Launch over concrete?

[dsd317]

I'm only stating that measurement from my own personal experience. I've launched countless times about 10 feet away from a sidewalk that I know is chock full of rebar.

BINGO! Which is the reason for my original post. Now of course I've only done my hand launching thing once, but launching above concrete at a height above 4ft (wall, table, balcony/lanai, etc.) I've done countless times without any issues whatsoever.

 

[msinger]

So, are you advocating that everyone should be launching from sidewalks? I'm missing the point you're attempting to make here.

And, I won't even touch on the hand launching topic. You are quite the daredevil

 

[mirrorimage]

Wait is this just for calibration or for launching? Won't a compass error go away as soon as I fly off the sidewalk or concrete? I've never had a compass error but trying to understand the issue. I always calibrate far away in the grass the. Launch from sidewalk or concrete.

 

[dsd317]

So, are you advocating that everyone should be launching from sidewalks? I'm missing the point you're attempting to make here.

And, I won't even touch on the hand launching topic. You are quite the daredevil

Nope! Not advocating anything! Is that what I said in my post? Just sharing my experience. Unless I was wrong in doing so.

 

[skysense]

I have to ask again. Does this affect ATTI mode?

 

[Numone]

Really interesting. I took my maiden flight at the disused Wisley Airfied, in Surrey. This was the test airfield owned by BAC, which became British Aerospace, and was the site of the test flights of Britains first "V" Bomber, the Valiant and the then radical airliner, the VC10.
I flew from the apron area that had the hangers located on it. Lots of flat highly reinforced concrete... everywhere! OK, so what's interesting is that I was really cautious - this was my first flight outside of the house and the Flight Sim, so I calibrated the compass and IMU.. the compass twice. Intake of breath and I got a green, safe to fly notification and entered auto takeoff. The aircraft rose up and at about two feet, it twitched violently to the right then left and then steadied-up. I proceeded with the 3 minute flight and it was uneventful (but totally am-maa-zing!) and the rest of the flights I've made, all so far at Wisley, have been incredible and again, uneventful. On the longest distant flight l've undertaken, running along the length of the 2000 metre runway, I did lose comms at the eastern end of the runway at 1000m but it did restore and then lost RC control, again for two or three seconds and it again came back. I'm wondering if the Wisley VOR, which is located at that end of the runway could've effected the signal? Be interested in your views. Also, could a Teslameter be of use to check the magnetic interference?

 

[dsd317]

Wait is this just for calibration or for launching? Won't a compass error go away as soon as I fly off the sidewalk or concrete? I've never had a compass error but trying to understand the issue. I always calibrate far away in the grass the. Launch from sidewalk or concrete.

I think it depends on how you look at it (calibration or launching).

I was getting compass error due to the amount of rebar/steel in the concrete (I think. I'll explain later). But I noticed that when I elevate the P3P above a certain height, the compass error would go away. I would still perform a compass calibration, but as soon as I place the P3P on the ground/concrete, compass error would return. Yesterday, I did not have anything high enough to launch from, so I decided to try hand launching....and as mentioned earlier....flew/worked flawlessly.

Skysense, the following may/may not pertain to your question. (I forgot that I've actually launched and flown from huge concrete pad INDOORS:

As for my rebar/steel comment above, I'm started to think it may be something else. As in my video shows above, I've launched and have flown indoors in a large gym with steel ALL OVER THE PLACE. It was a while back and I've only done it twice (different days), but I'm pretty sure I was in ATTI mode. So why did I NOT have any compass error? ATTI mode doesn't use compass?

 

[dsd317]

Really interesting. I took my maiden flight at the disused Wisley Airfied, in Surrey. This was the test airfield owned by BAC, which became British Aerospace, and was the site of the test flights of Britains first "V" Bomber, the Valiant and the then radical airliner, the VC10.
I flew from the apron area that had the hangers located on it. Lots of flat highly reinforced concrete... everywhere! OK, so what's interesting is that I was really cautious - this was my first flight outside of the house and the Flight Sim, so I calibrated the compass and IMU.. the compass twice. Intake of breath and I got a green, safe to fly notification and entered auto takeoff. The aircraft rose up and at about two feet, it twitched violently to the right then left and then steadied-up. I proceeded with the 3 minute flight and it was uneventful (but totally am-maa-zing!) and the rest of the flights I've made, all so far at Wisley, have been incredible and again, uneventful. On the longest distant flight l've undertaken, running along the length of the 2000 metre runway, I did lose comms at the eastern end of the runway at 1000m but it did restore and then lost RC control, again for two or three seconds and it again came back. I'm wondering if the Wisley VOR, which is located at that end of the runway could've effected the signal? Be interested in your views. Also, could a Teslameter be of use to check the magnetic interference?

Glad you got a great flight!
I've never used auto takeoff, so not sure about the experience you had. I'm trying to look for my electrical engineers to ask them about your question, but I think they're in a meeting.

 

[Numone]

Glad you got a great flight!
I've never used auto takeoff, so not sure about the experience you had. I'm trying to look for my electrical engineers to ask them about your question, but I think they're in a meeting.

Cheers. Be interested to know about the VOR too. It's a hugely powerful omnidirectional transmitter that's with a range of circa 180 miles, so who knows....
I just wanted to be on the safe-side with the auto takeoff. As I said, I've had another six flights at the same Airfied without incident and judging by the small sections of apron and runway that's been taken up, is full reinforcement (rebar I presume on your side of the pond!).

 

[dsd317]

Cheers. Be interested to know about the VOR too. It's a hugely powerful omnidirectional transmitter that's with a range of circa 180 miles, so who knows....
I just wanted to be on the safe-side with the auto takeoff. As I said, I've had another six flights at the same Airfied without incident and judging by the small sections of apron and runway that's been taken up, is full reinforcement (rebar I presume on your side of the pond!).

Not sure about the VOR, but in regards to your meter, one of my electrical engineers suggested:

Gauss Meter:Magnetic Field Gauss Meter - HHG191

 

[Hondo76251]

Forgive me if I missed something, read most of the post, but saw a response about "ATTI mode"

I get a compass error quite often. Many of my flying locations are covered in iron rock (which is magnetic) Needless to say, I get the error quite often. My solution has always been to switch to atti mode, get about 10 feet up, and wait for it to get its bearings... It has always worked for me.

The main thing is that you have to be comfortable flying this thing in ATTI mode... when you get it up its not always 100% stable at first, just man handle it until it is... I've crashed many, many, many $50 drones so I would gain the skill to fly a $1k+ drone... I wouldn't recommend it unless you're a fairly skilled pilot already. (Don't learn on a phantom, crash a Hubsan X4 about 4,000 times first... just my $0.02)

I wouldn't say do it every flight. I fly mine from an unstable location only about 1 out of every 4 flights so I'm pretty confident that my compass is set right once she gets airborne... I wouldn't do it 100% of the time (or a first time, either the virgin flight or after an upgrade or something...)

 

[Numone]

Not sure about the VOR, but in regards to your meter, one of my electrical engineers suggested:

Gauss Meter:Magnetic Field Gauss Meter - HHG191

Thanks... And please thank your colleague too! I guess what'd be useful too would be what level of interference would be needed to throw off the compass in the aircraft? Would your engineer have an idea?

 

[dsd317]

Thanks... And that skate your colleague too! I guess what'd be useful too would be what level of interference would be needed to throw off the compass in the aircraft? Would your engineer have an idea?

Just got home from work, so I can't ask any electrical experts now...but from what little I know, I think it would depend on hardware in our quadcopters. Different hardware can deal with magnetic interference better in some, not so good in others. So determining the level of interference would be difficult, I think. I'll ask tomorrow.

 

[skysense]

Forgive me if I missed something, read most of the post, but saw a response about "ATTI mode"

I get a compass error quite often. Many of my flying locations are covered in iron rock (which is magnetic) Needless to say, I get the error quite often. My solution has always been to switch to atti mode, get about 10 feet up, and wait for it to get its bearings... It has always worked for me.

The main thing is that you have to be comfortable flying this thing in ATTI mode... when you get it up its not always 100% stable at first, just man handle it until it is... I've crashed many, many, many $50 drones so I would gain the skill to fly a $1k+ drone... I wouldn't recommend it unless you're a fairly skilled pilot already. (Don't learn on a phantom, crash a Hubsan X4 about 4,000 times first... just my $0.02)

I wouldn't say do it every flight. I fly mine from an unstable location only about 1 out of every 4 flights so I'm pretty confident that my compass is set right once she gets airborne... I wouldn't do it 100% of the time (or a first time, either the virgin flight or after an upgrade or something...)

I keep asking about ATTI flight in this situations because i want to hear more Phantom experiences. Before Phantom i was flying and still am TBS DiscoveryPro with Naza M-v2 which has its gps/compass on the upside of the frame on a 10cm long holder, compared to Phantom which has compass on the landing leg, near the ground. Also 95% of the time i was flying ATTI mode, so i don't have much experience with this GPS-compass-metal-magnetic issues. Have flown numerous times on construction sites with rebar sticking out of everywhere and everything in ATTI ofc, didn't even think flying GPS simply because i'm used to atti don't trust gps handling 1500+$ or even more worth of equipment.

This video was made with Phantom 2 in ATTI mode, maybe that answers flying over concrete full of rebar question TBS DiscoveryPro with Naza flies also with zero problem in those conditions.


I see here many people have crashes-flyaways which are in most cases, in my opinion, caused by GPS-compass magnetic disturbance. I know GPS mode is really easy to fly, but don't be scared of ATTI mode, my advice is try it, practice it on an open field, it might be very useful and save you some Phantoms, money and nerves in magnetic field conditions

 

[Meta4]

So 10ft away from concrete area will guarantee compass accuracy? How is this different from elevating P3P 10ft above concrete?
At what height/elevation guarantees 100% compass accuracy before it gets interference from concrete?

There is no magic distance.
Everything is dependent on the distance from the magnetic influence AND the size of the steel object.
If you want to launch right next to the Queen Mary II you will have to get further away than you would from a small piece of reinforced concrete.

 

[Numone]

Just got home from work, so I can't ask any electrical experts now...but from what little I know, I think it would depend on hardware in our quadcopters. Different hardware can deal with magnetic interference better in some, not so good in others. So determining the level of interference would be difficult, I think. I'll ask tomorrow.

Thanks. It'd be interesting to know. I'm also asking in case one of the teslameter iOS apps would be sensitive enough to help. There's an excellent one here Teslameter 11th on the App Store

 

[mrcrane2u]

I'm working on a job site (Crane operator) we park next to it in parking garage. I want to get some before and as we go footage of the job as it progresses, i tried to fly it when I first got on the job from the top floor of garage and got all kinks of interference and compass error messages.i can still fly in attitude mode to take off and land back on the garage once in air I can put back on gps mode ??

 

[robinb]

Not a good idea if to take off if you get compass error. The garage roof probably has a lot of steel in it.

Try taking off from a "clean" area even it that means you having to fly to the your job a bit.

 

[mrcrane2u]

Yeah that's what I was thinking

 

[mrcrane2u]

Thanks for the reply