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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: FrSky Taranis - user chat
01/02/2020 20:31:21

There are a number of reported problems after updating to V2 firmware, equally others have updated and all is working OK.

Currently, I've update the module in my prototype Taranis, my prototype Taranis+ and a X9E, together with a X8R receiver.

The X9E seems fine, the X9D+ works on some RxNums, but not others, the X9D binds but doesn't work.

My personal opinion is FrSky will soon post a further update, but they won't have been at work for a couple of weeks due to the extended Chinese New Year.

I have sent them my findings, together with detailed technical data, for example, I know why the X9D doesn't work.

Mike

Thread: Have I enough power?
30/01/2020 19:19:28

Just read both a manual and a listing for the VQ Hurricane. The listing says 4S, 5000mAh and the manual says 14x8~15x8 for the propeller. It does say weight 3.3-3.6kg, so something seems to be wrong if 40oz of lead is needed for balance. CG is shown as 3.3-3.5 inches (85-90mm) back from the leading edge.

The manual does say some nose weight is needed, but 1.15kg seems too much.

Mike

30/01/2020 14:57:43

Something not quite right with those readings. You show 37.5A, but only 27.55A peak.
At 16V, and 37.5A you should have 600W.

Also with 16V in, I would expect the motor back emf to be between 13V and 14V. With a 580kv motor, 13V would be around 7500 RPM and 14V would be around 8100 RPM. Possibly the 16VM is a maximum value.

Mike

Thread: FrSky Taranis - user chat
26/01/2020 19:15:18

I did check D8 receiver telemetry and concluded they may not be legal. D8 operates differently to D16.

The Tx sends control data 3 times at 9mS intervals, then the Rx uses the 4th 9mS interval to send the telemetry data, and uses quite a few mS to do so. I believe the Rx transmits at the same power level as the Tx, so the MUF did, very likely, exceed 10%.

Mike

26/01/2020 15:06:42

I've updated a X9D and a X9D+ to the new (v2.0.1) firmware together with a X8R.

Both bind OK to a D8 receiver. The X8R, in D8 mode, does not bind to either Tx, nor to a DJT nor to a XJT module with pre 2.0.1 firmware.

FrSky informed me that, as D8 mode is no longer legal in Europe for new products, they are phasing D8 out, which is why the X8R, with 2.0.1, does not bind in D8 mode.

Mike

Thread: FrSky Major Update for most TX and RX
26/01/2020 09:15:17

All 'V; and 'D' series modules and receivers are unaffected. If purchased (or imported) before Jan 2015 then it is fully legal.

The DFT/DJT modules are no longer legal to be imported into Europe, but may be sold if imported before then.

Mike

26/01/2020 00:30:31

erskyTx is open source firmware that runs on many different transmitters (just like openTx does), including the Taranis. You were saying you give up on the Taranis because it is too complex. I'm assuming you are still using openTx on it, and I'm suggesting you might try erskyTx instead.

Mike

25/01/2020 20:06:35

Tim: It seems the LBT version is more prone to this problem, but it does affect both LBT and International.
Most of the time the CRC check picks up transmission errors. One thing FrSky did between the original 'D' protocol and the 'X' protocol is stop using the hardware CRC check available in the RF chip. This has been enable in the fix.

Yes there are some problems with this update, I think they have rushed it out, but don't have enough older hardware to test all combinations. I expect this update to be improved quite soon. However, provided you have copies of the current module and Rx firmware (so you could revert if needed), if you do update, the control link either works, or it doesn't. If it works it keeps working.

Martin: I definitely mean erskyTx firmware for the Taranis. Quick history: originally there was TH9X firmware for the Flysky 9x transmitter. This was followed by er9x firmware for that Tx. Then an upgrade board (call a SKY board) was made for the 9X, so er9x became ersky9x as well. Around the same time openTx was forked from these.

As FrSky started to produce transmitters, both ersky9x and openTx were made available for them. As more transmitters became available (the 9XR-PRO and others from FrSky), so both openTx and ersky9x were ported to them. I recently renamed ersky9X to erskyTx as it is not just applicable to the original 9X.

I've attempted to make navigating around erskyTx easy, and so easy to find settings you need.

The firmware is here: **LINK**, and there is a link to an er9x manual on that page as well.

Mike

25/01/2020 16:11:02

I've posted some technical information here: **LINK**

as to why this update is being done.

Martin: Have you tried erskyTx firmware on the Taranis, many people find it easier to use than openTx, while still providing the benefits of flexibility.

Mike

Thread: Theory of the operation of a servo
21/01/2020 15:56:23

"Simple description":

When an "analogue" servo receives a control pulse it generates a pulse from the feedback pot at the same time. Any difference is stretched, amplified and applied to the motor. Nothing else happens until the next control pulse is received.

A "digital" servo measures the input pulse, but is able to monitor the feedback pot all the time (not just once every input pulse). This results in the motor being driven to the target position all the time, and can also correct the output position if it moves due to an external load, without waiting for the next input pulse.

The terms "analogue" and "digital" refer to the control circuitry, the input pulse width and the feedback pot are both analogue values.

Mike

Thread: FrSky Major Update for most TX and RX
19/01/2020 22:24:29

The problem was noticed first in Germany, although when it was described some people in other parts of the world realised they observed the same problem. One person in Germany did extensive testing on the bench, and managed to create the problem in controlled conditions repeatedly. FrSky have been working on a fix for a while.

The original "D" protocol used a CRC built in to the RF chips, but, for some unknown reason, the "X" protocol didn't use this, and the software CRC check used apparantly missed some errors.

Mike

18/01/2020 20:37:47

I've seen reports that early Taranis transmitters (not plus) do not work with this module update. I can confirm that my prototype Taranis does not work, it binds OK but operation fails with the green LED on the Rx flashing occasionally and servos moving intermittently.

Mike

17/01/2020 22:56:50

The update from FrSky,, which this thread is really about, only affects the RF modules and receivers.
I've updated a Taranis plus internal module and a X8R for testing (and reverse engineering). The updated module still binds to a "D8" receiver (in D8 mode). In D16 (X) mode, the module and receiver will only bind to each other.

The X8R will not bind in D8 mode, even though linking channels 7&8 and powering it on does start it in bind mode.

If you update a module, it will only bind to an updated receiver, and vice versa.

The multi-protocol module will not bind to an updated receiver (yet!).

Mike

16/01/2020 19:06:51

Note that if you update a receiver then you won't be able to use a multi-protocol module (MPM) with that receiver as the MPM doesn't support this revised protocol (yet).

Mike

Thread: battery c rating
14/01/2020 16:56:53

My understanding is that lithium batteries degrade over time, regardless of whether they are being used or not. This results in the internal resistance increasing. Since a higher "c" rated battery starts with a lower value of internal resistance, it is likely to be longer before it becomes too high for the battery to perform well.

I also understand that this ageing process may be reduced by storing the batteries at a lower temperature.

Mike

Thread: ESC overheating.
09/01/2020 00:02:48

The MOSFETs in ESCs do have a maximum voltage rating, so ESCs are rated by voltage as well as current.

The whole operation of a brushless ESC is very complex. The motor windings act as an inductor, so when the ESC switches the current off, the inductance creates a "back e.m.f." (separate from the e.m.f. generated due to rotation). With brushed motors, this caused current to continue to flow and needed a "catch diode" to prevent a very high voltage spike from occurring. Brushless ESCs also need catch diodes, but these are built into the MOSFETs. One disadvantage is the voltage drop across these diodes is around 0.6V, and with a significant current flowing there is a noticeable heating effect. Some ESCs may avoid this by switching the MOSFET on to short out the diode, but this has to be done very carefully or the battery is shorted out by having the "wrong" two MOSFETs on at the same time.

It is also important to have some cooling for the ESC. I recently started using a FrSky Neuron ESC. This includes full telemetry including the ESC temperature. While the installation should have provided some cooling flow, it clearly didn't work very well, the ESC temperature kept going up through a flight, and I've seen it as high as 77 degrees C. I added a small air scoop to direct air in to the ESC, now it doesn't go above 31 degrees C.

Mike

Thread: Jumper 4in1 module problem
05/01/2020 15:19:57

You should find that if you plug the USB into your PC, the module appears as a serial port.

Mike

Thread: FrSky Taranis - user chat
05/01/2020 12:38:00

Should work fine.

Mike

Thread: Hobby Porter
03/01/2020 16:06:13

Interesting, but they should really go for D16 (XJT type) protocol as D8 protocol is not legal in Europe for new transmitters. This also doesn't have any telemetry apparently, so that limits its use to my mind.

Mike

Thread: CAA announce New drone trials !
27/12/2019 15:05:54
Posted by Martin_K on 26/12/2019 22:24:39:

The FAA have released their anticipated Notice of Proposed Rulemaking for Remote Identification. This is in America and not the final document. I mention it here to reinforce the fact that preparations for commercial BVLOS are advancing.

When we get the equivalent European draft laws I expect those of us with the inclination will discuss it in The Gov't, BMFA & UAV legislation thread.

What I found interesting in something I read on this linked from another forum is it includes:

" including the small UAS rule, which covers drones weighing less than 55 pounds other than model aircraft "

so it looks like they may be EXCLUDING model aircraft.

Mike

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