Question about wind flying

[MavicCF]

I've been flying a lot in the wind recently, doing flights two or so miles out, I always fly into the wind so I don't have to worry about not making it back (I learned from experience ). Now, say I'm flying against the wind in sport mode with speed maxing out around 25Mph (my wind meter is also showing a consistent 15Mph headwind) now after using 30% battery power I'm about 1 mile out and decide to turn around so I get a feel for how much battery I will use going both ways when I make the next flight on a different battery. On the return I'm doing 40-42Mph and it takes only 7% to get home. So even though the Mavic has a 15Mph tail wind, it still stays at its maximum speed of 40Mph. Now the question, it seems to me that the Mavic must actually be sensing the tilt needed to maintain a steady 40Mph speed and throttling back to counter the wind. In other words because of the wind, it is flying at a pitch and motor speed that without the wind would only equal 25Mph horizontal flight. Is this true? Technically, is the Mavic only flying 25Mph and using the wind to keep the speed up? Hopefully this all makes sence and I believe the answer should be simple. Thanks! -CF

 

[sar104]

The aircraft is pitch and speed limited in GPS mode so yes - your explanation is correct. It was pitch-limited on the way out (airspeed ~40 mph) and speed limited on the way back (ground speed 40 mph).

 

[MavicCF]

The aircraft is pitch and speed limited in GPS mode so yes - your explanation is correct. It was pitch-limited on the way out (airspeed ~40 mph) and speed limited on the way back (ground speed 40 mph).

Thanks, that's what I figured, wish it had manual ATTI, heck I could be doing 55-60Mph!

 

[JB999]

I can only confirm that i have exactly the same experience (with my Mavic Air) you will not "get there faster" with a tailwind, but with less battery power used. This is not the case with my P4P, that one is actually going much faster in a strong tailwind wind vs no wind.

 

[MavicCF]

I can only confirm that i have exactly the same experience (with my Mavic Air) you will not "get there faster" with a tailwind, but with less battery power used. This is not the case with my P4P, that one is actually going much faster in a strong tailwind wind vs no wind.

I do like the "with less battery power" part (although it does drop way faster going out agonst the wind so I don't really come out ahead) it's just cool to fly a mile with only a 7% battery drop!

 

[Missile Man]

Since the drag varies with the square of the velocity (air speed) it will always take more energy to fly a route on a windy day vs. non-windy day

 

[tictag]

Thanks, that's what I figured, wish it had manual ATTI, heck I could be doing 55-60Mph!

There is a hack - wrap kitchen foil around its arse like a nappy (see YouTube).

 

[Cymruflyer]

One thing to bear in mind, I am a real pilot too, not just a Mavic flyer, and the wind direction can and does change at different altitudes. On one flight, I found the most extreme change ever, it was 180 degrees different with just 1,000ft of altitude change. It is never normally that drastic of a change when I fly, so that one flight was an eye opener as to what can possible happen aloft.

So, bear in mind that wind speed and direction can change at different altitudes, and if you were flying our against the wind and you then changed altitude and continued flying a course, or returned to home, you might find that the wind would possibly change in direction and speed, compared to your outbound leg. Obviously I would not expect such a change with just a few hundred feet of altitude difference. Just don't get fooled into thinking it will always be the exact opposite for your return flight, because things can and do change up there in the sky.

With that said, if you did not change altitude, you could be 99.9% sure that if it was an out and back straight line flight, the wind would be as you expected with no change in velocity or direction.

 

[Wilbur&Garth]

So here's a question related to the OP. If you're flying with a 20 mph tailwind, the max speed you can go is still 40 mph. Normally, P mode can only go 20-30 mph (depending on OA), but can you reach up to 40 mph with the assistance of a tailwind, or do you need to be in S mode for that? If P mode can reach 40 mph with wind, would it be more efficient than S mode, or just the same?

 

[MavicCF]

So here's a question related to the OP. If you're flying with a 20 mph tailwind, the max speed you can go is still 40 mph. Normally, P mode can only go 20-30 mph (depending on OA), but can you reach up to 40 mph with the assistance of a tailwind, or do you need to be in S mode for that? If P mode can reach 40 mph with wind, would it be more efficient than S mode, or just the same?

If you are flying in P mode, your top speed will be the standard top speed in P mode (22 MPH) regardless of the wind.
The FC takes into account the wind speed and throttles back until it is within the limits of what it's supposed to be. So if you are flying in P mode (Max of 22MPH with sensors on) with a 20 MPH tail wind, the Mavic itself is only calling for a speed of 2 MPH while using the wind for the other 20 MPH. The same thing happens in Sport mode.
Essentially, the Mavic compensates for tail winds by "throttling back" or reducing pitch.

 

[Mossiback]

...Now, say I'm flying against the wind in sport mode with speed maxing out around 25Mph (my wind meter is also showing a consistent 15Mph headwind) now after using 30% battery power I'm about 1 mile out and decide to turn around...

You are smart to turn around with 70% battery on a windy day. The battery meter is only an estimate and does not take a number of factors into account. What also may happen in a mile distance is the wind can turn from a headwind to a sidewind and the Mavic will use extra power to counter that and stay on course.

 

[MavicCF]

You are smart to turn around with 70% battery on a windy day. The battery meter is only an estimate and does not take a number of factors into account. What also may happen in a mile distance is the wind can turn from a headwind to a sidewind and the Mavic will use extra power to counter that and stay on course.

I always try to fly directly into the wind on my 3+ mile flights, I also usually fly in ATTI mode which allows me to keep track of any wind changes and respond accordingly. Since I know what the wind is doing and that I'll have a good tailwind coming back, I usually feel comfortable using from 50-60% battery going out.

 

[Mossiback]

... I also usually fly in ATTI mode...

Are you using the foil trick, modded your Mavic, or flying something else?

 

[MavicCF]

Are you using the foil trick, modded your Mavic, or flying something else?

I re-programed the Sport mode switch to toggle between ATTI and GPS modes.

 

[Mossiback]

I re-programed the Sport mode switch to toggle between ATTI and GPS modes.

That's a great mod. DJI should have a button that provides that out of the box.

 

[MavicCF]

That's a great mod. DJI should have a button that provides that out of the box.

Definitely! The advantages are obvious, and all the Phantoms have had that option. It really is a bummer DJI didn't make it an easily accessible option for the Mavics.