RC Tanks Australia Forum

Kev, Ian,

Ok, the RC2HL isn't for me. You've given me some names there I'll have to look up Kev - this is a totally new language to me.

Ian, I did look at the aerial in the tank as well. In fact, that was my first suspicion. It looked ok though. I suppose interference in the area might be a thing, I'll fire it up again this afternoon after work and see if it has changed. Perhaps whatever is causing the interference might have stopped.

Something I just recalled. When i was driving the tank just before it started playing up, it actually stopped momentarily. I was at the back of the house and th tank about 7 or 8 meters away when it stopped. I stepped closer and turned my body so the transmitter was pointing at the tank, more or less, and it was off again. I thought nothing of it as I'd read that the controllers are short ranged. Perhaps that was the problem starting?

Michael

HI Michael

The RC2HL may be a good choice for you. What I was saying is that rather than the $99 upgrade package you would be better of with the Turnigy 9X radio. The 9X radio is a better all found radio just in case you wanted to go with any other system.

Each system has it's pros & cons. I'll just give my opinions of a few. You would have to weight up what you want with how much you are prepared to spend and how much time you have...

RC2HL
Pro:
Cheapest and only true plug and play option
Cons:
Uses the RX18 board as the controller and hence inherits all the flaws and QC issues of the RX18

El Mod:
Pro:
Darn nice, sounds and tank control.
Cons:
Expensive, and once you add the sound and battle modules too darn big

SGS:
Pro:
Better price vs performance over the El Mod system
Cons:
Best in the hands of experienced guys who can make use of all the extra functions. A bit confusing and not as user friendly as it could be.

I'm sure there are plenty of others out there willing to give advice on particular systems.

Cheers
KG

_________________

rctanksaustralia.com

Hi Kev,

I have been watching a Youtube movie on the Turnigy 9X. Interesting, but I'm confused.

This may be a stupid question, but why aren't there servo's in these RC sets? The only time I've ever seen them - and it was long ago - there were servo's in the plane or boat. The Youtube movie showed what comes with the whole set; a transmitter and a receiver. Does everything just plug into the receiver like in my HL Tiger? I thought that set-up was just because it is cheap...

If I were to get a Turnigy 9X, would I just plug my Tigers motors, turret rotation etc., into the receiver and program it to do my bidding?
Are the plugs on these things standard?

Incidentally, I have ordered new crystals to try out. They were pretty cheap, so I thought I'd take a punt.

Michael

HI Michael

There are no servos because a tank doesn't need to use them. Servos typically are used to move control surfaces, like the flaps on a plane, the rudder in a boat or the steering in a car. Also these vehicles are usually driven by a single motor and hence need only a single motor controller (ESC). Tanks on the other hand are steered by two drive units and have no flaps. Also the have a turret that rotates through 360 degrees something a standard servo doesn't like to do.

To drive a tank you need 2 motor control units and a motor control unit for a rotating turret so I guess the designers choose then to make the elevation unit motor controlled as well. There are other reasons of course, simplicity and cost. Plus motors can be controlled with a simple on or off.

Now the Heng Long system doesn't operate like a proper Hobby Style remote control system. With a proper Hobby system you have:

A Radio transmitter (like the 9x or Specktrum, Futaba,....)
and
A Reciever:
- each brand of transmitter binds to its own receiver and receivers can vary in the number of channels they have.
the output from the receiver go to either
Servos or a
Motor speed controller (ESC).
The ESC will typically also have a voltage regulator inbuilt that will supply your servos with the correct voltage for operation.

When you set up the system (2.4 ghz that is) you must first BIND the receiver to the radio. This tells the receiver to listen ONLY to the radio it is binded too and hence does away with the need for crystals and also allows a number of receivers to be bound to a single radio.

The channel outs from the receiver then go to what they are meant to control. For example

CH1 - goes to the servo operating the Rudder
CH2 - goes to the ESC to control the motor
CH3 - goes to the elevator servo
CH4 - goes to the Aileron servo/s

The HL system also has a radio and receiver but uses the older 27 mHz frequency and hence uses crystals. It too has a recevier in the tank (the thing you plug the other crystal into). BUT this receiver is where things go different. The HL system is a 4 channel system but to make cabling simpler the 4 channels are 'combined' onto a single signal which is sent to the RX18 unit via that 3 way cable (+, - & signal) . This single signal is then decoded by the RX into its 4 parts. CH1 &2 are 'mixed' together to allow movement using only one control stick. CH3 - if it goes above a certain level will trigger the gun or if it goes below a certain level will trigger the machine gun. Any small deviation below the middle will turn on the Elevation motor to make the gun go up and down. Likewise for CH4 any movement away from the middle turns the turret motor on. SO the RX18 operates a a Multi function unit combining both the ESC function and taking what would be servo functions and using them to turn on or off the turret & elevation motors instead

Now BECAUSE Heng Long uses such a system you can't just go out and buy a replacement 2.4ghz radio and receiver and plug the receiver into the RX18 as the RX18 wants to 'see' all the channel info coming down a single wire not on 4 separate wires.

Hence to operate on 2.4 ghz you need to either throw out the RX18 and get a control system that allows you to 'feed in' CH1, Ch2, CH3, Ch4 separately from your receiver (El Mod, SGS, etc.) OR you can get a RC2HL which takes the separate channels from the receiver and combines them onto a single signal wire which the RX18 expects to see.

It may help to thnk of the RC2HL as an adapter or translator. The old HL receiver board is replaced with a proper 6 or 8 channel hobby style receiver. Ch 1 to Ch 4 are feed into the RC2HL where they are combined to a single signal. This signal is then sent off to the RX18. Nothing else needs to be changed in your tank. You keep the RX18 as your MFU (multi-function unit)

WIth the other systems you throw out your RX18 & Heng Long receiver board. Now depending on the system you may have to modify some cabling in your tank and this can vary from very little to quite a bit. You will then have a different Multi-function unit controlling your tank.

Cheers
Kevin G

_________________

rctanksaustralia.com

Great write up Kevin. One thing I don't understand with hobby radios (sorry Michael hijacking your post a bit here) is how to make use of the extra channels from the radio i.e. ch5 upwards.

For example on my Planet T7 (7 channel) I have
ch5 is an on/off switch
ch6 is like a volume know
ch7 is a 3 positions switch up/off/down

But on the receiver I have a servo connections (+,-, signal) for each channel. So do I need another intermediate peice of hardware (like ESC, servo) to make these work?

Cheers

Ian.

_________________
HL/Asiatam Metal Tiger 1
HL/Asiatam Metal KV-1 (1941)
WSM T-34
SU100
HE Abrams
HL Leopard 2A6
HL Jagdpanther

HI Ian

On my to do list is to do a little write up on how the R/C system works. Maybe I'll get round to it. But here comes a quickie.

Ok for each RC channel the receiver gets info from the radio and then sends this processed info out on each channel to whatever. The info the receiver sends out is just a simple pulse, just an On then off. It is the length of time that this pulse is ON that is the important bit. When your sticks are in neutral the receiver is sending out pulses that are 'on' for about 150 milliseconds. As you move the stick down the length of time each pulse stays on shortens till at the bottom of travel it is around 100 milliseconds. Coversely moving the stick up the pulse time increases till at the top it is around 200 ms.

Reverse---Neutral---Forward
100ms----150ms----200ms

Now that is the basics in a nutshell. So Ian in your case for your Planet.

Channel 5 if it is just an on/off will only send out the bottom and top pulses
OFF--OR--ON
100ms--OR--200ms

There is no inbetween. So what ever is connected needs to be able to say ok that pulse is only 100ms long so I'm gonna turn off - That pulse is now 200ms long so I'd better turn on. If you connect a servo to that channel it will either be fully clockwise or fully anti-clockwise (no inbetween)

Channel 6 if it is a 'dial' pot means it will output all pulse lengths between 100 and 200 ms. So fully anticlockwise it will be 100ms and fully clockwise - 200ms. At halfway - 150 ms, 1/4 way would be 125ms. You get the picture. The nice thing about the pot is that where ever you leave it that is the pulse it will keep sending out. So if you connect a servo to it wherever you leave the dial that is where the servo will stay.

Channel 7 if it is a 3 postion switch you can probably now work out for yourself how it works... 3 positions for 3 pulse lengths..

PosA..PosB..PosC
100...150....200

Again any device conected to this needs to act as to what pulse length it is getting. If you connect a servo it will only move to 3 positions Fully anti-clock- middle - fully clock.

So Ian if you want to make use of those extra channels you need to get devices that operate as above. Now because tanks are out of the mainstream and Tamiya have had the run of the show for years VERY few devices exist that are realy good for tanks . It also hasn't helped that Heng Long did not adopt proper RC system. Nor for that matter has the new Taigen 2.4 system. The Taigen 2.4 system DOES NOT OPERATE like the proper hobby grade 2.4 ghz system. 2 of the 4 channels output the standard 100- 200 ms pulse lengths the other 2 channels do not. I hate to say it but the Taigen 2.4 gHz system should be viewed as a proprietary toy grade 2.4 system (end rant).

Even so with a bit of creativity you can do a lot with what you have got. I'll give you one example. You could set up Channel 5 to operate a very nice servo recoil system.
At postion A the servo moves the barrel so it is fully extended - when you flick the swicth the servo instantly snaps back pulling the barrel back to Positioon B (recoil). Now for the smart bit. If you then add a servo speed control unit to the mix you can tell the servo to SLOWLY go back to position A - this gives you fast back and slow return.

Cheers kg

_________________

rctanksaustralia.com

Hi Kev and Ian.

First, hijack my thread as much as you want Ian. It has prompted more good information from Kev!

Secondly - thank you very much for all that Kev. I appreciate that you must have trotted this out every time a "noob" joins up. It has certainly cleared up many misconceptions I had and also explained a few things. Going back to my previous preconceived ideas on radio control, I was puzzled a few years back when my son had a radio control hovercraft. He had broken it and it was on it's way to the bin when I had a look at it with a view to salvaging the servo's etc. Now I know why there weren't any.

I have thought about building a model tank in the past, and when thinking about it I pondered how to control it. Due to my limited knowledge of RC, I imagined servo's doing everything. So, I would have had a controller telling the servo to operate the switches in the tank to drive the motors, servo's to rotate the turret, servo's to turn the lights on etc. I can appreciate the motor controllers (ESC ?) cut out a few parts and make sense.

I also got the idea from your excellent text Kev, that it is possible to add servo's to the, say, 9X. It's functionality however would be governed by the type of signal on that channel (simple pulse or dial pot?). So am I right to assume you can then increase the number of things your tank will do up to the amount of channels the set has? That seems obvious, but I'm a noob remember

It looks like my gearboxes are here, or rather, have been here. The delivery people left a note. Hopefully I'll collect them tomorrow.

Once again, thank you for that information Kev. You're saved me a lot of Googling and I must say your posts were a damn sight easier to understand than what I've seen online so far.

Cheers,

Michael

Thanks Michael

Just quickly what makes the 9X such a great radio over Ian's Planet (sorry Ian) is that you can program any of the 8 channels to anything you want. So you are not limited to what you can put on the extra channels. Typically I use Channel 5 for the recoil servo, Channel 6 I connect to my volume control unit (PotHead). If I need to use a servo for the cannon elevation (like in my Su 76i) that is on Channel 7, Channel 8 is for any extra switching. I think I have one tank with a switch to turn on/off the smoke unit on CH 8.

This is why I recommend the 9X over the cheaper HK radio. The 9X with custom firmware is a very very flexible radio.

Cheers
KG

_________________

rctanksaustralia.com

Kev,

I think I'm sold on this Turnigy 9X at the moment.

Being new to the hobby, I'm still unsure what I'm going to be doing. I like the idea of having as much functionality as I can for a time when I want to do something different. I do have a plan in mind which is more around the construction side at the moment.

Next thing is to find where they are sold (please feel free to suggest someone if that's allowed).

Thanks again, you've given me much to think about.

Cheers,

Michael

Kev, for the on/off of the smoker, do you use a switch such as this one?