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Resurrecting the dead Gato project

R/C Submarine modelers

Re: Resurrecting the dead Gato project

Postby Chuck Chesney » Wed Feb 29, 2012 1:50 pm

Steve,
I've been following this thread with interest, and have a couple of observations.
It sounds like your making the whole thing way more complicated than it is in reality. For starts, almost all of the time your boat will be running just a few feet under the surface, maybe just a couple of feet, because in most situations you will want to be able to see your boat. Years ago I put an ADC in my boat, and found out that it was more trouble than it was worth. Jeff LaRue, is spot on when he suggests that a pitch controller is almost a must have item, but not the same with a depth controller.
I have always clung to the notion that a truly static diving boat elevates the probability of loosing it forever when (not if) there is a problem with the ballast system, the propulsion system (weed fouling, for example), or a loss of power. My boats have always been trimmed in such a way that even with the ballast tank full and the boat dead in the water, the top of the sail will still be just above the surface, even wilh a total loss of power, just like Jeff suggested. It takes a modest amount of forward movement to get under water, where the APC will take over the driving. Haven't lost a boat in almost thirty years.

SubTech makes really good and inexpensive seals for the drive shaft and control rods. You can get them at Mike's Subworks, or directly from SubTech , who are now in Malaysia, but were in the UK, and before that, the USA. Very well thought out and well made products.
Also, don't be too concerned that the drive shafts with counter rotating prop directions will be threaded both right and left. They almost always are threaded with standard threads, regardless of prop direction.
Listen to what Jeff advises...he's been one of the Yodas of this hobby since they invented water.
Chuck

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Re: Resurrecting the dead Gato project

Postby salmon » Wed Feb 29, 2012 3:29 pm

Steve,
I am building a Revell Gato and purchased the Raboesch propellors. They are indeed threaded the same standard thread. So, one will spin with the thread and the other against it.
If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.
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Re: Resurrecting the dead Gato project

Postby Stevolution » Wed Feb 29, 2012 3:38 pm

Yea. I always make things too complicated.... thats what I do :?

I am tinkering on the brink of binning the entire WTC and starting again. Shame, cause its come out well, but just too big for the hull.
Certainly going to have to shorten the ballast tank (which I am sure is too big) because I am left with little room to get the prop shafts out of the WTC - through a pair of universal joints and through the hull.
Same goes at the bow. My WTC is just too close to the front planes mechanism and connecting it all will be a nightmare.

The problems started due to the fact that - to get the large diamter pipe in, the WTC was originally in two halves. Front half went in first, then the rear end. Pushed together and locked in place.
This however leads to issues with linking the servos, battery power and in my case, I have a pipe that links both halves of the WTC to utilise all the interior air space.

Joined it all together now so its one unit - but its untidy in my mind with all the exterior connections.

The bearings for the motors leaving the WTC are my next thing. Looked at these ...

http://www.rcbearings.co.uk/index.php?r ... uct_id=841

Pair either side of the WTC cap with perhaps a rubber seal over the outer one. Might work?

Already decided to bin the ADC. Certainly going with an APC.

As for losing it. I don't intend taking anywhere that I can't go and get it back. I have made a tiny little SLB (Sub Location Beacon). Its a very simple buoy with a flashing led that gets released from under the deck on a tether upon loss of radio contact. Not sure if I will fit that yet (probably no room!)

As for the props - dab of solder perhaps? Dab of Threadlock?

Its a learning curve. See where we go.

Thanks for all the assistance guys. Pics will follow.
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Re: Resurrecting the dead Gato project

Postby StuartL » Wed Feb 29, 2012 3:52 pm

Stevolution wrote:As for losing it. I don't intend taking anywhere that I can't go and get it back. I have made a tiny little SLB (Sub Location Beacon). Its a very simple buoy with a flashing led that gets released from under the deck on a tether upon loss of radio contact. Not sure if I will fit that yet (probably no room!)


That's awesome :)

Stevolution wrote:As for the props - dab of solder perhaps? Dab of Threadlock?


Most prop shafts have lock nuts which are enough to stop a clockwise rotation from undoing the prop.
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Re: Resurrecting the dead Gato project

Postby JWLaRue » Wed Feb 29, 2012 4:29 pm

Steve,

>>> The bearings for the motors leaving the WTC are my next thing.

There really isn't any reason to go with any kind of bearing-based solution for where the motor shaft exits the dive module. You do not need the support and it might just end up cause binding. The SubTech BHS seals are literally all that you need.

>>> ...linking the servos, battery power...

I've seen this done severals ways. For my Type II I used flexible tubing instead of a hard (e.g. brass) as this allows some motion/flexing between the two and means that I can allow each section to sit down in the hull independently of each other.

-Jeff
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Re: Resurrecting the dead Gato project

Postby Stevolution » Wed Feb 29, 2012 5:16 pm

I can't find any kind of Subtech seal for actual driveshafts (must be looking in the wrong place). To be honest, my original idea of making a short brass tube through the bulkhead with prop grease in it will probably work just as well. Again, I think I am making this more complicated than it need be.

Surely however a set of stainless ball races is going to be the most friction free method.

One thing that has now occured to me. After changing around the way this sub is going to work, my lovely tiltable front planes are pointless.
I originally planned to use the front planes as the manual control surfaces along with the APC, and the rear planes were going to be controlled by the ADC.

Now that I have binned the ADC, and the rear planes are the manual control surfaces + APC.... the front planes are effectively redundant. I could have just fixed them in the straight out and deployed position.
Perhaps I will still connect them on one of my spare channels for fine tuning her level sailing.
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Re: Resurrecting the dead Gato project

Postby JWLaRue » Wed Feb 29, 2012 6:19 pm

>>> I can't find any kind of Subtech seal for actual driveshafts (must be looking in the wrong place).

Take a look at this web page: http://www.mikessubworks.com/page1.html
...any of these three would suffice for prop shaft seals. The servo seals are also something that you will need, whether from here or elsewhere.

>>> Surely however a set of stainless ball races is going to be the most friction free method.

You will still need some sort of seal. Adding a bearing race and making sure that your motor is mounted just right so as to align with the bearing race realy won't gain you anything. If anything the bearings are going to add friction. :)

>>> After changing around the way this sub is going to work, my lovely tiltable front planes are pointless.
>>> Now that I have binned the ADC, and the rear planes are the manual control surfaces + APC.... the front planes are effectively redundant.

It is not absolutely necessary to have the front dive planes operable. A lot of smaller boats don't use them. But it's really a personal preference whether to include them or not.

-Jeff
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Re: Resurrecting the dead Gato project

Postby Stevolution » Thu Mar 01, 2012 9:54 am

Arrhh, there's nothing like the smell of Acrylic and hacksaws in the morning....

Anyone got an idea of how high the periscope actually goes when its deployed? Can't find any info.

I am assuming that the masts lift individually. Periscope, Aerial (if that is what it is) and radar.

This show them up? Surely they raise further.

Image

This seems to show one up and one down.

Image

This one shows them all down

Image

Therefore, am right in guessing that the Revell sub model is showing the periscope and aerial up?

Image

I am planning to make the periscope raise. But not sure how far it actually goes. I am guessing not far, due to the space inside the sub.

As a side question. I see that quite a few guys are just sticking their servos in the water with pretty much no protection. Surely they ain't gonna last long. Same goes with the wiring, I am making sure all my connections are out of the water.
I am running in fresh water, but to my mind... keeping the electrics dry can only be a good thing.

Steve
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Re: Resurrecting the dead Gato project

Postby Chuck Chesney » Thu Mar 01, 2012 11:42 am

Steve, regarding putting servos directly in the water...I have read about various schemes and attempts to do that. From all that I can gather...they all will fail sooner rather than later. If you have unlimited money and time, so that you can replace the servos every time or so that you put your boat in the water, it might be be an interesting diversion. For a practical solution, it's not so good. Just think about it...electronics in particular, and electrical systems in general, don't like water, and don't do well in it.

Since this is clearly your first attempt to build a working model submarine, you may want to forget about the bells and whistles, ie, operating periscopes and such. The Revell Gato isn't a very big boat, and I would think that for a first attempt it will be plenty challenging just to get it working properly. Remember the Prime Directive...Keep it simple.
Chuck

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Re: Resurrecting the dead Gato project

Postby salmon » Thu Mar 01, 2012 12:24 pm

I can not agree more with Chuck. Take his advice. I am so guilty of chasing rabbit trails and focusing on the unimportant (although important to me, not get the sub working). That is why on my Gato the focus is get it working, then go back and obsess, detail, add fun enhancements. Like Chuck said there are plenty of challenges just to get it running. I am at the point of trimming my Revell Gato out. When I was researching to begin my first sub, I noticed a lot of people start, but few finished. I want finish so, I am trying to "keep the main thing, the main thing".
If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.
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Re: Resurrecting the dead Gato project

Postby Stevolution » Thu Mar 01, 2012 2:45 pm

I don't do simple.... but I'll try.

Not planning on making the periscope arrangement now, just leaving a connection available for the servo in the wiring loom.

My plan was to convert the conning tower into a stand alone watertight little box and add the mechanics in there. So for now, I will convert the conning tower into a module I can screw on/off from under the deck and leave it at that.

It was more that I was sorting through my research pictures and deciding what to keep / throw and I noticed all the different tower positions.
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Re: Resurrecting the dead Gato project

Postby salmon » Thu Mar 01, 2012 2:49 pm

Steve,
I can relate! Good idea to collect ideas and sort what you want and don't.
Peace,
Tom
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Re: Resurrecting the dead Gato project

Postby Stevolution » Thu Mar 01, 2012 4:05 pm

OK, just for clarification...

I think the front post is the radar (dish gives that away!)
Second post back is periscope 2
Third post back is periscope 1
Rear post is the antenna
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Re: Resurrecting the dead Gato project

Postby Scott T » Thu Mar 01, 2012 9:48 pm

Imagehttp://www.maritime.org/fleetsub/pscope/chap1.htm#1A
You might find a measurment of the Periscope length at this website.
But unless you make a well like the 1:1 sub you probably want get the same
scale length.

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Re: Resurrecting the dead Gato project

Postby Stevolution » Fri Mar 02, 2012 6:05 am

Thanks Scott.
Got a good plan for the periscope and it looks like my assumption that the periscope basically doubled in length max is about right.

I am going to try and get this baby ballasted today. I need to get the radio gear connected up so that I can operate the ballast with the WTC closed up.
Only thing I don't think I have to hand is much floatation material. I assume most people use foam or polystyrene.

Must have a quick Google to find the correct waterline as well.

This is going one of two ways.... either all will be well and I get her ballasted and floated correctly..... or she will be broken up and I will have to start again.
Personally I fear its 50/50 at the moment as I do not have much room inside the hull for either ballast or floatation material.

Pics will follow if all is well!

Steve
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