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

[David Ashby - Moderator]

We were chatting at the patch the other day and got to the subject of telemetry.

 

A few in the club (2 or 3 out of 120) have it and a use it, albeit not every flight but I wondered who is using it? Is it growing in use? Is it the next big thing?

 

Do you use it.....

 

regularly?

every model?

do you find it tricky to see the data when flying?

 

Someone said it could be dangerous, especially the Rx battery voltage readings as this could make people lazy with their battery charging and maintenance care?

 

Would be interested to know what others think.........

 

 

 

 

 

 

 

 

 

 

[James40]

I'm about to purchase the Spekky DX8, not for it's telemetry ability but more for my DX7 running out of useful switches.

 

I think I will use the telemetry once they have a few more features, battery voltage is great but temperature isn't really all that useful. I look forward to altitude and airspeed telemetry, airspeed especially would be handy if used as a stall warning with the vibrating TX.

[r6dan]

Does the telemetry show up live on a screen or is it downloaded after, because if it is live I think most would find it imposable to look at and fly at the same time ( unless you a flying an easy glider)

[David Ashby - Moderator]

It's live on the TX screen Dan.

 

I'm no 'expert' but as a 2.4 RX and TX form a 'link' so data can come back from the Rx and any sensors attached.

 

In this way Rx battery voltage, battery capacity used, rpm, even fuel tank level, speed, height etc. can be displayed in real time.

 

The radio industry is investing in the development but I wondered what the uptake is like and who's using it?

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited By David Ashby - RCME Administrator on 28/03/2011 10:10:47

[Tim Mackey]

Only used it once - on a friends Aurrora set. I could barely see the data screen, and simply stopped bothering to look after a short while. Pretty hopeless TBPH.

I do think the vibrating alarm system on the DX8 is a far more practical way to go - and I would use that to monitor my main flight pack levels, rather than the poor audible timer system - its simply not loud enough, especially when there are noisy IC models flying as well.

I personally prefer to use my inflight logger and examine in detail the data back home ( or at the field on a laptop ( or the dedicated small plug in display screen ).

[James40]

I don't think it will make people lazy with regards to battery voltage etc, I do think it is a very useful tool for warnings though, low fuel, low battery, stall speed are all possibly the cause of many lost models, a simple bleep or vibrating TX is all you need to tell you it's time to get her on the deck asap!

[Danny Fenton]

I use it all the time on every flight. I have the Jeti system and it provides me with real time information on how much flight pack capacity I have used. A real time fuel indicator. Works really well. After the flight you can look through the information for such things as max min volt, max current, avg current etc of the flight pack. I for example know that a go around with my Hurricane will cost me between 300 - 400 mAh.

 

I am really looking forward to the new Jeti Tx's so that I don't have to use a module in my PCM9XII

 

Cheers

Danny

[Josip Vrandecic -Mes]

For now I,m unable to use the telemetry system, but in the meantime, I use, so-called, "Close range method"......control the remaining fuel out of the window.It is only possible in my Cessna 182 ....

[Ultymate]

If it comes with a future setup I buy OK but I wouldn't spend money to get telemetry just for the sake of it.

[Pete B]

On the very few occasions I've flown my DX8 telemetry-equipped Tiger Moth and Beaver, I have to confess that I've forgotten to look at the data, after landing, before switching off the Tx............

 

It is impractical to examine the data during flight, certainly anything more than a very quick glance.

 

The flight pack alarm went off on the first flight as I''d set it at a conservative 3.6v/cell, so I've now reduced that to 3.1v/cell, which should give adequate warning. I don't fly to the alarm, just to the timer.

 

I've suggested to Andy Kunz, the Spekky guy on RCG, that a software upgrade to allow flight data to be written to the SD card be considered by Spektrum, in line with the DX10T which has that facility. I'm sure I'm not the only one who has asked the same!

 

Fortunately, I didn't buy the DX8 just for the telemetry - it is a big advance in versatility on my DX6i and I'm already up to a dozen models on the memory. Other makes may be, I'm sure, just as good or even better, but my investment in Spekky Rx's kept me with the brand, and I'm well satisfied with my choice.

 

When they have an altimeter/variometer module available, which must be sometime soon with the 10T now out, I can see real value in realtime data for sailplanes. They will, I think, need a variation in tone for these functions and, perhaps, use the trainer lead socket for an earphone.

 

Pete

 

[Snorbitz]

I really like the sound of it and it might even convert me to 2.4ghz on that feature alone. Ok you're never going to watch it for the whole flight but then when do you use the instruments in your car....my guess not very often and only then do you just have a quick glance down unless there is an alarm. I think its a fantastic idea. Especially the battery monitor. I use telem data almost every day in my work and it can be very useful.

[Steve W-O]

I have a very efficient telemetry system fitted to my planes.

 

If the battery, or one cell goes low, it makes a nice loud beeping which is transmitted to my ears, and received without taking my eyes off the model.

 

Battery voltage is about the only thing I want to know during flight, however I will be using data recorders to have a look at other data later on the PC.

 

 

I don't have a need for any other information while flying.

[Bob Cotsford]

I'm using the FrSky telemetry on a few leccies to monitor LiPo voltage, and on the Cularis with a vario. It's purely audio, when it beeps it's either a LiPo low voltage (slow beeps) or lift (fast beeps) depending which model it is.

It's useful, but not so vital that I'm throwing out my non-telemetry Rx and replacing them.

I don't think a visual display would be any advantage, just another distraction from flying.

[Danny Fenton]

A flight alarm is great for making sure you land without damaging the cells. However constantly being able to see at a glance how much fuel you have is very useful when trying to get through an F4C scale routine......... when you call a low pass from the right and the alarm goes off you could be in a pickle. Its like driving your car by using the fuel warning light rather than an incremental gauge. The Jeti system actually measures the current and voltage being consumed and calculates the mAh used it doesn't rely on the pack voltage indicating how charged the cells are.

 

Cheers

Danny

[Steve W-O]

Posted by Danny Fenton on 28/03/2011 14:05:45:

A flight alarm is great for making sure you land without damaging the cells. However constantly being able to see at a glance how much fuel you have is very useful when trying to get through an F4C scale routine......... when you call a low pass from the right and the alarm goes off you could be in a pickle. Its like driving your car by using the fuel warning light rather than an incremental gauge. The Jeti system actually measures the current and voltage being consumed and calculates the mAh used it doesn't rely on the pack voltage indicating how charged the cells are.

 

Cheers

Danny

 

 

That's great, as long as the pack was balanced and charged to start with, otherwise I think I would prefer a warning if any one cell went too low.

 

You mean I am not supposed to drive my car until the fuel light comes on? Even worse, i wait for it to start flashing!

 

Some renaults only had a temp light, no gauge, when the light came on, it meant too late, the head gasket has gone. My Zafira has no temp gauge, I hope the light somes on sooner than the Renaults!

[Ian Jones]

I converted my Hitec Eclipse7 to 2.4Ghz (just a module change really) and I hope to use the telemetry eventually, though the Eclipse7 itself can only provide the low battery alarm.

 

I will need a laptop or similar to be able to read and record the real time data. That will be a mixed blessing - I don't have a small laptop but would like one, it's another piece of equipment to cart around and could be cumbersome at flight time and as the data can be recorded then it can be reviewed afterwards - this I think may well be the most useful feature.

 

Why would I use it?

Well the battery alarm I regard as a backup to the checks I make at least every other flight and that extra confidence is very nice. Fuel level monitoring sounds interesting and I think this would be a tool for establishing the duration of a particular aircraft setup then using it next time a similar job is required on the same or another aircraft. Temperature sensors I haven't looked into properly but a warning when an ESC, battery engine or motor is getting too warm could be really usefull. GPS could have some uses more on a club basis I think - for establishing/checking exactly where the aircraft overfly.

 

So I see uses but I don't think we are getting mainstream yet.

 

Ian

[Martin Harris - Moderator]

I use a variometer module with my Jeti in a foamy ASW28 glider which signals by bleeps in addition to the viual display which I've mounted at the top of the transmitter so that I can hold the transmitter up and refer to it on odd occasions. To be honest, it would be better with an earphone socket on the tx module rather than the bleeper which might be annoying to other fliers. I'm a little wary of adding one due to the possible consequences of making modifications to kit which I also use with over 7kg models.

 

I enjoy the security of being able to check the received signal strength at any point in a flight in real time which seems so much better than the artificial low output test we do on the ground and knowing that I can see  the instantaneous voltage at the receiver in flight or during pre-flight checks is reassuring - as is the fact that a calamity might be avoided if I react quickly after a warning bleep.

 

I haven't used any of the EP current sensors as my electric flying is all low end stuff where a BEC out isn't likely to be much of a problem and batteries are cheap!

 

I suppose it's fair to say that it was the telemetry that swung the deal away from a Futaba module when I was looking to upgrade as (from Puffin) I was getting what I considered to be a good quality product  with better priced receivers than Futaba and extra capability.

Edited By Martin Harris on 28/03/2011 15:35:11

[Romeo Whisky]

I've never understood why the screen is positioned at the bottom of most TXs instead of at the top like the good old Sanwa RD6000 series (even the new 2.4GHz Sanwa TXs now have it at the bottom).

 

The Sanwa top screen was so clear and easy to read at-a-glance - and not cluttered with unecessary symbols and other "tripe" (I don't need the LCD screen to tell me I'm flying an aeroplane using a Spektrum on DSM2).

 

On the Sanwa it was so easy to see the count-down stop-watch displayed in large black numbers in centre-screen. If I want to know how long I've got left on the count-down on the Spektrum, hidden away in small blue characters at the bottom right of the screen, I have to hold it up and ask someone else to read it for me.

 

In-flight telemetry sounds great, but pointless if you can't read the data on the screen. If they put the screen at the top and redesigned (uncluttered) the display and improved the contrast a vibration count-down warning would not be necessary.

[Vecchio Austriaco]

Agree to the comments of Tim further up this thread - I personally have even problems to read my timer - especially with sunglasses you see nothing when you look quickly down to your TX. If I would fly some slow glider which is running in the thermals and is self stable this would not be a problem - but I prefer aerobatics which do not stay straight and level forever....

So every optical only system is problematic. If it would be displayed inside the sunglasses - ok. (Also a problem as I am already long sighted)

 

[Richard Wood]

I don't use telemetry as neither of my 2.4 sets (Fut F7 & Spek 6i)

support it, but I'd love to be able to monitor the motor pack voltage

in flight.

As others have said, squinting at a cluttered LCD when flying

is not for me - taking my eyes off a model in flight gives me the jitters.

A clear audible or vibrating alarm seems like a sensible way to warn

the user of a pre-set voltage level approaching & to make a landing

circuit.

The established use of a timer for electric is generally fine, but

there've been times when I've been caught out with an LVC dead

stick - such as more high throttle in windy conditions.

Can set the timer lower for these situations of course.

 

[Former Member]

[This posting has been removed]

[Martin Harris - Moderator]

Apperently the Jeti sytem with signal strength feedback can be used as a model finder - I haven't had to try it out yet (much wood touching) but I can't see why it shouldn't work effectively using the lowest signal from a pointed* aerial.

 

(* pointed at - not sharpened )

[Erfolg]

With the viewpoint of a glider guider, I can see the point of Telemetry.

 

I would be able to see when I gained and lost height during the power off phases, I would also have some indication to how high I acheived during the motor on periods, it could also indicate the angle of climb (or would it).

 

Knowing typical airspeed related to the various phases of operation could also be useful.

 

All of this data I would want to view later, very little in real time.

 

From time to time we do have a flyer who uses a Jeti system (I think) which does provide some interesting data. I was somewhat surprised how fast gliders can fly when penertrating, or moving to lift.

 

Real time data in the form of a variometer is possibly the most useful o me.

 

The biggest obstacle for me, is one of cost.

[Chris Bott - Moderator]

I have the DX8 and find it very difficult to look down to during a flight. However there's nothing to stop you having someone else look at it and keep an eye on the numbers. I would like a mAh used facility, like the Jeti. That would be really useful.

 

I think the most useful thing I've used it for so far was to keep an eye on a brushless motor temperature that I was worried about. Once I knew the cooling was adequate, telemetry came out of that model again. (It wasn't possible to access the motor quickly after landing for a "feel")

[Lazygit]

Posted by Danny Fenton on 28/03/2011 14:05:45:

Its like driving your car by using the fuel warning light rather than an incremental gauge.

Our fuel gauge packed up more than 10 years ago. Been driving on the warning light and trip meter ever since. Never ran out of fuel as we make sure we have enough in reserve.