Urgent help needed on filming maxi 72 sailing boat race

Spy_Corfu · Jul 5, 2017

Halo,
there is a maxi 72 sailing boat race around my area for another few days and i went with my boat to film the race.. although i managed to film some nice videos i had also several problems which i was hoping i would get an answer before i film again tomorrow:
1. big out of focus error. if there was no boat nearby i could not get the magic to focus at all! i touched the screen to focus but all tough it tried to focus eventually it went out of focus again ..
Fortunately when i was close to a boat it stayed in focus.
I tried hard pressing on the screen to have fixed focus but that did not work.
Note that i was using dji go 4 and NOT litchi which i know has focus problems.

2. Active tracking not working and i got a message front sensors not working or something like that.
I tried active track on me the day before and it worked just fine. so the sensors work fine.
I have also used the active track before on my speed boat and also worked fine.. i just don't understand why it does not work on a sailing boat.
i get a red square (not the green square) and no matter how close i go to the boat it has not worked so far.
I had to follow manually which is a bummer as active track makes the video really smooth and you can circle the boat automatically.

3. I changed the return to home option to me so the drone would go back to where i am now and not the recorded home point where it started. this is very important as the boat moves all the time and it is impossible to find the boat just using the mobile phone screen.
I had to set the option twice to make it work as i had the phone in airplane mode so i would not get any outside calls but then the gps was not working i think.
I almost lost the drone as i could find my boat.. the camera was out of focus all the time and could not get it to work and the home point was wrong!! it was panic time... i managed to set the home point to me again and with the gps working i managed to get the drone back to my boat!

thanks for any help or experience you can share with me!

will post videos once i edit them.

doccy · Jul 5, 2017

1) Disable the continous auto focus button in your settings. Then set focus to infinity and you should have much more usable footage. If you have a boat in view just reset focus on it and the setting will now stick as well.

2) It doesn't work if you are too low, too close, the light is too poor. Etc. Keep trying different ways.

3) The home point on RC does NOT follow your RC wherever you go. It sets it at the RC position and if you move the homepoint doesn't move with you.

Great you got your drone back - but you need to reset the homepoint just before hitting the RTH.

Or even better - don't get in a situation were you are relying on this... things could go wrong!

Spy_Corfu · Jul 5, 2017

doccy said:
1) Disable the continous auto focus button in your settings. Then set focus to infinity and you should have much more usable footage. If you have a boat in view just reset focus on it and the setting will now stick as well.

2) It doesn't work if you are too low, too close, the light is too poor. Etc. Keep trying different ways.

3) The home point on RC does NOT follow your RC wherever you go. It sets it at the RC position and if you move the homepoint doesn't move with you.

Great you got your drone back - but you need to reset the homepoint just before hitting the RTH.

Or even better - don't get in a situation were you are relying on this... things could go wrong!

Thanks for your immediate and very helpful answers.

yes i will try the fixed focus setting as it was really getting on my nerves!

I will have to remember that to change the nth position to where i am before i press rah button.

the conditions where terrible .. strong winds and the boats where sailing really far from the coast so flying from my boat was the only option.. i had to fly against the wind when the battery was full as a precaution to have the wind behind me towards the end in case there was not enough battery to RTH.

Spy_Corfu · Jul 5, 2017

i also got SYSTEM APP error .. what is that?

doccy · Jul 5, 2017

Spy_Corfu said:
i had to fly against the wind when the battery was full as a precaution to have the wind behind me towards the end in case there was not enough battery to RTH.

That was wise - probably saved your drone with that little bit of planing

Spy_Corfu · Jul 5, 2017

this is not the first time i fly with strong winds over the sea and last time i had a serious problem as i had to fly back against the wind and the mavic did not have enough juice to fly home even in sport mode..
fortunately i did what sailing boat do called a "zig zag" which basically you go at an angle against the wind not full heading against so to pick up some speed .. it seems like you fly away but then you change the course again and try to fly closer again .. you do a lot of zig zags basically and you slowly return to home.. much more distance to cover but i managed to get it back safely as the wind was not so strong close to the land.

Rbruz · Jul 5, 2017

doccy said:
1) Disable the continous auto focus button in your settings. Then set focus to infinity and you should have much more usable footage. If you have a boat in view just reset focus on it and the setting will now stick as well.

2) It doesn't work if you are too low, too close, the light is too poor. Etc. Keep trying different ways.

3) The home point on RC does NOT follow your RC wherever you go. It sets it at the RC position and if you move the homepoint doesn't move with you.

Great you got your drone back - but you need to reset the homepoint just before hitting the RTH.

Or even better - don't get in a situation were you are relying on this... things could go wrong!

When I shoot surf I always fly 100% manual, no tracking and no rth and always los , I walk all along the beaches etc while flying so rth won't work for me, so great advise for this person!

doccy · Jul 5, 2017

Spy_Corfu said:
this is not the first time i fly with strong winds over the sea and last time i had a serious problem as i had to fly back against the wind and the mavic did not have enough juice to fly home even in sport mode..
fortunately i did what sailing boat do called a "zig zag" which basically you go at an angle against the wind not full heading against so to pick up some speed .. it seems like you fly away but then you change the course again and try to fly closer again .. you do a lot of zig zags basically and you slowly return to home.. much more distance to cover but i managed to get it back safely as the wind was not so strong close to the land.

Don't want to contradict you mate but tacking (zig zaging as you say) into the wind is probably not helpful with a mavic!

It works on a boat as it allows the angle of sail to get forward momentum against a head wind as long as you avoid the 90 degree dead zone.

The mavic doesn't use a sail - so tacking is not going to help. You would be best to head straight into it and cover the shortest distance between two points in almost all scenarios.

I suppose there might be an odd situation were you can't move forward against a wind at all and going at an angle reduces the effective wind speed enough for you to make slight progress home - but this would cover a very small range of wind speeds (right at the limit of the mavics forward power) and would be marginal at best.

Spy_Corfu · Jul 6, 2017

doccy said:
Don't want to contradict you mate but tacking (zig zaging as you say) into the wind is probably not helpful with a mavic!

It works on a boat as it allows the angle of sail to get forward momentum against a head wind as long as you avoid the 90 degree dead zone.

The mavic doesn't use a sail - so tacking is not going to help. You would be best to head straight into it and cover the shortest distance between two points in almost all scenarios.

I suppose there might be an odd situation were you can't move forward against a wind at all and going at an angle reduces the effective wind speed enough for you to make slight progress home - but this would cover a very small range of wind speeds (right at the limit of the mavics forward power) and would be marginal at best.

Sorry to disappoint you but that is exactly what happened! .. heading straight towards the wind i had 0 speed at full throttle.. which means that eventually i would drain the battery and i would have lost the mavic.

What i decided to do saved my drone.. and ok yes the wind is not a wave which is why you zig zag on a boat but it did allow to pick up some speed and gain some

Spy_Corfu · Jul 6, 2017

In any case regarding my problem with the front sensors error and not tracking the sailing boat .. as i got the error message also on the dgi go app I decided to do a sensor calibration using my mac and now the message seems to have gone and hopefully today i will be able to use active tracking during the race.

doccy · Jul 6, 2017

Spy_Corfu said:
Sorry to disappoint you but that is exactly what happened! .. heading straight towards the wind i had 0 speed at full throttle.. which means that eventually i would drain the battery and i would have lost the mavic.

What i decided to do saved my drone.. and ok yes the wind is not a wave which is why you zig zag on a boat but it did allow to pick up some speed and gain some

Im not disappointed... just didn't want a lot of Mavic users reading your post and forlornly tacking their drones into the wind in a fruitless attempt to mimic a sails properties

Spy_Corfu · Jul 6, 2017

i respect your opinion but i mantain that the only solution to bring back your drone if you run into trouble because of strong winds against it and you are far away from the coast would be to zig zag.. the other option would be to run out of battery by truing to fly against the wind and gain 0 speed and fall into the deep blue waters!

geigy · Jul 6, 2017

There is a known focus issue similar to what you describe, where focus fails to lock correctly. That problem can be fixed by resetting the camera in camera settings.

The math for the zig zag technique simply does not work for a drone as it does for a boat because there is no contact with the water. If you are losing headway flying into the eye of the wind, you will lose even more flying at an angle to the wind. Something else was going on. Perhaps Poseidon saw your determination to prevail and gave your Mavic an invisible push..

Spy_Corfu · Jul 6, 2017

I did reset the camera settings and will wait to see what happens next time.
As i am not a airline pilot so I can not insinst in my hypothesis. You have a point .. you are saying there is equal resistance going at say 20-30 degrees to the wind? Maybe what did it for my was the fact that i slowly redused altitude and because of the montain behind me the wind force was redused.

gumaco · Jul 6, 2017

in this scenario I would also set it to hover instead of RTH.....

Grauniadangel · Jul 7, 2017

Interesting discussion on winds and point of sail. Sailing head on or at 90d to the wind gets you nowhere so you tack with an angle of about 30 degrees either side depending on your sail set-up and hull configuration. When you tack you cover perhaps twice the mileage but make headway with a sail because of the angle to the wind so more energy expended but at least you're moving forward!

The drone must have done likewise, in that you covered more distance by tacking, so used more energy but as you say you dropped altitude which probably lowered the on-the-nose wind effect.

At least you don't have to think about tides!

Spy_Corfu · Jul 7, 2017

Grauniadangel said:
Interesting discussion on winds and point of sail. Sailing head on or at 90d to the wind gets you nowhere so you tack with an angle of about 30 degrees either side depending on your sail set-up and hull configuration. When you tack you cover perhaps twice the mileage but make headway with a sail because of the angle to the wind so more energy expended but at least you're moving forward!

The drone must have done likewise, in that you covered more distance by tacking, so used more energy but as you say you dropped altitude which probably lowered the on-the-nose wind effect.

At least you don't have to think about tides!

There you are! .. someone agrees with me!! I am not crazy! I do sale a lot and i have a speed boat so i know about see and winds and what i did seems logical ..
I am just saying that airline pilots have a different way of handling wind conditions which i am not aware off..
In any case my drone at 90c was doing 0 speed and it would eventually fall to the see so i slough it away from me at say 30d as you say until it picked up some speed and then you basically try slowly to turn towards home point as long as you get some speed...
but like on boats .. there of course there is the wave factor which is very important as you don't want to waves to hit you head on or side ways .. but with the drone if you have plenty of battery you don't mind covering more distance as long as you can pick up some speed in sport mode.

Grauniadangel · Jul 7, 2017

Spy - apologies but I wasn't agreeing with you on the tacking front - the wind hitting the copter at whatever angle will be the same effect. It might appear to move more readily but you're travelling further and will have some slippage or leeway in sailing terms. I do believe that dropping altitude helped you, katabatic winds - and other sorts are notorious on a warm coast but if you dropped into the wind shadow of a mountain that would definitely help.

On the aircraft front i'll enlist my sister who's a senior pilot and a sailor to get a definitive answer. She's currently at altitude flying to KL so unavailable for comment.