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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: To stabilise or not to stabilise - the gyro question
10/09/2020 23:46:53

I use a FrSky SxR on several models. In stabilise mode, it just makes the model feel larger, so is useful for smaller models in windy (gusty) conditions. In "auto-level" mode it normally makes the model fly quite differently and gets in the way. I configure the Tx so that if I have auto-level enabled (on a switch), as soon as I move either aileron or elevator off centre, auto-level is switched off.


Thread: Unable to understand OTX configuration for landing gear
19/08/2020 21:53:01

I posted that more to explain how some things work. I've seen people asking how to set up 3-position flaps on a 3-pos switch. My preferred way is to use a mix with a switch as the source, then set the three output positions in the output screen by adjusting the 2 endpoints and the sub-trim for the middle position.


19/08/2020 11:17:21

Another "one mix line" method that may help, or be of interest.

A channel with no mix line defaults to 0% (centre position), but this may be changed by using the sub-trim in the outputs settings that moves the centre position.

So set the sub-trim to -100% and then use a mix line of:

+100% MAX switch(!SA^)

With SA up, the mix line is ignored so the output is the -100% set by the sub-trim.

With SA not up the mix line outputs +100%.


16/08/2020 22:55:29

The output of a mix with a 3-pos switch as input is:

Switch up = -weight + offset
Switch middle = 0 + offset
Switch down = +weight + offset

In all cases the output is limited by the endpoint settings. Using a weight of 200% and an offset of +100% gives:

Switch up = -200 + 100 = -100
Switch middle = 0 + 100 = +100
Switch down = +200 + 100 = +300, but limited to +100 by the endpoint setting.

With an offset of -100:

Switch up = -200 + -100 = -300, but limited to -100 by the endpoint setting.
Switch middle = 0 + -100 = -100
Switch down = +200 + -100 = +100

Just a single mix line, no curves.


Thread: Radiomaster TX16s Anyone tried one?
13/08/2020 10:38:10

The first flash is involved, but I now include a bootloader so any updates are then easily possible without opening up the Rx.

I also wonder about the RM Tx (and the Jumper ones), since they use a multi-protocol module that includes FrSky D8 and DSM2 protocols, neither of which are compliant with the current ETSI regs.


10/08/2020 21:39:03

The D8 protocol operates by the Tx sending data every 9mS, 3 times (27 mS elapsed time), then the Rx sends back the telemetry during the next 9mS, so the Rx doesn't use so much bandwidth. Depending on the actual transmit power, the Rx may well still be legal, it is the Tx that isn't.

If you have D8 receivers and an ACCESS Tx, you might consider flashing the D8 (note not the V8) receivers with the firmware I've written for them that supports the D16 (X) protocol to be able to continue using them.

See here: **LINK**.

This firmware auto detects the specific protocol at bind time (FCC/LBT, V1/V2).


Thread: Arduino programming for beginners.
29/07/2020 15:28:31

I have a few available, see **LINK**:

ServoReverser: allows a servo signal to be reversed, and/or to be slowed down.

SPortToHub: poll SPort sensors and output hub protocol.

SbusToPpm: 16 channel SBUS decoder.

APM_Mavlink_to_FrSky: Convert Mavlink telemetry to FrSky, either SPort or Hub protocol.

Note that most of these override standard Arduino libraries so I may have accurate control of timing.


Thread: Masks
25/07/2020 22:45:45

This is what we have: **LINK**

It goes down to your chin, so does reasonably stop droplets.


25/07/2020 16:14:54

Bob, the requirement (as I understand it) is for a "face covering", not specifically a mask. A face shield qualifies so you might try one of those instead. My wife got us a couple of face shields that we use when food shopping, more comfortable than a mask and you can breathe more easily.


Thread: (Last) Flight of the Phoenix
22/07/2020 20:51:37

Just wondering how stiff is the tailplane. If it is not stiff enough you could be suffering from "control reversal".

Spitfires had an aileron reversal speed of 580mph. What this means is that above that speed applying aileron caused the wings to twist in the opposite direction (ailerons act like trim tabs) with the result the aircraft rolled in the opposite direction to that intended. Later Spitfires had stiffer wings.

If the tailplane is not stiff enough then applying up elevator pushes the trailing edge of the fixed part of the tailplane down resulting in the tailplane as a whole applying pitch down. The harder you pull up elevator, the more the pitch down effect!


Thread: Radiomaster TX16s Anyone tried one?
19/07/2020 20:11:07

I have erskyTx running on most of the radios that run openTx (I'm just sorting it for the RM TX16S). Note that erskyTx is offered by FrSky as an option for the X9Lite.

erskyTx is much easier to navigate than openTx, while providing about the same flexibility (both were forked from er9x).

When you go to set up a model, you first get this index page:


From where you may easily see what is available to configure.

So if you are having difficulty with openTx you might consider erskyTx.


Thread: Taranis problem
17/07/2020 17:42:59
Posted by Phil Lockwood on 17/07/2020 16:05:08:


I don't understand "Bump"


The Taranis shows "Usb connected" on it's screen - from what I can gather, it is that "StM32 Bootloader" is missing on my computer and that is the problem. Mind yopu I don't know where its gone, everything was working fine up to the software crash.

Trying to keep this all in one thread, so this quote is from the "other" thread.

"Bump" is just a way of making a thread have a recent post, so it doesn't get missed.

The Taranis has TWO bootloaders. One (STM DFU Bootloader) is built in to the processor, and is active if you connect the USB cable with the power OFF. The other is part of the flashed program, is active if you power the Taranis on holding the two horizontal trims inwards, and should connect showing as two hard drives.

The "Usb connected" display shows when you power on using the trims, and displays when the firmware detects the 5V power from the USB connection. It doesn't indicate that data is actually working.

So, please leave the Taranis off, use a known, good working USB cable (not just charging only cable), and connect the Taranis to the PC using the USB. You should get the PC sounding that a USB device has been connected, and have a "STM device in DFU mode" appear. if neither of these things happen, then you need to check the soldering of the small board inside the radio that connects the USB socket to the other board. To do this, remove the battery, then undo the 6 screws holding the back on and remove the back.


17/07/2020 15:50:40

Down the right of this web page you have a list of the "Latest Forum Posts". At the bottom of this list you have a link to "More Latest Posts. . .". Click on that, then look for you other thread entitled "Taranis Problem".


17/07/2020 14:01:43

I assume then you do not get the "USB device connected" tones on the PC. If so, then see my reply in your other thread.


17/07/2020 12:27:37

The "STM device in DFU mode" is the Taranis! (DFU stands for Device Firmware Update).

Try plugging the Taranis in again and the PC should find it and reinstall it in Device manager.


Thread: Taranis problem
16/07/2020 23:06:30

The USB connector is on a small board that is mounted at right angles to another board. It is quite likely a solder joint between these boards has fractured.


Thread: X8R update
16/07/2020 20:32:43

The Taranis has two items of firmware, the operating system (openTx in your case but could be erskyTx), and the (internal) module firmware. If you update the Rx to V2.1.0, then you need to update the module firmware to V2.1 as well. If you do update the Tx module, you will need to update all your receivers to V2.1 as well. V1 module/receiver firmware is not compatible with V2.1 module/receiver firmware.

The reason for the V2.1 firmware is a problem was found with the V1 firmware. Under certain conditions, the Rx could lose the radio link for up to 0.9 seconds, and during this time it may also cause one, or more, servos to move to full deflection. Since if this happens near the ground it could cause the model to crash, V2.1 has been released that fixes the problem. It could not be completely fixed by just changing the V1 firmware (although V1 can be made to lose the link for only a very short time and only have the servo glitch for that time (less than 0.1S). I have done that for the firmware I have that allows a D8 receiver to operate in D16 mode.


Thread: Help! Can't charge my Lipo
11/07/2020 22:12:22

Keith: I use audio reports so don't need to look at the Tx while flying. Most are enabled by a switch so I can turn them off. The one item I find most useful is capacity used. That way I know how much battery is left.


11/07/2020 16:06:00

You haven't mentioned what radio gear you are using. Many modern radios include telemetry back from the model. With suitable sensors you can get the flight pack voltage and the motor current displayed (and even spoken). This may well avoid the need for a wattmeter. I have one, but haven't used it for a long time as I use the telemetry.

Recently I've started using FrSky Neuron speed controllers with FrSky radio gear. The Neuron has built in sensors and sends voltage, current, RPM, capacity used and temperature back.


Thread: Flaps. Servo speed.
11/07/2020 12:25:02
Posted by Richard Clark 2 on 11/07/2020 06:49:38:
Posted by john stones 1 on 10/07/2020 18:14:03:

What's your thoughts on reducing servo speeds when deploying flaps ?

I don't bother. Nobody ever does, me included, on a real plane. So if it's 'manual' it is near instant, if it is powered it depends on the speed of the hydraulics.

Well the Cessna I learnt on had electric operated flaps and they were quit slow to deploy.

I have my flaps set up on both a 3-position switch and a slider, with slow on the switch. So I may use the switch to set "up", "take off" and "landing" positions, but have the option of anything in between by using the slider.

When deploying flaps in the air, always reduce the aircraft speed first, otherwise you will likely get a significant pitch change that then reduces as the aircraft airspeed drops.


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