Vision Plus lost

[Big Ben]

Winds at altitude will quickly become much stronger than at ground level. And those pretty clouds? Were they perhaps Cumulus clouds? Those are the ones with thermals below and inside them glider pilots are so fond of because the air also has vertical speed there.

If the Phantom enters a thermal which at cloud base will be (much) stronger than at lower altitude it will be sucked into the cloud. I have flown near cloud base in gliders and you have to fly a lot faster there to keep descent rate big enough to not enter the cloud which in VFR flights is NOT allowed, and for a very good reason. If the Phantom tries to maintain altitude it will slow down its motors giving it less ability to move horizontally. In a situation like that it is quite likely to be moved horizontally at considerable speed.

I'm afraid too many people have too much blind faith in the abilities of the Phantom. They are very limited in those abilities and are far from foolproof. You are dealing with many real aviation aspects when flying a Phantom and people need to acquire the knowledge necessary to fully understand these. Same as people have to do in 'real' aviation. You're not allowed to fly up there unless you have proven to have the proper knowledge and experience. Since there is no requirement (yet) to do the same when flying model aircraft it's up to each individual flying them to make sure they do have the necessary understanding.

 

[pault]

Agree that some kind of updraft might have got hold of your aircraft, you mentioned a storm earlier in the day so there may have been a lot of energy around. Also agree with the idea of doing a calculation based on wind direction, altitude and the amount of time it would have taken to fall from that height. Just might help you narrow down the search a bit.

Really hope you get it back and I really must get a tracker for mine. As you say, it is so easy to become complacent as 99% of the time these things behave perfectly.

 

[proximo]

Winds at altitude will quickly become much stronger than at ground level. And those pretty clouds? Were they perhaps Cumulus clouds? Those are the ones with thermals below and inside them glider pilots are so fond of because the air also has vertical speed there.

If the Phantom enters a thermal which at cloud base will be (much) stronger than at lower altitude it will be sucked into the cloud. I have flown near cloud base in gliders and you have to fly a lot faster there to keep descent rate big enough to not enter the cloud which in VFR flights is NOT allowed, and for a very good reason. If the Phantom tries to maintain altitude it will slow down its motors giving it less ability to move horizontally. In a situation like that it is quite likely to be moved horizontally at considerable speed.

I'm afraid too many people have too much blind faith in the abilities of the Phantom. They are very limited in those abilities and are far from foolproof. You are dealing with many real aviation aspects when flying a Phantom and people need to acquire the knowledge necessary to fully understand these. Same as people have to do in 'real' aviation. You're not allowed to fly up there unless you have proven to have the proper knowledge and experience. Since there is no requirement (yet) to do the same when flying model aircraft it's up to each individual flying them to make sure they do have the necessary understanding.

They could have been cumulus clouds... but they were very low and there was another layer above them. Could not see any blue sky. I have gained a much greater respect for the wind after this.

Since my search on ground has turned up nothing I keep thinking that another Phantom flying over the same heading could find it. Do you guys have any input on this idea? I could take off near the last known position, fly maybe 150-200ft above the ground taking video. If it was stuck in a tree I would surely see it. I'd have to take the video then watch it on a bigger screen later.

Also, anyone have a favorite GPS tracker they would recommend? :lol:

 

[mtpisgah]

PROXIMO, ROUGH CALC. ONLY

GIVEN: t = 3 minutes , h=1800' , a=32.2'/sec^2 , fomula v=d (t) and x = 1/2 a(t)^2
hence: hovering from 2000' to 3000' p2v+ moves away from you cause of winds difference of 1000' in 3 minutes.

thus: v = d/t = 1000' / 3mins = 333.3 '/min = 6'/sec. of winds and opposing the p2v+ from hovering.
assuming p2v forces to resist the wind in my exp. data vmax = 30ft/sec.
then : wind velocity = 6'/sec + 30'/sec = 36'/sec

thus : x = 1/2 a(t)^2 then 1800' = 1/2 (32.2 ft/sec^2) (t)^2
solve for t = square root of product = approx. 11 second the p2v+ to hit the ground !

therefore, distance to look for your p2v+ : d = 36ft/sec x 11 sec = approx. 400 ft. (radius)

but, reference from the original point 3000 ft + 400 ft = 3400 ft. and use 400 ft as your radius of search.

again, this is only a rough calc. you might want to review my calc. and formula

good luck !

 

[proximo]

PROXIMO, ROUGH CALC. ONLY

GIVEN: t = 3 minutes , h=1800' , a=32.2'/sec^2 , fomula v=d (t) and x = 1/2 a(t)^2
hence: hovering from 2000' to 3000' p2v+ moves away from you cause of winds difference of 1000' in 3 minutes.

thus: v = d/t = 1000' / 3mins = 333.3 '/min = 6'/sec. of winds and opposing the p2v+ from hovering.
assuming p2v forces to resist the wind in my exp. data vmax = 30ft/sec.
then : wind velocity = 6'/sec + 30'/sec = 36'/sec

thus : x = 1/2 a(t)^2 then 1800' = 1/2 (32.2 ft/sec^2) (t)^2
solve for t = square root of product = approx. 11 second the p2v+ to hit the ground !

therefore, distance to look for your p2v+ : d = 36ft/sec x 11 sec = approx. 400 ft. (radius)

but, reference from the original point 3000 ft + 400 ft = 3400 ft. and use 400 ft as your radius of search.

again, this is only a rough calc. you might want to review my calc. and formula

good luck !

Wow! That's some advanced calculating. Thank you very much, mtpisgah! This will help for sure.

 

[jimdenburg]

Couple other questions...did you have prop-guards on? Were you in ATTI or GPS mode? While the Phantom can handle quite well in the wind, there's only so much it can take, especially if the battery is getting drained.

If you get another craft, or know somebody with one, it might not be a bad idea to do a recon mission starting from where your Find My Phantom put it. Shoot some passes over the area and then go back and review your files for a white dot.

Find My Phantom will only work as far out as you have wifi...how else would that info be transmitted to your phone? 1800 feet is just too high to take the thing, especially when you have no idea what the wind speeds are up there. Best in any wind to fly into it and work your way back with a tailwind. That way if anything happens you'll at least have it coming back your way. Of course at that altitude and with calm winds on the ground, you'd have a hard time determining which way to head to go into the wind.

You can figure that out as well as get a good gauge on wind speed aloft by taking the craft up to your cruising altitude (and within sight), and switching to atti. If there's a even a gentle breeze, you'll immediately see which way the Phantom is being pushed (just don't let it go too far because it can get away in a hurry!). Then just keep heading in the opposite direction of that drift and you'll have an easier time getting it back home. Hope you find it!

 

[Ohary]

PROXIMO, ROUGH CALC. ONLY

GIVEN: t = 3 minutes , h=1800' , a=32.2'/sec^2 , fomula v=d (t) and x = 1/2 a(t)^2
hence: hovering from 2000' to 3000' p2v+ moves away from you cause of winds difference of 1000' in 3 minutes.

thus: v = d/t = 1000' / 3mins = 333.3 '/min = 6'/sec. of winds and opposing the p2v+ from hovering.
assuming p2v forces to resist the wind in my exp. data vmax = 30ft/sec.
then : wind velocity = 6'/sec + 30'/sec = 36'/sec

thus : x = 1/2 a(t)^2 then 1800' = 1/2 (32.2 ft/sec^2) (t)^2
solve for t = square root of product = approx. 11 second the p2v+ to hit the ground !

therefore, distance to look for your p2v+ : d = 36ft/sec x 11 sec = approx. 400 ft. (radius)

but, reference from the original point 3000 ft + 400 ft = 3400 ft. and use 400 ft as your radius of search.

again, this is only a rough calc. you might want to review my calc. and formula

good luck !

You're assuming it'll be falling in a vacuum when in fact it will be falling at some acceleration until it hits terminal velocity. I'm not sure what that is for a quad, but if the props spin freely backwards it would probably be in the 50-100 mph range? Not sure that's only a guess, but needless to say it will significanty increase your search area.
FWIW 60 mph = 88'/sec. Assuming it fell at 60 mph and wind is blowing at 30, you'd be looking at an approximate 900' radius.

 

[Big Ben]

One more remark. Hopefully for the future when you will be flying again. Hopefully with a retrieved Phantom.

Since the Phantom very likely was blown away due to strong winds that means that the autonomous manoeuvring speed the Phantom uses for position hold in GPS mode was insufficient to maintain position. Only active flying at high/top speed would have been able to make headway against the wind.

Since RTH also uses only the lower autonomous speed switching to failsafe did not change anything to the situation. The Phantom was most likely already flying into the wind at its maximum autonomous speed ever since the wind speed had exceeded that speed and it started to drift away. Your best option would have been to switch to Home Lock mode, for which you would have needed to enable NAZA-M mode, and pull the right stick fully towards you. At the same time lowering the altitude would have brought the Phantom at altitudes with decreasing wind speeds which would have increased its ground speed towards you.

That's the best action to take when your bird is both high up and far downwind without line of sight.

 

[proximo]

One more remark. Hopefully for the future when you will be flying again. Hopefully with a retrieved Phantom.

Since the Phantom very likely was blown away due to strong winds that means that the autonomous manoeuvring speed the Phantom uses for position hold in GPS mode was insufficient to maintain position. Only active flying at high/top speed would have been able to make headway against the wind.

Since RTH also uses only the lower autonomous speed switching to failsafe did not change anything to the situation. The Phantom was most likely already flying into the wind at its maximum autonomous speed ever since the wind speed had exceeded that speed and it started to drift away. Your best option would have been to switch to Home Lock mode, for which you would have needed to enable NAZA-M mode, and pull the right stick fully towards you. At the same time lowering the altitude would have brought the Phantom at altitudes with decreasing wind speeds which would have increased its ground speed towards you.

That's the best action to take when your bird is both high up and far downwind without line of sight.

Thank you very much for the good advice, Big Ben. I did attempt to pull it out of RTH and lower it myself realizing the wind could have been the issue. Alas the connection broke while I was attempting this and I assume it went back to RTH shortly after that. It all happened so stinking fast I hardly had time to react.

Call me crazy but I just ordered another Phantom. I take it out tomorrow to resume my search by air!!! So excited. I won't give up on this bird. I plan to sell the new one once I recover it. I also bought a GPS tracker that I will mount!

 

[mtpisgah]

PROXIMO, ROUGH CALC. ONLY

GIVEN: t = 3 minutes , h=1800' , a=32.2'/sec^2 , fomula v=d (t) and x = 1/2 a(t)^2
hence: hovering from 2000' to 3000' p2v+ moves away from you cause of winds difference of 1000' in 3 minutes.

thus: v = d/t = 1000' / 3mins = 333.3 '/min = 6'/sec. of winds and opposing the p2v+ from hovering.
assuming p2v forces to resist the wind in my exp. data vmax = 30ft/sec.
then : wind velocity = 6'/sec + 30'/sec = 36'/sec

thus : x = 1/2 a(t)^2 then 1800' = 1/2 (32.2 ft/sec^2) (t)^2
solve for t = square root of product = approx. 11 second the p2v+ to hit the ground !

therefore, distance to look for your p2v+ : d = 36ft/sec x 11 sec = approx. 400 ft. (radius)

but, reference from the original point 3000 ft + 400 ft = 3400 ft. and use 400 ft as your radius of search.

again, this is only a rough calc. you might want to review my calc. and formula

good luck !

You're assuming it'll be falling in a vacuum when in fact it will be falling at some acceleration until it hits terminal velocity. I'm not sure what that is for a quad, but if the props spin freely backwards it would probably be in the 50-100 mph range? Not sure that's only a guess, but needless to say it will significanty increase your search area.
FWIW 60 mph = 88'/sec. Assuming it fell at 60 mph and wind is blowing at 30, you'd be looking at an approximate 900' radius.

im from florida...i didnt know that there was a hurricane at that time :roll:
yes, the calc. was fundamental. no vector, no 3 dimensional, nor aerodynamics. just plain physics.
i am just giving him my educational guess and most of all, "hope"

 

[abacus01]

No offense, hope you find your bird, but flying at 1800 feet altitude which definitely can and will interfere with low flying aircraft is reckless and unfortunately it just takes one person to cause a plane crash and this whole hobby is kaput. Is it that important to get video of clouds and possibly endanger human lives ?