Setting up RC Systems

[Armortek]

The Knowledge Base Topic on setting up Spectrum RC System now has an explanation of some basic radio stuff, which can be confusing if you're setting up a system for the first time. It's a subject that comes up regularly, so I've now included a simple explanation of the relationship between radio channels, controls, modes and mixing. I hope it does the trick but would welcome any comments, particularly if we can make it even simpler.

I've not changed the Topic for Futaba as fewer people seem to be using their radios.

http://www.armortek.co.uk/Forum3b/viewt ... 7cc#p49290

Thanks to Adrian for your recent input to a thread.

Stephen

[Mark Heaps]

Just read through the link and found it good. Easy and enjoyable to read, simple to follow.
2 comments however.
1) Setting up the Failsafe positions - Removing the bind plug is mentioned twice. It should be clarified at what stage the bind plug should be removed.
2) It fails to mention that other modes are available which effectively switch the controls between left stick and right stick to cater for example for left-handed people who may prefer to control tank movement with left stick and turret with right stick.

[Armortek]

Thanks for the feedback Mark, I'll add your points. Stephen

[Adrian Harris]

Another change is that the new range of Spektrum receivers with built-in telemetry also now come with a bind button, rather than needing a special plug.

Adrian.

[Vince Cutajar]

Hi Stephen

Just to advise that the DX8 has both the ELEVON and also the ELEVON B selections. I used ELEVON as per instructions but would be interested in knowing the difference between the two.

Set pre-set failsafe using the receiver documentation and as Adrian said did not use the bind plug.

Vince

[Adrian Harris]

The difference between ELEVON and ELEVON B are that the directions are reversed.

In ELEVON, the Right Aileron goes to 100% when the stick is pushed forwards
In ELEVON-B the Left Aileron goes to 100% when the stick is pushed forwards.

I usually have a problem when setting up single stick, whereby the tank moves forwards and backwards correctly but turns left when I want it to turn right and vice versa.

I've always meant to sit down and write out the best way to defeat this, as it can be done by changing the Elevon setting, or by reversing the channels in the transmitter, or by reversing the connections on the motors, or by swapping the left and right aileron connections on the receiver, and I've never made a note of the simplest way to do it.

Adrian.

[Armortek]

Vince, Adrian, I'm wary of adding confusion here but the simple explanation is that in aeroplane use, ElevonB reverses the direction of the Elevator function. It's to do with the way the mixing is programmed. ElevonB was introduced to allow for canard configurations. For our setup, ElevonB should give you the correct sense. If it doesn't, the simplest way to correct is to swop the leads plugged into the Ail and Elev sockets on the Rx.

[Vince Cutajar]

Thanks for that info. If mine starts going in the wrong direction most probably that's what I will try first : change from elevon to elevon b. Will keep you posted on what works best with the DX8.

Vince

[Vince Cutajar]

Today I temporarily put most of the electronics in the tank. Did a quick test and tracks are going in the right directions (also in turns). So I guess with the help of my beginners luck, Elevon setting on the transmitter worked for me.

Vince

[Michael Röder]

Hello!

Thank you in advance for the excellent instructions for setting up the spectrum radio system.

http://www.armortek.co.uk/Forum3b/viewt ... 7cc#p49290

I am currently building the Armortek control into my StuG and now have the following problem:
If I drive straight ahead, the right chain starts turning earlier than the left.

The instructions for setting refer to the Sub Trim Menu here.
Does anyone have experience with this setting menu?
Which channel has to be set / trimmed? For RH motor or LH motor?

Regards Michael

[Stephen White]

Michael, thanks for the kind comment on the Knowledge Base Topic, good to know it's of use.

Your problem is very easy to fix. The sub-trim menu allows you to move the centre position of the relevant channel electronically, in the same way you would use the physical trim control on the transmitter face. This will then allow you to return the physical trim to neutral and retain the same trim offset until you next change it.

You can trim the model running on the ground but select an even surface such as concrete. Better still, raise the model so that the tracks are off the ground. You didn't say whether you're using one or two stick driving.

With two stick driving, it's not really necessary to alter the trims because you'll naturally steer the vehicle by altering the relative speed of the two tracks.

I'm assuming you're using single stick driving. In this configuration, the forward/reverse channel and left/right channel are mixed proportionally. So although the model turns by changing the relative speed of the two tracks, the radio "steers" with the left/right channel. You can therefore trim out any tendency to turn when you are trying to drive straight.

With the model on smooth ground or raised, apply forward stick and see which track moves first. Use the physical trim control on the transmitter to trim out any imbalance. You can do this in real time. Once you've got the tracks moving forward at the same speed, check that the same is true in reverse. You may find you have to find a compromise position.

Once you've got the tracks starting and stopping together, look to see in which direction the physical trim control is offset from centre. Now go to the sub-trim menu and apply trim in the same direction. Finally, re-centre the physical trim selector. You've now established in which direction trim is needed but may not have the correct amount. You can adjust the sub-trim in real time, so start the tracks moving forward and make a fine adjustment to the sub-trim. That setting will now remain until you change it.

Stephen

[Michael Röder]

Hi Stephen!
Thank you very much for the detailed explanation.
Yes, I use a single stick driving.

I made the settings, the forward driving works great after the setting, but as you wrote, there are now problems when reversing. So I have to compromise. So far I have only tested in a jacked up position. I am excited to see how the compromise affects real driving behavior.

Regards Michael

[Tim Page]

I am sure things would be far simpler if there was a dedicated tank radio with built in rotary encoders.
Just think, no messing about with elevons , ruddles and ailerondoodas.

I expect that i probably only use 15% of all the functions on my Spektrum DX9 and it is basically way too complicated for what most of us need.
I dont need a mega expensive receiver with a range of 5 miles but its what i have to buy to get a decent number of channels.

Simplified tank radios with 6-10 channels and half the price are what we need.

Just a thought.
Tim

[Jerry Carducci]

I am sure things would be far simpler if there was a dedicated tank radio with built in rotary encoders.
Just think, no messing about with elevons , ruddles and ailerondoodas.

I expect that i probably only use 15% of all the functions on my Spektrum DX9 and it is basically way too complicated for what most of us need.
I dont need a mega expensive receiver with a range of 5 miles but its what i have to buy to get a decent number of channels.

Simplified tank radios with 6-10 channels and half the price are what we need.

Just a thought.
Tim

This is obvious of course but it's been my experience since I began in this facet of the RC hobby that the only contingent of RC enthusiasts that hold
significant sway with RC systems manufacturers are aircraft people. My inquiries with one major label years ago with regards to even simply non aircraft specific programming - for general use was met with essentially "why would we do that?" My point was not even to ask for specific labels (and images) for RC interfaces, ie ailerons, elevator, etc to be replaced with CNTL1, CNTL2 within a generic model template. The ire from the manufacturer rep was
not even subtle. When 2,4Ghz systems hit the market I asked the same rep about the suitability of the new systems in ground based vehicles, specifically metal ones and they said 'that will never work'. Fortunately they were wrong.

That attitude and pricing were contributing factors in gaining interest in Turnigy and FRSky products and the use of open source OS...
Along with the relatively enthusiastic support to customize those systems programmatically and hardware wire.

Jerry

[Stephen White]

Jerry, you make a good point. Why would radio systems manufacturers do something which didn’t offer any commercial advantage. There are 35000 registered model aircraft pilots in UK. I don’t know what the equivalent number is for RC cars and tanks but I doubt it is more than a quarter of that. We simply don’t have much commercial muscle.

Your second point is very valid. Quite a few of us are moving to open source software defined radios, particularly those hosting OpenTx. It does seem very complex to start with but once you understand the system architecture, it becomes quite manageable and very powerful indeed. Things like stepped gear changes become possible.