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Member postings for Mike Blandford

Here is a list of all the postings Mike Blandford has made in our forums. Click on a thread name to jump to the thread.

Thread: Turnigy 9X range issues?
03/12/2018 20:16:45

One way of powering on the radio is by plugging a trainer jack plug in. This works independent of the power switch.

Connect your battery, then go to the "Trainer" menu. If in trainer mode, it will just display "SLAVE". This will test to see if the trainer jack socket is the cause of your problem. You won't get the "SLAVE" display, if the trainer source is not set to "JACK PPM" at the top right of the display.


03/12/2018 09:17:31

Did you miss my question?


02/12/2018 09:43:20

Does the firmware run normally, when you now just plug the battery in, or just a buzzing noise with nothing on the display?

The 9Xtreme has a "soft power switch", so that once it is powered on with the switch, it keeps the power on, even when you switch off, so it may ensure all data is written to the EEPROM before it then turns itself off.

The 9Xtreme fully supports TWO modules, one mounted internally and the other externally. Both have software controlled power switches and separate signal outputs so you may select either (or both) to operate on a specific model. You wire the DIY module to a connector on 9Xtreme.

Details of the connector are here: **LINK**.


Thread: Radio channel setting Opentx
23/11/2018 09:41:38

No. You create a new model for this helicopter and just set the mixer to have the correct channel order. The setting for the channel order in the radio setup is just the default order used when creating a new model.


Thread: "SD Card Error" warning Taranis X9D Plus
22/11/2018 16:00:34

I'm seeing some confusion here regarding the comms. If companion is looking for a DFU device, then it isn't looking for the SD card. A DFU device will only be found if you connect the USB with the Taranis powered OFF.

Please start the Taranis in "bootloader" mode (hold the two horizontal trims towards the centre of the radio, then power on). You should see "Bootloader" displayed on the screen. Now plug the USB cable in. You should get two hard drives appearing. Don't be surprised on a Mac if it takes a long time for them to appear (even a minute or two). The Mac is known to want to do something such as "indexing" these drives, and as the USB is only "Full Speed", not "High Speed", acccessing the drives can be slow.


Thread: lipo battery charger
14/11/2018 23:06:55

Many answers, as usual, to this sort of question.

I got one of these earlier this year: **LINK**

Mains or 12V battery input, two independant outputs and also does the ESR measurement. I also have a GTPOWER A8, so I also sometimes have 3 batteries charging at the same time.


Thread: Which Set Should I buy
10/11/2018 00:29:19

Most of our radios currently don't have the equivalent of a mouse/clicking or a touch screen, so this limits some of what may be achieved. The screen resolution also limits things.

I have made a significant effort to make things easier to find in ersky9x firmware. When you go to edit a model you first get an "index" display where you may select the "type" of item you wish to change:


I'm open to feedback to make this even easier to use.


09/11/2018 22:37:11

Posted by Erfolg on 09/11/2018 20:34:38:

. . .

The one exception that seems to tick all or most of the boxes for me is Frsky. Until it has an intuitive interface, that is not tree structure based, or needs lines of something approaching code, not all the boxes are as yet ticked. Yet no one has a intuitive coloured interface as yet, I believe it will come.

. . .

Perhaps you could define what an "intuitive interface" actually is.
Also, regarding FrSky, are you referring to openTx, FrOS, or something else?


Thread: Returnee to EF seeking advice
07/11/2018 00:50:45

You aren't restricted to openTx on most FrSky radios (and some others as well), you also have the option of ersky9x firmware.

As an example, here is the menu index display (from a FrSky QX7) you get when editing a model. The menus are, in my opinion, easier to follow and find settings than in openTx.


BTW PatMc, my QX7 does have a slider. I added one, and used one of the coloured LED outputs for the switch as the extra analog input. A slider is far more use than three colours for the power switch LED.


Thread: Have I done serious damage.
03/11/2018 19:14:16

If the charger is 500mA, and the battery is 2500mAh, then it will take 5 hours to charge from completely discharged.

If you left it on discharging so it is very discharged, then you will likely find a "Smart" charger will detect a "false peak" very early when charging.

What speed controller do you have in the glider? You may need to configure it for NiMh batteries as it may be deciding you have a 2 cell LiPo and cutting off early when the NiMh voltage gets too low.

Also, what connector are you using from the battery to the speed controller? If one of the Tamiya type like on this battery **LINK** then you should replace it with something more capable as the Tamiya is not suitable for high currents. In my opinion, this type of battery should not be sold with that type of connector.


Thread: TX talking to 2 RX's in different models at the same time?
04/10/2018 09:05:03

David, the "receiver number" is selectable, it is not specifically tied to a "model slot", so you may choose one for each model.


Thread: Autumn is been flying ?
01/10/2018 12:47:23
Posted by David Davis on 01/10/2018 05:41:19:
I managed to land everything on the patch this time so things must be improving! Still haven't got the hang of slowing my landing approaches sufficiently using the elevator. I will continue practising. smiley

Depending on your transmitter capability you could try the following, it depends on your Tx having flight modes with trims specific to each flight mode.

Set up a switch to select "Landing" mode with a unique trim for elevator. Now just (at a good height) switch to "Landing" mode, shut the throttle then adjust the elevator trim to get a slow glide for landing. Makes things easy.

I don't consider this "cheating", I was taught to use the elevator trim (with flaps) on full size for landing.


Thread: Make your bets please Ladies and Gentleman
20/09/2018 20:44:37

YMMV - Your Mileage Might Vary! Almost what you are saying anyway!


Thread: Lipo Battery Storage
19/09/2018 17:01:29

A reason not to store fully charged is "fully charged" depends on temperature. A battery that is fully charged at one temperature becomes over charged at another (I think lower?) temperature.

I store my batteries at storage charge, which is 3.8V per cell according to my chargers. I usually take a charger ti the field with me, so after using a battery, unless I need to recharge it, I put it on storage charge, which usually doesn't take long.


Thread: Battle of Britain Day
15/09/2018 00:21:18

I think he is asking why the "other" thread is titled "Battle of Battle" not "Battle of Britain", with an aside as though from the Polish pilots (in the BoB film) requesting "Repeat Please" as they peel off one by one to engage "bandits".


Thread: Lipo charging
14/09/2018 09:45:16

Dave, that is exactly the circuit I expected.VT13, VD4 and L1 form a buck (step down) switch mode regulator, while VT15, VD5 and L1 for a boost (step up) switch mode regulator.


13/09/2018 22:09:57
Posted by Dave Hess on 13/09/2018 13:45:57:
I can't see any inductors to smooth the PWM. I can't see a reason to do that anyway because charging lipos doesn't need a smooth voltage. The inductor at the other end of the PCB looks like it's part of the buck converter circuit to raise the 12V high enough to charge a 6S battery - probably something like 25V.

The chargers I have use the inductor in both buck and boost modes, converting the supply voltage to that required to charge the battery. They operate using the charge current to regulate the output voltage that is controlled by the PWM mark-space ratio. The PWM frequency used is sufficiently high that the inductor, with the associated output capacitor, produces quite a constant voltage/current, in the same way any switch mode power supply works.


Thread: What gauge wire
09/09/2018 22:13:12

A bit difficult to see exactly what those waveforms are showing, and they don't look much like the ones I got on my digital storage 'scope, where I could capture and "freeze" them.

The ESC outputs are square wave voltage, and the non-driven wire shows a sinusoidal feedback voltage. The current is likely to be reasonably constant as the inductance of the motor tries to keep the current flowing, and the parasitic diodes in the MOSFETs provide a current path.


09/09/2018 17:29:01

The motor, as you have said, includes inductance, in the same way a switch mode power supply uses an inductor. When operating a switch mode power supply in step down mode, the current in the output may be higher than the current in the input, the power in each is the same (except for losses). The same can happen with a brushless motor.

I've just put my 'scope on the wires to a motor. The pwm frequency remained fixed. The outputs to the motor followed a sequence of 6 "phases".

"A" at supply voltage, "B" pulsing low, "C" not driven.
"A" at supply voltage, "B" not driven, "C" pulsing low
"A" not driven, "B" at supply voltage, "C" pulsing low
"A" pulsing low, "B" at supply voltage, "C" not driven
"A" pulsing low, "B" not driven, "C" at supply voltage
"A" not driven, "B" pulsing low,, "C" at supply voltage

On the wire that is not driven, you can see a sine wave, which is the induced voltage in the undriven winding.

(OK, a sample of size 1)

This is as I described.

BTW Kirchoff;s law is for a "node" not a circuit.


09/09/2018 14:40:32
Posted by Focae on 09/09/2018 10:05:14:

Mike, the output current can never exceed input current. A certain gentleman named Kirchoff determined that in one of his Electrical Laws. ‘The sum of the output currents must equal the input current’. You will also never have the same current in two legs of the motor wiring. Outrunner motors are essentially three phase ac motors. The rotating field is created my rapidly switching dc to the legs in turn. The voltage and therefore current in these legs will never be instantly at the dc voltage because the motor windings, being inductors will cause the voltage to rise relatively slowly creating a sinusoidal wave in each leg. Because the windings are 120 degrees apart, you never have all of the current in one leg being opposed by an equal and opposite current in another and you can never have all of the current flowing in one leg. Also consider this, how thick are the wires that form the winding? They are essentially just a continuation of the wires that connect them to the esc. If you did have all off the current flowing in one leg for longer than the ‘average’ switched time, the smoke escapes, usually at the winding because it is thinner than its supply wires.

"the output current can never exceed input current" No, but there are capacitors on the ESC input that provide the "extra" current for the current pulses.

"Outrunner motors are essentially three phase ac motors" No, they are DC motors with electronic commutation.

The ESC connects one of the three motor wires to the positive supply, a second to the negative supply and reads the induced voltage on the third wire to time the commutation.

Yes, the inductance will limit the current rise, but actually sufficiently slowly that the current is essentially constant.

"you never have all of the current in one leg being opposed by an equal and opposite current in another" Yes you do as it is a DC motor, I just described how the commutation is done.

"how thick are the wires that form the winding?" About the same thickness as the wires from the ESC. You may look at the windings and see quite thin enammelled wires, but, for ease of winding and to get more copper in place, the windings are made of multiple, parallel thin wires.


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