Telemetry - talking radios

This is a new thread for discussing the pros and cons of telemetry, and who has done what and why?
I was inititially impressed by Jay's telemetry which gave him vocal feedback on airspeed and fuel capacity on his Jeti based system; so I decided to see what I could do to alleviate the problem of not always being sure when my models were over-the-hedge on landing approaches. I discovered that my Futaba T14SG Tx was capabable of voice telemetry if I fitted an external speaker to the earphone socket. I then purchased an R7018SB Rx and a Futaba FASSTest Telemetry GPS Sensor P-SBS-01G. I found with some experimentation that I can set up my Tx to give me an alarm when my model is inside a programmable radius from the Tx. I have also set the Tx up to give me vocal indication of speed (OTG at moment) and distance, but enabled only when the flaps are down (i.e when landing). It all works to plan on the ground, and I will be trying it out soon to see how it work in the field (on an older model first of course). Ps my telemetry also gives me warning of low Rx battery, altitude, and speed limits.

John - Very interesting, I look forward to other inputs, with increased use of such voice systems
is there any guidance on the use of ear pieces.
I will continue using my vintage Mark 1 eyeballs which are still serving me well.

Colin.A.

Earpieces have the disadvantage that they mask other alerts and calls, whereas a speaker has the disdvantage that it can be distracting to other people in the box. Personally I think that telemetry is great for "mission crtitical" information but I really don't want to be be subjected to the entire altitude profile of someone elses glider with updates every 10 seconds just because it can!
I am sure some controversy will come with this thread - lets hear it

I have experimented with voice telemetry over several years now and 'as we all do' started with it telling me everything every 20 seconds or so. Soon switched it off! Even I got fed up with the constant 'Babble' which was often many seconds out of date as it joined the digital queue for voicing.

However, I find that different model types benefit from different messages. I often set an over 400' alarm (in models with telemetry) for models over 7kg when flying in areas that restrict height e.g. FIR or restricted airspace, not our field because it is NOTAMed as higher. The two main things I find really useful is regular voltage readouts for the motor LiPo on electric models, to prevent over discharging or that rapid power fade at the end and the Time to Go on countdown timer readout (usually every minute) when flying turbine models, which prevents eyes being taken away from flight observation to alleviate estimated fuel remaining anxiety!!!

The alarm function is good for things that are really difficult to judge accurately, which is not usually speed as we have all become quite adept at this, more by how the model 'feels'. However, height and distance can vary significantly with different model sizes. I am a trained Met Observer who has been judging height of cloud for most of my Air Traffic Control Career and found I was way out on model height, once I had something to measure it with, we fly a lot higher than we think!

JRI wrote: ..........set up my Tx to give me an alarm when my model is inside a programmable radius from the Tx.

I'm going to move the pilot's box 10 meters closer to the hedge

Dave,

Knowing how most modelers have very fixed habits/rituals it would probably be easier to move the hedge 10 mtrs closer to the pilot box!

DaveBright wrote:

JRI wrote: ..........set up my Tx to give me an alarm when my model is inside a programmable radius from the Tx.

I'm going to move the pilot's box 10 meters closer to the hedge

Bothered? I will use my pocket gps to plant my feet in exactly the right place then my laser distance meter to check the hedge is where it should be - and if you find a small spot on the back of your head getting warm, I might well have forgotten to turn it off

On a more serious note, until someone brings out true imminent stall sensors (e.g detectors that can measure airflow breakaway over wing leading edge) speed measurement is of limited value, other than speed freaks proving how fast their model went on the 'beat up'.

In a naive attempt to see if speed info could help inform me about how my model was flying I had set the Air Speed Indicator (e.g. pitot tube detected, not GPS detected, which is only ground speed) lower speed alarm on my Sebart Suhkoi 50e at 10mph (having started at 20mph) thinking this would give me some sort of warning for 'about to fall out of the sky' but it triggers regularly in the vertical maneuvers and still appears to fly quite happily below this speed in straight and level flight, dependent upon power setting/angle of attack etc. The other problem is that the way the Spektrum telemetry works is that the various sensors are scanned in a set order, so until the telemetry module gets to the info from the particular sensor it doesn't do anything, then seems to take a while to transmit info back to the Tx, look the info up in the alarm table I have set within the TX and then convert it to voice info for me to react to. Stall warnings in full size aircraft usually give you, at best, a second or two to react and are regularly sounding during the flare and touchdown, just watch/listen to any You Tube video of a light aircraft landing taken from within the cockpit.

Of course once one learns about the complexity of the stall, (angle of attack, C of G, G Force being pulled, bank angle, overall weight, air density etc. etc.) a reliable stall warning is just not possible from air speed alone. This is why we modelers become such good detectors of the imminent stall by how a model feels. Our models give good visual feedback (wing wobble, nose nod, looking mushy in a turn etc), which along with the increasing control inputs we are having to make to maintain control give us much more instant and reliable feedback in most cases. We just need to develop/improve our mental processing and reaction response to prevent the stall occurring.

JRI wrote:

DaveBright wrote:

JRI wrote: ..........set up my Tx to give me an alarm when my model is inside a programmable radius from the Tx.

I'm going to move the pilot's box 10 meters closer to the hedge

Bothered? I will use my pocket gps to plant my
feet in exactly the right place then my laser
distance meter to check the hedge is where it should be - and if you find a small spot on the back of your head getting warm, I might well have forgotten to turn it off

:woohoo: LOL