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Member postings for Tim Ballinger

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

Thread: The Norwegian Gnat Squad
06/04/2020 09:48:22

Lucas,

what is clear is that thrust to mass ratio is crucial with all the mini jets. The gnat is perhaps the leanest but still needs max thrust to get away from a hand launch in light winds. I spent some time testing with larger cheat intakes to get the figures I quoted. I only managed 2 sessions between flooded fields and virus lockdown but it flew away with virtually no dip.

Can not help much on the glue front except to say that a couple of folks have had the fan come loose when it belly flopped following a failed launch so make sure it is secure. I used multiple hot glue blobs .

Timz

06/04/2020 09:09:08

Lucas,

sounds as though it could be a bit marginal to me. My static tests gave me 42A , 600g thrust at 49000 rpm ( the rpm figures in the static test I showed in the build blog were out by a factor of two as I confused poles and pole pairs when calibrating the rpm sensor). Those figures were with a newly charged 40C battery. I’ve seen others measuring 38A but not sure of the battery status.

Tim

Thread: New EDF Mini Jets- Jet Provost & Folland Gnat
01/04/2020 09:39:29

Barry,

Glad you seem to have sorted your power problem. I assume you are concluding that the original 4S fan was faulty?

Interesting that the blades are interchangeable, I had assumed there would have been a pitch change as well as a KV change between the motors but it does not seem so from your comments. Did you measure the max current as an insurance ?

Tim

Thread: Forum members' new models: Let's see them.
30/03/2020 19:40:34

Nice model and even more luxurious modelling bench !

Tim

Thread: Clevis, Thead, Crimp, Glue or Solder
29/03/2020 15:33:32

Just been fitting rods to the end of snake inners and ball clevis’s using the aforementioned 2 mm threaded rods. These are soft and threads cut easily if required. I find the rods just the right diameter for screwing into the inner but of course a 2mm die is too large. Being old and grey I still have some BA dies and an 8BA cuts just enough thread to make a good screw fit into the inner. The rolled 2mm threaded end screws into the 2mm ball clevis as is.

I suppose I could buy a smaller metric die but in this case ‘old’ money works just as well.

Tim

Thread: The Norwegian Gnat Squad
29/03/2020 13:02:00

Lucas,

Several of us started off before the mass build evolved and we all just chipped in snippets to Tony’s original build log which actually cover all the mini jets but I suppose mainly the JP and the Gnat. This the original thread......

All Forum Topics > Tony Nijhuis plan builders > New EDF Mini Jets- Jet Provost & Folland Gnat

Tim

29/03/2020 09:38:59

Hi Lucas,

Glad to see you have started. You probably noted from earlier build logs that some of us found making the wing join much easier as you do the final assembly into the fuselage. It is a bit of a fiddle with the completed wing and you stand a chance of breaking balsa as you manoeuvre them in. Others seem to manage ok but I decided to join in situ after making sure the brace was a perfect fit of course.

Tim

Thread: recommendations
28/03/2020 16:14:35

I standardised on 4Max esc having monitored the SBEC voltage output on several others and not been impressed. Even then on anything precious I always used a separate BEC for the Rx. These are always clean and constant.

Having said that I am now trialing 2 FrSky Neuron S Esc. Again clean and constant output trace on the telemetry. Big bonus is they have inbuilt voltage, current, temp and rpm sensors which for me easily offsets the extra cost. Despite the extra sensors ,they are also the smallest/lightest around. You need to be on FrSky Sport compatible Rx’s of course. Not been released that long so yet to have a view on their longevity/reliability but they look well engineered.

Tim

Thread: New EDF Mini Jets- Jet Provost & Folland Gnat
27/03/2020 18:47:26

Barry,

it is now many years since I finished in the aircraft industry and jet propulsion in particular. So with the huge caveat that there is a huge scale effect involved which generally makes small scale less efficient....

First thing is that thrust is made up of change in momentum of the air flow and the difference in static pressure at exit multiplied by the exit area ( there is also a drag associated with intake flow but I will ignore that). If you push air down a convergent tube it will increase the speed and reduce the static pressure. There is an optimum balance to be had between the increased momentum and loss in static pressure. So one thing early to note is that engines generally have jet pipes and nozzles. The jet pipe is really just a means of getting from the engine to the nozzle. The longer it is the less efficient it is. What we really have in our small scale gnat is just a long jet pipe .
I have never undertaken measurements at this scale so I am just guessing that the jet pipe gives more losses than any marginal increase in momentum.
I guess the thing to remember is that all the input energy is in the fan , after that you simply exchange one form of energy for another. If it is an inefficient exchange you will loose out.

Just ramblings of an old engineer . At this scale You really need measurements to find the sweet spot.

Tim

Thread: FrSky Major Update for most TX and RX
26/03/2020 19:01:41

Andy ,

Thanks. Hope it cures your problems. There are not too many of using the FrOS so you have to be, shall we say, resourceful at times.

Tim

26/03/2020 16:51:29

Andy,

Sure you are aware but just in case, that is only a beta version and it is down for a new beta as soon as they can sort out the sensor/telemetry peaks. Might not be too long I am guessing as they seem very keen to turn their attention to ACCESS viz ACCST D16 problems.

Bob, While I ‘m happy to wait a bit longer , luckily for me, I can fly my glider and some models from my own field so as soon as I think the odds are better with new than without I’ll make my move.

Tim

26/03/2020 12:29:43

Andy J,

I think that The latest GRX Rx’s firmware are only available as betas atm so if you only used the 16 Jan firmware That may be the issue but you would need to check on that one to be sure. The RX8Rpro was updated along with the Horus update on 24 March which is why it was ok.

Tim

26/03/2020 12:16:46

Allan,

Just my view you understand.

if you check the Rx’s noted above that still have bug reports and you do not use them then I think it is probably time to implement the latest firmware release for Tx and Rx’s. Personally I use a Grx6 which is in the list but the odd spike in telemetry value does not worry me and has probably always been there. The miniature Rx (XM series) looks more concerning , to my eyes these mainly input into flight controllers via Sbus . I do not use those. If you use stabilised Rx,s then there looks to be some issues to sort out.

Tx dependant issues were the big one at the first release, I am seeing less ( perhaps none) of those reports now but as I am a Horus user on FrOS I tend to concentrate on anything in my camp .

I am in still in no rush to update but I will do it in the next few weeks if nothing drastic is flagged up.

None of that may help you but that’s where I am atm.

Tim

25/03/2020 17:00:26

Congratulations you’ve become the first tester and now the expert !😉

25/03/2020 16:16:49

Andy,

You select the bin file according to name that matches your setup . Yesterday’s release has 3 options EU, NEU and Flex. EU means LBT so that is the one you should pick. Some upgrades also select by mode but I am not sure why.

Always bearing in mind I have only ever undertaken 3 firmware upgrades so they might do something different each time. Release notes are to say the least ‘ very brief’.

Tim

Edited By Tim Ballinger on 25/03/2020 16:17:21

25/03/2020 12:28:26

Andy ,

The iXJT is in the main bin file for FrOS updates that is why it is not in the latest FrOS download as an explicit item. Plus had it not been included your original Rx would still have worked.

At least that’s how I read it. OpenTX loads it separately I believe.

Tim

25/03/2020 12:10:05

Mike,

I see this from the github testing

Sounds like there are still problems despite the full release. Any advice?

  1. Receiver XM/XMP
  • RSSI output wild fluctuation
  • SBUS output FS bit is not set correctly
  1. Receiver G-RX8/G-RX6
  • Telemetry data peak issue
  1. Receiver S6R/S8R
  • S8R quick mode startup slowly
  • S8R works with RB20 without telemetry back
  • S8R Aileron Inversion Problem in V-Tail-mode
25/03/2020 08:54:53

Andy,

The December issue of 1.3.06 is fine. It did not include the iXJT upgrade and did not need the Rx upgrade.

I assume the iXJT upgrade from the jan release would be removed if you re flashed with an older firmware but this is new ground for me so I can not be certain. Certainly the December release would not work with the upgraded Rx.

The Rx upgrade process change is I guess not unexpected as the System Files capability was only added in the December release.

Absolutely right about keeping backups of old versions, I have all my Working Rx firmware files archived.

Sure more help will come as folks assess the virtue of the latest release.

Tim

24/03/2020 18:11:09

Andy,

As I mentioned earlier I was not undertaking this upgrade (16 jan) until it had been debugged and a new version issued. That said I have not seen any reports of Suitably updated Rx’s not binding.
I did not know about today’s releases of Tx and Rx firmware until I read your post. I see it is there now but will still wait for good reports before doing it so Not sure I can help you.

What I would do in your position is upgrade the Tx firmware to 1.306 as issued in December and make sure that works. That functionality I can vouch for as I have been running it since it came out.

Tim

24/03/2020 13:27:02

Mike,
Thanks, I always like to know how things work.

Tim

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