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Member postings for Andy48

Here is a list of all the postings Andy48 has made in our forums. Click on a thread name to jump to the thread.

Thread: X9D+ 2019 or Q X7S?
30/08/2019 22:32:23
Posted by Andy Blackburn on 28/08/2019 08:04:00:

I'm so sorry, perhaps I should have been more specific.

What I obviously meant to say was "The printed documentation that comes with it is not good..."

Yes, there are a set of free downloadable manuals but they're PDFs and if you don't like looking at manuals on the screen you'll have to print them out, in which case it'll cost you the paper and and arm and a leg for the ink, and unless you get someone else to do it it won't be nicely bound.

So, why pay £15 when you can get a comprehensive manual for free? Because it's good value for what it is, and I don't have to print it out myself. And because my printer doesn't do automatic double-sided printing.

Just my personal opinion, of course...

Edited By Andy Blackburn on 28/08/2019 08:13:34

I've a Canon ink jet printer, and I pay less that £1 a cartridge. Less than a fiver for all 5 cartridges, enough to print the whole manual out and more, but then if you want to pay more for your printing requirements....

28/08/2019 07:35:45
Posted by Andy Blackburn on 14/08/2019 08:28:24:

Cautionary note: I'm not an expert! However...

  1. Documentation is not good for those (like me) who loathe fast-forwarding through videos to get to the part that you want and then missing it. However, this manual Taranis X9D Plus OpenTX User Manual 2.2 helped a lot.


Edited By Andy Blackburn on 14/08/2019 08:29:04

What do you mean documentation is not good? There is a free 250 page manual here for the OpenTX which can be downloaded and covers both the transmitters you are looking at. Why pay £15 when you can get a comprehensive manual for free?

Comprehensive OpenTX Manual

Thread: Flair Puppeteer wing fixings
21/08/2019 19:44:37
Posted by John Bisset on 21/08/2019 17:58:38:

I am intrigued by the comments about chopping the fuselage behind the wings to make car carriage easier. How is that done? How does the fuselage fasten together and how do the control runs connect?

(I have a long dormant Puppeteer build tucked away - one day soon I shall get back to it...)

Mine fastens together with just 2 bolts and 4 locating pegs. One bolt is in the cockpit and one underneath. The tail servos are in the rear section so you just have 2 servo leads to connect up just as you do usually for ailerons.

21/08/2019 15:11:23

Hi Barryt

I'll try and find some photos, I will have them somewhere but in the process of moving house and the pup is in storage. The motor was a big one, and a 5S battery too, simply to get more weight up front. I'd rather have the weight in something useful rather than chunks of lead! Mine might also be a tad heavier in the tail because I used hardwood stringers in the tail rather than balsa. I did find they were prone to breaking here.

Basically I cut a disk of ply to fit just inside the cowl, and glued fixing brackets onto the inside of the cowl to attach it. Then the motor, speed controller, and dummy motor are fastened to that. At the bottom I bolted on a hinge, and at the side are two brackets securely fastened to the ply disk with M4 T nuts attached. Then with corresponding supports in the fus, I am able to use a couple of M4 hex nuts to bolt the assembly in place. There is no join as the cowl slightly overlaps the fus.

You might be better extending the fus a couple of cm to get a better balancing model.

Enjoy the warped ply formers!

20/08/2019 11:18:27

When I built mine, I not only chopped the fus behind the cockpit, and strengthened the wing fixing, but mounted the motor and ESC in the cowl, and fitted a hinge to the bottom of the cowl so the cowl would drop down. Then there was plenty of room to slide a battery in from the front,and keep as much weight as possible as far forward of the CofG. The motor itself sits inside a dummy rotary engine crankcase.

Thread: Prop size and efficiency
19/08/2019 21:33:46
Posted by eflightray on 19/08/2019 20:07:56:

Many many years ago, (nicads and brushed motor), I did some thrust testing for I think it was my first electric model, found and used a prop that gave the best thrust.

The plane wouldn't fly much beyond a sinking powered glide.

Eventually it dawned on me, (Please excuse the the following, I'm not singing it).

'Thrust - It don't mean a thing if it ain't got that swing ....'. for swing read rpm, for rpm read pitch speed.

I'ts the right prop turning the right speed (pitch speed), that flies the model how you want, not just how much static thrust it measures.


Its not just about the "best" thrust. I work on the basis that if the static thrust is the same or higher than the all-up weight of the plane it will fly well. So far I have not been proved wrong with a whole variety of planes.

19/08/2019 14:50:46
Posted by Martin Harris on 19/08/2019 13:29:10:
Posted by Andy48 on 19/08/2019 10:38:49:

Incidentally, before someone comes in and says static thrust does not relate to what happens in the air, I tried a few tests on a very windy day >25mph, and found the static thrust to be within a few % when pointing into the wind and when pointing with the wind.

This is an extremely interesting observation - it certainly flies in the face of accepted wisdom and I'm surprised it hasn't raised any comment. Could you post a picture of your test rig?

Check out an issue of RCM&E some years ago it was in there. No idea which one now, I've thrown it out. Basically all you need is a simple but reasonably accurate luggage scale.

Has anyone ever done any tests on models as opposed to real aircraft, because most data seems to apply to the latter. Take this graph for instance:


Notice the efficiency at 15mph is roughly that at about 75mph. Its only above that that airspeed has a significant effect. Most of my planes fly at up to 60-75mph as measured with a pitot tube air speed indicator. Thus this graph would seem to back up exactly what I found.

19/08/2019 10:38:49

I think those charts are over simplistic. I tried something similar but using a simple practical test rig that measured the actual static thrust and current for any throttle position. I came to the conclusion that there was no simple answer, and now I test every new motor type with a variety of props at a range of different currents. At full power, results are very misleading as efficiency drops off considerably. I do know, contrary to Cuban8's post that the largest prop is not always the most efficient, and there is some difference between different makes of propellor. Also one must consider the maximum current the system can cope with. Too large a propellor can take the current consumption way above what is prudent.

Also in every case, a higher voltage battery (within the propulsion system limits) produced a far more efficient system at half power.

Incidentally, before someone comes in and says static thrust does not relate to what happens in the air, I tried a few tests on a very windy day >25mph, and found the static thrust to be within a few % when pointing into the wind and when pointing with the wind.

Thread: FrSky Neuron ESC
31/07/2019 22:09:20

Yes I know what you mean, the individual cell sensor is great for identifying a low cell in an old pack. Can still use one with the Neuron though. I've adapted a current sensor to work with the XT30 plugs by unsoldering the XT60s and replacing them. This is great for those smaller models, thus I'm never without that telemetry.

31/07/2019 17:08:12

I used an Arduino Nano to program it, very easy.

In terms of size, the 80a for about £6 more seems the best bet, all three are the same size.

The BLHeli suite has some novel features. The model finder for instance, though if the battery is still connected, the tx RSSI signal provides a good indication. (Got the tee shirt in a 4ft high field of rape in flower and a yellow model!!!)

I particluarly like the ability to limit the current to prevent the motor/speed controller burning out.

Its a pity there isn't a full lipo sensor as you say, however, I only find that useful for indicating when a battery is nearing end of life, otherwise the current sensor is far better for judging flight times.

Thread: Voltage sensor
09/12/2018 15:26:17

Many thanks for the disparaging comments Chris, and Onetenor!

I explored the FBVS-01 thoroughly before writing my documentation for OpenTX, and I now have at least 4 X4Rs running with FBVS-01 in them. It is perfectly suitable for the OPs use in a boat using a SLA battery. Essentially it is a simple resistor divider, and as the OP has one it makes sense for him to use it, rather than have to go about getting hold of the correct value resistors.

As so often the FrSky documentation is less than perfect and is not written the X4R receiver. I had to play around with the wiring for quite some time to get it to work correctly. I suspect if the OP follows my documentation, and discovers sensors again, it will work with no problem.

Sadly it seems pointless having spent months and months exploring, testing and writing 250+ pages of documentation when it is rubbished by a few who have never really followed it through.

08/12/2018 18:03:07

CARPERFECT, reflashing the Tx is completely unnecessary, the OP is using an X4R receiver which works perfectly well with the FBVS-01 as shown in the documentation I linked to.

Gordon, basically the FBVS-01 is a simple resistor divider. The documentation I supplied the link to above shows how to wire it up to your X4R.

08/12/2018 14:47:14

The simplest, and smallest, voltage sensor for the X4R is the FrSky FBVS-01. For some reason, T9 have never sold this. It is about £3 from BangGood.


Also the instructions for fitting it can be found in this documentation. Go to Section 10 part 2, the second "How To" section.


You will need a soldering iron. OpenTX can be adjusted to give the correct reading for a SLA battery.

Thread: which is cheaper,IC or ELECTRIC?
06/12/2018 18:44:33

To give you a guide as to what my Wot 4 setup cost:

ESC Emax BLHeli series 80a UBEC £26.00 (Found these heli ESCs work just as well)

Turnigy SK3 4250 500kv 1350watts motor £30.61.

Motor Mount, included with motor

Battery 5S 4000 40C battery £31 (heavier battery balances the Wot 4 without extra weight.)

Charging cost per battery (2 flights at least) less than 1p.

06/12/2018 14:32:04

I've just finished and tested a new Wot4 running on electric with a 13x8 prop. It uses 5S 4000 batteries. With static thrust I get about 3.5kg thrust at full throttle. While I had some batteries, I bought a couple extra, and far from the £60 quoted above, these new 40C batteries cost £30.88 each from HK with free delivery.

In flight, the thing goes like the clappers, as might be expected on 5S. I have full telemetry on board so I can measure the current actually used. At half throttle (plenty fast enough for most of the time) it uses just 15 amps. After an 8 minute flight there is easily enough for a similar length flight again and a 20 minute flight is, as Bob suggests, well within the battery limits provided one is sensible with the throttle. Again at half throttle, there is little stress on the battery and its life will be extended.

There is one thing to bear in mind for those who move over to electric, whilst the relationship between the thrust and the joystick position is linear, the current consumption rises significantly above half throttle. At full throttle my Wot 4 runs at 65amps. Thus if you fly flat out all the time on electric you will get very short flights. Bear in mind that with drag being the square of the speed, you will likely not see a great increase in overall speed flying like this.

As for robustness of motors, I now stick to Turnigy SK3 motors and these have proved very reliable, but cheap. No bent shafts, no bearings worn out and no magnets come loose in the last several years.

Thread: New field needed urgently!!!
02/12/2018 14:16:18

Why not join Teesside MFC, its only 10 miles away, though further for those that fly helis.

Thread: "SD Card Error" warning Taranis X9D Plus
22/11/2018 13:30:50
Posted by Stephen Belshaw on 22/11/2018 06:53:33:

Ok, a bit more detail:

I need to update the Firmware on the radio to match that of OpenTx Companion version in order to eliminate the on screen warning.

I download the correct Firmware version via Companion, connect the radio via USB, delete all contents on the SD card and then load the new version by dragging and dropping - this takes a few minutes to copy. I disconnect the comptuer, press enter to write Firmware and get the message "Directory is missing".

Here's the thing, when I look at the folders on the Firmware I have downloaded I can see files, in for instance Wizard, when I have copied this on to my SD card I look in the folders before disconnecting and there are no files visible. So now I have no Wizard set-up, no model pictures etc.

One thing that crops up is the need to get the opentx.sdcard.version at the root of the directory - I take that to mean at the top of the list above the various folders (Crossfire etc.). I try to do this but it won't let me place it at the top.

You are making a very simple task difficult. If you read the document I referenced above, it shows you a 1 minute cure. All you need to do is restore your previous files to the SD card, then simply edit the text for the version number. Job done.

In your last post you asked if someone could help, I offered the help with a dead simple solution, and you have chosen to ignore it.

21/11/2018 19:13:02

I'm sorry to say but it was entirely the wrong thing to do in deleting all the SD card files. As you have found you have lost any sound and picture files you stored. If you have stored a copy of the SD card on your computer you can recover it.

There are several ways of getting rid of the error message, its pretty trivial, and can be quite annoying.

There is a section in the documentation here on updating the Taranis, and getting rid of the SD card error. it also explains how to update the bootloader.


Check out Section 7 on the Taranis transmitter.

I would also say it is considerably easier to use the Companion rather than using the transmitter for programming especially with the Taranis and X7 with their more limited screens.

Thread: Opentx 2.2.2 flashing problems
19/10/2018 11:54:49

Its likely you have a conflict on the USB ports. Mine does exactly the same. The solution was to unplug the printer cable. My bog standard Canon printer causes the conflict. Try unplugging all USB connectors to the computer except keyboard and mouse.

Thread: Flair Puppeteer wing fixings
14/10/2018 13:12:09
When I built my electric pup I chopped the fus behind the cockpit. This avoids removing the wings. The tail servos are then fitted to the tail section.
The battery is installed by using a hinged cowl which holds the motor and speed controller.
This layout may save you any problems with the fus.The Flair pup kit does not contain complete plans.

Edited By Andy48 on 14/10/2018 13:13:46

Edited By Andy48 on 14/10/2018 13:14:25

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