ir3aus 1:72 Revell Gato Build

[jim h]

Hello all ,I just got the Gato that Iran started here and will be happy to take her and run with this build . I have a few things to repair ,I guess usps doesnt know how to read fragile handle with care . Oh well I have had alot worse happen to a sub hull. Oh yes I will give credit where its due nice start Iran on this kit she is going to come out nice. I also have to thank my wife, she bought this sub for me ,after she caught me looking at it on the forum.

Jim

[Subculture]

A sub modeller in the UK- Roger Suitters, came up with a novel solution to purging damp air from his 'Perry' submersible model without having to unbutton it.

He added two pipes into one of the bulkheads/endcaps which could be uncapped. He attached a small air pump to one side which sucked the air out of the sub and pumped it into a small cylindrical tub with silica sachets inside. The air was then fed back into the sub via the second pipe. He leaves this on for a few minutes after a days run.

[ir3aus]

Back on the sub electronics installation. Need a source for a toggle switch to go on the endcap in the battery compartment. After building the reed switch battery control circuit, once it is mounted in the WTC and the top deck is on, the magnets are not strong enough to actuate the reed swiches that I used. Thus, back to the watertight switch. I checked most of the switch suppliers and the mounting shank for the switch(s) is about 1/2" long. The end cap for the WTC is about 1/2" thick so a switch with a longer mounting shank is needed. I notice that Dave successfully mounted a switch on an endcap. Is there a source for switches with longer mounting shank. Any info would be appreciated.

Thanks,

Iran

[He Who Shall Not Be Named]

Iran,

The 'remote' switch for turning the system on/off between runs at an outing is a viable reason to work in the magnetic reed switch.

However, abandon the concept of keeping the watertight spaces of your model buttoned up during the majority of its storage time: You want to keep the otherwise sealed portions of the boat open to the air during storage. Water that gets inside (and some always does), no mater how little, will eventually -- if the environment is sealed -- over time, turn the insides of the dry spaces, and within the cases of all those electronic devices, into a damp, corrosive, tropical forest! In no time at all that green mung, growing in the water laden air of the so-called dry spaces, will start bridging the leads on the IC chips and other surface mounted components of the boards. First, you will get intermittent glitching, then eventually entire sub-systems will fail.

Vent that hull all the time it's not in the water! Plan on keeping the insides well vented when not in use.

David,

[ir3aus]

Thanks David,

Of course, this whole exercise was academic. My goal was to not remove the top of the sub for any reason. This would only work if I had a nuclear reactor for a power plant. I still have to charge and/or change the battery. This means either bringing wires out to a watertight box with a charge connector in it or opening up the WTC to get at the battery. If I do bring out the battery charge wires I may as well include a switch. I still may put in the magnetic switches to turn the SD on/off between runs.

[He Who Shall Not Be Named]

Iran,

Thank you much for the clarification and identification of sources. We (Caswell-Merriman) are indeed thinking of adding a magnetic reed based mission switch to our product line. However, we'll likely go with a solid-state type relay switch, something recommended by Andy Lawrence.

Your explanation of the electro-mechanical relay, as applied to this problem, was most instructive as to switch logic and method of operation. Well done, sir.

David,

[ir3aus]

I think I need to clarify what is happening. The relay is just a standard DPDT or DPST relay. It is not a latching relay. In the circuit diagram the relay is latched through one of the sets of contacts. This is necessary because switch S2 will open as soon as the magnet is removed. The relay remains activated because current is running through the Normally Closed switch, S1 and the relay contacts. When the magnet is brought to switch S1, this switch opens releasing the relay. This opens the set of contacts on the relay that are acting as the latch and since S2 is open, the relay will not pull in again. S1 closes back up when the magnet is removed but since S2 is open the relay stays open.

The relay I am going to use is All Electronics in the San Fernando Valley, Los Angeles. The number is OMRON G2RL-2-12VDC, 8 Amp/250VAC contacts and a 360 ohm coil. All Electronics has normally open reed switches but do not have the normally closed switch. I had to order the normally closed switch from Allied or Newark. They do not have minimum orders. Not expensive but by the time postage is added it makes the price a little high. I tried doing a search for NC small reed switches but the suppliers had minimum orders that made them expensive for a small order. Perhaps if this technique becomes widely used, Caswell/Merriman can buy in sufficient quantities to make it relatively inexpensive.

Hope this helps,

Iran

[He Who Shall Not Be Named]

So, with the power and coil shunt switches closed (I assume they are spring loaded and have to be pulled shut by the solenoid), the relay is pulling a constant 35mA's -- that's not much at all, and this current is pulled off the battery only when the system master switch (the latching relay with its internal switches) is 'on', sending current to the other sub-systems within the SD.

Neat!

Do you have sources and part numbers for the magnetic reed switches and double-poll, double-throw latching relay?

Hey, Kevin: What say you?

David,

[ir3aus]

Diagram For Forward WTC Battery Control

Thanks David. This makes relay selection easy. I am including a diagram of what I will be implementing. The switches are magnetic reed with one being normally open and one being normally closed. The relay is a low current coil drawing about 35 milliamperes and the relay contacts are 8 amps at 250 volts AC which works out to about 8 amps at 30 volts DC per the manufacturer. When a magnet is brought near S2, the contacts close and the relay picks up. The relay is latched through one set of contacts on the relay. The other set of contacts passes power to the rear WTC. It is possible to use a single pole relay but it is good design to isolate the latching contacts from the power supply contacts. When the magnet is removed from the vicinity of S2, the switch opens but the relay remains latched. When the magnet is placed in the vicinity of S1, the switch opens up releasing the relay and the relay becomes unlatched. When the magnet is removed from the vicinity of S1 the system remains off. This will all fit nicely in the forward WTC of the Gato SD and the switches can be operated from outside the hull. A very convenient way to control power and maintain complete water tight integrity. Photo is included.

Thanks,

Iran

[He Who Shall Not Be Named]

Iran,

At full throttle (props in the water), total battery drain is a bit under 5 Ampere's. You're good, you won't weld the relay contact points.

David,

[ir3aus]

Took a bit of a hiatus from the Gato build. I am looking into using magnetic reed switches and a relay(s) to turn the Gato SD on and off. These parts would go into the WTC battery section. There are quite a few 12v, low primary current relays available with contact ratings of up to 10 - 15 amps. Under normal operating conditions, what continuous current would be consumed by the ESC controling the two motors for the Gato. If under 10 amps then there are several inexpensive relays to choose from from local suppliers.

Thanks,

Iran

[He Who Shall Not Be Named]

This will be my last comments on the need for the extra channel. After reading the ADF2 instructions, it appears that the ADF2 should be set up without the pitch input which goes to the RX Channel 6. The ADF2 will still send signals to the stern planes. This will free up CH 6 for the Bow Plane Extend/Retract. If others have used the ADF2 in the GATO, please comment. If I am the first, then who knows.

Thanks,

Iran

Keep your questions coming, Iran ... unlike too many others your observations, questions and comments are well thought out and challenging -- they have, in no small way, made me think again at how to better explain and demonstrate how things go together and integrate with our products. Something Jim has been after me for from the beginning.

Keep the questions coming.

Yes, indeed, you can omit the receiver from the angle-keeper input and let the angle-keeper work autonomously. However, that means you have to work a bit to get the unit aligned just so. But, once you have the angle-keeper portion of the ADF2 working autonomously, you will indeed have a channel free for other functions. Good thinking.

David,

[ir3aus]

Update with schematic

This will be my last comments on the need for the extra channel. After reading the ADF2 instructions, it appears that the ADF2 should be set up without the pitch input which goes to the RX Channel 6. The ADF2 will still send signals to the stern planes. This will free up CH 6 for the Bow Plane Extend/Retract. If others have used the ADF2 in the GATO, please comment. If I am the first, then who knows.

Thanks,

Iran

[ir3aus]

After looking everything over for the n'th time including the CD's, all 6 channels are used in a very specific way. It does not appear the Gato Bow Plane extend/retract will be implemented without a seventh channel. I am just wondering if I am going to be adept enough to operate the bow planes with the pitch stick and operate the stern planes with the pot. Someone has got to explain to me why the stern planes are on CH 6 and controlled with a pot on the transmitter and also by the ADF2. It seems to me that when a sub is put bow down to dive or bow up to decrease depth the bow and stern planes are in opposite directions.

I would hate to have to lock the bow planes down in the extended position and waste a servo.

Help please,

Iran

[ir3aus]

Thanks for the reply. As soon as I get everything under control I will post my final electronics and Snort installation. I checked the schematic and it show the LIPO guard in channel 4. I assume that this is for monitoring RX or BEC power only. Missing from the schematic is the Bow Plane extend/retract servo channel. I believe that I can move the LIPO guard to channel 7 or 8 on the Sambra Labs RX and the LIPO guard will be happy. I can then use the pot on the transmitter to control the bow plane extend/retract on what ever channel that it is assigned to.

Thanks,

Iran

P.S. Just reread one of Dave's responses and he sugests the CH 4 be kept for the Ballast Purge/Vent servo. Does the angle keeper need to be plugged into an active port on the RX. If it were is CH 7 or 8 for power only, then there would be no problem; otherwise, the Gato with all the goodies will need a 7 CH transmitter.

Thanks again,

Iran