New - B question regarding aerodynamics...

[sonicpilot]

As a former commercial helicopter pilot, I had to learn a great deal about helicopter aerodynamics as well as the effects of wind in flight. I notice that the forum does not have any section for such discussion. Are there no significant aerodynamic concerns in drone operations?

 

[Phantomrain.org]

As a former commercial helicopter pilot, I had to learn a great deal about helicopter aerodynamics as well as the effects of wind in flight. I notice that the forum does not have any section for such discussion. Are there no significant aerodynamic concerns in drone operations?

The GPS does so much for the drone that really the only wind that truly needs to be negotiated is the head wind that your flying into and using to get back. For long distance flights wind really comes into play but most of us stay within the VLOS to some extent.

There are a very few that purposely use atti mode where the drone needs a lot more attention to fly in the wind as your loosing GPS signal.

Something you might enjoy is the Telemetry on your videos showing winds speed ect similar to this thread:
If you interested Zeus has posted a fantastic step by step on how to add this to your videos.

Mavic Air 2 range test with Wetsuit + Rescue Jacket under severe weather conditions.

I want to share this test performed under very severe wind conditions. I decided to do it because will be the perfect worse case scenario for anybody and see the limits of my setup. I want to thanks my supportive wife, daughter and my brother for serve as spotters from the ground during the...

mavicpilots.com

Phantomrain.org
Gear to fly your DJI in the Rain and Land on water.

 

[Thomas B]

As a former commercial helicopter pilot, I had to learn a great deal about helicopter aerodynamics as well as the effects of wind in flight. I notice that the forum does not have any section for such discussion. Are there no significant aerodynamic concerns in drone operations?

Due to wide differences in various drone flaying characteristics these are posted within the category for each drone with specific question by OP of the thread.

 

[Deleted member 93449]

While there may be specific differences from one model to another all drones I'm familiar with have a compass and Inertial Measurement Unit (IMU) that help maintain stable flight in various wind conditions. The IMU senses changes in pitch, roll and yaw and uses motor controls to compensate.

 

[bumper]

Some things are similar between both helicopter and drone. Vortex ring state being one of them. In drones, that's mostly avoided by limiting rate of descent. Not sure, but transitional lift may be somewhat of a factor in drone efficiency, though probably not to the extent it is in helicopters.

Disclaimer: I've only been a passenger in a friend's Eurocopter EC-120B, and flown models (though not very well). I'm a fixed wing pilot.

 

[sonicpilot]

Vortex ring state (settling with power) and effective translational lift are some of the issues I was thinking about. I guess the technology in many drones can compensate and thus avoid these issues. Interesting!

 

[bumper]

Vortex ring state can affect both. I think for the most part it's avoided in drones by a programmed limit to descent rate. I imagine transitional lift affects both as well. I've only flown early model helicopter (those with a tail rotor gyro only), and I wasn't very good. I'm a fixed wing pilot

 

[Gringorio]

There are a very few that purposely use atti mode where the drone needs a lot more attention to fly in the wind as your loosing GPS signal.

What does this even mean?

 

[DanMan32]

I believe vortex ring is also avoided by the angle of the prop motors.

 

[Meta4]

There are a very few that purposely use atti mode where the drone needs a lot more attention to fly in the wind as your loosing GPS signal.

I'm not sure how this is relevant to the OP's question but if you use a drone that allows switching to atti mode (Mavics don't), switching to atti mode does not lose GPS signal at all.
It just disables GPS assisted horizontal holding.

 

[Stickynick]

As a former commercial helicopter pilot, I had to learn a great deal about helicopter aerodynamics as well as the effects of wind in flight. I notice that the forum does not have any section for such discussion. Are there no significant aerodynamic concerns in drone operations?

I too am a former Helicopter pilot and these modern drones have what we would call an SAS system on steroids - you can leave the controls while the drone hovers in place in any wind within the limits (which are impressive) As for vortex ring - you can hear the increase in blade noise (perhaps the beginnings of vortex ring) when you do a fast vertical descent but I have yet to see any evidence of settling. As for the translation dip - I have not seen that either but perhaps a carefully watched low level hard acceleration with no headwind may cause a dip but I suspect it will be minimal. As for acceleration in any direction it is all about blade RPM on different motors - interesting but nothing like the affects of pitch/rpm on torque and blade pitching with the cyclic.

 

[maelstrom]

translational lift

Any potential translational lift effects are overcome by the electronics. As you accelerate, the drone automatically maintains height by varying the motor speeds.

 

[Meta4]

As for vortex ring - you can hear the increase in blade noise (perhaps the beginnings of vortex ring) when you do a fast vertical descent but I have yet to see any evidence of settling.

VRS was a potential issue with the earliest DJI drones.
But DJI solved this by of-setting the motors and reducing the descent speed back in 2015.

 

[Cymruflyer]

As a former commercial helicopter pilot, I had to learn a great deal about helicopter aerodynamics as well as the effects of wind in flight. I notice that the forum does not have any section for such discussion. Are there no significant aerodynamic concerns in drone operations?

Flying aircraft we actually sit in means we are flying them and as the PIC you have to control the aircraft and counteract what the wind wants to do to it etc. In drone flying all we do is steer it around the sky, the drone itself does all the control of keeping it in place and on track, for example, via the GPS and the electronics.

In a helicopter if you hover in a cross wind and were able to let go of everything, it would be blown with the wind direction. In a drone if you let go of the sticks, the electronics along with the GPS signal keeps it right there where you left it until you make it do something else. Principles of flight still apply but it is like sitting in the helicopter with an autopilot doing everything for you. All you do is choose a heading and speed and altitude and the autopilot will do the rest for you like keeping it right on track without you having to adjust the jaw to keep it on a straight line track along the ground. Hope that explains it.

In real flying when you are heading from point A to B, you hardly ever have the aircraft pointed in a straight line like a car does, when travelling along that ground track because you have to adjust the jaw to counter what the winds may be doing to your aircraft. If you pointed the aircraft to point B from A, you would never get there because there is always some sort of wind aloft that will be blowing you in some direction or other. Therefore you must compensate for that, to keep yourself on a constant track across the ground. Having said that, I must admit that there have been a few odd times when the air seemed dead still and I could just point my aircraft to a spot in the distance and it would get there without having to crab at all. But hose time flying are rare.

 

[Cymruflyer]

What does this even mean?

It means that as long as you leave the drone in one place, the GPS signal along with the onboard electronics will keep it right there, regardless of the wind speed and direction (within reason of course). Move it forward and then release your sticks and the drone will stop and hold right there.

In ATTI mode, it does not have the GPS working along with the electronics to keep it in one place when you let go or do nothing else after giving an input to the sticks. Therefore, it is like a boat in the water or a river. Give it throttle and stop the throttle, the boat will keep going in the direction you sent it off in plus the river's current will make it flow in that direction too. That means when in ATTI mode you have to think of everything you are doing and what you need to do to stop it doing anything further when you release the stick input.

So if you make it move forward, it will go forward and when you release the forward stick to neutral it will keep going that way until you give a control input to arrest that forward movement. Plus if there is a cross wind, it would be going forward and be blown in the direction of the wind flow while going forward, much like that river current I mentioned. So flying in ATTI mode is more like being in a real aircraft, it needs to be constantly controlled or it will crash eventually, or fly into something. So in your drone, the GPS signal is still there but it is not doing anything like sending a notice to the electronics to hold the drone motionless in place, when you let go of the sticks. Now I hope you understand.

 

[Cymru]

You don't really "fly" a drone in that sense of the word. You merely move it from one place to another.

The computer itself handles all the engine powers, pitch, tilt and so on. It requires no piloting skills or even knowledge what-so-ever.

Even ATTI mode you dont adjust power, maintain altitude and have automatic levelling in both pitch and roll.

Mavic drone operation at least you're basically just manipulating an extremely good, stable autopilot system with no scope for bypass.

 

[Zbip57]

The original DJI Phantom was susceptible to vortex ring state if descending straight down into its own propwash. With that one it was important to always maintain some forward motion, or sideways, or spiral, anything except straight down whenever descending. Subsequent DJI drones all now feature a limited descent rate to avoid ever encountering VRS when descending.

Here's a hilarious example of an early Phantom in vortex ring state as it's descending. At 1:30 in the video, the bird goes into the wobble of death and plummets into a lake. That's not the funny part though. What's funny is how they tried to dry it out after recovering the drone. Watch to the end...

 

[CactusJackSlade]

Here's a hilarious example of an early Phantom in vortex ring state as it's descending. At 1:30 in the video, the bird goes into the wobble of death and plummets into a lake. That's not the funny part though. What's funny is how they tried to dry it out after recovering the drone. Watch to the end...

Actually, I've heard a lot of instances of electronics dried off in the oven.... but keep the door open and don't forget, well done plastic is not good for anybody! I was pretty impress the GoPro kept recording under the water and the file was not corrupted.

 

[Cymruflyer]

You don't really "fly" a drone in that sense of the word. You merely move it from one place to another.

The computer itself handles all the engine powers, pitch, tilt and so on. It requires no piloting skills or even knowledge what-so-ever.

Even ATTI mode you dont adjust power, maintain altitude and have automatic levelling in both pitch and roll.

Mavic drone operation at least you're basically just manipulating an extremely good, stable autopilot system with no scope for bypass.

Well obviously you are not really flying it, I thought that was a given that we all understand. With that said, you do in a sense, "fly" the drone, it is just tnat a drone has different control systems to say a 3-axis RC aircraft. So, your stick input to turn or jaw, would be the same stick movements with a 3-axis RC aircraft, it's just that the drone does fly in a different manner. In a sense, you do still fly the drone to some extent, because you could also call flying an RC aircraft, :Just steering it around the sky". Semantics maybe?

However, in ATTI mode if you give forward command and then release the stick, I don't believe the drone stops, it keeps going from the inertia that was started with the forward power command/input. To stop it, you have to apply a rearward power command with the stick, enough to stop the forward movement. And when you have done that it will still float around the sky from the winds aloft movement, because it does not use the GPS to hold a set position. At least that is what I have been led to understand. Please correct me if I have that wrong.

 

[Cymru]

However, in ATTI mode if you give forward command and then release the stick, I don't believe the drone stops, it keeps going from the inertia that was started with the forward poser command. To stop it, you have to apply a rearward power command with the stick enough to stop the forward movement. And when you have done that it will still float around the sky from the winds aloft movement, because it does not use the GPS to hold a set position. At least that is what I have been led to understand. Please correct me if I have that wrong.

Not on the mavic and phantoms - even in ATTI releasing the sticks returns to 0 roll, 0 pitch. So whilst it doesnt brake to maintain a position it coasts to a halt. You dont need to return pitch to 0 by applying reverse stick although you can if you want to speed up the process.
It drifts on the wind yes but from a neutral pitch and roll.

I fly atti on the M2 quite a bit in areas where GPS is weak or intermittent to stop it suddenly jumping around several meters as the signal quality changes (narrow canyons, woodland in summer etc).