[secant0give]

You don't need Telemetry to learn to fly RC just as Gazz and Claudio have pointed out.
When your learning to fly you need all the head space you can muster untill things become reflexive and telemetry can unnecesserily add, to an allready heavy work load.

FPV is another matter and the telemetry in my systems is overlayed on the video display handily there is no seperate TX for that as it all comes over the AV link and is recorded on the HDDVR in real time.

Having said that I use telemetry on all my bigger non FPV models. As Kieran mentioned I use the FRsky system and I like it. It's cheap reliable and simple, the alarms I use are all audible, Tho' it can be set up to log all sorts of data on the ground or even plug it in to you lap top, I think there may be a Phone app for it as well.

Why do I use it you might ask ?
1) I monitor RSSI which stands for recieved signal strength Indicator. (this alarm has never gone off) But it's handy to have there and adds confidence basically it monitors the performance of your RC link. Something that must work 100%

2) I monitor the voltage of the powersupply that goes to my RC link and servos. This is a seperate alarm also audible

3) I monitor the voltage of my flight packs, this has a two stage alarm.

The latter is the most usefull. It lets you use a number of different lipo packs with confidence that you won't run out of juice.
Also it enables you to run very close to the money as far as getting the maximum power to weight out of your system.

How you might ask ?

Well when you set up your system with a motor, ESC, prop and battery that is all right on the limit, you can only run it at maximum power for a short burst. You'll see this on motor, battery and esc ratings, something like, so many amps continious and so many amps for 10 seconds. Some very wise people set up their models so that no matter what they wont burn them out by matching there power system components so they can't exceed the continious rating.

However I like to use the burst rating, all of it, why not lets face it it's there to use isn't it, but not for too long other wise the smoke will get out.....right? A 5 second vertical rolling climb at max power looks and sounds great !!...........and it's fun too.

When you draw heaps of current from a lipo pack, enough to put it in that 10 second burst mode, the voltage begins to fall steeply. This doesn't mean that your lipo pack is discharged, just that it's right on the limit and cant give any more. The internal resistance of the pack is limiting the power it can put out and you'll see this in the voltage drop across the battery. As soon as you start drawing less current the voltage rises again and we fly around happily in continious mode.

What I do is monitor the lipo packs voltage and set the telemetry to make an audable alarm when it drops below that voltage threshhold. The FRsky allows two alarm tones one more urgent than the other so there are two voltage threshholds to use for giving the pilot an idea of how the hard system is being pushed and what's left in the pack. I still use a timer for all my flights.