Testing the Mini in very strong wind

[Ian in London]

We've had a couple of big Atlantic storms rolling in over the last week and I took the opportunity to push the Mini to its limits flying in very strong wind; with a few tricks you can re-control it when it starts to blow away...

Cheers, Ian

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[old man mavic]

@Ian in London flippin heck Ian i dont know about the MM being blown away ,there were moments in that vid when i thought you were going to be blown away
you were definitely pushing the envelope there

 

[EyesWideShut]

We've had a couple of big Atlantic storms rolling in over the last week and I took the opportunity to push the Mini to its limits flying in very strong wind; with a few tricks you can re-control it when it starts to blow away...

Cheers, Ian

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Great video Ian. You clearly demonstrate the better aerodynamics of the mini facing away from the wind. There was a heated thread here in the forums months ago about how "tacking" or reverse to offer less wind resistance wouldn't work and heading straight into the wind was clearly the only way. Glad you disproved it.

 

[scro]

Interesting video and exactly the kind of thing I've done to really get a feel for how the drone behaves when it all gets a bit too windy. Do a controlled flight in windy conditions and you will learn a lot!!

However, I don't agree with the "zig zag into the wind" technique proposed at around 4:50. A drone is not a sailboat and does not behave in the same way. A sailboat uses the wind to propel itself forwards and a drone doesn't, so the physics are quite different. Fly directly into the wind for the best chance of overcoming the wind. The direction the drone is facing isn't so relevant so you could, for example, fly backwards into the wind. The important bit is have the drone try to move directly against the wind for best results.

Flying backwards into the wind may seem better if you have slightly deformed rear props. Did I hear a beeping ESC at the end of the flight (6:56). The sort of beep that alerts you to which props are deformed and need changing??? I've not been able to prove to myself that the drone flies better backwards in wind than forwards with good props on all 4 motors. I've specifically tried this and analysed the flight data and the difference between flying front-first into the wind and rear-first into the wind was negligible. I would very much expect to see a difference favouring flying backwards if the rear props were flattened a bit and not operating at full efficiency but I don't want to mash a set of props just to prove it.

 

[scro]

@EyesWideShut I don't think Ian proved that "tacking" into the wind with a drone would help overcome the wind. He merely suggested it might help.

Tacking doesn't work for drones. Sailboats only tack because they use the wind to propel themselves forward. Motorboats don't need to tack. It's like thinking you can run faster on a treadmill by running zigzags across it rather that straight forwards on it.

 

[nhgill960]

Great video! I’m a big fan of the channel! We recently had a hurricane come through and I flew in about 20 mph wind with the mini just to see what it would do, and it handled it surprisingly well for me. However I’m definitely gonna stay away from strong winds in the future just out of caution. Good advice if I ever find myself in a rough situation!

 

[boblui]

However, I don't agree with the "zig zag into the wind" technique proposed at around 4:50. A drone is not a sailboat and does not behave in the same way. A sailboat uses the wind to propel itself forwards and a drone doesn't, so the physics are quite different. Fly directly into the wind for the best chance of overcoming the wind. The direction the drone is facing isn't so relevant so you could, for example, fly backwards into the wind. The important bit is have the drone try to move directly against the wind for best results.

Very true. Flying with the nose pointing straight into the wind gives the best chance of bringing the drone home. If you go zig zag, the side of the drone will be subject to air resistance as well and that will create more overall drag because the side area of the drone is larger than the frontal area.

Flying backwards into the wind may seem better if you have slightly deformed rear props. Did I hear a beeping ESC at the end of the flight (6:56). The sort of beep that alerts you to which props are deformed and need changing??? I've not been able to prove to myself that the drone flies better backwards in wind than forwards with good props on all 4 motors. I've specifically tried this and analysed the flight data and the difference between flying front-first into the wind and rear-first into the wind was negligible. I would very much expect to see a difference favouring flying backwards if the rear props were flattened a bit and not operating at full efficiency but I don't want to mash a set of props just to prove it.

I concur. For some reasons the rear props of the Mini tend to be deformed a lot more easily and in the majority of reported cases of uncommanded descent of the Mini, the rear props failed to generate sufficient thrust so the craft has difficulty in tilting forward ( nose down ) but tilting backward is less a problem. That's why it is easier to fly backward when going against wind. The solution is to replace the bad props instead of actually flying backward because obstacles cannot be seen that way.

 

[Ian in London]

Very true. Flying with the nose pointing straight into the wind gives the best chance of bringing the drone home. If you go zig zag, the side of the drone will be subject to air resistance as well and that will create more overall drag because the side area of the drone is larger than the frontal area.

In my experience, nose first is not the best approach when it's completely failing to overcome the wind. Look at 5:58; it's facing the wind from the north west, but still gets blown off course to the south east. Then at 6:05 I turn around, consider a remote landing, but realise it's starting to make headway against the wind and I can reverse and increase altitude slightly. So for me, in this situation, tail first into wind is what got me out of this. But ultimately, whilst this is my experience, with all these things, it's your personal preference.

Very true regarding the sail boat and zig zag; the propulsion of the sail is completely different to the propulsion of rotors, but I've had many people suggest zig zags and I have sometimes found this better for myself, but for me, reverse was the single best thing to overcome the wind.
Ian

 

[scro]

@Ian in London I find it interesting that you had a noticeable improvement when flying backwards. It's fairly clear in the video too. However I'm tending to think that may be as a result of the rear props being slightly deformed and not performing at full efficiency. 2 things may confirm that: 1. have you had any "change the props on the beeping motor" warnings? 2.Let the drone hover in still air (inside and away from walls/floor etc is ideal) and then examine the flight log file to see what the motor speeds are - notably higher speeds on the rear motors indicates they are working harder to compensate for deformed props.

Regarding finding zig-zagging into wind as helping: I think it might just be an illusion, as the drone moves across ground quicker, but it doesn't move upwind any quicker. If you want to make headway into the wind then the best way to do that is always tackle it straight on. The drone may move slowly, but it will be making the best progress it can against the wind. By flying diagonally into the wind the drone may move faster and it might look good, but the drone is actually making less progress against the wind since it is spending half of its energy going laterally and only half in moving into the wind.

Good video, generally, though and I'm a big fan of doing some carefully planned flights in quite windy conditions

 

[Ian in London]

@Ian in London I find it interesting that you had a noticeable improvement when flying backwards. It's fairly clear in the video too. However I'm tending to think that may be as a result of the rear props being slightly deformed and not performing at full efficiency. 2 things may confirm that: 1. have you had any "change the props on the beeping motor" warnings? 2.Let the drone hover in still air (inside and away from walls/floor etc is ideal) and then examine the flight log file to see what the motor speeds are - notably higher speeds on the rear motors indicates they are working harder to compensate for deformed props.

Regarding finding zig-zagging into wind as helping: I think it might just be an illusion, as the drone moves across ground quicker, but it doesn't move upwind any quicker. If you want to make headway into the wind then the best way to do that is always tackle it straight on. The drone may move slowly, but it will be making the best progress it can against the wind. By flying diagonally into the wind the drone may move faster and it might look good, but the drone is actually making less progress against the wind since it is spending half of its energy going laterally and only half in moving into the wind.

Good video, generally, though and I'm a big fan of doing some carefully planned flights in quite windy conditions

Aha, well, yes, like 95% of Combo owners, yes I have the props error message; in fact during the video you see the messages including 'props rotating too fast' and I catch it at the end, you hear the ESC beeping error. So you think that may be the issue? I genuinely think it's the actual profile of the aircraft. When it's hovering at 2:35, you see it fairly steady facing away from the wind, but then when I rotate it into the wind 10 seconds later you hear the props pitch varying wildly and the aircraft moving about all over the place...... What do you think? Great to hear you're a fan of testing in strong wind too

 

[SpitFire]

Wanted to quote something about the fact that most flight problems are caused by
"Wind speeds in excess of the design limits of the aircraft." Its one of those things where people say don't try this at home. One person has success in doing it , others try it and fail, losing the aircraft. Im more on the side of being safe, and careful. Each pilot has to make that choice.

 

[Ian in London]

Wanted to quote something about the fact that most flight problems are caused by
"Wind speeds in excess of the design limits of the aircraft." Its one of those things where people say don't try this at home. One person has success in doing it , others try it and fail, losing the aircraft. Im more on the side of being safe, and careful. Each pilot has to make that choice.

Yep; this was indeed a "don't try this at home but if you suddenly find yourself in trouble, this may help" situation........

 

[scro]

I've been fortunate enough to not yet have a prop error message so can't speak from 1st hand experience. However some people who experienced the dreaded "uncommanded descent" problem were able to trigger the phenomenon much easier by flying forwards compared to flying backwards. What was happening is when the drone tries to fly forwards it speeds up the rear props to tilt the drone forward. However, the rear props are already running near their max speed just to keep the drone level so the drone is unable to tilt forward. It then slows down the front props in an attempt to tilt forwards, but ends up just not having enough downthrust to stay airborne and consequently ends up lowering down to the ground.

Some pilots have apparently managed to recover from this "uncommanded descent" by flying backwards. This speeds up the front props again and gives just enough boost to the downthrust to stop the descent, while also tilting the drone backwards.

If you have slightly deformed rear props (and it sounds like you do) then the front pair of props will be the stronger pair compared to the rear, so when flying backwards, wind or no wind, the rear motors won't be maxing out as much as when flying forwards.

I've tried flying forwards into a stiff wind and then spun the drone 180 and tried flying backwards into the wind. There was no discernible difference in speed going forwards or backwards with reportedly good props all round. If I had a set of "bad" props to fit on the back then my guess is it would achieve better speeds flying backwards, compared to flying forwards.

Regardless, I think the tip to fly backwards in very marginal conditions has some merit, though with the warning that you can't easily see where you're going Aerodynamically it can't be any worse than flying forwards, and factor in the possible effect of slightly under-performing rear props, it could make the difference between lost drone and a safe return to home.

 

[dnapro]

WOW, full props to you! (excuse the pun) I am a complete noob and have bought the mini after getting a much cheaper drone for Christmas, amazing to see what you can do with this thing, I wouldn't even dream of trying it though. Your video's are informative, thank's.