Negative altitude RTH

[Davis476]

Hi everyone,

I was wondering how RTH feature would work if say you launch the phantom from a cliff or bluff and then navigate at a lover altitude than the recorded home position. When fail safe is engaged will the phantom ascend to 20m above the recorded home point altitude? Or sea level (barometric) altitude?

If the latter is true, RTH might result in the phantom hitting the cliff side...

Any thoughts?

 

[Shrimpfarmer]

I have been having the same thoughts. Here in Sussex we have the White Cliffs and I would like to fly my phantom down to the lighthouse. That would be a few hundred feet below my launch altitude.

 

[Peter Patricelli]

The whole process is based on the GPS/Home lock system. The bird knows your take-off position AND the altitude. It's programming is to, when the RTH routine is initialized (by various means, including loss of transmitter signal) maintain its altitude IF that altitude is > 20 meters over home altitude OR ascend until the bird is 20M higher than the home altitude....and fly directly to and over the home lock position. So, yes, the bird should ascend from a negative altitude position.

Make note....the whole process is straightforward by the numbers and BLIND. If there is anything BETWEEN the bird ascending to the programmed height or BETWEEN the direct line to the home position at whichever altitude the bird is coming back on....tough ***** . The RTH system is supposed to be a last ditch, emergency process....not perfect or to be used lightly, but better than nothing.

 

[fly-catchers]

I have been having the same thoughts. Here in Sussex we have the White Cliffs and I would like to fly my phantom down to the lighthouse. That would be a few hundred feet below my launch altitude.

I was thinking it would be cool to film the Beachy Head lighthouse.

 

[Shrimpfarmer]

I have been having the same thoughts. Here in Sussex we have the White Cliffs and I would like to fly my phantom down to the lighthouse. That would be a few hundred feet below my launch altitude.

I was thinking it would be cool to film the Beachy Head lighthouse.

I did this about 6 years ago with my Raptor 50 Helicopter with a digital camera strapped to it. I had no control of where the camera was pointing and of course no video downlink. Needless to say the Raptor had no technology at all to hold its own position either. With the Phantom this will now be a fairly simple flight I reckon.

This is what I got last time. I remember being so scared flying it over the edge of the cliff.

https://www.youtube.com/watch?v=TXmdIMVARSc