Anybody seen this problem ?

Martib · Aug 1, 2014

I have added a Ziess lens Sony QX100 camera (extra 240 grams) with intervalometer (120 G)to the P2 and have kept the FC200 for telemetry and FPV. A heavy payload indeed...
I have set the gains (as best I can) and tried several firmware/software versions and have had 4 crashes/fly aways all with various versions of the software/firmware. (I know it is not the firmware/software causing the issue)
The issue I am having is this:
I can ascend at close to 2.5m/per sec on full throttle, (this tells me the motors can handle the extra weight) on descend the craft soon enters an unstable flight and wobbles ... It is very slow to react to the throttle (ascend) with a delay of up to 5 seconds.. then (sometimes) it ignores all stick commands and goes into a rapid descent while oscillating and other times just flys away oscillating with no responding to the stick inputs at all (fly away)

I have tested this several times (in deep grass for a soft landing) and it is a random occurrence after a fast descend only (one must descend at some point ! ) It is random and happens even when battery is full power and over 12 satellites on the GPS... Switching to atti and back to gps has no effect once it starts to go unstable and fall out of the sky.

I have set the Gains at 100 with attitude at 220 ..
Any advice would be much appreciated... The Sony QX100 takes amazing photos BTW ! I dont want to destroy it....

ProfessorStein · Aug 1, 2014

You are experiencing the Vortex Ring of Death... or prop wash... I'd say. Probably even more prominent with your heavier payload... but lots of folks have experienced it just with their stock Phantoms. And it's actually pretty dangerous... it can cause your bird to fall completely out of the sky with no control at all.

Just get into a habit of moving laterally while descending. That should eliminate it.

And, if you're feeling up for it, update to the latest firmware. They've limited the max rate of descent to try to stave off the problem. But it might not be enough for you since your Phantom is so much heavier than usual.

What kind of flight times are you getting with that weight, anyway?

Mal_PV2_Ireland · Aug 1, 2014

I think you are trying to carry too much, WAY TOO MUCH.
You are definitely in VRS, trying to throttle up when your phantom is wobbling and descending will do nothing, you need to forget doing that and try move forward, backwards, ledt or right. But my guess is you have overloaded your phantom. It wasnt made to do what you are trying. Either lose your sony or lose your fc200, I'd lose the sony or be willing to spend a lot of money on a heavy lift multirotor.

Martib · Aug 1, 2014

Hi guys...

Thanks for the input on VRS.. I am aware of this issue and have been testing vertical ascend/descend to find out when it happens... I will try more angle on the descent to avoid it... It is interesting that it happens so randomly though.. Sometimes I can ascend out of the rapid descent with no problem and power to spare.. Sometimes the P2 just ignores all my stick inputs... I have tested the system while tethered to see if I have an intermittent control fault with no negative results...

When ascending I can reach 2.5 M per second which is a good climb rate and tells me that the motors can handle it. I can get flight times over 15 minutes with no problem, therefore the endurance is well within what I need for the photos I want to get...

I need the FPV from the FC200 especially the telemetry when flying the craft... I need the resolution of the 20 Mp @ 50- 100mm Sony camera for the photo quality (not interested in gopro style wide angle) as I am photographing communication towers..

I understand there are much more expensive heavy payload qauds/hexacopters on the market... I would rather buy 2 or 3 Phantoms and perhaps loose one, than spend $5000 and have all the eggs in one basket...

I think I might need to adjust my Gain settings again and do some more testing...

Thanks again for your input..

Mal_PV2_Ireland · Aug 1, 2014

Honestly I think you are banging your head against the wall by just adjusting the gains. I think you should be using the correct tool for the job at hand. Why exactly do you really need the sony for inspections? You can get very close to anything you want to inspect and just use the fc200. Just because you arent interested in a fisheye lens doesn't mean its not the right camera unless there is something you are missing?

Mal_PV2_Ireland · Aug 1, 2014

Another thing I find strange is I'm a satellite dish and terrestrial antenna engineer working on a lot of broadcast masts. When I got my phantom first I thought it would save me a lot of climbing. I realised after 3 minutes this was never gonna happen. There is no way I could see if there was a loose coax cable, dodgy connector or if the wind had shifted an antenna a few mm with it. Even using something light lightbridge and a s1000 with a cannon 5d seeing everything in HD with fpv could I tell this. What can a sony qx100 do for you that the fc200 cant? Are you just taking pics of communication towers for the fun of it?
Another thing is what sort of communication towers are they? Cell towers? Maybe a reason you are having flyaways? I'm just really trying to get my head behind your reasoning first rather than your problems because its such an obscure situation you present. Have you tried to fly around these towers without the added weight of the sony? Did you get crashes without it? I'm trying to go through a process of elimination.

Martib · Aug 2, 2014

I need to get a telescopic view of tower infrastructure to Identify corrosion issues. This is the purpose of using the P2. The QX100 is light (220g) and has an excellent Zeiss lens that is very fast, I have already tried the Sony QX10 (70g lighter) and it worked very well except the lens was not up to the task. The FC200 is much too wide angle to identify corrosion details unless flying very very close. I already have a Canon 5D but am not interested in putting the risk/$ into it . The larger copters are a higher risk to fly near the infrastructure and have very short flight times. The freqs of the cell/comms towers are generally not near the free spectrum of 5.8 Ghz and have tested near many with no issues.

By chance I work for Hughes doing VSAT installs too.. Mal if you are based in Australia, lets try to solve these issues with the Phantom together.

Mal_PV2_Ireland · Aug 2, 2014

I'm in ireland mate and our work isn't too far away from eachother. Using a uav is not gonna help you at all, believe me I wish it could. You are just gonna have to climb the tower which, in a way is a reason why I love the job. Climb and inspect with your eyes, no camera or uav is going to beat that. The reason we get paid so well is to climb the towers that others wont. Make it easier and our pay will come down. Im not an employee, I own my own business doing this. Again I'm sorry but I think you are trying to do a wishful thinking thing.