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Author Topic: Hamina Class Missile Boat 1:28 Scale  (Read 53558 times)

Harrison

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Hamina Class Missile Boat 1:28 Scale
« on: November 21, 2009, 10:13:19 AM »

Hi,

As the title suggests, I am building a 1:28 scale Hamina Class Missile Boat.

Unfortunately, as I am an 80's child I am not satisfied with 2 channels of scale action. I required a little more from this most recent build, I also don't have massive amounts of time to spend on detail. I found that on most previous builds the detail dragged out and in some cases was never completed, I needed something with very little detail and a large gun relative to the size of the boat.

After several weeks I found the Hamina Class Missile Boat, there are only 4 all serving with the Finnish Navy and based out of Upinniemi (Finland of course). Most info about the boats can be found here http://en.wikipedia.org/wiki/Hamina_class_missile_boat



What I am doing may seem a little extreme, I don't know as I have not come across anyone else doing something like this. Maybe there are others on the forum doing similar work, if there are then I would very much like to meet up and share this interest.

Anyway, less of the speal and more about the build.



As all the real complicated unknown engineering as far as I could see was based around the Bofors Mk111 57mm I decided to approach that first.

It really was a case of starting from the ground up, I had a few ideas of how it was going to work but nothing really solid. Fortunately for me I am an engineer (Electronic and Mechanical) so I have access to several software packages which allow me to produce designs and physical hardware from those designs, this made getting a few concepts modelled and simulating relatively inexpensive.

it doesn't take too long of cost much to make parts in plastic so this was the medium of choice, I had to select a projectile which of course meant that the barrel was going to have to accommodate the round and could end up not being to scale but I figured it's only one barrel. As long as everything else is to scale then it doesn't matter.

The MK111 has both rotation and elevation which I needed to recreate reliably and proportionally, I decided to go for 2 x 1:150 Micropile motors from www.cornwallmodelboats.co.uk to drive both azimuth and elevation coupled with potentiometers (just like a servo motor). This means I can get precise repeatable positioning and accuracy, they are also very small so plenty of space for all the other gubbins.

The MK111 also fires at 4 rounds per second, this also seemed like a difficult challenge. I know you can get electric BB guns firing at faster rates but to be honest plastic BB's aren't going to cut through ply and balsa!

I needed 4.5mm Steel BB's, 4 or more rounds per second at air pistol power in a super small space. After a few days of head scratching I came up with a design which I felt was a good starting point, here is a picture of the internal design of the first prototype and progress up to the current form which is pretty much ready for the electronics controller PCB which controls all motors, firing, CO2 temperature monitoring and coolent(warment) flow, rate of fire, power of shot, round store level and monitoring motor current.

I'll update as I go, I'm close now to moving on to the Hull which is Aluminium with composite everything else.






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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #1 on: November 21, 2009, 10:19:39 AM »

I'm using a couple of Graupner Jet drives (aluminium of course) as the full scale boat uses these, also great for transporting as you don't have props and rudders to trash in the car of at lakeside!

I've put my Mini-Z next to them in a photo so you can get an idea of the size, the boat is 1800mm long so it will need some serious power. They will be driven with 2 Hacker A50 S10 brishless motors on six Li-Po cells, I am designing the speed controller on tot he main control board for the boat.
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #2 on: November 21, 2009, 10:48:11 AM »

I've used 4.5mm BB's for the Barbette bearings as I had a few kicking about, there wasn't really much space up in the gun for custom bearings using this BB so I opted for some nylon ones instead.

You may have noticed the big white gear on the side, this is part of the auto feeder.. When 10 shots are fired from the hopper in the main gun body, the gun will tip back and line up with the feeder output. The feeder motor will then run until the magnets pass over the reed switch 10 times, the gun will then return exactly to where it was before reloading.. I will just need to select the number of rounds and power for that fire.

I had noticed that after about 6 shots the CO2 cylinder gets very cold and power drops off, I've come up with an idea of running the motor/speed controller cooler pump backwards... Normally the water will come in via the speed controller then motors and finally through firing valve metalwork, with a few one way valves when the pump is run backwards it will be in a closed loop and when the temperature reaches a set point the speed controllers will run two of the motors coils so it will warm up but go nowhere thus warming the CO2 parts.. At least that's the idea.
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #3 on: November 21, 2009, 11:33:07 AM »

I found a few more pictures of the Bofor build.

I had a 1:62 small is motor which I used to test the azimuth drive, worked very nicely. The barrel shown was temporary, the stuff you get in the model shop has an OD of 6mm but an ID of something like 5mm so not a snug fit for BB's. My local tunring firm cut me a length of 6mm OD 4.5mm ID stainless seamless tube which was perfect.
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #4 on: November 21, 2009, 11:41:10 AM »

I've used magnets in the feeder so that the balls get picked up one at a time and carried up then pushed through as there is a wedge just behind the magnet, difficult to explain in words but I think you can see in the photo what happens. The feeder holds about 65-66 BBs with 10 or so in the hopper.

I'd just like to add, in case there are any 'Jobsworths' out there (people who iron there underpants and would shop their grandmother for not paying her poll tax), yes the barrel is less then 30cm. The boat however is 180cm, thus exceeding the 60cm legal minimun for air weapons under 12 ft lbs. As the maximum that it is capable of is 5 ft lbs and I am well over 17 years of age it is not a firearms contravention.

God, I can't stand people who try and stop others from having fun!

Anyway, that's my moaning out of the way.. Back to the build.
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #5 on: November 21, 2009, 01:36:55 PM »

I've just finished milling the the last motor drive gear for the gun, apart from the out skin (which will be painted solartex) that's pretty much it.

I'm now moving on to the PCB layout.. I did the schematic last weekend (circuit diagram) and hopefully I'll get the layout done before Monday, I usually get a few circuits made on a panel as it's a standard price for a sheet about 1.5 x A4.

Probably a few weeks away before I have full motor and gun control as it takes 10-15 days to turn around PCBs, I could do it all on veroboard but it would take hours and you only have 1 each time.
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #6 on: November 21, 2009, 02:39:32 PM »

I'm not knocking standard remotes but there usually isn't any two way comms which isn't good if you have things like motor/speed controller temp, active radar, fault reporting etc..

I came up with my own design of remote which returns the data I need and has unlimited channels/functions, I'm currently doing the coding(software) for a colour display which has a bit more area but this one works ok for now. It's 433MHz.

Please excuse the rubbish phone camera photos.
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andyn

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #7 on: November 21, 2009, 05:09:37 PM »

Fantastic  O0 :-))
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Jani

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #8 on: November 22, 2009, 10:00:19 AM »

I'm not knocking standard remotes but there usually isn't any two way comms which isn't good if you have things like motor/speed controller temp, active radar, fault reporting etc..

I came up with my own design of remote which returns the data I need and has unlimited channels/functions, I'm currently doing the coding(software) for a colour display which has a bit more area but this one works ok for now. It's 433MHz.

Please excuse the rubbish phone camera photos.

Splendid work there! I'll be enjoying your progress reports with much interest  :-)

I'm interested in what solution you have found for two-way data communications? rfPIC12F675F (would be at that frequency range) or something else? How much data rate you are having?

Cheers,

^Jani
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #9 on: November 22, 2009, 10:45:23 AM »

Hi Jani,

I'm using chipcon CC1000 transciever chip with PIC18F46K20 micro running things, boat side the micro is 18F26K20 with a mac approach using a bus and separate micro for each main system. The rate is set to 9600 to keep it reliable, not a great deal of data is coming back.. Going out is a check packet to make sure it doesn't go out of range or carry on if data is lost, also the joystick position(if changed) confirmation is sent back on each command.

The radar will be using a camera and laser with line filter, depending on the position of the line with reference to the center of the image it will calculate the range to target and direction.

I'm quite a way off that bit just yet but the idea will be that the boat can be set to fire on any targets that come in to a set radius.
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kno3

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #10 on: November 22, 2009, 11:15:39 AM »

Really interesting how you're building the gun. Congratulations!
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #11 on: November 22, 2009, 10:49:08 PM »

I've just finished the PCB layout for the gun which is quite exciting.

I had planned to use a brushless motor for the azimuth drive which would mean no need for a pot but I couldn't find a geared one small enough, as I didn't leave a contingency for this it has left me with a minor issue in that I need some method of precise position measurement.

As there is no place in the center of rotation and I can't use linkages or couples because of excessive play I have had to come up with something else, I am planning to use microchip mTOUCH capacitive sensing in a 180 degree arch mounted on a ring PCB suspended under the Barbette, I've ordered a dev kit which should be with me on Tuesday but it means I'm probably about another 4 weeks away from azimuth control with feedback    :((

It does mean that I may have to have a funky touch sense on/off button somewhere on a face of the composite superstructure!

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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #12 on: November 23, 2009, 12:37:02 AM »

As it took 3 main bodies and 5 wheels to get the design working nicely I figured that I should post a close up of the final feeder design, below are a few previous parts which didn't quite make the grade.
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #13 on: November 23, 2009, 10:24:09 AM »

This is the current state of the gun, I have Azimuth and feeder control along with coil (which has been working for a while). I need to wait for the PCB before I have elevation control as I am using the PCB as the motor mount, I will try and get a google video account sorted out today as I have a video of a test fire to post.
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dreadnought72

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #14 on: November 23, 2009, 11:20:14 AM »

Cracking stuff - very good indeed.

Andy
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Enjoying every minute sailing W9465 Mertensia

Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #15 on: November 23, 2009, 11:26:57 AM »

Ok, so I've created a YouTube account and posted a test fire 5 shot rapid fire. This is about the fastest possible rate (1 shot every 150ms), I think it's a case of BB's getting pushed upwards in the hopper and not coming back down before the next shot is fired. The magnet helps a lot as it keeps the next round in place and then pulls it down in to place sharply when ready.

http://www.youtube.com/watch?v=cL8wjKh9ZMM
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #16 on: November 24, 2009, 03:57:01 PM »

Goodies arrived today, I've got two different mTouch (Microchip cap sense) development boards which I plan to use to develop the barbette ring PCB for azimuth positioning. I think that I will also need to have a nice on/off button somewhere on the superstructure.

The panel on the right is based around a PIC24FJ256, which I think will be the one chosen option but I will know for sure after some playing.
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Arrow5

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #17 on: November 24, 2009, 04:26:56 PM »

Great stuff, way above the average modellers skills but could be the future we are looking at, keep going.   BTW Harrison ,are you into robots by any chance?
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..well can you land on this?

Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #18 on: November 24, 2009, 04:40:13 PM »

Wasn't there a movie in the 70's called "robot love slaves"? I suppose, it would need to look very human like though.

I could switch her off or maybe turn down the volume if she starts going on about something uninteresting!

I'm only kidding of course, I started to make a tracked robot which is still in progress pending some camera work I am currently doing. This is the same camera which will be doing the radar and auto aiming stuff, it takes ages to do the software which is processing the image and there are only 30 hours in a day.
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Arrow5

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #19 on: November 24, 2009, 05:07:26 PM »

No no no, I dont need one of them ! The Lady Muriel (the wife) has been mine for over 49 years , oh er, hmm nearly 50 , think I`m in trouble.  The reason i ask is that someone is trying to start a robot-wars type event for boats. Any interest ?
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..well can you land on this?

Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #20 on: November 24, 2009, 05:10:39 PM »

Only if projectile weapons are allowed, it would be a bit silly to see boats with hatchets making a mess on the lake!

Sign me up if it's guns, missiles and depth charges!
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steve pickstock

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #21 on: November 25, 2009, 07:44:13 AM »

I believe the film was Cherry 2000 with a very young Melenie Griffiths - but I don't think it is on her CV. Awful movie.


I have been following this for the last couple of days drooling at some of the stuff you're doing. Love the work man, please keep it going. Where will this beast sail? I would love to see it when it is done.
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #22 on: November 25, 2009, 08:25:48 AM »

There are a few lakes nearby which may get to see her, I run my other two boats occasionally down in Newhaven. It's fairly flat once you get in past the defences and there is plenty of space... I'll probably look out for a club in East Sussex once she is ready, it will probably be another 4-6 months before she's completed.
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steve pickstock

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #23 on: November 25, 2009, 08:34:34 AM »

That is a bit too far for me - I assume it will be u-tubed eventually?
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Harrison

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Re: Hamina Class Missile Boat 1:28 Scale
« Reply #24 on: November 25, 2009, 09:10:14 AM »

I will try and take images and video of everything as I go, I was thinking of doing some kind of promo trailer as per the full size version http://www.youtube.com/watch?v=MVih2G0TMBQ
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