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Author Topic: IRON DUKE 1914  (Read 109277 times)

raflaunches

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Re: IRON DUKE 1914
« Reply #250 on: March 28, 2016, 07:31:36 PM »

I'm certainly looking forward to seeing her for real at Mayhem. :-))
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Re: IRON DUKE 1914
« Reply #251 on: March 29, 2016, 01:46:09 PM »

Attached are some updated pictures of progress with the gunnery system. A number of comments and observations:


1) I'm still fed up with taking every component apart a dozen times but to be fair as this is in the R&D phase once I have worked out how to do things it will be much easier.


2) The larger fan has made a significant difference and once the "cones" at the end of the piping were fitted I was surprised at the significant increase in pressure/blast they made. I know that as you reduce a gas flow the pressure has to increase but it was more than I anticipated.


3) Clearly one larger fan is the way to go.


4) Given the layout of the piping which is like a letter F but with an extra prong somewhat as anticipated the further from the fan the higher the pressure as the air flow is easier. There is a noticeable difference from A&B and X&Y but I'm hopeful that once enclosed the pressure will equalise between all smoke boxes. Engineers tackle this in practice by using reduced diameter piping to increase back-flow so all sections are the same but I don't think I'll need to do this in a model.


5) The alloy plates are heat protectors under the valves - the operating solenoid can be clearly seen


6) It was very time consuming to align the smoke box inlet with the outlet nozzles. The connection at that point is a small sheet of rubber with a hole in it such the nozzle forces its way through creating both a seal and allowing for limited misalignment. It seems to work.


7) Not visible in the pictures are some 3D cut outs in Q and X&Y smoke boxes due to space requirements for the air piping.


8) Because the smoke containers did not need to be as large as expected (following test experiments) there is room beneath A&B to fit two large gel batteries on their side which helps both battery capacity and ballast.


More to follow


Cheers


Geoff
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Geoff

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Re: IRON DUKE 1914
« Reply #252 on: March 29, 2016, 01:52:06 PM »

To caption some of the pictures:


The second picture shows the original "T" connections for the fan and Q turret. The fan was later moved to the bow compartment as this the space next to Q was designed to take a large 12 Gel battery


The third picture shows the fan in the bow compartment. I hope the restricted air flow won't be a problem once the deck is on. There are lots of open features in the deck to permit air flow.


The fourth picture shows the method I use to operate the turrets. there is a small sail winch on the right which is operated by a servo-morph. The spare threads/lines take the drive to "Q" turret


The fifth picture shows the ex hair-dryer fan unit using a plastic bottle for the cone


Cheers


Geoff
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Geoff

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Re: IRON DUKE 1914
« Reply #253 on: March 29, 2016, 02:01:36 PM »

Sorry, to clarify a little with the turret turning mechanism - with "X&Y" the direction of rotation has to be reversed hence the two idler wheels which also take the drive to "X" Barbette which in turn drives "Q" and "Y" thus equalising the pull in both directions.


The white bottle with the other fan unit was a B&Q a PVA glue bottle - the shape appears good but in practice was not as good as using a plastic wine glass which has a more gentle curvature. The plastic cones at the ends of the white piping also came from the plastic wane glass stem - this worked well.


Sorry for the repeated amendments but its hard to recall everything at once!


Cheers


G
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dreadnought72

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Re: IRON DUKE 1914
« Reply #254 on: March 29, 2016, 02:12:40 PM »

...and in image #2 the coal scuttles have turned up. I've been waiting quietly for them!  :-))


Andy
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Geoff

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Re: IRON DUKE 1914
« Reply #255 on: March 29, 2016, 02:17:03 PM »

Well spotted! I haven't fitted them yet as they should really be flush with the deck rather than proud. I'm tempted to try to counter-sink them but may mess up the planking if it goes wrong. I'll probably just stick them on for expediency and safety!

Cheers eagle eyes!  :-)
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dreadnought72

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Re: IRON DUKE 1914
« Reply #256 on: March 29, 2016, 02:34:02 PM »

A very sharp scalpel and a small (hand carving) chisel should do the trick. Mind you, there's a lot to countersink.


(I'll keep schtum if they should appear stuck on, later.  %)  Everyone will be gasping as the smoke-breathing monster, anyway!)


My acres of Dreadnought deck planking almost cry out for little features like this to break up the monotony of endless planks.


Andy
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ballastanksian

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Re: IRON DUKE 1914
« Reply #257 on: March 29, 2016, 09:03:21 PM »

Wow! Considering the eclectic variety of materiels used in its construction, the system looks very very tidy. I imagine you will be lifting the superstructure off many times to show us how the system looks and works in situ.

I am glad you found a good powerful fan as I know the worry about a forest of small fans was putting a dampner on the project for you.

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Geoff

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Re: IRON DUKE 1914
« Reply #258 on: March 29, 2016, 10:24:12 PM »

Thank you. its a bit like the "X" files, the answer is out there, somewhere!


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ballastanksian

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Re: IRON DUKE 1914
« Reply #259 on: March 29, 2016, 10:44:16 PM »

It's in your battleship! I know what you mean though Geoff, somethings take a little fiddling about with before the answer comes to you.
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Geoff

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Re: IRON DUKE 1914
« Reply #260 on: March 31, 2016, 01:27:51 PM »

A further update. Its always the little things that cause problems. The silicon tube I ordered to join the barrel to the center of the Barbette for smoke transference turned up, exactly as ordered, but I still can't make the connection as it kinks and there is actually so little room between the two points.


I was using 10mm copper elbows modified to guide the smoke out of the barbette to the rear of the gun as this gives a nice curve but left very little room to make the connection. Plan "B" was to point the elbow to the rear and run a loop round to the back to the front to join the barrel. This has the advantage of a gentler curve but would increase the distance the smoke has to go with attendant condensation and drag.


A new plan "C" is to construct a square pipe from the rear of the barrel to go over the hole in the barbette. Yes its square so it won't be quite so efficient but because I can use the whole distance between the end of the barrel and the center of rotation the join angle will be easier and it will be easier to construct. To put this onto perspective its only going to be about 1 inch long!


I can also construct it on a base plate inside the turret such the barrels can be pulled out and the whole assembly removed. Based on past experience I think I'll need to remove it dozens of times!


As mentioned before because this is R&D the knowledge gained would lead me to design a different style of barbette so the smoke hole is on the edge and in a straight line to the barrel - one lives and learns!  :-) .


More pictures to follow once there is something to show.


Cheers


Geoff
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ballastanksian

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Re: IRON DUKE 1914
« Reply #261 on: March 31, 2016, 07:35:53 PM »

One does indeed. Would winding wire around the tube help keep its shape? You would be making hose of the type seen for fuelling ships and the like.

If you already have the solution in effect then ignore me!
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warspite

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Re: IRON DUKE 1914
« Reply #262 on: March 31, 2016, 08:10:28 PM »

Is it not possible to take some evergreen type abs, just cut the abs tube into segments and glue them on to the outside of the clear flexible tube, it would make the tube resist the urge to kink. like making a segmented bend with every other segment missing (web search - segmented bends).
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Re: IRON DUKE 1914
« Reply #263 on: April 15, 2016, 08:48:18 AM »

By way of an update, I decided to construct the awkward shape as a square section in plastic card leading from the center of rotation (the smoke tube) to the rear of the gun. It was still an awkward shape and each one was custom built but it does appear to work. I hope the change in shape of the ductwork won't have any adverse effect on the smoke discharge but only time will tell.


I then spent something in the region of over 5/6 hours over two days trying to get the servo morphs to work properly with the turret winches. Much fine tuning and fiddling about but I was unable to get the desired result. The slow characteristic was perfect but I found it impossible to get 180 degrees of movement with any repeatability. It is possible its characteristics of my system in some way but the net result is that neither of the two servo morphs now work at all and they are in the junk box.


I'll need to go back to plan B and put physical stops on the transmitter to limit the throw of the joystick and thus the movement of the turrets. With the sail winches this does of course give me self centering when the joystick is in the middle. This works fine but there is some slack in the system so I have to fiddle to get the exact center point but I can live with that. If I move the joystick slowly then the turrets turn slowly , not ideal but it does work.


I have been struggling to get all the batteries in and have had to re-build the funnel smoke units but at least I have three  12 volt/7.2ah batteries in place and I have found room for three 6 v batteries for the main propulsion.


I hope to do some floatation tests over the weekend to sort out the final ballast and may get some pictures - first build the test tank!


Cheers


Geoff



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ballastanksian

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Re: IRON DUKE 1914
« Reply #264 on: April 17, 2016, 06:27:55 PM »

I am excited about seeing the floatation tests.
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Geoff

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Re: IRON DUKE 1914
« Reply #265 on: April 19, 2016, 01:35:19 PM »

Okay, some more pictures.


I'll do the narrative in the next post


Cheers


Geoff
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Geoff

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Re: IRON DUKE 1914
« Reply #266 on: April 19, 2016, 01:49:37 PM »

Okay, now for some narrative in sequence:


1) Midships section showing two funnel smoke units offset to port and starboard plus 3 12 volt 7.2 amp hour batteries.


2) X&Y Smoke box showing internal construction - note plastic funnel and rubber seal - the smoke unit is the fireproof rope with a wrapping of nichrome wire. It sits in a bath of fog fluid. All of this box will be fixed to the deck. There is no reason for the red paint - I just had a can handy!


3) One 6v 7.2 amp hour battery under the gunnery control unit. Far left is the air inlet pipe to A&B smoke box (not shown)


4) Gunnery control unit - not a good picture but it gives the idea - a small engine and gearbox turning a plastic cylinder with cams which in turn operate the bank of micro-switches - 8 seconds for smoke generation- one second overlap then two more seconds for fan unit - overlapped with two seconds for valve opening - overlapped with signal for 2 second sound unit - overlapped with one second for light flash - followed by an off switch.


5) Main engines (Two blower units from very old Talbot Horizons 12 volt 12 pole motors running on 6 volts. If you look closely you can see the rubber belt drive to the outboard props. Wooden platform over universal joints showing edge of two 6 volt 3.1 amp hour batteries for main engines. Gap in the middle is intended for the sound unit with the sound exiting a wire mesh floor in the aft superstructure between Q and X/Y turrets.


6) Rudder linkage and receiver and servos - bottom right shows the cam on one servo which operates a push on, push off switch to operate the funnel smoke. Micro switch operates the gunnery control unit.


I didn't get around to the floatation test over the weekend - maybe next weekend.


Enjoy


Cheers


Geoff
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ballastanksian

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Re: IRON DUKE 1914
« Reply #267 on: April 19, 2016, 08:10:09 PM »

Crikey, it looks very sophisticated. I wondered if the micro switches might trigger individual turret detonations. I look forward to see this in action in a few weeks.
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Geoff

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Re: IRON DUKE 1914
« Reply #268 on: April 19, 2016, 11:04:41 PM »

I'll actually be triggering all three gun smoke generators at the same time. A&B and X&Y are double size so will feed both forward and aft turrets simultaneously so I will fire one shot from each turret at the same time. I'm hoping this will collectively give me the smoke volume to simulate a broadside from all five turrets.


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Geoff

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Re: IRON DUKE 1914
« Reply #269 on: April 24, 2016, 02:27:21 PM »

Ok, some progress. ID has now been ballasted. I used lead flashing and put in about 6 pounds to get her to the waterline in the homemade test tank.


Sunday at Southchurch Park in Southend - first sailing which revealed a few issues:


1) She is only just fast enough which was a puzzle but just about okay.


2) terrible radio interference and complete loss of control. I'm on 27 and have never experienced a similar problem. Even a change of crystals made no difference. Traced it down to interference caused by the funnel smoke generator. I'm using step up voltage regulator for 12v to 24v. It has a completely separate power supply. Does anybody have any ideas?


3) Main engine batteries last 90 mins which is not as long as I wanted but within the capacity range of the batteries. I'm not sure what I can do about that other than to carry some spare batteries


4) Otherwise she sailed quite well albeit in an unfinished condition.


I'll post some pictures shortly but the main query is the interference


Cheers


Geoff
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ballastanksian

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Re: IRON DUKE 1914
« Reply #270 on: April 24, 2016, 02:33:11 PM »

A silly question from a noob in the RC world, but is the aerial exposed enough to catch the radio transmissions? I think this is more an issue for 2.4 but worth a look.

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Bob K

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Re: IRON DUKE 1914
« Reply #271 on: April 24, 2016, 03:52:57 PM »


 Traced it down to interference caused by the funnel smoke generator. I'm using step up voltage regulator for 12v to 24v. It has a completely separate power supply. Does anybody have any ideas?


Could depend on which type of step up regulator you are using. Most 'traditional' ones involve converting to AC (inductor / transformer) increasing the voltage then converting back to DC.  A 2A "inductor" can generate of lot of RF locally.

When needing 24V I try to use additional batteries to avoid this, although Component Shop now do a nice compact step up unit without large coils.  I have recently bought one for my 24V mister but not had a chance to trial it yet.
http://www.componentshop.co.uk/voltage-booster-with-green-led-display.html
Not bad for just under a Tenner

Bob K
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Re: IRON DUKE 1914
« Reply #272 on: April 24, 2016, 04:00:45 PM »

I think most of the 12/24 units will have inherent RFI.
2G4 will probably be immune.
Worth borrowing a set up to test before parting with cash.


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warspite

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Re: IRON DUKE 1914
« Reply #273 on: April 24, 2016, 05:32:33 PM »

just read the bit about the pipes and their diameters, in an air conveying system (although this is smoke it's still air being used to convey it), the action of reducing the diameters is to increase the pressure as it moves from the nearest offshoot to the furthest, all the outlet diameters and the pipes for each run should be the same, i.e. each branch should be the same, that means for 3 connections they should all be the same irrespective of their lengths, so the furthest is, say, 100mm dia then the second furthest should be 100mm as should be the third, the diameter change from the furthest to the second furthest should be as close to the branch where they meet, doing a trouser branch (60 equally branch) is ideal, the diameter back should be equal to the same cross sectional area of the two connections, the same applies for the connection to the closest connection though here the problem is that the small diameter and the furthest branches run of pipe diameter is different so a 30 branch is used with a cone down to the larger diameter from the feed duct, again is now sized at the same cross sectional area of all three connections (4 connections at 100mm would equate to a doubling in the diameter of a duct to 200mm).

this ensures that the pressure is the same across all 3 ducts, as air will like water take the least line of resistance, in practice calculations are taken based upon the furthest duct when sizing a fan for the pressure and duty, at this scale however, all the above is throw out of the window as the differing diameters, lengths and fan pressure will be to small to make a noticeable difference  :D, also in practice, dampers are used to throttle the air pressures, where a damper could be almost 2/3's closed before it had any effect and then the effect would be quite big or little depending upon how the system wanted to behave.

You could also have 3 lines of piping all identical in length and that would create the ideal equal pressure system.

As you discovered, small cones are not as efficient in airflow as longer cones, the back pressure is more prenounced so the speed reduces.
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Geoff

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Re: IRON DUKE 1914
« Reply #274 on: April 24, 2016, 11:28:51 PM »

It was the component shop step up voltage unit that I used. It works fine but as above mine gives terrible interference. I had the ariel both inside and outside the hull but it made no difference. All very strange!


Cheers


Geoff
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