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Author Topic: HMS Lundon  (Read 18604 times)

Subculture

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Re: HMS Lundon
« Reply #50 on: November 15, 2013, 10:34:00 AM »

You should be able to calculate quite accurately the displacement of the items that sit above the waterline and then see if that works with your tanks volume.

The wet sections can be calculated by laying out the area of the superstructure that projects above the waterline and assuming a material thickness to obtain volume. In truth the material thickness may vary a little especially if it's a hand laid laminate, however you should get within 10-15% of the true figure, and that IMo is good enough to see that you're on the right track.

If you use a good quality epoxy laminate for the upper structure, a laminate thickness of about 1mm is perfectly acceptable, and for smaller structures like the conning tower 0.5mm would be adequate, although it would require careful work to make a strong composite at those thicknesses. If you use polyester resin for a laminate, I would double those figures, as polyester resin is weaker and more prone to warping than epoxy therefore requires a bit more bulk.

Some hull shapes can be very tricky to layout, e.g. WWII type subs with their complex superstructures which curve and weave around. Modern subs tend to have simpler geometry, so that makes life easier.


Davy1

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Re: HMS Lundon
« Reply #51 on: November 15, 2013, 12:13:47 PM »

You could use laminate but  you could also consider a 100% scale material - sheet steel in the form of tinplate.

Advantages are:
- best strength and weight for a material with minimum displacement.
- from  a scale point of view, free flooding holes look much more realistic than glass fibre  which looks too thick.
- can be easily cut (old scissors) and soft soldered (use a +50 watt iron)
- would fit neatly into your college workshop sessions.
- quite good for WW1 &  2 subs with simple curves (not easy with compound curves e.g modern nukes.)
- Your original drawing shows  a fairly simple superstructure with a relatively simple fin (conning tower) - so it may be suitable.

Disadvantages:
- Can be a seen as a little bit "retro" for a modelling material. Although subs are a special category and I see a recent article in "Model Boats" restating the benefits of tinplate.
- You can't get moulded surface detail.
- Sheet tinplate is less easy to obtain than you may think. (Biscuit tins have long gone. You can get thin sheets from RS Components. ) If you can't get tinplate you can use brass sheet - more expensive but can give stunningly realistic appearance . (Reference my fellow club member Dave J's models)

So get a bit of tin and a soldering iron and give it a go!

David
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Subculture

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Re: HMS Lundon
« Reply #52 on: November 15, 2013, 02:37:35 PM »

Although low in displacement, steel and brass are very dense- at least four times the density of an equivalent thickness laminate. I'd be thinking anything less than 0.5mm thick sheet could be tricky to work with, so that would be at least twice the weight of a 1mm GRP laminate and considerably less rigid. Aluminium is much lighter, but much weaker and difficult to solder, although you can epoxy it together.

So be mindful of top weight causing stability issues if things are getting a bit marginal.

SwedishProjectBuilder

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Re: HMS Lundon
« Reply #53 on: November 15, 2013, 03:24:52 PM »

Thanks for all the advises! :-)

I will get going with the calculations of upper structure volume/mass.

The sheet steel is an interesting solution, but unfortunately I don't posses any experience..
Which me and a friend do have, when it comes to epoxy laminate and carbon fibre (which I wont use but similar process).

I'm leaning towards some type of epoxy laminate for the structure above waterline.
With "plugs" and molds. A bit time consuming, but worth it.
Probably epoxy laminate for the aft and stern sections too.

Will get going with the molding in the weekend, primarily the aft and stern.
Awaiting an order from engel-modellbau with rubber bellows and u-joint couplings. When it arrives, I will be able to finish the "end-cap" and then do some water testing. Either reuse the old rc-kit from the old submarine or buy a new one for the testing.

Have a great weekend!

Cheers
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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #54 on: November 16, 2013, 02:39:55 PM »


I would like to once again announce a big thanks to GPA-Plast in Hjärnarp Sweden and Carlsson & Möller in Helsingborg Sweden, for their help with providing material for the submarine and thereby helping me keeping the costs down.

 Cheers!
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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #55 on: November 24, 2013, 12:10:25 AM »

Hello,
Did not get much done last weekend, but this weekend looks promising!
Foam core for the plug



Some putty(?) on



Lots of leftover epoxy that will be sanded of/refinforced with more..
A bit worried about the rubber bellows, they fit perfect on the pushrods but a bit to loose on the brass pipes.
How do you all fit them secure? At the moment I have secured them with cable ties..









Had a left over brasspipe that fits perfect as protection.



hehe :-)



hose clamp, will it be enough you think? (Got these at all connections with water in/out-lets)



I will continue with the "plugs" for the molds tomorrow.
Cheers

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Davy1

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Re: HMS Lundon
« Reply #56 on: November 24, 2013, 07:46:06 AM »

The bellows will be fine, clamped with cable ties. If the bellows are a loose fit, slide some plastic or silicone tubing over the brass tube before you slide the bellows over. Then put the cable tie.

Your hose clamps are more than enough, I would think.

David
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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #57 on: November 24, 2013, 05:33:50 PM »

The bellows will be fine, clamped with cable ties. If the bellows are a loose fit, slide some plastic or silicone tubing over the brass tube before you slide the bellows over. Then put the cable tie.

Your hose clamps are more than enough, I would think.
Ok, very good! Thank you for the advice! Then I only need to add some more grease in the shaft seal and for the pushrods in the brass pipes before water testing!


Besides continuing with the stern and aft molding, next up will be to design the electronics.


Cheers

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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #58 on: November 27, 2013, 09:26:34 AM »


Hello,
Placed an order on two of these yesterday, one for the tanks and one for the propulsion.
Brushed ESC with reverse.
http://www.ebay.co.uk/itm/320A-7-2V-16V-Bidirectional-Brushed-ESC-Speed-Controller-RC-Car-Truck-Boat-HE-/360796473708?ssPageName=ADME:L:OU:GB:3160
Cheers
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Davy1

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Re: HMS Lundon
« Reply #59 on: November 27, 2013, 11:30:34 AM »

 That's a very good price for a speed controller which can control 320 Amps! You should have quite a built in safety factor!

David
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Colin Bishop

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Re: HMS Lundon
« Reply #60 on: November 27, 2013, 11:33:41 AM »

320 amps through those little wires??????

Colin
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Subculture

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Re: HMS Lundon
« Reply #61 on: November 27, 2013, 11:39:29 AM »

That's probably momentary current (e.g. fraction of a second, when starting up). Take a zero off the end for something closer to the truth for continuous output.

SwedishProjectBuilder

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Re: HMS Lundon
« Reply #62 on: November 28, 2013, 12:30:41 PM »

That's probably momentary current (e.g. fraction of a second, when starting up). Take a zero off the end for something closer to the truth for continuous output.
Spot on  :-)
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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #63 on: November 29, 2013, 08:44:47 AM »

I've been looking for a suitable rc-system (sender and receiver), 6-channel, 27-40MHz at a maximum price of 100€~, without success..

Any tips?


Cheers  ok2
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Davy1

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Re: HMS Lundon
« Reply #64 on: November 29, 2013, 09:07:36 AM »

I am not sure of the situation in Sweden, but in the UK new equipment for these frequencies is very rare because of the arrival of 2.4Ghz.The model submariners dilemna!

With that in mind and with your budget you are probably best to look for second hand. There have been some bargains on ebay as people have upgraded but I have not seen much recently.

Lets see what other people have to say and good hunting!

David
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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #65 on: November 29, 2013, 09:27:53 AM »

I am not sure of the situation in Sweden, but in the UK new equipment for these frequencies is very rare because of the arrival of 2.4Ghz.The model submariners dilemna!

With that in mind and with your budget you are probably best to look for second hand. There have been some bargains on ebay as people have upgraded but I have not seen much recently.

You'r quite right, the market is overflowing with 2.4GHz..
There are some at ebay. Ebay will probably be the answer of my question.





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hollowhornbear

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Subculture

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Re: HMS Lundon
« Reply #67 on: November 29, 2013, 11:37:56 AM »

That's a very good set. Before the advent of 2.4ghz I used a RD6000 on 35mhz for aeroplanes, which served me very well. The only thing I would say, is that the control layout may not suit your boat very well, as it looks like all the functions beyond the sticks are switched. Generally we require a set with a rotary or linear slider for some of our controls. Older analogue sets could be adapted to suit, but a lot of the later digital sets are bit more restrictive. So it pays in the long run to look carefully at the set you purchase.

Two or three years ago many suppliers were clearing their stock of 40mhz kit, and there was a lot of very good equipment going for what must have been close to cost price. However those days are now gone, and therefore secondhand units off ebay and small ads are the best way to get cut price radio on the lower frequency bands. I do find that receivers tend to be easier to get hold of than transmitters.

SwedishProjectBuilder

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Re: HMS Lundon
« Reply #68 on: November 29, 2013, 12:39:39 PM »

How about this?
http://www.ebay.co.uk/itm/Sanwa-Rc-8-channel-Remote-Control-RD8000-40-MHz-RX-851-Receiver-Mode-1-/321258805993?pt=UK_ToysGames_RadioControlled_JN&hash=item4acc845ae9
Yes, I saw that one.
That's a very good set. Before the advent of 2.4ghz I used a RD6000 on 35mhz for aeroplanes, which served me very well. The only thing I would say, is that the control layout may not suit your boat very well, as it looks like all the functions beyond the sticks are switched. Generally we require a set with a rotary or linear slider for some of our controls. Older analogue sets could be adapted to suit, but a lot of the later digital sets are bit more restrictive. So it pays in the long run to look carefully at the set you purchase.
Thanks for the input! I think I will place an order on the Sanwa. Will give it some thought first.

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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #69 on: December 16, 2013, 01:08:44 PM »

Hello,


I've received my ESCs and waiting for the Sanwa RC-unit.


A few days of finals in school left, but I'm planing on building during the holidays!


Happy holidays everyone!
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salmon

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Re: HMS Lundon
« Reply #70 on: December 17, 2013, 01:58:15 AM »

I might be too late, but would this work?
http://www.sub-driver.com/electronics/radios-transmitters-and-receivers/wfly-6-channel-transmitter-40mhz.html


I think they might have an 8 channel
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If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

SwedishProjectBuilder

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Re: HMS Lundon
« Reply #71 on: December 17, 2013, 08:27:50 AM »

I might be too late, but would this work?
http://www.sub-driver.com/electronics/radios-transmitters-and-receivers/wfly-6-channel-transmitter-40mhz.html


I think they might have an 8 channel


Hmm, yes it would. But its roughly the same price and I've already ordered the Sanwa.
But thank you anyway  :}
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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #72 on: January 05, 2014, 01:23:09 AM »

A few meatballs later..
I'm back!  :-)


Tomorrow soldering will begin. Santa stopped by my place, dressed in a DHL costume, and handed over a brand new RC unit from Sanwa which thus far works well (haven't tried all the cool features yet..).
A proper update with pictures and all will be uploaded tomorrow, but here is a teaser..



Cheers!
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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #73 on: March 27, 2014, 12:04:44 PM »

Well Hello hello hello everyone,
Tomorrow soldering will begin.
quite optimistic there... But now I've finally had some progress!


hehe












uploaded some video too https://www.youtube.com/watch?v=3tKpzpA1v1k&feature=youtu.be



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SwedishProjectBuilder

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Re: HMS Lundon
« Reply #74 on: March 27, 2014, 11:25:37 PM »

Uploaded a new one instead:
https://www.youtube.com/watch?v=gGdqYy8CgRA&feature=youtu.be


Cheers :-)


*EDIT*
I would like any good advices on how to solve the servos "twitching". At the moment 2 channels are combined with a V-tail mixer, the two outgoing channels from the v-tail mixer is then split too 4 servos. I suspect the V-tail combined with splitting is what makes them twitching. There is an built-in V-tail solution in the radio which I will try to explore further.



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