Topic: Oliver's HMS Kelly

[hotjava]

Hi,

I think the J/K Class Destroyers are very popular on this forum so I had to title my build "Oliver's HMS Kelly".  I know Tommy is building the HMS Javelin and I hope to build one as fine as Robin's and Dicky's.  Robin's was the inspiration behind my choice for this my first Deans Marine model.  I'm using his model as visual reference. 

Here is my progress on the HMS Kelly.  I'll update this thread as I progess.

Deck Support

Deck supports are installed based on the guidance found in the instructions, the plywood deck pieces and the styrene deck, but even this wasn't enough to ensure a good fit.  In particular, the printed deck at the stern was much narrower than the hull.  So, what I did was turn the hull upside down and trace the deck onto a piece of cardboard and using that as a pattern, I placed it over the plans and the printed sheets and then adjusted the supports and styrene deck to fit.  The deck framework is based on the openings found on the styrene deck and recommendations by Robin who's HMS Kelly inspired me to choose this model.

The bulkheads had similar fit problems where they were either too small or too large.  Using a technique that Tommy on this forum used, I took solder and got the rough shape of the bulkheads which I redrew on the patterns.  I then cut and sanded to shape.

The supports and bulkheads were epoxied to the hull using the "cheap, hobby store branded" 15 minute epoxy that I purchased at a local HobbyTown.  It's not marine grade and in the past, I've found it durable for my R/C needs.  Prior to gluing, I didn't use Bondo or other fillers.  I simply washed the inside of the hull and lightly sanded the area where I wanted to glue.  Then, I mixed epoxy with Microballoons filler.  I've found Microballoons add joint strength and it acts as a good filler for gaps like where the stuffing box extends out of the hull.

In constructing the deck supports, I used nearly all the wood found in the kit - both ramin and balsa.  Where I added more cross members than in the kit photos, I used bass or pine wood.  In other words, I just used what was available from scrap.  In areas where I had to shim the top of the deck so that they would be even, I used 1/16" balsa.









Rudder Support

I didn't use the brass rudder tube supplied with the kit.  It was too thin.  I made one from a tube with the same diameter but with thicker walls.  Next, digging through my scrap box, I found a small piece of bass wood and drilling a hole in the center, I super glued the brass tube in place with about 1/8" of brass extending from the top and the bottom.  Using epoxy, I glued the rudder support onto the hull and then glued a cross beam on top for added strength. 



Oliver

[hotjava]

Hi,

Electronics
The electronics setup is pretty straightforward using a single Mtroniks Viper 20A ESC ( purchased from eBay UK ) powering two Deans Marines Kondor Motors wired in parallel with two 7.2V 2000mAh NIMHs purchased from Tower Hobbies. 

The Kondor Motors rest on rubber material taken from the back of a mousepad and are held down with wire ties.

Here's a nice shot of them all together.



The Futaba receiver is located near the bow.



Oliver

[colin]

your moving on good there Oliver....  nice to see you have started your Build

i have re-sized your Pictures in your last post as there were rather large, and breaking the boarders of the forum
when you use the "img" "/img" BBC code you can enter a Width and Height in the first "img" code

have a look at your last post in edit mode and you will see them.

[hotjava]

Colin,

Thanks!  Will do!

Oliver

[hotjava]

Hi,

Propellers and Rudder
The propellors are locally made in Northern California by Gordon Briggs.  I sent him the white metal ones and with those he made mine.  Here's the drawing that he sent back.



Gordon's propellers are wonderful and very economical at $25 for the pair.  He makes "WWII destroyer" propellers but little did I know that he meant US destroyer style -- Gearing, Sumner and Fletcher -- but not British.  If these don't work out, I'll visit George Sitek's site.



I made a mistake in the stuffing box. The correct distance between is 40mm.  In the instructions -- not the plan -- they are "40 cntrs" or 40mm ( I'm not sure why the instructions don't just say 40mm instead of "40 cntrs" and why they were separated from the plans because that would have been easier to find ).  In any case, I set the stuffing box before I realized the correct distance.  So, my distance from propeller to propeller is 48mm.



My hull also lacked the drill dimples that would show where to place the struts.  Robin was kind enough to supply me with the information based on his beautiful HMS Kelly.

The rudder is stock.  If turning becomes an issue, I'll increase the size.

Have a good day!
Oliver

[colin]

slowly but surely your progressing.... doing a grand job.. 

if you do have problems with your props there are Destroyer props in the Deans online shop 3 and 5 blades

click here for the 3 bladed

if you have problems with your turning circle there is a speed controller that has two controllers in one and also a mixer, this will when the rudder moves slow the inside prop down and speed the outside prop up, if the ship is stationary it will send one motor forwards and the other in reverse, in other words turning on the spot.

click here for more info on the speed controller

[Tommydean]

Oliver looking good    yha i had the same question about 40cntrs/40mm i went with 40mm seem to work out fine.

[karlgalster]

Hi Oliver, just got back from a hill walking trip so only just read your post. Your Kelly is looking really great - I like your support of the rudder post - mine was as the kit instructions and I hit an underwater obstruction and the post support failed. Now reinforced. My propellors look about 45mm apart.

Colin - I have independent control on Kelly and Z37 but its hardly worth the added complexity. For instance it takes an awfully long time to turn the model through 180 degrees with opposite thrusts and in any sort of wind you cannot turn the bow against the wind - I would not bother with indepedent control let alone a mixer - with props only 40mm apart with a 1.2 metre model its not really practical. On Z37 I do have a transmitter mounted switch to remotely switch between one (parallel ESC control) and two stick motor control but rarely use it except for docking in steering competitions, but even then it is tricky to balance port and starboard control in a confined space- one slight misjudgement and oops!  On the other hand Kelly might need a bigger rudder!

Robin

[hotjava]

Hi Colin, Tommy and Robin,

Thanks for the kind words and information.  I appreciated the Action Electronics link.  I had heard about them in another thread and it's nice to know there are options.  I opted for brass props because the white metal ones required me to file and sand.  They were also quite malleable.  I took the lazy approach!  I'll be sure and check out Deans' prop offerings as well.

I agonized over the 48mm for about a day and then realized that it really didn't matter because the HMS Kelly is such a fun build.  Besides, I'm not a rivet counter and if it comes out looking half as good as Robin's and Dicky's, I'll be ecstatic!

Thanks all!
Oliver

[hotjava]

Hi,

Battery Holder
Here's something a little mundane.  The instructions don't talk about how to secure the battery.  So, like everyone else, I have a battery holder.  My two batteries are located in front of the ESC or slightly forward of midship.  I wanted something that would allow me to easily remove the batteries for charging and then just as easily put them back in.  I also wanted something that would be removable just in case I decided to change the size/capacity of the batteries. 

The battery holder is made from "L-shaped" ABS gray plastic strips by Plastruct and glued onto a small sheet of Tyvek.  The ABS was purchased at a local model railroad store and the Tyvek was from a envelope courtesy of the United States Postal Office.  Tyvek has paper-like qualities but is much more durable.  The purpose of the Tyvek is to allow me to easily position and accurately secure the battery holder within the narrow hull.

To achieve a snug fit, I simply trace the two 7.2V 2000mAh batteries onto the Tyvek and then superglue the plastic strips which hold the battery in place so that they don't move while the model is underway.  The entire holder is then taped to the bottom of the hull using foam double-sided tape.

Battery holder


Battery holder inside the hull


Battery holder with two batteries


Take care!
Oliver

[karlgalster]

Hi Oliver,
Tyvek - never heard of it before but "Googling" it seems as though it is a useful material - interesting. Must admit my 2 7.2 volt 2000mAh batteries are not as well located as yours and sometimes require poking with a rod to remove any list! Not sure I can get my batteries out either without some surgery. They are Sanyo and good quality and appear to be of long life - hopefully.
Robin

[hotjava]

Hi Robin,

I'm glad to know that I was able to provide some new information that you didn't know about!  I opted for the inexpensive Duratrax 7.2 2000mAh NIMH's from Tower Hobbies.  We'll see how they'll fair.  I'm quite sure your Sanyo batteries are way better than mine.  Anything with Sanyo in them usually are.

Take care Robin,
Oliver

[karlgalster]

Hi Oliver,
Hope you don't mind my asking but how did you decide on the location of the batteries? Reason for asking is that in my HMS Kelly I did some ballasting/trim test early on in the test tank (bath) and came to the conclusion that the batteries (by far the heaviest components) needed to be as far forward as I could place them. That is hard up against the bulkhead at the forecastle break. A factor my be that I used two Electronize ESCs which are quite bulky compared to your single small ESC. I did my ballasting tests early on with all electronic components roughly installed but little else apart from the running gear but of course with a watertight hull! I weighed the contents of the component trays and the plastic sheets. By some judicious placement of weights on the hull representing the measured components I decided that my batteries needed to be positioned forward. All this was of course with a wet finger in the air but it paid off when it came to final ballasting to the desired waterline.  I shall continue in a second post as I am running out of space........... 

....to continue.
Another point - destroyer models have a habit of being a bit tender. They are very critical to vertical location of heavy items. You need to get the centre of gravity (or at least the marine engineering term for it) as low in th the hull as possible. One does tend to see destroyers heelling over dramatically with sudden helm control or a gust of wind. To minimise this I would suggest three things -
a) Aim to trim the ship as deep in the water as realistically possible - i.e ship in war time displacement with extra crew, maximum stores loaded, full ammo load, full bunker and fresh water tanks. "The Kellys" reference has a nice broadside photo of the Kelly at speed looking very low in the water. If you aim for this sort of waterline this will reduce the "tenderness".
b) I used the kit fittings on my HMS Kelly - it would be better to replace some of the items with scatch styrene parts. Things like the white metal ventilation panels which are very heavy white metal parts and mounted quite high, similarly depth charge rack - mount just one not two and replace the white metal parts with plastic.
c) DM use 1mm plastic almost everywhere for deckhouse construction. I did but for Z37 I replaced a lot of 1mm material with 0.75mm and 0.5mm and even 0.25mm where I could. Makes a difference to handling and looks better - e.g. vertical screens around the bridge.

Have Fun, Robin


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there is a couple of dark bars at the bottom of the post window, just above "lock this topic"
if you pull that down you will enlarge the window for the message.

[hotjava]

Hi Robin,

What great information!  With regard to your question --

"How did you decide on the location of the batteries?"

I did one bath tub ballast test with ESC, motors, props, rudder, etc. and semi-confidently declared, "This is the place to put the batteries!"  I'll re-ballast again once I have more of the superstructure and fittings in place.  Fortunately, if need be, I can remove the double sided type and move the batteries forward.  I too can only push the batteries up to the forecastle break.  I have a bulkhead there. 

Thanks for the advice on keeping the center of gravity down and low.  I agree with your assessment.  I had read those discussions regarding your beautiful Z37 and I believe Tommy is also very weight conscious with his HMS Javelin ( i.e. ventilation panels, etc. ).  Where I can -- that is, if it is within my skill set and where economical -- I'll do that.  I had intended on using as much of the parts and fittings from the kit.

And yes, one more thing.  Your vertical screens around the bridge make a huge difference on the "look" of your HMS Kelly!

Take care Robin,
Oliver




 

[Belgium Crazy Team]

Oliver,

Make also sure that the batteries can't slide forward or aft...
When that happens when you our sailing it will get tricky...

Also plan to close all your hatches as good as you can.  On a normal day you're not going to need them, but when you're sailing in rough weather, you will be happy that you can close them.

Nice progress btw!
regards
Kurt