Power Experiment

[rogellis]

I guess we could disable transmit on any stationary type other than helicopters ?

And gliders, stationary in wave (zero groundspeed).
And balloons, drifting in a 2 kt wind.
And hang-gliders, when they get the mini-PAW.

R

[rogellis]

I don’t think that the Flarm units stop transmitting, more that the receiving units are programmed to filter out stationary units (I believe that the full Flarm string includes velocity and heading along with position and height) how this is handled in wave I don’t know.

Indeed, but that velocity would be gps groundspeed, not airspeed. 
So if a glider was gps stationary in wave at 6,000 ft (doing 40 kt into a 40 kt headwind), it would be filtered out - which would not be very useful.

R

[exfirepro]

Indeed, but that velocity would be gps groundspeed, not airspeed. 
So if a glider was gps stationary in wave at 6,000 ft (doing 40 kt into a 40 kt headwind), it would be filtered out - which would not be very useful.

R

In determining collision risk, FLARM’s algorithms must therefore presumably take into account ‘height above ground’ rather than simply ‘position’.

Regards

Peter

[rogellis]

In determining collision risk, FLARM’s algorithms must therefore presumably take into account ‘height above ground’ rather than simply ‘position’.

I am still not sure that Flarm does this, because most Flarms will not have a terrain database to derive the airfield altitude from.  Certainly the cheapo Flarms used at our gliding site do transmit on the ground, as always pick them up while flying.

I might suggest that the more ‘professional’ flyers at Lasham are keeping their electrics off until the last minute, to save power.  There are so many instruments in modern gliders, and running out of battery power on the way home is a minor calamity.

R