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WTC 101 - fundamental stuff

R/C Submarine modelers

Postby Ramius » Sat Jun 28, 2003 12:01 pm

I have a used WTC 3.5 with no instructions.It has no electronics in it.Here are my questions.
There is a third linkage exit in the back.This will not be used on the Alfa it is going in.What is the best way to seal that,maybe where it can be used later,maybe not.
I bought a futaba 4 channel setup.The rx fits well in between the tray on the forward engine compartment bulkhead,but the wires seem too tight when you do the plug-ins.Should I trim the upper tray out,or is there another place to set this?
The servos obviously go in one place.Is there a good way to mount the little buggers?I saw zip ties on one last weekend,but would like to here all ideas.
The transmitter antenna is 33 inches long.The WTC external antenna is 2 1/2 inches short of that.With the antenna wire inside the WTC also,it will be slightly longer.Is that a problem?
I plan on using Thor electronics.Is there a good arraingement for where to put the speed controller,pitch control,and afail safe?
Anything else I need to check for this setup?
How about batteries?What is the latest ticket that works the best?
These are really basic questions.No fear in asking.
Would like to here some good result ideas.
Thanks
"A little revolution now and then is a good thing"
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Postby Tim Morris » Mon Jun 30, 2003 1:19 am

as for the extra seal without a job on the bulkhead, Matt Thor gave me the idea of using a solid rod cut to size with wheel collars on both sides, and it worked great. I used aluminum rod as it was already in the shop.

the antennae length question is one i posted a short time ago also and was not able to make much out of the answers
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Tim Morris
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Postby Tim Morris » Mon Jun 30, 2003 1:27 am

i used servo tape to attach the servos on the tray in a tranvserse manner. i liked the angles better that way.
one thing i plan to do is to add a reciever battery. but i am not sure if it is ok to do that and also have that speed control plugged into the reciever that delivers DC..would that be too much when using a SC-10? i dont know.
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Tim Morris
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Postby Skip Asay » Mon Jun 30, 2003 9:42 am

Tim -

First and foremost, DON'T use a receiver battery AND a bec at the same time. That's an invitation to trouble. The battery voltage will be different from the BEC voltage and, well....you don't want to go there.
That said, you might be able to get away with it if you put forward biased diodes in each positive lead but you would have to use Schottky diodes since they only have a nominal .2 voltage drop, but....why would you want to use a battery AND a bec?
Personally, I would go with the bec alone.

As for the RX antenna, whatever the combination of internal/external wire there is, the total length should the same as the original that's attached to the RX. If you cut it to put 12" outside, the inside length should be 21".

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Postby Tim Morris » Mon Jun 30, 2003 2:35 pm

the reason i was thinking of using a bec and a rx battery is in case there was a problem with the main power source and then there would be a way for the compressed air to be discharged via the fail safe.
thanks for the simple solution on the antennae length thats the answer that makes the most sense.
as for using a rx battery separate from the bec i think i will take your advice and not use the additional battery. i had been seeing some jumpiness from the reciever and i think the power wires were possibly causing that interference. i was concerned about how the servos were jumping while the transmitter was turned off (fail safe test) and thought the extra battery may help smooth things out. anyway i was not comfortable with putting this boat in the water until this problem of jumpy servos was completely solved because i was concerned that the fail safe may be compromised.
this is why i keep asking so many questions about electronics, because it pretty much keeps me in 'dry dock" until it is solved. :(
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Tim Morris
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Postby Tim Morris » Mon Jun 30, 2003 2:37 pm

it runs like a top when the tranmitter is on. everything is super then.
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Tim Morris
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Postby Trafalgar » Mon Jun 30, 2003 4:48 pm

Tim Morris wrote:the reason i was thinking of using a bec and a rx battery is in case there was a problem with the main power source and then there would be a way for the compressed air to be discharged via the fail safe.
thanks for the simple solution on the antennae length thats the answer that makes the most sense.
as for using a rx battery separate from the bec i think i will take your advice and not use the additional battery. i had been seeing some jumpiness from the reciever and i think the power wires were possibly causing that interference. i was concerned about how the servos were jumping while the transmitter was turned off (fail safe test) and thought the extra battery may help smooth things out. anyway i was not comfortable with putting this boat in the water until this problem of jumpy servos was completely solved because i was concerned that the fail safe may be compromised.
this is why i keep asking so many questions about electronics, because it pretty much keeps me in 'dry dock" until it is solved. :(

Here is a reply to a similar problem from another board.......

I am a bit surprised with your running time, I get a running time greater than 4 hours ( I don't know the exact running time as I always get bored before the battery), running pretty much continuously underwater.
The jumpy servos is caused by RF interference or because of the BEC
If you are running your sub with the BEC from the ESC you will get jittery servos (at best) or lose reception (at worse). The problem is that gel-cell are not designed to provide a lot of power quickly, so the engines and pistons are hogging all the power and the BEC circuit is not feeding enough power into the receiver, causing glitches.
The only way to solve this problem to have a second battery pack for the receiver.
If you are not using the BEC, then the problem is coming from poor RF shielding.
Trafalgar
 

Postby ThorDesign » Mon Jun 30, 2003 6:04 pm

Tim,

Skip is 100% correct. Go with the BEC and skip the additional battery pack. You can run into a competing voltage scenario and that can be ugly if you are not properly setup to handle that. You may want to check the cell condition in your supply pack and make sure you are shielded properly.

Also, make sure you are not grounding out on something in your WTC. If your servos are nominal when the transmitter is on, it is very possible you are getting some over-ride interference. I run my boats very close to the NOAA facility here in Wichita, and when they are transmitting I sometimes get jittery servos with the transmitter off. You will, more, than likely be fine, but take short spin and keep her close. Have you done a range check with your radio?
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Postby Tom Spettel » Tue Jul 01, 2003 1:29 am

Tim
When i was still building my alpha i kinda saw that it was going to be tough to get a RX battery in my pressure hull with all the other stuff
in there to, the BEC is all part of the KISS method! learn it..know it..
live it.. you get your sub in the water faster to.
Tom
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Postby Ramius » Tue Jul 01, 2003 8:39 pm

Tim,
I used the idea of making a short "blank" with the wheel collars for plugging that third linkage hole.I was really trying to overthink that one.That idea is the way to go and should be a standard for that solution.Keep it simple.Keep it simple!
Ok, I grounded the motor case and put the capacitors (3) across the motor terminals.It did not take long,and should make the motor "quieter" to the servos and stuff.
For good measure,I have new o-rings coming for the wtc,and some spares for the future.
At my dealership shop,I found silicone grease used for the disc brake jobs that comes in small packets that may be perfect for o-rings and seals.Will try that.It is already on the spare linkage plug.
Now,working forward,it's servo time.As I said before, the only working boat I ever saw (2 weeks ago) had zip ties holding it down.Are there other ideas? I saw mention of servo tape too.
Any advantages to mounting those lenghtways,or sideways is better?
Thoughts on best placement of electronics too.Whats bad,what works?
Saw a picture of Tim Smalley's Alfa.It has a big mo-honker of a battery in it,with foam crammed everywhere.Looks like good run time can come from it.Ideas on batteries,etc?
Some good ideas are filtering in. I would love to see more wtc tips and tricks as I go along that others have learned and will share.
Thanks,so far.
Wayne
"A little revolution now and then is a good thing"
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Postby PaulC » Tue Jul 01, 2003 11:02 pm

Ramius,

The zip ties I used on my servos are backup for the servo tape. I found the servo tape to be kind of a pain to work with and also allowed for some "give" in my particular setup (WTC 3.5). So, I added the zip tie around the works to keep everything set where I want it.
Warm regards,

Paul Crozier
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Postby Tom Spettel » Tue Jul 01, 2003 11:31 pm

Batterys!!! Nickel metals!!! they are more expensive but worth it. they have alot of juice in a small area and you get some great run time!!
Tom
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