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[bobk]

I am hoping someone can recommend a radio control system for me.  What this will be used for is . . .

a)    A dynamic diving K Class submarine.  Two props / motors (variable speed for each), rudder, diving planes, gas-blown ballast chamber valve, and snort pump valve.  I think that makes 6 channels.  On-board servos/controllers should be compact are durable.
b)   also to be used for a WW1 destroyer of almost same length.  Two props / motors (variable speed for each), plus rudder. Using 3 of the 6 channels.

I intend using the same transmitter / hand controller for both, but not at the same time of course.  No point in getting two systems.
The submarine application will be the most demanding.  ie:  Receiver aerial able to work under water.  Good sensitive control.  Maybe separate plug-in frequency modules, one for each ship so I only have to change it in the transmitter.  I assume 40MHz would be the desired band, and also assume 6V.

What would you recommend please.  I am decades out of date on this stuff   

[Shipmate60]

Bob,
If you are using the radio on a submarine then 2.4 Gig is out.
This frequency bounces off the surface of the water without penetrating.
It would be better to get a 40 Meg set.
These are very cheap second hand as modellers trade "up" to 2.4.

Bob

[dodgy geezer]

What would you recommend please.  I am decades out of date on this stuff   

You seem to be fairly well up on what is needed!  The only thing that has changed in the last 10 years is that cheap park flyers and helicopters have boomed, and so there are lots of very cheap radios available from China. These will usually be 2.4Ghz or 35Mhz, and often have complex confusing computer set-ups intended for trimming helicopter controls, but there must be some simple 40Mhz ones around that the submariners know about. You can get them on the web...

Otherwise, it's one of the classic names from your local model shop - or a cheap second-hand as mentioned above....

[bobk]

Thank you both for your advice.  Is there much advantage in getting a more "up market" system, or do most do very much similar jobs?
ie: Any "get what you pay for" factor?  I don't want to get something then later wish I had opted for something better, more long term, upgradable etc.
Are there particular makes/models that make controlling two prop motors with one hand whilst operating dive/rudder controls with the other?
Appears like you could need three hands at times. 
Please bear in mind this is new to me, my only other RC boat (nearly 40 years ago) merely had rudder control and a Mamod Marine steam engine that ran at constant RPM.   

[dodgy geezer]

Is there much advantage in getting a more "up market" system, or do most do very much similar jobs?
ie: Any "get what you pay for" factor?  I don't want to get something then later wish I had opted for something better, more long term, upgradable etc.

There are some reviews of the really cheap Chinese 2.4ghz radios elsewhere in this section. I have no experience of Chinese 40Mhz - I don't even know if they exist - but if they are similar they will not be very well finished or upgradable. But if they cost £20-£40 that's not really an issue. It depends what your taste is like in radios. A lot of people are using them....

Are there particular makes/models that make controlling two prop motors with one hand whilst operating dive/rudder controls with the other?

There is one well-known specialist boat Radio - the Robbe/Futaba Navy-14. Not cheap but good. Here's some comment - http://www.rcgroups.com/forums/showthread.php?t=1132621

[Mankster]

Getting better quality radio really pays off with subs where good reception and glitch rejection is rather more important than surface craft. You've already worked out you need a 40MHz set for subs. For my smaller model I now use a 7 Ch Multiplex Cockpit SX with an multiplex synthesised IPD reveiver. Firstly a really nicely built light weight and small Tx and the battery last for ages. Both Tx and Rx are synthesised so no crystals to buy, no frequency clashes at the Sub meets and Dive Ins. Rececption is excellent even in chlorinated water, almost as good as my larger dual conversion receivers. The IPD system is great at filtering out glitches that would otherwise trip the fail safe and bring your sub to the surface and even does a pretty good job of rejecting signals from another Tx that may be inadvertantly switched on on your frquency. Easy to convert to 2.4Ghz if you would like that for your surface craft - just pug the module into the trainer port when needed and you have 2.4Ghz. They are prety cheap too if you source them online from Germany rather that buy it locally. Performance is much better in subs than the Robbe F series and similar radio.
Oh and get a rudder mixer to control differential throttle steering- trying to control twin throttle in one hand and coordination the action with rudder is a nightmare., especially with subs where you other things to worry about.

[bobk]

Many thanks Mankster for your very detailed and informative reply.  I shall certainly look for a 'rudder mixer' as I was already worried about how to juggle relative prop speeds whilst turning.  As you say, plenty of other thing going on at the same time (tee hee !).  As a slender boat the turning circle could be as poor as the original boats.  I like the idea of not having to change crystals (I told you my RC experience was well out of date !).

Any system that can control the submarine should easily run the destroyer, just requiring the RX and boat controls duplicated.  I do not anticipate ever running both at the same time.

[Guy Bagley]

bob- feel free to pop over to your local lake.. (black park) if you haven't already - there are alot of knowledgeable people over there- and if its subs then talk to dave wright, - a good bloke and great model sub man - he's there most sundays!

[bobk]

Guy,
I have already done so, and can proudly say I am now a member of the BPMBC.  I was at the club house meeting a couple of weeks ago.  Very friendly people.  It was great talking to members and learning much from their super models. 

[Subculture]

The Multiplex sets are very nice indeed. If i had to purchase another set, they would be my first choice.

They tend to have a very nice user interface, with the right amount and type of controls, which are often lacking in other makes.

You don't need anything fancy for subs or boats. Computer sets are very nice, but many of the features go unused. What you do need are plenty of channels. I would opt for a minimum of six and preferably eight. You will need a minimum of five channels for full house control of a K-class, and to introduce things like ballast shifting and retracting funnels more still, unless you want to get into things like microcontrollers to integrate certain functions e.g. funnels retract when taking on ballast.

Andy

[bobk]

Thanks Andy.  I will need 6 channels, including the snort pump, and understand that for subs I need a 40MHz system.
The Robbe F14 has been recommended, but will need proportional sliders and extra switches.  The total cost including batteries, charger, two on-board speed controllers etc, would exceed the £279 cost for the sub-driver from the States.  Which makes the sub-driver sound great value.
I will check out 'Multiplex'.
By the time this project completes I could be using tons of Pound coins for ballast 

[Subculture]

F14 can be had for a lot les than that, and can be modified with switches and pots for peanuts. I have the Robbe FC16 which is basically an F14 with a computer bolted on. I make my own add ons, as Robbe charge a kings ransom for their extra modules.

However if you go for a Multiplex Cockpit set, I think you'll find it has all the sliders and switches you need as standard. Plus it has that sexy synthesized tuner- nice!

Andy

[bobk]

I have trawled around Google for the Multiplex Cockpit set, but almost everywhere they are quoted well over £200 basic, many a lot more.  Also they seem to be 2.4GHz, which I was given to understand is not likely to work under water?  I have been told I need 40 Mhz for a submarine. 
confused.bob

[Mankster]

This is where I got mine from  (it was on sale at the time and a £50 discount to the current price) http://www.hobbydirekt.de/product_info.php?language=en&products_id=109751
You'll be wanting to pick up a charge lead as well (plugs into the trainer port)

or you might want to pick it up from their ebay shop http://cgi.ebay.co.uk/COCKPIT-SX-Standard-Set-40-Mhz-Synthesizer-Multiplex-25-/230606038845?pt=RC_Modellbau&hash=item35b130e73d

You can download the manual from the Multiplex site and make sure it does what you want before commiting.

http://www.multiplex-rc.de/cms/vorschau/upload/d_anleitungen/t_cockpit_sx_v1_gb.pdf