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Futaba 14SG chat

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Tim Flyer27/04/2018 11:06:41
1157 forum posts
220 photos

Interesting point there. Maybe there is a marginal benefit putting the Y lead on the elevator as they’d the last thing we would like to fail?

Frank Skilbeck27/04/2018 12:32:01
4557 forum posts
101 photos

Tim, is not a matter of protecting against a failure but just that if you are using a Y lead to connect the battery up then it effectively divides the current between the two loads connected to it, in my example rudder and then receiver and remaining servos. There is a small voltage drop across every connection which is proportional to the current. On a big aerobatic model the most powerful servo is usually the rudder so it will take most current, by connecting that direct to the battery the current flowing to the receiver (and remain servos) is reduced and hence the voltage drop across the connector feeding the receiver is also reduced.

Adrian Smith 127/04/2018 12:40:06
2317 forum posts
1102 photos

Trust me to get hold of the wrong end of the stick, sorry Frank! blush

I am thinking of putting the y-lead on the Rudder CH (3) as suggested and there is only one servo on that. I have 2 elevators and 4 ailerons and of course the throttle CH.

The way the Test A/C set up on the TX is as follows:-

CH 1 aileron one, CH 2 elevator one, CH 3 Rudder, CH 4 aileron two, CH 5 aileron three, CH 6 aileron four, CH 7 throttle and CH 8 elevator two. On the Futaba 7008SB RX the battery plug is suggested for CH 7, but I would rather keep that away from the throttle given that connection goes straight to the ESC.

Tim Flyer27/04/2018 14:32:06
1157 forum posts
220 photos

Thanks for clarifying Frank. I’m certainly no electrician! The 14SG is a great radio (apart from weak antenna)and this chat is very useful as is Malcolm’s book.

Edited By Timothy Harris 1 on 27/04/2018 14:33:10

Adrian Smith 110/01/2019 15:56:33
2317 forum posts
1102 photos

As one who never sets any Expo, I thought I would experiment on introducing some on the ailerons on one on my aerobats. The reason for this is my thumb occasionally slightly wanders when doing a loop, introducing a slight aileron effect. Not good! I thought a bit of aileron Expo would stop this effect. I know doing this in isolation without the model (in workshop) is not the most sensible thing to do, but I just want to be clear on the methodology. So here goes - into the MDL menu for Dual Rates.


I have assigned the rate to SA switch which has three clicks to it.


I have set the Expo to +20 on the ailerons. This appears to be operational when the switch is fully UP.

p1050612.jpgThis is what the ON/OFF menu looks like. When the switch is fully DOWN then the rates don't register on the screen menu. Am I going in the right direction?

Edited By Adrian Smith 1 on 10/01/2019 15:57:02

Gary Manuel10/01/2019 16:18:19
2036 forum posts
1515 photos

I'm not a Futaba user but the curve looks to be the wrong way to me - i.e. try -20 instead of +20.

Here's a tip for checking that you have gone the right way with the expo. Set it initially to some really high value that allows you to really notice the effect. e.g. -50 or more. If it's working the right way, reduce it to a more suitable figure with the same sign i.e. -20.

Jon Laughton10/01/2019 16:20:21
1182 forum posts
72 photos

As a Futaba user I can confirm that the pictures / curve do indeed show +20% exponential not -20%

Malcolm Holt10/01/2019 16:29:14
93 forum posts
2 photos

You only need to assign a switch if you want to be able to switch between different rate and/or exponential settings. If you simply wish to add exponential to a model without an aileron rate switch you should remove SA by re-setting it to --.

Now go to the two EXP settings and, as noted above, set NEGATIVE values of your choice such as -20.

If you want to use more than one rate and/or exponential then leave the switch assigned. When SA is UP you will see the black arrow next to the number 1 (First rate). Any rate and exponential settings entered on this screen will apply when the switch is in this position.

Now move SA fully DOWN. You will see the arrow move to number 2 (Second rate). By default, the rates on this screen will be 100 and the exponential will be 0. Change the rate and/or exponential values to those you require for the second rate setting. You might, for example, want the rates reduced to 70 while maintaining the exponential at -20.

Finally, doing this without the model is absolutely fine. That’s what the servo monitor is for and, as it gives precise values, you can sometimes get a clearer picture of what is happening

Adrian Smith 110/01/2019 19:09:02
2317 forum posts
1102 photos

Hmmm .... as you can see Gary & Jon I am not too clever on this! Appreciate your input.The Futaba manual is none to helpful I can tell you.

Thank you, Malcolm. Your explanation makes it all clear and I will give it a go later. I do have the download of your book somewhere, but it's some while since I looked at it so I just have to go and search where it is on my PC!

Thanks again.

Adrian Smith 111/01/2019 15:36:49
2317 forum posts
1102 photos


I am a bit puzzled, Malcolm.

With the plane in front of me in the work shop, I removed the SA rate switch setting and added the Aileron EXP settings at an arbitrary -30 for both readings. I didn't notice any perceptible difference.


The curve graphic seems ok, but I didn't really notice any difference on the plane. Tuned in to -90 to see what the effect was. Didn't see any different when activating the ailerons even with such a large reading. I must be missing something obvious here although for the life of me I can't see it.......

Edited By Adrian Smith 1 on 11/01/2019 15:37:27

Malcolm Holt11/01/2019 16:25:06
93 forum posts
2 photos

With the exponential set to -90, move the aileron stick from its central position half way to the right while watching the amount of aileron movement. Now move it from the half way position to fully right while again watching the aileron. The amount of movement in the first case should be less than in the second. What happens on your model?

Adrian Smith 111/01/2019 16:50:52
2317 forum posts
1102 photos

Will do, Malcolm. I will have a look tomorrow. I am prepared to believe that I am not prepared for the subtlety of it. I am not sure what to expect really I guess. Will report back tomorrow. Thanks for your patience Malcolm.

Adrian Smith 112/01/2019 15:44:52
2317 forum posts
1102 photos

So after a bit of testing this what I have established. Firstly, the ground rules. The aileron servos are Savox Digital SC-0251MG's. The full throw is 30% either way.

I set the EXP at -90.


I moved the stick halfway across its range and the aileron registers around 8% as per the next snap ( not too clear, but take my word for it)


So next I reduced the EXP to 30%:-


Stick movement again to halfway, the aileron throw now increases to around 15%.


So the EXP function seems to be doing its job. I just wasn't sure what to expect visually and the effect of these arbitrary readings would have.

Edited By Adrian Smith 1 on 12/01/2019 15:45:50

Malcolm Holt12/01/2019 15:56:55
93 forum posts
2 photos

Yes, the exponential is working as it should.

I can't help but ask why you are only using 30% throw on the aileron servos. This places a much higher load on them and reduces the resolution. Can't you achieve the required throw by moving the connections to the horns and servo arms?

Malcolm Holt12/01/2019 18:31:46
93 forum posts
2 photos

Just occurred to me. Do you mean 30 degrees?

Adrian Smith 113/01/2019 08:05:27
2317 forum posts
1102 photos

Yes Malcolm its 30 degrees. My Apple keyboard doesn't seem to have a degrees sign and I got lazy! That said I should probably look at servo geometry as well as part of the whole deal. I find the current the roll rate is quite fast with 30 degrees, but for anybody wanting to do 3D it would not be enough. Thanks for your observations, Malcolm.

Keith Evans 303/04/2019 19:53:45
378 forum posts
81 photos

I'm currently setting up a hobbyeagle A3 Pro flight stabilizer and am having a few issues .

I've looked at a few forums for advice but am still struggling.

I have actually got it to work but I don't really know why .

I have connected the ppmbus/g lead into channel 5 and identified this as "gear".

I'm usuing a futaba R2008SB Rx.

I've allocated this to slider RS .As set up , max. gain is at the top position and zero at the bottom. I didn't do this setting ,it was already set to this .When I went into hardware to look to see if I could re configure this , the screen with all the switches on , had no "on/off" icon to allow me to do this .

Similarly I allocated "mode" into channel 7 and called it AUX 1 .I then assigned this operation to switch SG.

Again trying to configure the switch I was facing the same issue --no "on/off" icon .

The switch does actually change the mode of the A3 pro and all seems to be fine .

I'm a bit reluctant to fly like this as I don't fully understand what is happening to the switch and slider .

I'm probably doing something stupid .

Another thing ,if I allocate channel 5 to anything other than "gear" then RS does not work .

Any suggestions would be gratefully received .

Denis Watkins03/04/2019 20:23:24
4014 forum posts
73 photos

Is this a glider or a fixed wing Keith?

6 or more channels

Are you using Gear, Flaps or Aux1 for anything else?

And you are right, the slider is iffy as an on/off switch

Malcolm Holt03/04/2019 21:44:46
93 forum posts
2 photos

I am not familiar with this stabilizer but what is often required is a toggle switch which allows you to select three different modes of operation and a proportional control (usually a dial or slider) which allows you to adjust the gain from zero to maximum. This is exactly what the setup you describe provides.

You have assigned SG as the control for AUX1 on channel 7. If you check the servo monitor you will see that the three positions of the switch deliver -100, 0 and +100 and these values appear to be what is needed to switch between the stabilizer’s different modes. This is normal. There is no ON/OFF icon because SG is not operating as a switch in this situation. It is simply controlling the position of whatever is connected to channel 7. If you had assigned a stick, the servo monitor would show proportional movement between -100 and +100. Because you have assigned a toggle switch it can only output three positions. You can reverse the operation in the Reverse Menu but otherwise cannot reconfigure the operation. However, as all is working, you do not need to and need not worry.

Similarly you can check the operation of RS in the servo monitor. It moves the “Gear” channel proportionally from one extreme to the other and should adjust the Gain perfectly. Again you can reverse its direction if you wish but it appears to be working fine and you have nothing to worry about. (If you allocate a different function to Channel 5 RS will still work but you will need to re-allocate it in the Function Menu next to the new function).

In summary, as long as you check very carefully that everything on the model is working correctly before you fly, you should have nothing to worry about.

The difference between using a toggle switch as a control in the Function Menu and as an ON/OFF switch elsewhere causes a lot of confusion. If you want a bit more explanation have a look in the introduction to my 14SG book. You can read it here for free.    (You will need to copy and paste)

Click on “Look inside”, scroll down to the Menu and click on “Controls and switches”

Edited By Malcolm Holt on 03/04/2019 21:49:02

Keith Evans 304/04/2019 10:15:45
378 forum posts
81 photos

Thanks Malcolm that was just the info. I was looking for . The servo monitor confirms everything was correct .

I'll certainly follow up on the "Controls and switches" suggestion .

For completion -it is an 8 channel Rx ----fixed wing aeroplane ---and I'm not using --gear --flaps --and AUX1 for anything else .

Thanks again for the input .When the weather gets better I'll give it a whirl .

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