Telemetry - do you use it? What do you think of it?

[Martin Harris - Moderator]

I've recently upgraded to the Jeti Profibox - now instead of having a beep to identify an alarm (I can never seem to remember the different tones) it tells me what the problem is in clear (slightly Czech accented) English. That, and the ability to display multiple parameters on the screen has made what was a very useful feature into a highly user (and with the earphone jack, flight-line) friendly system.

[Danny Fenton]

Nice one Martin, I am still on the older Jeti box, will the Profi work in place of the original box do you know?

If Jeti would just bring out the DS16 I would be a happy bunny. Latest is January now

Cheers

Danny

[Martin Harris - Moderator]

You have the option of using it in monitor mode where it gets info wirelessly from the airborne receiver - the box has an internal battery or can be used attached to the transmitter via a link from the transmitter data port like the old one. Wireless mode means someone else can monitor the telemetry or download it to a PC display in real time. The box can be set to store all in-flight parameters for download later as well.

In addition, the box can be used as a standalone transmitter module with full telemetry. To this end, they can supply a bracket and connector with flying leads for wiring permanently. This is maybe a bit pricey on the face of it (@£15) but it fits the box perfectly and I've invested in one to mount my box in the ideal place where it is possible to take in the clearly displayed information during non-critical phases of flight if you fly hand held and can raise the transmitter to the eye line.

I've been using mine in this mode and have removed the old module and replaced it with an old empty Futaba module casing to protect the pins.

The new box works as the old box for non-EX modules and settings changes on receiver parameters but with a much clearer display. An instant and vast improvement to the Vario module that I have is that the climb and sink indications are now very clear - the old beeps weren't very easy to distinguish between.

As an interim solution to investing in the new transmitter (my FF10 still feels too new to be contemplating replacing) it seems to tick virtually all the boxes - and will do when they get round to releasing the software that will allow me to upload my own sound files.

[andy harrold]

I fly FrSky telemetry. just the basic beeps for low signal strength and battery.

In my 3m moulded glider it it reassuring . I get the occassional beep when aerial orientation is not ideal.

I have also put it in travel air type planes. if you do a poor install of the aerials it will soon let you know! It will give a lot more beeps than usual but at least you have the opportunity to fly it back to a safe landing unlike non telemetry where the first tell tale signs mat be the walk of shame!

i have never had it beep for low volts. I wouldnt trust it!

andy

[Eifion Herbert]

What would I need if I wanted to put a vario on my Radian? I find it hard to tell sometimes if its climbing or not. Currently I have a Spektrum DX6i, so I think I'd need to upgrade the TX at least. Had a look at their website and they've got an altimiter module that will transmit to an iPhone / iPod but doesn't seem to have a vario function.

[Chris Bott - Moderator]

Eifion if you want a vario function there are a few options.

With Spektrum radio, you'll need at least a DX8 transmitter. Even to use the iPhone app and dongle you need a telemetry capable transmitter. Spektrum only have the altimeter at present but apparently a vario is in the pipeline. I use the altimeter with a glider and the iPhone speaking height every 15 seconds. It's very useful, but a vario would be better.

Futaba have a single sensor that does altitude and vario.
I think Jeti have the same.
Hitec seem to only have the vario.

[Frank Skilbeck]

For Futaba FAASTEST, JR DMSS, JR Graupner HOTT, Jeti and Multiplex M Link users check out the SM Modelbau Unisens E sensor, volts, amps, mah, height, vario and motor speed all in one neat little unit.

For Vario to be really useful you do need the rising tone output and a sensitive sensor, and the ability to switch the tone on and off in flight is also useful

[Frank Skilbeck]

For Futaba FAASTEST, JR DMSS, JR Graupner HOTT, Jeti and Multiplex M Link users check out the SM Modelbau Unisens E sensor, volts, amps, mah, height, vario and motor speed all in one neat little unit.

For Vario to be really useful you do need the rising tone output and a sensitive sensor, and the ability to switch the tone on and off in flight is also useful

[Ian Jones]

Posted by Chris Bott - Moderator on 22/04/2013 08:58:35:

Eifion if you want a vario function there are a few options.

With Spektrum radio, you'll need at least a DX8 transmitter. Even to use the iPhone app and dongle you need a telemetry capable transmitter. Spektrum only have the altimeter at present but apparently a vario is in the pipeline. I use the altimeter with a glider and the iPhone speaking height every 15 seconds. It's very useful, but a vario would be better.

Futaba have a single sensor that does altitude and vario.
I think Jeti have the same.
Hitec seem to only have the vario.

 

Hitec have had a GPS altimeter for some time and can be set to indicate height above sea level or relative to the ground. They recently introduced a vario too. The Hitec Eclipse 7 Pro will emit sound for climb and sink so I presume othe Hitec transmitters do to.

 

Edited By Ian Jones on 22/04/2013 10:07:11

[Simon Chambers]

I wouldn't recommend the Hitec vario, as there has been a lot of complaints about its usefulness.

Here is the response from Mike Mayberry - a Hitec USA representative (I think the sales manager for Hitec USA now):

Hitec USA has chosen to discontinue the Vario and any combos including it at this time until its implementation can be improved. If you have purchased one and are unhappy with it then please contact us and we will swap it out for something of equal value.

Mike Mayberry
Hitec/Multiplex USA

If Hitec USA have stopped stocking it.... 'nuff said really!

Si.

[Eifion Herbert]

That's interesting, I guess the Hitec GPS unit will work with the Aurora 9, which can be got for a decent price, and I'm fast running out of memory slots on my DX6i. So do I go for a Hitec, and keep the DX6i untill such time as I can buy a bunch of Hitec receivers, or upgrade to Spektrum's DX8, hope the vario unit comes out soon, and not have to switch recievers, or get a Hitec, keep both Tx's and use the Hitec for things I want telemetry with. Hmmm, never easy is it!

Editted to add-

Just seen Simon's post, guess that puts paid to the Aurora 9 idea...

Edited By Eifion Herbert on 22/04/2013 11:12:54

[Ian Jones]

Good find Simon.

I haven't used the GPS with Sink/climb sound switched on yet, I would presume it's intended just for the vario but as documentation is sparse I'll go out and try it. If that works with GPS it would be something useful though I doubt that it would be as accurate/sensative as the vario.

The GPS works the with the Aurora 9

[Chris Bott - Moderator]

Spektrum also have a GPS sensor, and a couple of G force sensors that might do the job.

[Martin Oldershaw]

It's a shame that a lot of this telemetry doesn't include a speech module. Connecting with a phone (and I know a lot do it without issues) goes against general advice. I hope FrSky develop one soon because their prices are amazing **LINK**. At the moment because I want speech I'm using a HOTT system and find the vario pretty good but do have to take in to account about a 1 sec lag.

[Bob Cotsford]

The FrSky transmitter due out soon is shown as having a speech module, should be interesting if it comes in at the promised £130 mark.

[Ian Jones]

I've just been to the Greenacres/RCM&E Summer Fly In, the weather was pretty awful and by way of various unfavourable events I only had fairly light wind loving models available.

One of them was my Sportster from RCME Vol 41 Issue 13 (£2.65) 11 Dec- 7 Jan 1999. "A classic 30s sportster for .26 4stroke". It seems was originally in the "Flying Aces" pages of March 1935 Aero Modeller, rubber band powered & approx 15" span. It would hardly seem a contender for 18mph gusting 38mph then.

However it does have telemetry on board and from that I learned that in level flight at full power it achieved 45 mph, in a not too severe a dive it could just touch 70mph and a fast landing speed would be 12-15 mph. All this into a 5mph headwind.

So, back to the Greenacres story... and the question to fly or not to fly and with what. Well armed with the above information I reckoned that the Sportster would at least be able to make slow progress into the wind so that was reassuring to know and it also made it clear that a powered landing would be required. This model usually lands so slow that anything more than tickover and it won't come down! (Yes, that was the hard bit but isn't it always )

I took her out into the gusting wind twice and sure enough she coped, it was tricky but it wasn't a gamble thanks to telemetry.

[Bandit]

Hi sorry to come in to the conversation so late, don't know if anyone has seen this idea:

**LINK**

Good idea I thought

[..]

I am just about to upgrade my TX and have been looking into the telemetry thing. At the moment I use a Futaba 7c and have been very happy with it from day one.

Having looked at my options the Futaba 14sg seems to tick all the boxes in terms of what I want however its telemetry capabilities don't really do it for me at the moment. The only feature I can see that I would use is the RX battery low voltage indicator.

I had a chat about telemetry capabilities with a club mate at our club Christmas party this week , the guy in question is a full size glider pilot to so talking about anything flying related is with him is always interesting. He is also telemetry capable so to speak but doesn't use it . During our chat he came up with an interesting comparison involving photography and having an all singing & dancing camera at a live event then despite getting some great pictures you realise you missed the actual event.

So I have decided to buy the radio via the TX only option leaving the telemetry option open for the future if I feel the need .

[ken anderson.]

I don't have the telemetry in my radio gear - but I do know people who do...and mainly use the altimeter ......but after a while you get sick of listening to the thing telling you how high your model is........as regards the other functions you can have-I think that they are handy for a certain percentage of modeller's ....but a novelty to most.......(my opinion) ...

 

ken Anderson n e...1 ..novelty dept.

Edited By ken anderson. on 14/12/2013 09:50:47

[Frank Skilbeck]

Having used telemetry for over a year, I would tend to agree that for IC its a nice to have, knowing the condition of your Rx battery and being able to see the signal quality are reassuring features, I didn't realise that a couple of batteries i was using that came up fine on the battery checker were well down after just 3 flights. But for electric planes I find the amps and mah used really useful and much better than relying on a timer, also useful to get real inflight performance checks on your flight batteries. For gliders the vario capability is also quite useful in catching those elusive thermals.

But for a the regular sport IC flying then the benefits are not that great.

[john melia 1]

its a good idea for monitoring rx packs , but I'm using life rx packs now and I dont think telemetry is any use for them . or is it ? am I wrong

[Frank Skilbeck]

If you check the Rx pack voltage frequently to tell you how much is left then probably not, but you do get a reading of Rx volts so can see without having to plug a checker in what the life pack voltage is and as this is like a Lipo the resting volts are proportional to the % mah left.

I had one case where I was able to grab some quick flights one day even though I'd not charged up my Rx pack, the telemetry keeping me informed on the Rx pack.

[Stuart Eggerton]

I have recently purchased a variometer from Wstech and this device gives all sort of information to the pilot. Climb rate in a thermal, altitude, ground speed (air speed if an asi is fitted). Glide ratio and battery voltage. A great bit of kit for a glider pilot

You can even view your flight track in three dimension on Google Earth and this will be great to find thermal "hot spots" on the field.

Edited By Stuart Eggerton on 14/12/2013 15:09:29

[Simon Chambers]

Posted by Frank Skilbeck on 14/12/2013 14:53:42:

the life pack voltage is and as this is like a Lipo the resting volts are proportional to the % mah left.

Becareful, the discharge curve of LiFe packs is very different to LiPo. LiPo as you say will drop the voltage fairly proportionally as pack depletes. However LiFe packs have a dead flat discharge curve - so voltage alone is not accurate on remaining charge.

So between 5% and 85% discharged, you're looking at less than <.1v per cell difference. So if you check your pack before you fly, it could be just as easily 85% discharged as 5% discharged. Obviously taking off at 85% used could be a very different flight from 5% used...

This makes telemetry even more useful, as if the voltage starts dropping, you know you're at around 90% discharged and need to land immediately.

However the flat discharge curve does mean that the servos will operate (speed and torque) in the same manner whether the pack is fully charged or part discharged - especially important and useful characteristic for acrobatics. Also the very low self discharge means that the pack will stay fully charged and given they are lighter than the equivalent ​NiMh packs, you can fit a larger pack in the first place (having more flight capability and negating the discharge problem above).

Si.

[Simon Chambers]

Incidentally the discharge curve of NiMh packs has the same 'fall off the cliff' style drop at the end like LiFe packs do. Given that there is only around 100mV of difference in pack resting voltage between 5% and 85%, again you can't accurately gauge the charge level of a NiMh pack based on voltage alone. In fact, most of these so called battery life remaining checkers only have around 25mV accuracy anyway.

You really don't want to be in the air when the pack hits 1v per cell! I reckon the majority of receiver 'brown-out' problems are caused by receiver packs that are almost flat. Draw a 5A load (easily achievable with most modern servos) when 1.8Ah have been consumed, it'll go from 1.2v a cell to 0.8v a cell - 3.2v for a 4 cell pack. A lot of receivers operating on 3.2v will brown-out and then reset.

Si.