress - I'll try a bit more dry running and see if the figures go down much more before I try running under load.  There is loads of side play in the shaft outboard end bearing, so that's never been tight, but I don't know what happens in the inboard one, and I don't really want to disassemble it. I wonder if there's an O ring in there - has anybody had a look?

Is anybody out there finding any of this in the slightest bit interesting?
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DickyD

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Re: Chinese 20 warships
« Reply #40 on: August 05, 2008, 09:47:17 PM »

I am  O0 and you've had 1074 views.
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Damien

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Re: Chinese 20 warships
« Reply #41 on: August 06, 2008, 12:02:03 AM »

In the words of my neighbour "Vellly intelestin" keep it coming m8
Damien.
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MikeK

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Re: Chinese 20 warships
« Reply #42 on: August 06, 2008, 08:19:31 AM »

I'm not even into power, but have found your delving into the guts of this cheap import very interesting. Keep 'em coming please Tobyker  O0

Mike
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MCAT

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Re: Chinese 20 warships
« Reply #43 on: August 06, 2008, 10:14:19 AM »

I fined this most interesting, as having a go at turning a static kit into rc for the first time. and I'm sure many points you bring up
will if not now, will help me in the future on builds.

keep going  Many Thanks   Mick
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Captain Povey

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Re: Chinese 20 warships
« Reply #44 on: August 10, 2008, 08:18:17 PM »

Well I took mine to the lake today with Granddaughter intow. She was not too happy as it was not very impressve. It was very erratic in runing and the radio was a pain for the man next door so we gave up. I came back from my son's with the radio from an old car he does not use with the idea of simply replacing the radio with a decent one. Oh dear what a suprise was in store. I have now stripped it to the state of Tobyker's but not checked the motors yet. Thanks Tobyker for all you are doing on this I will be following your next moves closely as I am not very good with electronics bit. I think I will just put in the new radio and some electronic speed controllers. Any suggestion as to the size? Lets face it my granddaughter wants in running fairly quickly. For example I am unsure about using the existing on off switch and charging socket. Cheers Graham.
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tobyker

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Re: Chinese 20 warships
« Reply #45 on: August 11, 2008, 12:06:40 AM »

I'm still bench running as I haven't set up my test tank yet to measure the amp draw (if that's what it's called) under load. And until I've done that, and probably measured the draw with nicer propellors, I can't make decisions about the ESC(s). And the number of ESCs, whether I use a BEC and 7.2 volts, or no BEC and 6 volts, and whether I use a mixer too, will depend on the amps and on the likely weight of the bits including the new Rx, rudders and steering servo.

One thing I will do is replace the breeze block weight with a bit of lead flashing - that will get the weight, which I shall probably have to reduce, lower down. This may also provide scope for extending the radio box down into the hull to make more space and get the weight lower.

The motors seem to be running a lot more freely with the end float on the shafts, and there is a lot less vibration. However one problem I am having is with the motor wires fracturing at the end of the solder - I  suspect you get a less damped vibration running the motors on a shelf rather than in the water. That is something else to be addressed before the deck gets screwed on again - the wires will have to be supported properly.

 I have yet to decide about the on/off switch and charging socket - they don't weigh much and plugging a charger in to the boat will be less likely to damage the wiring and fittings than uncoupling the battery each time, especially if you want to charge at the pondside from a car when your hands are cold. However I will let you know how I get on.

Nb the end (steel) weights weigh 62 grammes each, and the breeze block 195g.

This project is turning out to be far more fun, and interesting, than I thought it would.
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Captain Povey

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Re: Chinese 20 warships
« Reply #46 on: August 11, 2008, 10:08:47 AM »

Thanks for that Tobyker. It is certainly more of a challenge than I had expected and will be worth it I think even if the bits I put in cost more than the initial cost. Cheers Graham.
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malcolmfrary

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Re: Chinese 20 warships
« Reply #47 on: August 13, 2008, 05:28:21 PM »

To stop the wires fracturing they need some strain releif - simplest is to rout them past a solid it of motor and fix them down with a dab of bostic or similar.  This will give a graduated change from "rigid" to "flexible".  Have a look at where the wire comes out of your mouse - there will likely be an elongated grommet to give the same effect for the same purpose.
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Captain Povey

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Re: Chinese 20 warships
« Reply #48 on: August 19, 2008, 10:51:03 AM »

Hello all, After a lot of thought, internet surfing, some basic measurements and conversations with two suppliers here is an update on the plan of conversion. 'Action' have been very helpful and I now have two P68a speed controllers and a P82 mixer. This lot is going to be powered from a 4.8v NiMH battery, fitted with the correct connector, care of 'component shop'. They are also a superb supplier and after I messed up the order on the internet they sorted it for me without problems. I also bought from them a charger that will just about do everything i want on this and other boats. All at good prices. So all I have to do now is fit it all. I am thinking of putting the Rx in the battery box now there is room with the aerial running around the inside of the deck and then up the superstructure. I have already removed the lump of brass that the supplied aerial was fitted to. The speed controllers and mixer can probably go in the old radio box. I have not checked the weight of what I have removed and what I am replacing it with but my guess is that it is about the same or even less. Cheers Graham.
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tobyker

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Re: Chinese 20 warships
« Reply #49 on: August 20, 2008, 09:50:24 PM »

There has been a slight delay on mine while I got my propellors ordered - they should arrive in a couple of days and then I've got to get them to fit. I was also in touch with ACTion but I want to see what the amp draw of the motors is with the new props, as Dave recommended a different combination if they drew over 1 amp each. Meanwhile I'm building a support for the rudder servo and trying to work out a robust but light twin rudder linkage. Pics to follow when I get it sorted. When we've all got our destroyers sorted we'll have to get together and compare the results - but don't hold your breath! The whole point about a hobby is that it should be relaxing, so i try not to get pressured - If I don't do any modelling for a month or so, no problem.

I bought some tubes in Halfords today (the grandson is borrowing one of my bikes for the paper round and I appear to be his pit crew) and got a 15% off voucher. Very tempted to splash out on a cheap hybrid with narrow tyres on the strength of it.

 Capt Povey - please post photos to show radio fit. Are you going to rename her HMS Troutbridge?
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