Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Navy - Military - Battleships: => Topic started by: dreadnought72 on August 28, 2008, 03:52:07 pm
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Hi everyone,
I have re-edited and placed the mass of my build of HMS Dreadnought (http://personal.strath.ac.uk/andrew.goddard/dreadnought/index.html) online.
For some of you it may seem vaguely "familiar" ::), but hopefully there's material there (and there is more to come) which might prove interesting.
I'll use this topic to announce updates.
If you'd like to comment on the build, there's an email address on that site. Or do it here. See if I care! :D
Thanks,
Andy
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My HMS Dreadnought (http://personal.strath.ac.uk/andrew.goddard/dreadnought/index.html) website has been updated to include all the information about my build so far, and it's been given a makeover too. ::)
Regards,
Andy
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Andy,
This site is like talking to a mirror - apart from Martin and Stavros we are all Andrews
Thanks for the links to your build - lovely work and ship, and thanks for the "reasons for scale" etc.
I confess to a little disappointment you didn't go for 1:1 , but can see such a model (replica, remake new build?) might have some snags in portability. It wouldn't even fit in a Grand Espace!
I have also passed the link to Cap - friend Joe in the US who is doing a USN destroyer at 1/35th and I think he will be inspired/encouraged by your build
keep up the good work
andrew
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Wow,Andy!
Super Web Site about a superb build keep it going, I shall follow with great interest.
You other guys, take a look.....it is impressive and you will learn a lot and have great pleasure doing so.
Roger in France.
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Had another look at Andy's build - left me speechless :-X
A truly amazing build - Inspirational :)
A great site on "How To" build a model. Will come in very handy for my future 1:72 Battleship build.
Andy - you are incredible O0 O0 O0
Martin doon under
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Thanks for all the kind words.
I should, in return, thank Ron for inspiring me with his HMS Iron Duke build, which I found inspirational, entertaining and extremely informative. And thanks also to Oz's Task Force 72, who work solely to the same scale.
Hey, we've got eight years until the 100th anniversary of the battle of Jutland. I might have finished building by then! How about how about a 1/72nd Grand Fleet get-together in May 2016? ;D
Andy
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Hi Andy, mine is ready, yours is looking good, if im around one never knows,
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I take it 1/72nd flower class vessels are not allowed
1. they did not take part
2. they were not around in that guise anyway (other than whalers).
BOOO HOOO !!!!!!
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I should, in return, thank Ron for inspiring me with his HMS Iron Duke build, which I found inspirational, entertaining and extremely informative. And thanks also to Oz's Task Force 72, who work solely to the same scale.
Andy
Andy,
By any chance, are you a member of TF72 ??? ;) O0
Martin doon under
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Martin, if I wasn't 18000 km away, I would be! O0
Andy
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New update - decking 7 - detailing the forecastle decking and the trickiest, most unpleasant and fiddly flippin' work on margin planks to date.
Andy
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Martin, if I wasn't 18000 km away, I would be! O0
Andy
We also have members in China, Canada, UK and Europe - what's your excuse ::)
Martin doon under
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The commute to events? :D
The Warspite book is being held for you, should you need it, other Martin.
One of the Andys
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Martin, if I wasn't 18000 km away, I would be! O0
Andy
We also have members in China, Canada, UK and Europe - what's your excuse ::)
Martin doon under
Martin what about the USA ?
O0
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Andy,
Thanx for the update - the planking is impressive, and the joggling absolutely superlative ;D
Well joggled that man!
andrew
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Many thanks, err, Andrew. (Should we number ourselves?)
Thing is, and to resurrect another thread, I now can't help looking at my laminate flooring without thinking of how I would love to lay them diagonally across the rooms and do similar work at the edges! ;D
Andy #1963#
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Joggler Andy*1963*
Thats a bad case you have there - if you show ANY signs of wanting to do purfling please seek nautical help immediately.
This and discussing plank joint rotations are serious indications
But beautiful work you are doing - please keep on and keep showing us.
andrewH*1949*
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Gunnery!
On this page (http://personal.strath.ac.uk/andrew.goddard/dreadnought/gunnery1.html) (which currently only seems to work in FF) I detailed how I can achieve realistic turret tracking whilst holding a course.
But that's not enough, is it?
IDEALLY, I want to set a bearing for turret pointing, and then - no matter what future course changes are undergone - the turrets would remain on target, go to "park" if they lost "sight", or move from park to "acquire" depending on what angle the set bearing is, relative to the hull's machinations. Make sense? (It would certainly look the bees' knees).
I've thought about this for some time (often during those mindless, cold and soulless hours of deck planking) and the word gyros popped up. Now, the inelegant solution would be to use a mechanical gyro, mounted with the axis horizontal, to plot and plan the turns of the hull, enabling the 'chip and software to turn turrets based on the initial input and feedback from the gyro. A "bit" of drift would be acceptable over a minute or so.
But that's too mechanical and clunky, so then I considered (for a microsecond) the elegant solution - a laser gyro, where light is sent two ways around a ring (not unlike the LHC) and the distance the light travels as the ring turns can be measured to determine turn rates. Perfect! But that would require selling the house, and a generator on the boat to both afford it and run it.
So...the mid-range option is a piezo-electric gyro, as used in model helicopters. Today these can have really low drift rates (less than 5 deg/minute) and are designed for vibration-rich and variable temperature environments. In a boat there's little to no vibration, and the benefit of consistant temperatures. So...I've emailled a long list of questions to a reputable maker of heli gyros to see if there's the perfect solution out there.
I'll report back once I hear from them - but awesomely realistic (and largely automatic) turret training might be on the cards - and at a couple of hundred quid all-in for hardware and servos, not out of the reach of affordability for those boat builders like me who seemingly take years on projects.
Andy
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Andy
The LHC will ONLY JUST fit in your ship
andrew
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Hi Andy
Just another question about Dreadnaought , Do you know if the boats that are nested have the thwarts removed from the bottom boat or not. I would be inclined to think that it would depend on the size of the boats involved but I don't know.
Also in response to your query as to if my Dreadnought is powered or not. It is just a static model.
I have built quite a few boat models and find most of them sit on the shelf under glass and never get their feet wet, so I dont power them any more..I also find that certain aspects have to be altered to accomodate the power and control which leads to loss of scale fidelity.
Dan (Dreadnought)
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I don't think so, Dan. Thwarts are pretty integral to maintaining the shape of wooden boats - I can't see that you'd take them out, even down to the 27' whaler.
Page 58 of the first edition of the AoTS book shows a photo of the 36' pinnace over the 42' launch, and the smaller appears to be resting on the thwarts of the larger.
The lower (bigger) boats certainly have shaped chocks - but it looks like the upper boats are simply strapped to the lower ones. Maybe their keels resting on a small block to avoid damage?
Regards,
Andy #1963#
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Hi Andy,
Just a quick note to tell you that I have discovered how ships boats were nested. While leafing through my copy of anatomy of the ship HMS Hood I found on page 125 Illustration K/27 a drawing of the nested boats. There is a portable crutch on the thwarts of the bottom boat and the two are lashed down together.
Dan (Dreadnought)
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Just surfing, as you do, when I found these wee gems. %%
Now, has everyone got some popcorn ready?
Quiet when the lights go out!
Launch of HMS Dreadnought (http://www.screenonline.org.uk/media/stream.jsp?id=1113678)
Torpedo Attack on HMS Dreadnought (http://www.screenonline.org.uk/media/stream.jsp?id=1113736). (Not quite as dramatic as it sounds, but there's some good destroyer and submarine shots - plus a few on-deck moments aboard the Dreadnought, from this 1907 silent film.)
Loads more early film at www.screenonline.org.uk
Andy #1963#
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Andy, Great work, scale fidelity indeed. Andrew did send me a link to your page but I can't seem to make the shockwave program install so I've been unable to see the demonstration of the gun director, do you have any photo's or other sketches you can post? As Andrew said I'm building a DD and have been pondering the gun director for some time. It never occurred to me to add the target tracking feature (thankfully), I've had a hard enough time with the basic pointing feature. With my typical mode of operation I've neglected to inquire about this until too late, just yesterday I epoxied the base in for the "clunky" mechanical director in place and am dead set on it, but I'm sure I can still benefit from seeing what you've done. I'm sure you know this but mini compasses are available that might be useful for keeping the guns pointed in a single compass direction, I have no idea how well they work (this is just one I saw on inet : http://www.trossenrobotics.com/devantech-magnetic-compass-sensor.aspx?feed=Froogle). Also I'm not much on microelectronics and so forewent the microprocessor control (it's my fall back O0). Anyway great work, would like to see more. Cap (Joe)
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Thanks Joe!!!
That compass sounds exactly like the device I need!!! O0 If you've a problem with the shockwave player, try it on Firefox - or downloand the Flash player. But in all honesty I can't get it NOT to work.
Meanwhile, what I'm trying to achieve ... a couple of definitions first:
Heading - the angle of the ship's course from north, measured in degrees, clockwise from zero.
Relative bearing - an angle from the bow, measured in degress, clockwise from zero.
So ... a dose of pseudo code:
1/ During a sail, at some point I set the target's relative bearing on the TX. green 060, for example, while due to my bizarre rudder control I've ended up steaming NW (315 degrees).
2/ Using the compass, the microprocessor turns this relative bearing into a true heading. (Hey - target is 15 degrees East of North)
3/ When the turrets are set to "acquire" on the TX, they'll train to this relative bearing, if they can see it - if they can't see it, they'll stay parked or return to park.
Now the loop:
4/ As and when the ship's heading changes, the relative bearing gets updated, and the turrets can then track the target, or park, or acquire the target from parked positions as and when necessary.
The loop ends when the turrets are set to "fire" or "park" as decided by the TX.
Perfect!!!
The coding's a doddle using <£50 microprocessors - it really is. And the loop can occur hundreds of times a second without any trouble, meaning that the "following" of a target can appear constant.
Now, if only the attic would warm up and let me plank my decks again! I've still got a pile to do...
Many thanks,
Andy #1963#
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Hi all....& a great build Andy......... :-))... I am new to Mayhem but haven't seen any references in this thread to pointing & non pointing Zones...[I too could not download the self installing software as above]
In modern day warships, these complex Zones are controlled by computers, when the Dreadnought was built the same complex Zones were controlled by mechanical computers
ie., to intrinsically prohibit [not limit] firing ordnance over [OR AT] any part of the actual vessel
A better example is say a Doyle class FFG...when she deploys from port...the MK 75 gun is trained at ZERO pointing toward the stern ...also with ZERO elevation, being the axis of the vessel...just aft of the MK75 is the Phalax [CIWS] ...so the non pointing Zone for the MK75 is a pre determined arc centered off the Phalax when the MK75 is @ ZERO train + ZERO elevation, however a pointing Zone for the MK75 could be ZERO train but with + XX degrees of elevation.....
Sorry to go off at a tangent.............Derek <*<
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Andy, I'll give it one more try (the shockwave download/install), I'm sure it's not that difficult. Sorry I didn't read back much, nasty habit I have, lazy I guess. I didn't realize you were having it track the target on a heading too, wow, that's pretty niffty. I guess once you've got the onboard computer it's not a stretch to do that part of it as well, the electronic compass might give you the global reference you need. Now how come your boat is static? It seems it should move so that you can watch it track the target, will you build a turntable for it? %) (hope I didn't misread or not read enough again). I'll save up for some microprocessors (I'll need at least two as I tend to melt electronics)
Derek, your pointing zones are as far as I got and am building a mechanical director that will control the zones of the five turrets (there is only really 2 zones on mine). As simple as it is, doing it mechanically has been a puzzle, for me anyway, interesting though. I'll basically have a CW CCW control for the director on the radio, it will be able to turn 360 deg. The guns will follow the director unless they go to the no fire zone at which point they return to their zero position and wait. Fortunately I have about two cubic feet of space for it :embarrassed:!
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Hi all...Capricorn & Andy...again this is a little off the original thread but see how we go
My experience is not sea time based, but 1504 days as an above water weapons forman at Australia's Garden Island Naval Dockyard in Sydney many years ago - with British or Australian designed vessels....the turret designation's from the bow going aft ...post WW11 were A , B, X & Y but the NPZ are far more complex than you may imagine [now simply termed as A, B or X...and PZ or NPZ]
The B may be physically higher in elevation than the A .....but if the A barrels are @ say 30 degrees elevation, with the B turret at Zero elevation......the barrels of the A would be within a pointing Zone of B.... :police:....so hence these positioning revert to NPZ
In real life warfare, a turret that progresses toward a NPZ does not return to Zero elevation or train.....but waits for the vessel fire control system computers to alert the scenario & has the potential to offer the control & alter the vessels course to provide the required trajectory via a NPZ be it for a shell or missile
Your scenario of ....The guns will follow the director unless they go to the no fire zone at which point they return to their zero position and wait ....certainly be the most practicable course to follow ........Derek
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Hi all!
Sorry for your problems with the Shockwave. This is the direct link to the example (http://personal.strath.ac.uk/andrew.goddard/dreadnought/turrets.swf), which might load for you. I know there's been recent trouble with IE and some Flash players.
The turrets on the Dreadnought were (bow to stern and left to right) A, P, Q, X and Y. I believe there were mechanical limiters built in to avoid any (ahem) "embarassing moments". %)
Each turret has an arc of fire greater than normal servo throws, so on the model they'll need to be geared up to rotate the extra distances. The way the shockwave demo works is that the normal, parked position of each turret is at 50% servo throw for turrets A, X and Y (since these can rotate left and right of their rest position) and at 0% servo throw for turrets P and Q - these wing turrets can rotate 180 degrees aft of their parked positions to cover each side.
There are relatively cheap microprocessors that can export servo pulses to a high accuracy, which makes setting the position of each turret straightforward - just a bit of maths - though any sent bearing angle will require different outputs for each turret A, P, Q, and the X/Y pair (which can train over the same angles). While making the demo, it was easy to make a mistake with regards to the direction of rotation desired - but faults like that will be ironed out before the real thing is operational.
Making the target bearing independent of the ship's heading was the next challenge, and I'd had thoughts of using model helicopter gyros or a home brewed gyro compass - but neither seemed suitable or practical. The idea of a solid state electronic compass wasn't one I'd thought of, so full kudos to Capricorn Joe for raising this as an option. There's not much metal in the model, and I think I can distance a compass like this and faraday-cage the motors in order to prevent unwanted magnetic effects, but as you can imagine the director and guns should then be able to track a "target" (albeit one that's stationary and at infinite range) independent of the ship's heading changes.
Which would look good, to my thinking.
Andy #1963#
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Interesting stuff especially since I'm in the midst of it right now, thanks for all the info derek. Andy I sure know what you mean about the mistakes in rotation direction, I'm counting on them being ironed out by reversing wires as needed. I print out the wiring for the director and sit down and try to check it and I see the polarity is wrong in one circuit, so mark it up, then I follow it through and decide no, the polarity was right, then the third time... Just curious on the servos, you mention gearing them up, are you concerned with them rotating the turrets a bit fast? I'm sure you have that covered, but if not you can imagine taking the pot out or the servo and gearing that to match the turret limits you want, and then gearing the servo shaft down to turn the turret slowly.
I could not tell you if the compass would work inside a model boat with all the motors and metal parts, seems you know enough - faraday cage... I will say that I'm concerned about all the servo's I'll have on my boat, with quite extended leads, mainly the steering servo way at the back, that's an important one, but I'll use them to elevate the main guns and probably for the bofors. Any thoughts on that? Cap
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Would GPS be a better way? Apparently some receivers output course data in a serial format called NMEA. GPS course data is derived from position changes and is immune from magnetic interference.
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Hi Andy
Well now that the Christmas rush is over I am again getting down to business on the
Dreadnought build. As you mentioned earlier the planking on the compass platform
runs for and aft not the other way as shown in the AoTS Dreadnought drawing.
I am now about to proceed with the navigating platform and was wondering which way
it was laid..
Checked out your build today, did not know how to do it up to now. (not very computer
savvy) sure is impressive. I will be up to date on it now though.
Hope you have a good new year.
Dan (Dreadnought)
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Hi all......Andy......your representation as per the link is very impressive...
http://personal.strath.ac.uk/andrew.goddard/dreadnought/turrets.swf
but how will it work?
a) does the director have a preset program of target locks?...to which the respective turrets follow?
b) will the barrels elevate?
You may see old footage (Iowa Class] of each individual barrel in a turret returning after firing to Zero elevation at different times....this essentially was a function of shall we say basic manually controlled loading & the requirement that one gun could be taken off line without affecting the other two
Many years ago at work, I had the pleasure of witnessing a multiple dummy load + train + elevate in the STDB compartment of the FWD turret on BB663
From Capricorn........"and then gearing the servo shaft down to turn the turret slowly".
I understand the Dreadnoughts were 12 " as against 16"...... so scale is different here, however would consider both were a majestic but relatively slow process of full train & elevation
So Andy, Capricorn & now Dan.....keep up the good work :-)) all very interesting ........Derek
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"and then gearing the servo shaft down to turn the turret slowly"
If it is any help, you can get a piece of electronics that will do this. It just fits inline on the servo lead and slurs the signal so to speak.
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Hi all...........snowwolflair .......do you mean a servo slowdown?.....which are adjustable & maintain high torque? & about AUD$20.00 each......what a great idea.....Derek
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Yes, thats the ones.
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Servo slower? What a great idea, I heard you could get slow servo's but they are expensive. I'll look for servo slower, I'm not up on all the electronics obviously, still back in the industrial era. Cap
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Andy, Since it's all on the computer, it seems it might be easy enough to have a secondary control for the P and Q turret parked position. It's just a minor thing, I see when you point to 185 the P turret points to 185 and Q to 0, when you switch over to 175 the P turret rotates all the way back to zero, while the Q turret rotates to 175, if the target is at 180, you have a bit of turret rotating going on when it moves either side of 180. A simple solution would be to have the P and Q parked position at 180 with the target is anywhere 45 degrees from 180. Anyway, just thought I'd throw that out there, without off center turrets to not have that exact issue but the rear turrets will osillate around 45 and 315, and the front ones around 135 and 225. I'm ignore it though %). Cap
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You might like to have a look at ACTion's Servomorph. It sounds as if it might be what you are looking for.
http://www.action-electronics.co.uk/pdfs/P96.pdf
Colin
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Colin, that's a the most useful gadget I've ever seen :-)). I've been searching a bit and haven't found much, the Dionysus servo rate reducer, hyperion servoslow, but they must not be very common, thanks for the info, I'll look into that too. Cap
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Hi All,
A bit rushed, but answering as many points as I think were raised:
Re: turret rates and directions. I don't need to swap wires or add in servo-slowing controllers (though servo slowing will be needed - it took the Dreadnought about a second to train a turret four degrees link here (http://www.navweaps.com/Weapons/WNBR_12-45_mk10.htm) ). The easy way to do all this is in the coding on the microprocessors.
The servo output command on the very cheap Picaxe microprocessor, for example, is set to a digit between 75 and 255, which outputs a signal between no-throw and full-throw for the servo (an accuracy of about half a degree on the servo, and maybe one or two degrees on the turret, depending on the gearing necessary). So in the programming loop, I can simply send the turret towards the desired end location at any rate I like - the servos will then run like (smooth) step motors to a final position. Since this rate will be slower than the servo rate, there won't be any chasing.
Gun elevation - it would be very nice, but I'm not sure it's as visually important or obvious as tracking. And - on a more practical level - I'd be needing another ten servos. {:-{
Parking positions for P&Q turrets. I see the meaning here - and there's another issue with regards to X, which has a dead zone aft, while Y doesn't. Possibly the easiest thing is, as you say, to leave a turret at its "last useful train" until that train moves such an angle away that it's worth parking the turret. Again, this will be software controlled, so it will be easy to adjust/augment this once the system works.
Setting the director position. This is going to use three functions from the TX. One stick has been "desprung", and can be placed and held at any position in the square box that it can move around. This will be used when the "train" function (an on-off switch on the TX) starts the main programming loop. The position in the box of the stick will be converted to an angle of target bearing, then the turrets will do their thing until another train function is sent or - now I think local bearings can be calculated using the compass - they will track the target independent of the TX, and relative to the turns of the model, until another train function is sent.
And finally - if I can acquire and track, then a "fire" option is becoming an idea. I've seen a fabulous photo of a (UK) model of a pre-Dreadnought two-turret battleship "firing". I need to think about this some more, but I have a few ideas - and a sack of Christmas Party Poppers to play with! %%
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Hi all......Andy, Capricorn & Dan...re elevating turrets
Many years ago, I saw an example of turret elevation by a simple V shaped cam ring as per the attachment
I we consider the A turret, the shaded section turret stationary follower is a cutout of the ring & could be centred @ ZERO train & then diminish in height to any required arc to STDB or PORT - the barrel is spring loaded to the stationary follower ring
Depending on the method of construction...the turret stationary follower ring could have a negative cutout or a positive opposite profile lip etc
So from ZERO train...any + or - train results in a + elevation either side of ZERO....does not require any additional servo function....Derek
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Statistics!
I see I've spent nearly a week on Mayhem, and made 254 postings. Hmmm ... time spent when I should be building!!! ok2 But at least it means I read more than I type!
When I set up the Dreadnought site about four months ago, I stuck on a stat counter to monitor its usage. I'm pleased to relate that the count (which is invisible) passed 500 in December - no bad figure - and that nearly a quarter of all visitors have hung around for more than twenty minutes. Which would be a success for any commercial site, and must mean they've either read the lot ... or maybe fallen asleep at their keyboards ...
The bad news? Five of the visitors were using Netscape. Ugh. And a few are using screen resolutions popular in the eighties.
The good news? The visitors have come from all around the world. If there's any interest, I'll bung up a map. The bulk have been (no surprise) from the UK and western Europe, but there's a fair few Americans, Australians, and a couple of Russians stopping by. Interestingly, after the url appeared in a Polish model making forum, Eastern Europe is well represented.
Perhaps I should have a "sponsor a plank" week? I think it's the only thing that'll get me to finish the decking! %%
Kind regards and a Happy New Year to all. Except to my Chinese visitor, who doesn't get his well deserved 新年快乐 until the 29th of January...
Andy #1963#
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Derek, that's a clever method to elevate the guns especially for smaller scale models where there isn't room for much else. Andy, congrats on your site activity, I may have skewed the results slightly, I have a tendancy to read a couple sentences and then wander off scratching my head. I originally intended to fire BB's from the 5" turrets on my model, then I saw a tank model that fired .22 cal blanks and I was hot for that (quite an impressive design, complete drawings for it posted by the fellow), I've now sort of decided to use ring caps (the type for toy cap guns). Basically the gun barrel is the hammer, an envolute shaped cam releases the sprung barrel which detonates the cap, as the cam continues to turn it "slowly" recoils the gun. Main problem is rigging up the cylinder to turn and get it to all fit in the turret. Obviously a single shot would be fairly simple, a single cap would have to be manually loaded each time though which could be quite a project depending on how your turrets are fastened down. Cap (attached schematic of where I'm headed)
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Now that's a neat solution. And I suppose once you've got a cam in place, you can gear down a rotor to carry strips of caps into the right position for subsequent shots? (Trying to remember my cap pistols of <ahem> some 40 years ago...)
Andy #1963#
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Andy, There have been some changes in the cap gun world over the last 40 years. They have ring caps, a plastic ring with either 8 or 12 shots, quite a bit more pop compared to the paper ones. I choose the 12 shot naturally, that means I need a 12:1 ratio between the cam and the cylinder, however12:5 works too. The toy guns use a ratchet of some sort so when you pull the trigger it turns the cylinder 30 degrees, that should be simpler than a 5:12 bevel gear but it hasn't panned out for me yet :P. I mean to pick one up but most common here is the eight shot, I think they are cheaper. Anyway, it's a ways off yet for me. Cap
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Now look what you've done, I've been divererted from the task at hand with this talk about gyros :P. I always like to start from scratch with everything I do, sort of neanderthal that way, but will allow myself to be steered as well. Andrewh helps that way, I got on this idea of adding a gyro to my boat now that would theoretically allow the gun elevation to be keyed to a gyro rather than the boat hull, so as the boat heels the guns remain pointing at the same elevation to the horizon (nothing new or particularly complex there). I just don't know if it's something I can build easily enough or not. Let me know what you think of the idea, as I mentioned to Andrew I need a servo tester that has two qualities, a) the knob is synced with the servo (ie turn the tester knob 5 degrees and the servo turns 5 degrees) and b) has a pot knob that doesn't take a gorilla to turn (ie the pot turns easily enough that a gyro can hold it in place when the boat heels). Any input great (if I'm invading your string unwanted let me know) Cap
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Hi Cap,
Reading Patrick O'Brien, and back in Aubrey's day, they'd have "fired on the roll" ... which isn't a nice thing to do to bakery products, but there you go... %%
Gyro-stabilised guns? Like the things modern tanks have?
I don't think it can be as simple as a one-pot-shop. For example, if the turret's trained to port, the movement of the barrel will have to be the inverse of when it's trained starboard, for any given angle of roll. And if you were to take pitch into consideration, then you'd need two-axis calculations, plus info on which angle the turret's trained, before you could generate a figure for a suitable "level".
But it gets worse: once the turret axis is off vertical, and if the ship is rolling, pitching and yawing, then you can calculate a gun angle which will remain locked on a particular vector, but it'll be having to train and elevate/depress constantly in order to do so - and you'd best be in the world of <gulp> quaternions. :o
A not-very-brief aside (and apologies to all if this is stuff you know) -
Back when NASA did proper manned stuff in space, rather than just ferry toilets the eight minutes to low Earth orbit, there was a thing called gimbal lock. It makes an appearance in the film Apollo 13. When the axes of a gyro line up, the gyro's information becomes useless. Your heading information is lost. That's gimbal lock, and it's best avoided if you want to fire a thruster with any idea of where you'll end up.
Because modern jet aircraft and smart ordinance can end up at any old angle, and we have computers that can do impressive sums in real time, there was a move towards using quaternions - which do not suffer a mathematical version of gimbal lock. These were invented around the end of the 19th century for no reason whatsoever, and lie quite squarely in the "insane" area of mathematics. But with them, you can happily add or subtract any angles you like from a start position and rest safe in the knowledge that the final angle is "correct".
I got an A-level in Maths back in 1981 (and by 'eck it were tough back in my day) and I use maths everyday in my work. I needed to use quaternions for some 3d animation modelling I was working on a year or so ago. Now, maybe it's my age, but it took me a good fortnight to begin to get my head around what was happening in the calculations, and I had to assume the use of the square root of minus one had any "reality" (they appear in quaternions), and finally FINALLY! got the model working.
Within a day of writing the script, little of the maths made sense. I had to just accept it. A month later and it was like looking at ancient Mayan. Today I've returned to the blissful ignorance of not understanding them any more. Have you ever read any H.P.Lovecraft? That's quaternions.
In conclusion -
Gun stabilisation would look extremely cool for modern single-gunned frigates and the like, cutting speedy S-curves and rolling in the bends. But it's a can of worms I'd approach with extreme care! (And wouldn't gyro-controlled stabilisers be better - a one-axis, and therefore considerably easier & more practical application?)
Andy, fitting gunwales to the 42' sailing launch...
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I got an A-level in Maths back in 1981 (and by 'eck it were tough back in my day) and I use maths everyday in my work. I needed to use quaternions for some 3d animation modelling I was working on a year or so ago. Now, maybe it's my age, but it took me a good fortnight to begin to get my head around what was happening in the calculations, and I had to assume the use of the square root of minus one had any "reality" (they appear in quaternions), and finally FINALLY! got the model working.
Andy, fitting gunwales to the 42' sailing launch...
Andy! When you have used the Quaternions, PLEASE put them back. I went to look for some t'other day and the jar was empty. I eventually found enough way up the i axis
andrew
btw - aren't they something to do with malaria?
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Andy, I don't know what quaternions are, it's not in my old (Websters) dictionary so it doesn't need to exist and can therefore be put in the Oxford dictionary :P (or in a jar). As far as gimble lock goes I will ignore that too because I only have one gimble so it can't get confused. But you are probably right about it, let me just make sure I conveyed how it would work.
The gyro would consist of a brass disc mounted directly to an electric motor shaft (high speed), the back of the motor would be mounted to a piece of wood with a rod through it and a ball bearing each end. So it hangs below the horizontal axle (more like a pendulum then a gyro maybe). Turn the motor on, it spins and hangs straight down. That is supported on a bracket to suspend it and the bracket is sitting on a turntable, the turn table is geared to turn with the director. The axle of the gimbal is always then parallel to the axle of the gun trunnions. When the guns are trained to port and the boat rolls the gyro will stay vertical (and adjust gun elevation accordingly). If the guns are trained dead ahead the axle of the gimbal is perpendicular to the axis of the boat, if the boat rolls the gyro will roll too* but only if the boat pitchs will the gyro change the gun elevations. *here's where the other missing gimbal could be a problem, the spinning gyro will have to be rotated - is that causing a problem with quaternions? Or are you telling me to use 3d cad? Except for that problem (which might be solved by adding the missing gimbal back in) I see it as flawless :P! Also after looking at geometry it's sensible to connect the end of the gimble axle to the pot with servo arm and link so disparity in angle of rotation of the controller pot and servo's can be adjusted for (we think). Cap
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Well done Cap - an explanation without pictures or arm-waving that I can understand!
I get you now - axis parallel to trunnions.
However ... your "*" is possibly a valid concern. If you rotate a gyro around an axis that is perpendicular to your single pivot (i.e. the hull rolling while the director's straight ahead) the gyroscope will want to precess. One way or the other. I'm never sure which.
If the effect is to pendulum-control the gun independent of roll and pitch, why not (types Andy quietly from the back) use a pendulum? Damped to avoid the crazies, heavy enough to move the pot, and swinging through the same single axis as above, while rotating with the turret? It'd save you electricity, if nothing else!
Andy,
42' launch now ready for thwarts and other internal gubbins.
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Well, yes a pendulum would be much simpler, but how do you dampen it? I thought maybe the gyro would tend to act as a dampened pendulum. You've convinced me to consider it for sure, a handy place to hang the pendulum from would the the vertical shaft for the director turret, it's handy in that it turns as needed (the platform), and has a pretty decent vertical height if needed (see attached sketch). I would take suggestions on how to dampen it though because if the guns teter up and down it sort of ruins the effect O0.
As for the gyro, I thought adding the second gimble would make it exceptionally complicated and not worth trying but looking closer it doesn't take anything extra but the second gimbal nested in the first, easy enough. Cap
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Well, yes a pendulum would be much simpler, but how do you dampen it?
Mount it in oil?
No idea whether this would work - just thinking of something denser than air for it to push against.
Lance
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Guys....one of the issues you have here is that dreaded word SCALE >>:-( >>:-(
A model of a Dreadnought [at whatever scale] with the scale 12" guns training & elevating to scale would look like .......very computer/robotic in motion...& WAY TOO FAST...something more akin to a current missile launcher or high speed 75 mm rapid fire gun
So your model vessel may pitch & roll to scale........but remember those 12" barrels in sets of three trained & elevated majestically...so this is another example where a VISUAL function cannot necessarily be scaled to provide a realstic depiction
Sorry if I appear tung tied here...another way to explain this scale anomaly is.......
We a full size humans stand on the deck of the full size vessel & view the gun train & elevate - OK
We as full sized humans view the scale model gun train & elevate but for correctness we [the people] need to have a view & perspective to the same scale...... O0 {-) <:(...Derek
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Hi Derek - I know what you mean.
Thing is, when I go for scale speed (in order to generate a realistic wake) then the model's top speed has to be about two and a half knots. (21 divided by the square root of 72).
This means the model needs to move on the water at about 1.27 metres per second - which is 91.67 metres per second when scaled. But 21 knots is really 10.80 metres per second, so "scale time" runs 8.48 times slower. (That's the square root of 72 turning up again).
If the turrets were set to train at 34 degrees per second on the model (because it's 4 degrees a second in reality), and the hull's metacentric height was identical to the original ship, AND the model was videoed, then the video slowed down by 8.48 times - the result would be that the wake, wave speed, roll rate and turrets would all appear to move at their correct full-size speeds. That's the science bit.
But (outside films) we don't see models in slo-mo.
I agree that a watcher of the model will feel that turrets at this speed would appear to be too quick - they don't suggest a mass and inertia that we "know" was present, so I'll have to have the turrets train slower than this. The beauty of a microprocessor driving the turrets is that I can eventually set the rotation speed to any amount I like (well, up to the maximum servo speed, of course), and therefore the "art" is in finding a value which suggests "turret inertia" and to avoid turrets that look like car-assembly robots.
Ultimately, of course, this raises the feeling that the bigger the scale, the better - and (pipe dream) wouldn't it have been good if the UK hadn't trashed all our battleships? {:-{
(Imagine how amazing it would have been to have the Warspite moored up for public visits in the 21st century...)
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We know that angular velocity doesn't contain length units so it doesn't get scaled right? The rotation rate of the model should match the actual rotation rate. Furball, do you mean submerge the entire pendulum in oil? That might be tricky, it would also slow the response. Cap
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Angular velocity does contain "length units" - except these "lengths" are degrees or radians, not metres, etc...
Oil damping should work well - you want to slow the response time a little, but it could be messy and would need experimenting with. I suppose the microprocessor answer would be to feed the angle of the pendulum to some code, and "damp" short-term oscillations and oddities using software, exporting the final "preferred" pendulum angle (from some averaged angle over the last few seconds?) to a servo controlling gun angle. But that would be a little around the houses, and if done that way, then you might be better off controlling all gun angles from a single pendulum swinging in two axes, taking into account each turret's train and how that would affect it.
Complicated - but kind of neat for programmers like myself!
Regards,
Andy #1963#
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Andy, angles are angles not lengths, if you multiply the radian angle by a length you get an arc length, but on the scale boat any length you multiply the angle by is already a scale length, like the length of your gun barrel. So when the model turret turns at the actual angular velocity the scale speed of the end of the barrel moving is correct. If you turn the model turret faster than the actual angular speed of the real turret, it is turning too fast. <*< However if you use the filming and slow down scenario then you would want the model turrets to turn faster. Cap
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Hi all.....& as Andy says.........
The beauty of a microprocessor driving the turrets is that I can eventually set the rotation speed to any amount I like (well, up to the maximum servo speed, of course), and therefore the "art" is in finding a value which suggests "turret inertia" and to avoid turrets that look like car-assembly robots
:-))...this will be the best scenario...where you can trail elevation & train speeds simply without great upset to any system etc.......& get the best realistic visual irrespective of what SCALE suggests it should be.....Derek <*<
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We know that angular velocity doesn't contain length units so it doesn't get scaled right?
Correct. rotation does not get scaled, similarly radars also run at the same rotation rate as full scale.
Think of it this way a real radar turns 400 times in a nautical mile. So a scale radar should turn 400 times in a scale nautical mile. You make the adjustment in the speed the ship travels so further adjustment of the rotation rate is unnecessary. The guns are the same.
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Today's a great day.
I'm about a year into deck planking, and tonight (or certainly at some point this weekend) I will be past the halfway point. The entire port side of deck is very very very nearly complete. %%
(I'm an optimist - I see this as progress!)
Zen and the Art of Deck Planking (http://personal.strath.ac.uk/andrew.goddard/dreadnought/index.html) is the latest update on the front page of my site. Photos of the work should be around early next week.
Andy NA553568B
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Well that put a smile on my face
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Andy NA553568B
Love your account - "diary of a lofty decker"
I had an alternative title but it seemed tasteless :}
Good luck with the decking - and other build tasks as the weather warms up.
What is the significance of the new handle? are you an airfoil of 5500% thickness, or an airplane with US registration?
andrew, just andrew
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Hi Andrew,
That'd be some airfoil. ...But think of the lift! %%
Surely you recognise two-letters, six-digits, one-letter? A clue: I was told it before work about thirty years ago and have never forgotten it.
Odd how these numbers stick. 15 years ago I stopped working for the BBC, where - touching on The Prisoner thread - I had spent nearly a decade known as 257697B. (And at this point in proceedings, no doubt all those who did National Service will recall their numbers with absolute clarity. And yet not remember where the car keys ended up when put down fifteen minutes ago!)
As to the boat plans for the first quarter of 2009: I need to get this thing on the water. So the push will be for the decks to be done, sealed & sanded by the end of February, the hull to receive its bilge keels, and more G4 on the outside before a thorough paint job before the end of March. I need to test the electrics and ballast "as soon as", before I get moving onto the superstructure and bits.
Andy
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50% (http://personal.strath.ac.uk/andrew.goddard/dreadnought/decking8.html)
%% :-)) O0 {-) ;)
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Andy
Well done that man!
Keep up the good work, keep us in the picture and keep us entertained with the process :-))
OK - I don't remember mine, or perhaps I do but can't remember that I remember it or.........
We expect to be present at the launch, virtually. Will the quaternions be sending a contingent?
andrew
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As previously noted......but I must question?????? >>:-(
1) "Correct. rotation does not get scaled, similarly radars also run at the same rotation rate as full scale".
2) "Think of it this way a real radar turns 400 times in a nautical mile. So a scale radar should turn 400 times in a scale nautical mile"
For the latter part of 2) to be correct........the leading comment in 1) must be false O0 ....also director rotational speed is totally independent of distance travelled by the vessel
This belongs to the same scenario as scale BLURRRR...and a radar director rotating at true scale would be just that....a BLURRRR
Think of this rotational issue in another way..... %)..if propellers did not rotate in +++++ to scale RPM....the vessel would be like a near dead frog in the water....[this has no reference to the Moderator %% in France]
The action of a [model] propeller function is both :-)) a mathematical & physical function to perform the desired & required scale result
The action of a [model] radar director is visual only to perform the desired & perceived result
Propellers rotating @ 200 RPM OR 2000 RPM are a BLURRR & our human visual perception cannot necessarily distinguish the ratio of rotational variance between both examples.....
Consider looking through the eyes of a human...if the director rotated @ 1 RPM on the real Dreadnought....try 1 RPM on the model.....Derek
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The constants are rate of angle of rotation and time, distance is scaled.
time does not get scaled, distance does, so the ship travels a shorter distance (a scale nautical mile) by sailing at scale speed.
Rate of angle of rotation in time is made up of two constants. and therefore does not change.
Another mathematician will also tell you you can scale time and leave rate of angle of rotation and distance as the constants (someone earlier talked about this by videoing in slow motion).
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Andy NA553568B, Congrats on the halfway point! I'm sure it looks great, I'd come watch the launch too but it's a bit far for me. I like your zen piece very well, I mentioned the catlike reflexes when the xacto rolls off the table and all the response I got was to get a knife that doesn't roll (and or level my workbench). So congrats on your ability to move quickly still too.
Sorry to belabour the angular speed bit Derek, but the rotational speed of the propellers on the model boat, as it relates to the boats speed, is a different question, definitely related to scaling but different. I would describe the angular speed in terms of the speed that the end of the gun barrel moves when the turret turns. If the turret and gun barrel length are all scaled properly and the angular speed of the model turret matches the real one then the linear speed of the end of the gun barrel when the turret turns would be the correct scale speed. Whether that "appears" too slow is another question too. Cap
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regarding the last few posts
My head hurts now!
does it matter so long as the look is what the constructor / owner wanted or even strives to get to.
R, signing off for before a mental meltdown happens
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Think of it this way a real radar turns 400 times in a nautical mile. So a scale radar should turn 400 times in a scale nautical mile. You make the adjustment in the speed the ship travels so further adjustment of the rotation rate is unnecessary. The guns are the same.
Sorry for my delay in getting back to you on this - but I've been thinking. While planking. Possibly not the best combination.
Clearly we've no problem with scaling linear dimensions. All models do this. Lengths, area, volumes (and thereby masses, since we can keep densities the same) can be reduced to make a model that reflects the original vessel.
Problems arise when we want to make a working model, since we can't scale one important effect: time.
If I climbed the original Dreadnought's foretop and dropped a hammer over the edge of it, the hammer would fall 4.9 metres in one second.
On the model, I'd expect to see the (tiny) hammer fall 6.8 centimetres (=490/72) in the same period. Now the time taken for this fall under "full size" gravity is 0.118 seconds - 8.49 times quicker than I'd expect. So (the "video effect") if I ran a video of the model 8.49 times slower than "real life" I'd see what appeared to be realistic effects of gravity on the model.
8.49 is the square root of 72 (what a surprise!) and it's this time alteration which brings us to the scale speed: not surprisingly, since wave formation is tied into gravity.
We know that the scale speed is the one where the model hull generates an accurate representation of the wake of the original. For a 1/72nd scale model, where the original could steam at 21 knots, that means:
Scale speed = 21 / SQRT(72) = 2.47 knots.
The original vessel could do a nautical mile in 171 seconds.
The model's nautical mile is 1/72 times shorter, and at 2.47 knots, it takes only 20.2 seconds to cover. No surprises here, the model is 8.49 times faster.
So, to be strictly accurate, a radar (assuming the Dreadnought had one) rotating at 400 revs per 171 seconds - about 140 rpm - should be sped up to 1190 rpm.
The turrets, which could train at 4 degrees a second, should be sped up to 34 degrees per second on the model.
But clearly this is nonsense. We don't tend to view our boats via video; and whizzing radar, along with turrets moving like dingbats, doesn't read "true" to us. But that's ok, since we can't scale the viscosity of water or surface tension either - and we've all seen older films which included model boats where it's the non-scaling ability of water (big droplets, no "spray") which make us yearn for cgi to be invented.
So the answer must be: follow the "rules" for scale wakes, and apply the "art" for good looking radars and turret movement. I can live with that.
Incidentally, cgi - computer generated graphics - can be fantastic. I'd recommend watching "Ratatouille" for not only a great piece of entertainment, but for a computer generated world which rings absolutely "true". They spent, for example, an enormous amount of time to recreate the physics of liquids during the cooking sequences, and it all pays off.
(Spot the computer programming geek enjoying films.)
Best wishes,
Andy, wondering how I went from physics to rats in one post. %%
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Think of it this way a real radar turns 400 times in a nautical mile. So a scale radar should turn 400 times in a scale nautical mile. You make the adjustment in the speed the ship travels so further adjustment of the rotation rate is unnecessary. The guns are the same.
Sorry for my delay in getting back to you on this - but I've been thinking. While planking. Possibly not the best combination.
Clearly we've no problem with scaling linear dimensions. All models do this. Lengths, area, volumes (and thereby masses, since we can keep densities the same) can be reduced to make a model that reflects the original vessel.
Problems arise when we want to make a working model, since we can't scale one important effect: time.
If I climbed the original Dreadnought's foretop and dropped a hammer over the edge of it, the hammer would fall 4.9 metres in one second.
On the model, I'd expect to see the (tiny) hammer fall 6.8 centimetres (=490/72) in the same period. Now the time taken for this fall under "full size" gravity is 0.118 seconds - 8.49 times quicker than I'd expect. So (the "video effect") if I ran a video of the model 8.49 times slower than "real life" I'd see what appeared to be realistic effects of gravity on the model.
8.49 is the square root of 72 (what a surprise!) and it's this time alteration which brings us to the scale speed: not surprisingly, since wave formation is tied into gravity.
We know that the scale speed is the one where the model hull generates an accurate representation of the wake of the original. For a 1/72nd scale model, where the original could steam at 21 knots, that means:
Scale speed = 21 / SQRT(72) = 2.47 knots.
The original vessel could do a nautical mile in 171 seconds.
The model's nautical mile is 1/72 times shorter, and at 2.47 knots, it takes only 20.2 seconds to cover. No surprises here, the model is 8.49 times faster.
So, to be strictly accurate, a radar (assuming the Dreadnought had one) rotating at 400 revs per 171 seconds - about 140 rpm - should be sped up to 1190 rpm.
The turrets, which could train at 4 degrees a second, should be sped up to 34 degrees per second on the model.
But clearly this is nonsense. We don't tend to view our boats via video; and whizzing radar, along with turrets moving like dingbats, doesn't read "true" to us. But that's ok, since we can't scale the viscosity of water or surface tension either - and we've all seen older films which included model boats where it's the non-scaling ability of water (big droplets, no "spray") which make us yearn for cgi to be invented.
So the answer must be: follow the "rules" for scale wakes, and apply the "art" for good looking radars and turret movement. I can live with that.
Incidentally, cgi - computer generated graphics - can be fantastic. I'd recommend watching "Ratatouille" for not only a great piece of entertainment, but for a computer generated world which rings absolutely "true". They spent, for example, an enormous amount of time to recreate the physics of liquids during the cooking sequences, and it all pays off.
(Spot the computer programming geek enjoying films.)
Best wishes,
Andy, wondering how I went from physics to rats in one post. %%
Yes but you are mixing apples with pears. Gravity and viscosity may have bearing on scale but have nothing to do with roataional velocities.
I if you expand your mixing of constants and variables to its logical conclusion, you should include the lunar tides, the Gregorian calender, not to mention the slowing of the roataion of the earth, and the colour of the ships cat. %%
First rule of engineering KISS - Keep It Simple Stu***.
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A brief update to the ship's boats (http://personal.strath.ac.uk/andrew.goddard/dreadnought/boats2.html) has been added.
Deck planking, meanwhile, is progressing at what can only be described as alarming speed. I'm well past halfway, moving outwards and forwards along the starboard side. X and Y turrets are engulfed in a sea of woodwork, the rear of the superstructure cut-out is about to follow.
Hmmm...a quick dash past Q turret, the forecastle's starboard side, and I can almost imagine the end!
....In a week or three. %%
Andy
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And one week on I'm at:
...80%, at least.
New pictures up tomorrow. Not that there's much new to see really, other than planks. And caulking. And, errr, that's it.
But that will give me the opportunity to mention an RSI from PVA-bottle lifting, along with what could be a dose of Dupuytren's contracture.
:o (...which is very possibly the first thing I've ever had in common with Margaret Thatcher.)
Andy, finishing plank in sight!
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Andy, Good to hear you are moving along, interesting how these things go in spurts, I'm in the dumps now, not getting anywhere. I used CA when I was planking my DD hull (not near as many planks) and the fumes were most unpleasant, so at least you've avoided that. Cap
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Thanks Cap.
I promised pictures yesterday - but the only SD card I could find is bust, so it'll be tomorrow at the earliest. Work has diversified (which helps cuts down the "gawd not more planks" factor)...
1/ The rear subdeck aft of the torpedo net shelf has been trimmed to the hull outline, and the space for the margin planks has been cleared. What's great here is that, in removing the ends of the fore and aft planks to make this space, I've been cutting and lifting plank ends that were glued - PVA between limewood and ply - a few days ago, and they are now satisfyingly solid. The wood's coming away, but leaving a thin veneer of ex-plank firmly attached to the ply. Scraping the remaining limewood off has been the only answer. Top marks, modern waterproof PVA!
2/ The cartridge paper plates at the sides of the hull were coated with G4 several months ago. While sanding the edges of the subdeck to fit, my sanding block eventually rubbed against these plates. Normally "sanding" and "paper" is not a good mix, but the resulting smell of warm resin dust - a very GRP-like pong - is fantastic news. The G4 has totally soaked the cartridge paper, and the result is a very tough, resin finish, which is sandable with ease. It is like plasticard. 10/10 for G4!!!
3/ I've finished a small amount of ply work at the starboard forecastle, so I'm ready to plank that area in the next few days. And once that ply work was done, I started adding the superstructure coaming. This is made of 15mm-high strips of plywood, stuck within the hull opening, to leave a 1/16th inch "gutter" for the superstructure base between coaming and margin plank.
While most of the coaming is a set of straight lines, there are a couple of areas of curves - for example, the turn inside of the P and Q turrets. For these, I soaked ply strips in hot water, elastic-banded them around a pot of the right diameter, and (two hours later, after they dried) have cut and glued these on using Evostick. People often seem to rush contact adhesives like this, but if you follow the instructions (let the surfaces dry before lining up and attaching) the stuff is magnificent. Way to go, Evostick!!! :-)) :-))
All is good. And it's staring to look like a model boat.
So, naturally, my thoughts are moving forward ... and given the complexity of the shape of the superstructure, along with a need for strength in such a narrow, weirdly-shaped beast, I'm leaning towards making it out of another material. Brass sheet? Any other recommendations?
Regards!
Andy
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Andy, I thought I was looking at the new pictures, but I guess they were old. Mostly the same I suppose, but glad they are getting done. What is Evostick? I'm not up on all the adhesives, use elmers, epoxy and CA is all. I'll be doing a similar coaming if I understand you right and will have to glue a curved one in like yours, but the radius will likely not be quite as tight, so maybe I'll try your method. I never liked soaking wood though, I don't think I'm patient enough to let it dry out thoroughly, maybe it's the adhesive I use though O0.
I've never built something like a ship superstructure with brass sheet, I've seen it done (pictures) and it certainly can be done nicely but I'm not sure I could do it. I usually need to use a lot of sand paper on the corners of stuff I build. I'm going to use thin plywood for my DD but it's 1/35 scale so I've got a bit more leeway. Back to the brass sheet, I guess I don't even know how it's fastened together, I've tried to solder each end of a piece of brass before and when I do it the solder at both ends melts. Cap
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Evostick - this is the smelly contact adhesive, popular for work surface sticking.
It comes in red tubs or tubes over here, and you have to be over 18 to buy it, as it's understandably the solvent of choice for young ne'er-do-wells.
You run a bead along both surfaces to be joined, wait five minutes until you think "that's way too long", bring the surfaces together and they bond instantly. There's no real chance of adjusting the work after that point. It sets in another five minutes and it attains full strength in 24 hours. It doesn't soak into the wood as well as CA or PVA (it's quite rubbery) so it's more of a surface glue than a penetrative one.
Because I'm effectively sticking edges together for the coaming, not the flat surfaces that it's really designed for - I'm going to reinforce the joins with a strip of glassfibre later on...
(http://personal.strath.ac.uk/andrew.goddard/dreadnought/section.jpg)
(The coaming will be taking more than a few knocks, so it needs beefing up. Except, as a vegetarian, I'll naturally be nut-roasting-it-up. %%)
Soaking the ply - I leave a strip submerged in hot/boiling water for ten/fifteen minutes or so, and get on with other jobs. Then take out the wood and strap/bind/band it to a curve somewhat smaller in diameter than that required, and leave it for an hour on the radiator. "Job done". That said, there's one small curve on the port side of the coaming of about 4cm diameter which I had problems with last night. Too tight for my 1/16th ply with water soaking alone - I think I'll have to laminate card for that one.
Andy
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If you are worried about the instant bond "get it right first time" nature of Evostik you could try Thixofix with gives the opportunity for minor readjustment before setting.
http://www.thegluepeople.co.uk/index.php?main_page=product_info&cPath=6_7&products_id=17
Colin
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Thanks Colin - though I have to admit quite liking the frisson of terror with Evostick. That whole "there's no second chance" thing. I suppose it's a bit like lining up the space shuttle for a landing. Only, without the risk of pain, death, or at least a terribly embarrassing court-martial. ;)
For those mad enough to want to see Yet More Planking (http://personal.strath.ac.uk/andrew.goddard/dreadnought/decking9.html). Now you can! %%
Andy
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In the past, I have used waxed paper as a barrier between the two surfaces. The paper doesn't stick to the contact adhesive. You can line things up and then slide the paper out of the way, (starting at one edge to get the "register"), applying pressure as you remove it.
Martin
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Looks great, not much left at all... Your deckhands appear friendly however for a moment it looked as though they might engage. Now the deck may be fine with a cat on a pillow on it but a full fledged catfight? That would have to result in some serious gouges among other things, better get a squirt gun O0. Cap
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Dreadnought, you are an indefatigable master-planker :}
Thanks for sharing - the last half has flown by, and the result is wonderful.
Are you going to simulate the treenails or bolts used to attach them? This is not a serious enquiry! I don't think it is easy to buy a forstner bit of .02mm diameter. Don't mind me - I'm talking nonsense
andrew
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Good tip regarding Evostick - thanks for that.
The cats. Jack's taken to demanding his cushion is placed on the deck, so he can get a better view of the work. He'll have to shift when all the "thingummies" are applied later, and it all gets more delicate. Now and again the odd paw disappears down a turret hole, in order to fish out spare limewood planks which I keep in the hull, but there's been no attempts at claw-sharpening on the decks so far. I do wonder what he makes of it all, though.
Meanwhile - treenails. I have no idea how the original planking was applied to a steel-plated deck. Presumably they didn't use PVA and giant felines to weigh 'em down while the glue set. %%
(Well, maybe they did on HMS Lion and HMS Tiger.)
It would seem to be an endless, thankless task if they were all bolted into place...does anybody know the real technique?
Andy, almost finished planking.
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Andy,
Evostick can readily be persuaded to "let go". It is basically (I believe) neoprene latex suspended in a solvent. If you flood the area with acetone or cellulose thinners the glue will revert to liquid. Diluted evostick is the adhesive of choice for covering aircraft parts with mylar film. prolly explains a lot about aeromodellers and their relationship to reality (he said from the planet zoG)
If you need a little "fiddle time" to adjust bits held with evostick either don't leave it to dry completely before pressing together
or at the point of pressing together give the surfaces a swipe with solvent.
I believe (navy) planking on a steel deck is held down with "bolts" at about the same intervals that treenails would be used. I don't know if there is a nut and washer used, or some kind of upset or swage, but the hole is covered with a plug cut out of similar wood - but end-grain, I think.
I would not fault you if you use cross-grain plugs :}
What are you going to finish the decks with?
andrew
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What are you going to finish the decks with?
Well, I'll be having an extremely jolly big whisky. %%
That's "jolly" as in <word not allowed>
Oh.
I see. :embarrassed:
It'll be getting many coats of matt varnish. The first few thinned, to penetrate the threads and wood until they become a mass of imperviousness. Then sand, varnish, sand, varnish, sand, varnish, sand, varnish, sand, varnish
The thing is, after the hundred or so hours spent on this, I won't be regretting a couple/six more on getting it "just so".
Back when I were a lad, in my dinghy racing days, it took about two weeks of six/eight hour days to prep and paint a hull ... the final half day spent wet-or-drying the perfect top coat (used wet) to get the bugs off, and matte it, to create a surface that'd gain me a few boat lengths through pure sleekness alone. That was time never wasted.
Interesting stuff on the treenails. I'm not sure I'm up to doing 5000+ when they're going to be half a mill in diameter. Though I did buy my eldest son a microscope for Christmas.
Andy
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Andy....in Australia we have a product called Feast Watson Carnauba Wax - [it is not unlike neutral shoe polish/wax]
http://www.feastwatson.com.au/WaxesWax.asp
Successive coats of this wax produce a natural protection against moisture [suffice to say I would never use it underwater] without the matt translucence build up you get with polyurethane
The wax also adds depth [but does not darken] to the differing natural timber tones between each plank
Not sure about the representation of 5000 treenail plugs >>:-( >>:-( ......but if you do contemplate them...consider using a jig....maybe a length of K&S brass strip the same width as the planks...carefully mark & drill 0.5 mm diameter holes at the nominated spacing....then :P ......Derek
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A quick check of the Dreadnought stats this morning shows me that a recent visitor came from Vienna, Virginia, USA. Instead of the usual "broadband" or "corporate" internet service provider listed in the stats, this visitor has:
PENTAGON
:o
Now, while I guffawed at their WinXP, I.E.7 and 800*600 platform, it did get me thinking. "What if they're in the Naval Procurement department, and planning vessels for the USN around the 2015/2020 timeframe...?" %%
Ok - updates. I've slung three original photos up online (http://personal.strath.ac.uk/andrew.goddard/dreadnought/original1.html), contemplated Derek's wax idea (but fear it might make my thread go white), and will be resuming planking next week, once I get some free time again.
Andy
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Hi,
I am currently in the process of building a model of the USS Nevada. So, I found this thread and have been following it with interest. And I do appreciate Andy, the fact that you are sharing this with everyone. I know some of the ideas and techniques you have shown will help me with Nevada. I don't know if you are still interested in the planking process used on battleships, but there is a rather good description of it used in the reconstruction of the North Carolina's teak deck. According to their website, "The project got underway in mid-1999 with the removal of the original teak decking and preservation of the steel deck underneath. After drying and milling the new teak, crews started the painstaking task of fitting the teak, welding studs to the steel deck to fasten the teak boards to the deck, then spreading a bedding compound onto which the teak boards were laid and fastened with special barrel nuts. After the compound dried, teak plugs were installed over the barrel nuts and a synthetic sealant poured between the teak boards. Finally, the entire deck went through a sanding process to provide a smooth surface. In the end, just over 55,000 square feet of teak was installed on three decks of the Battleship". There are some interesting photos of the process at this link ---> http://www.battleshipnc.com//lucky_bag/pjt_photos1.html
Rob
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I have been reading this post this morning with an increasing sense of wonderment and awe.
My God sir! This is something else all together. And not just the model - the science stuff if pretty awesome too.
However if I may - I noted in January a discussion about firing the guns and the thoughts turned to caps and recoiling mechanisms. the suggestion was at that time 12 shot ring caps. which means 15 sets of re-loading. Coming from an airsoft background it may be worth looking at airsoft pistols which are often made so that the gas doesn't just fire the BB but causes the pistol slide to recoil as well. The gases expanding from the muzzle add to the effect as well but the mechanisms could be built with one gas reservoir per turret, so each can be reloaded simply.
Under the auspices of the VCR Act it is less easy to buy a replica pistol, but brightly coloured gas blowback pistols can be obtained here
http://www.actionhobbys.co.uk/Pistols-Revolvers-Gas-Powered_B22C4D.aspx
There is also the likes of this one which is a cheap 'blowback' electric.
http://www.actionhobbys.co.uk/Cyma-Beretta-Electric-blowback-Pistol-2-Tone_ALB5H.aspx
Merely a suggestion. I look forwards to more of your work.
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Thanks very much for the posts, Rob and Steve.
I must apologise for not updating this build since (ahem) February, but real world things have a habit of stopping by and nibbling you when you least expect it. Work will recommence soon enough - I've promised the hull that it'll be at least afloat this year, ballasted and trialled.
Oh yes. <*<
Andy
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I look forward to the day when I can see this magnificent obsession afloat and tracking targets while crossing a notional 't'. As well as all of that it is 1/72 as well, the true scale.
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Thanks very much for the posts, Rob and Steve.
I must apologise for not updating this build since (ahem) February, but real world things have a habit of stopping by and nibbling you when you least expect it. Work will recommence soon enough - I've promised the hull that it'll be at least afloat this year, ballasted and trialled.
Oh yes. <*<
Andy
Oh dear.
%)
Well, of course, it's now January 2010, and the hull's not afloat. Barely progressed from when last seen on this thread, in fact. BUT!
(And it's a big but)
I've just taken redundancy from work, partly because there was a generous deal on offer, and partly because "working for the man" seems (at 46) to be a bigger waste of money compared to "working for myself". A gamble, for sure, but as Commander Walker would say, "always take a chance and don't be sorry for a might-have-been" (no points for spotting the quote if you've been following the build thread :-) ).
And as to the build thread - that's currently offline as it moves home. It was hosted on my work's server - when my new Dell arrives at the end of this week it'll be located in its new and permanent home. The Dreadnought, meanwhile, has found itself out of the attic and in the freed-up "craft room" recently decorated and ready to go with regards to boat-building. :-))
So wish me luck over the next few months! And, incidentally, if you need a website developing for whatever purpose, drop me an email and we can talk costs! ok2
Best wishes to all in 2010,
Andy
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Andy
Happy New Year!
Thanks for keeping us updated with your decision to break out as a solo artist - hope it all goes well for you.
Actually you can refer prospective clients to your Dreadsite and claim " a person who can plank an Acre of deck can make light work of your detail requirements (and joggle your margin planks)"
andrew
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Happy New Year to all Andrews and Andys (and everyone else too). I've been absent for a while, any updates? It seems the HMS Dreadnought website is gone or moved. Cap
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Hi Cap - as I mentioned, the site was hosted on my previous employer's server. I need to put it up on a new server, and will do so soon, though I'm waiting until there's more work done on the build.
Thanks for stopping by!
Andy
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Right, that's the site back online (http://www.thefreckledfish.com/dreadnought/index.html). But there's nothing new there this time around. More soon!
Andy
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Andy, Glad to see you have your site back up. Very neat graphics for the controls, especially the gun training. I have been tinkering with gun directors again myself and I still think stepper motors are the way to go, servos work for sure but not quite right (my opinion). You do need the microprocessor and stepper motor drivers. I've been using phidget stepper motor controller which is nice because it has 4 independent contollers. It could work exactly like you have it set up too. Anyway, is the planking done?? More photo's. Cap
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Hi Cap! Thanks for the message.
Stepper motors - I think you're right: these are the way to go. They're a bit pricey, but with toothed belts and different sized wheels it'd be possible to reduce the (typically 1.8 degree) step motion to really small amounts, and with the coding driving the stepper motors, it'd be a cinch to accurately point each turret. (Count the steps and stop when done.)
Hmmm.
I think what I need to do is assemble the parts and make (outside the hull) a working model. Cost is a bit excessive, however - I'd be looking at ~£400 or so for the components, all in.
(Files it under "Job for the future".)
Meanwhile, planking has stopped while Real Life gets in the way: I've gone freelance and need jobs & cash coming in at the moment. And my current modelling priority is to finish planking Racundra and get her off the building board.
(Definitely time to consider cloning myself in order to get all these things done. :o )
Best wishes,
Andy
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Andy, No rush on the planking, some things just can't be rushed. Surplus stepper motors can be had for relatively cheap (3$ US), it depends on how exact you want it. The cheap ones are often 7.5 degree motors, but with half steps that 3.75 deg per step, gear it down 4:1 and you have about 1 degree of resolution. I have a proto type set up (outside the hull), it's not the best video but it's just a proto.
http://s262.photobucket.com/albums/ii92/capricornzzz/?action=view¤t=director1.flv (http://s262.photobucket.com/albums/ii92/capricornzzz/?action=view¤t=director1.flv)
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Now THAT is wild sweet.
Imagine it coupled to a solid-state compass (I see some for ~$20) that would enable the turrets to "track" whilst the vessel changes heading. :-)) :-)) :-)) :-))
Excellent work.
Andy
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Andy, it's inspired by you, and Nico. And the tracking feature is a must O0. I suppose dreadnought would need 5 independent stepper controllers due to it's unusual layout. It will be kool %%. Cap
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cap,
AWESOME stepping director rig, can you give us a tutorial on the whole enchilada?
PLEASE
Andy, just between us scots, steppers are FREE, and Cap has been using at least one free one (perhaps his fourbears emigrated to the colonies)
floppy disc drives use them for at least one of the functions; and printers use several of varied types. I guess that you would be able to "liberate" some printers and drives without too much difficulty
<<Imagine it coupled to a solid-state compass (I see some for ~$20) that would enable the turrets to "track" whilst the vessel changes heading>>
How about building in one of the modren phones or Wii controllers with lota of accelerometers and have the guns maintain elevation too.
-of course for real scale fidelity it should fire (very quickly) shells which fail to explode :embarrassed:
andrew
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Hi Andrew, Right now the steppers are connected to a phidget, and that to the laptop via usb plug, so it's not worthy of a tutorial, yet anyway. I haven't a current project for them to go in so it's more of an experiment, tracking the heading and keeping the elevation would make it a much more interesting experiment for sure. When and if it ever is I'll post it. Cap
Speaking of scots there was an article in our local paper on Saturday featuring your own alexander mccall smith, whose writing I enjoy very much.
http://www.startribune.com/entertainment/books/91920104.html?elr=KArksD:aDyaEP:kD:aU1ccmiUiD3aPc:_Yyc:aULPQL7PQLanchO7DiUr (http://www.startribune.com/entertainment/books/91920104.html?elr=KArksD:aDyaEP:kD:aU1ccmiUiD3aPc:_Yyc:aULPQL7PQLanchO7DiUr)