Is Tacking A Viable Solution To An Overpowering Headwind?

[sar104]

I understand what you’re saying but you weren’t there. When I flew directly into the wind, it just wouldn’t move. At maximum speed the drone was just hovering against the wind. Yet by tacking I got it back. Don’t know what else to tell you.

I don't need to have been there. Your assertions break basic physics. Therefore there is another explanation. Such as the wind speed dropped after your initial attempt to return directly, or the wind speed or direction was not constant and was less on the path that you ended up flying. Or the drone was making slow progress into the wind and you didn't realize it. Or you flew the zigzag at reduced altitude. Etc., etc. What it was not was an example of tacking in the air. You can't tack in the air - you have nothing to push against.

 

[bzmot]

I don't need to have been there. Your assertions break basic physics. Therefore there is another explanation. Such as the wind speed dropped after your initial attempt to return directly, or the wind speed or direction was not constant and was less on the path that you ended up flying. Or the drone was making slow progress into the wind and you didn't realize it. Or you flew the zigzag at reduced altitude. Etc., etc. What it was not was an example of tacking in the air. You can't tack in the air - you have nothing to push against.

I asserted no such thing. I merely described my experience.

 

[sar104]

I asserted no such thing. I merely described my experience.

You said that you were tacking. You were not tacking.

 

[bzmot]

You said that you were tacking. You were not tacking.

Ok then, keep your mittens on. Flying in a zig zag pattern. Better?

 

[sar104]

Ok then, keep your mittens on. Flying in a zig zag pattern. Better?

That's fine - I just think it is rather important not to give other users the impression that tacking, or zigzagging, or whatever one might call it, has any utility in making progress against a headwind. All other things being equal it will always be less effective than a direct route - i.e. it will not get back as fast or it will drift further away than it would have done without that maneuver.

 

[EyesWideShut]

That's fine - I just think it is rather important not to give other users the impression that tacking, or zigzagging, or whatever one might call it, has any utility in making progress against a headwind. All other things being equal it will always be less effective than a direct route - i.e. it will not get back as fast or it will drift further away than it would have done without that maneuver.

Maybe the wind resistance lessens as the profile changes from head-on to the wind to a slightly offset profile when zigging or zagging allow more headway home?

 

[sar104]

Maybe the wind resistance lessens as the profile changes from head-on to the wind to a slightly offset profile when zigging or zagging allow more headway home?

It's not a question of wind resistance - it's just an airspeed problem. If the wind speed exceeds the maximum airspeed of the aircraft then no amount of geometric gymnastics is going to allow it to make progress against that wind. Minimum drift rate downwind is obviously achieved by applying all available tilt into the wind. Any of that tilt applied in any other direction will result in faster drift downwind.

 

[EyesWideShut]

It's not a question of wind resistance - it's just an airspeed problem. If the wind speed exceeds the maximum airspeed of the aircraft then no amount of geometric gymnastics is going to allow it to make progress against that wind. Minimum drift rate downwind is obviously achieved by applying all available tilt into the wind. Any of that tilt applied in any other direction will result in faster drift downwind.

Not being an aeronautical engineer I'm not sure if this makes a difference but do you get better advancement with less headwind drag? Pick up your mini and give this a try. Trying it and seeing for yourself is better than my explanation.

When I hold the mini up in front of me and tilt it simulating forward motion (rear end up) and view it as the wind sees it straight on like a stream's current. When head on there is a lot more surface area (drag) being seen. In addition to the huge surface area of the top of the mini's body there's the full length of all 4 arms plus the props and legs are exposed as drag.

Then try turning the mini slightly sideways (with the same forward tilt) and the surface area to the wind drops drastically. The "water current" drag of the far rear arm and most of the prop disappears as does the near front arm and some of the leg. The far front leg's length to the current is also lessened. I believe the overall drag to the wind is drastically reduced. There is still the drag to the mini's forward motion but as I said I'm not an engineer and don't know how that plays out on getting the AC home.

 

[Meta4]

Then try turning the mini slightly sideways (with the same forward tilt) and the surface area to the wind drops drastically. The "water current" drag of the far rear arm and most of the prop disappears as does the near front arm and some of the leg. The far front leg's length to the current is also lessened. I believe the overall drag to the wind is drastically reduced. There is still the drag to the mini's forward motion but as I said I'm not an engineer and don't know how that plays out on getting the AC home.

If there was any increased airspeed due to a reduced cross-sectional area exposed to the wind, it would be trivial and never make enough difference to help you.
No matter how much some would like to believe this myth, if the wind is too strong and your drone is not making headway, tacking or zigzagging is only going to make the problem worse.

 

[Deleted member 114292]

Not being an aeronautical engineer I'm not sure if this makes a difference but do you get better advancement with less headwind drag? Pick up your mini and give this a try. Trying it and seeing for yourself is better than my explanation.

When I hold the mini up in front of me and tilt it simulating forward motion (rear end up) and view it as the wind sees it straight on like a stream's current. When head on there is a lot more surface area (drag) being seen. In addition to the huge surface area of the top of the mini's body there's the full length of all 4 arms plus the props and legs are exposed as drag.

Then try turning the mini slightly sideways (with the same forward tilt) and the surface area to the wind drops drastically. The "water current" drag of the far rear arm and most of the prop disappears as does the near front arm and some of the leg. The far front leg's length to the current is also lessened. I believe the overall drag to the wind is drastically reduced. There is still the drag to the mini's forward motion but as I said I'm not an engineer and don't know how that plays out on getting the AC home.

Drag has nothing to do with it.
The body of air is moving with the ac in it.

 

[sar104]

Not being an aeronautical engineer I'm not sure if this makes a difference but do you get better advancement with less headwind drag? Pick up your mini and give this a try. Trying it and seeing for yourself is better than my explanation.

When I hold the mini up in front of me and tilt it simulating forward motion (rear end up) and view it as the wind sees it straight on like a stream's current. When head on there is a lot more surface area (drag) being seen. In addition to the huge surface area of the top of the mini's body there's the full length of all 4 arms plus the props and legs are exposed as drag.

Then try turning the mini slightly sideways (with the same forward tilt) and the surface area to the wind drops drastically. The "water current" drag of the far rear arm and most of the prop disappears as does the near front arm and some of the leg. The far front leg's length to the current is also lessened. I believe the overall drag to the wind is drastically reduced. There is still the drag to the mini's forward motion but as I said I'm not an engineer and don't know how that plays out on getting the AC home.

Sorry - it's not a drag problem except in as much as drag limits airspeed. But the maximum airspeed of the aircraft doesn't improve by turning it sideways, and it certainly doesn't help to make progress against the wind - if that were the case then all you would need to do is fly it sideways into the wind. If my airspeed explanation doesn't help you then I don't know what else to say.

 

[sar104]

Drag has nothing to do with it.
The body of air is moving with the ac in it.

I just cannot figure out why this is not completely obvious, but apparently it really isn't.

 

[Deleted member 114292]

I just cannot figure out why this is not completely obvious, but apparently it really isn't.

A flight instructor explained it to me and said as far as the ac is concerned:
There is no wind.

 

[sar104]

A flight instructor explained it to me and said as far as the ac is concerned:
There is no wind.

That's correct - as far as the aircraft is concerned the air is stationary and the ground is moving under it at the speed of the wind.

 

[Drgnfli]

The question has come up in a different thread about using tacking (zig-zagging diagonally to the wind) as a workable solution when faced with an overpowering headwind. This works with sailboats but will it work with a drone or aircraft?

As a retired sail boater the answer is NO!... LOL!...

 

[Drgnfli]

The best solution is to not get in those situations
but when it does happen
find an altitude with the lowest wind velocity and go into sport mode and hit it hard
if your battery is dying or you are going backwards
find the best place to land and go find your drone
Better than being blown miles away or getting stuck in a treeView attachment 99683

Got to say it again! If your landing pad needs to be anchored to the ground with rocks or stakes... It is TOO WINDY TO FLY YOUR DRONE! ! ! !

 

[RogerDH]

I understand what you’re saying but you weren’t there. When I flew directly into the wind, it just wouldn’t move. At maximum speed the drone was just hovering against the wind. Yet by tacking I got it back. Don’t know what else to tell you.

Perhaps the attached vector diagram will illustrate the problem. If the wind drag is greater than or equal to the maximum forward thrust that the drone can deliver, then the drone cannot make headway in that direction. If the drone's thrust is turned at a 45-degree angle to the wind, then only about 70% of the maximum thrust is counteracting the wind drag. The drone must lose ground to the wind regardless of how much sideways motion is achieved.

 

[raymacke]

I started this thread when my response was questioned about what I feel is a basic physics problem. I had no idea the misunderstanding of this principle was as widespread as it seems to be. Obviously, there are pilots that adamantly feel this is workable as they recount instances where it appears they were successful implementing it. But realistically it can't. The perceived situation either unknowingly changed or the initial observations were not totally accurate. In my mind, this is just more or less a drone version of the fascinating phenomenon of the placebo effect - getting a positive result but misinterpreting the cause of that result.

 

[Deleted member 114292]

I started this thread when my response was questioned about what I feel is a basic physics problem. I had no idea the misunderstanding of this principle was as widespread as it seems to be. Obviously, there are pilots that adamantly feel this is workable as they recount instances where it appears they were successful implementing it. But realistically it can't. The perceived situation either unknowingly changed or the initial observations were not totally accurate. In my mind, this is just more or less a drone version of the fascinating phenomenon of the placebo effect - getting a positive result but misinterpreting the cause of that result.

The fact is that no actual data was measured or recorded so what they have to say amounts to a myth.

 

[Mossiback]

I think the reason people think "tacking" against a headwind works is that when they change the angle away from a headwind their GPS speed increases. Unfortunately their ground speed towards their destination would not change appreciably given constant wind speeds. What might happen is when tacking is they found less head wind and made more progress. Much like a river of water, the wind speeds in a river of air are not constant across a wide area.

I have not tested the above, it just seems logical. Of course, I may be full of hot air myself.