Stability - P4P v MP - mild wind hover

AlanTheBeast · Apr 24, 2017

Shot this video today (two vids, edited together) to see if one or the other seems more stable while hovering into the wind.

Winds were from the front to back of the drones (towards the camera) 5 knots, gusting to 10 (Mk I guesstimator).

inkytog · Apr 24, 2017

Possibly the lower profile of the Mavic makes it more steady?

AlanTheBeast · Apr 24, 2017

inkytog said:
Possibly the lower profile of the Mavic makes it more steady?

In an other thread I showed a calculation that suggests that it may have an edge in power to weight.

The P4P also has the camera dangling down, and that may add to its buffeting (your "lower profile").

I'll try to repeat on Friday - winds are forecast to be a bit stiffer. Try to improve the video taking method as well.

PhantomEvan · Apr 24, 2017

Just tested it. I have no clue what the heck you did to your p4p, but I just flew in 10mph winds with 15mph gusts, and it was rock steady, didn't move at all. I suggest a calibration. After several reviews I've seen online, plus me flying it myself, the p4p is just more stable. It's simple logic, really.

RPP · Apr 24, 2017

PhantomEvan said:
Just tested it. I have no clue what the heck you did to your p4p, but I just flew in 10mph winds with 15mph gusts, and it was rock steady, didn't move at all. I suggest a calibration. After several reviews I've seen online, plus me flying it myself, the p4p is just more stable. It's simple logic, really.

The P4P is one tough cookie. I flew it earlier this month a couple of times in marginal conditions in Iceland where the winds were more than I would be comfortable with, and it held its own. I should say, however, that I would never send it out very far in these conditions. I only wanted still for which I needed to put it up 20-40 metres within a stone's throw of my location. The thing you have to look out for are unexpected gusts.

PhantomEvan · Apr 24, 2017

RPP said:
The P4P is one tough cookie. I flew it earlier this month a couple of times in marginal conditions in Iceland where the winds were more than I would be comfortable with, and it held its own. I should say, however, that I would never send it out very far in these conditions. I only wanted still for which I needed to put it up 20-40 metres within a stone's throw of my location. The thing you have to look out for are unexpected gusts.

I honestly have no idea what's wrong with this dudes p4p. His is as stable as a phantom 3, and most p4ps are rock solid.

smiller · Apr 24, 2017

PhantomEvan said:
Just tested it. I have no clue what the heck you did to your p4p, but I just flew in 10mph winds with 15mph gusts, and it was rock steady, didn't move at all. I suggest a calibration. After several reviews I've seen online, plus me flying it myself, the p4p is just more stable. It's simple logic, really.

Something does seem a little funky with that P4P.

Raptorman0909 · Apr 24, 2017

Part of it is that the camera is closer to the P4P which makes any motion appear more significant by comparison. But, there are some design factors favoring the MP as others have mentioned -- the MP has a less pronounced landing gear, a slimmer vertical profile, and the camera is smaller and hangs down less. But, quite frankly, the fact that the camera was closer to the P4P is perhaps the most significant factor and the truth may be that they were both about the same.

Brian

phantomAlex · Apr 24, 2017

I think the camera should be straight in the middle, same distance and angle. Not on the back of the P4P, and the camera should be on a tripod. The movement of the camera doesn't make justice to the drones, the camera recording the video shakes even more than the drones!

PhantomEvan · Apr 25, 2017

Raptorman0909 said:
Part of it is that the camera is closer to the P4P which makes any motion appear more significant by comparison. But, there are some design factors favoring the MP as others have mentioned -- the MP has a less pronounced landing gear, a slimmer vertical profile, and the camera is smaller and hangs down less. But, quite frankly, the fact that the camera was closer to the P4P is perhaps the most significant factor and the truth may be that they were both about the same.

Brian

Around there yes. But on my flight today after a fresh imu, the p4p seemed even more stable then the mavic shown here. Just my observations.

AlanTheBeast · Apr 25, 2017

PhantomEvan said:
Just tested it. I have no clue what the heck you did to your p4p, but I just flew in 10mph winds with 15mph gusts, and it was rock steady, didn't move at all. I suggest a calibration. After several reviews I've seen online, plus me flying it myself, the p4p is just more stable. It's simple logic, really.

I did nothing to my P4P. I cal'd the IMU and compass about 3 weeks ago. The MP I cal'd a few days ago. Both were buffeted about the same in the video.

"Logic"? It has nothing to do with logic. It has to do with physics. Things get buffeted in winds and the P4P is no different.

AlanTheBeast · Apr 25, 2017

phantomAlex said:
I think the camera should be straight in the middle, same distance and angle. Not on the back of the P4P, and the camera should be on a tripod. The movement of the camera doesn't make justice to the drones, the camera recording the video shakes even more than the drones!

You're exaggerating the movement of the camera but otherwise I agree. (And movement of the camera penalizes both, so that's sort of a wash).

I didn't have a tripod and I was using my iPhone for this. (I don't own a video camera). Also I framed that so there would be no tree clutter in the background.

Next time will be a better set up and stronger winds/gusts.

sar104 · Apr 25, 2017

PhantomEvan said:
Just tested it. I have no clue what the heck you did to your p4p, but I just flew in 10mph winds with 15mph gusts, and it was rock steady, didn't move at all. I suggest a calibration. After several reviews I've seen online, plus me flying it myself, the p4p is just more stable. It's simple logic, really.

It also depends on the variability of the wind, both in direction and speed. At one extreme, in steady, laminar flow, the aircraft should be very steady. As the flow becomes more variable, and possibly even turbulent, it becomes a much tougher test.

So not all wind tests are necessarily equal, even for similar nominal wind speeds. And if you only tested a P4P then you don't have a very good basis for comparison with the Mavic.

AlanTheBeast · Apr 25, 2017

sar104 said:
It also depends on the variability of the wind, both in direction and speed. At one extreme, in steady, laminar flow, the aircraft should be very steady. As the flow becomes more variable, and possibly even turbulent, it becomes a much tougher test.

So not all wind tests are necessarily equal, even for similar nominal wind speeds. And if you only tested a P4P then you don't have a very good basis for comparison with the Mavic.

Agree - (except both aircraft were side by side (a metre apart) facing the same wind.)

First off, as said, the wind was gusting a little - so much for "steady" and that was the point.

Secondly, this test was at about 2 m above the ground. So unlikely, even in a steady breeze, to be turbulence free.

Finally, The wind was coming through and around a stand of trees which surely stirred things up some more.

Maybe today I'll go out to a closed airport and do it smack-dab in the middle of the runway. (Sort of not legal as there's another airport about 5 km away - Canadian rules are stupid as can be made by stupid bureaucrats and politicians).

sar104 · Apr 25, 2017

AlanTheBeast said:
Agree - (except both aircraft were side by side (a metre apart) facing the same wind.)

First off, as said, the wind was gusting a little - so much for "steady" and that was the point.

Secondly, this test was at about 2 m above the ground. So unlikely, even in a steady breeze, to be turbulence free.

Finally, The wind was coming through and around a stand of trees which surely stirred things up some more.

Maybe today I'll go out to a closed airport and do it smack-dab in the middle of the runway. (Sort of not legal as there's another airport about 5 km away - Canadian rules are stupid as can be made by stupid bureaucrats and politicians).

That was my point - your test, with both aircraft side-by-side, should be a direct comparison. Another test, with just a P4P, for example, is not necessarily comparable at all.

I also forgot to mention that stability, in conditions where the wind speed is within the aircrafts capability to hold station, is a different metric than the maximum wind speed in which an aircraft can hold station. It is possible that even though a P4P can hold station in higher wind speeds than a Mavic, the Mavic is more stable than the P4P at lower wind speeds.

AlanTheBeast · Apr 25, 2017

sar104 said:
That was my point - your test, with both aircraft side-by-side, should be a direct comparison. Another test, with just a P4P, for example, is not necessarily comparable at all.

I also forgot to mention that stability, in conditions where the wind speed is within the aircrafts capability to hold station, is a different metric than the maximum wind speed in which an aircraft can hold station. It is possible that even though a P4P can hold station in higher wind speeds than a Mavic, the Mavic is more stable than the P4P at lower wind speeds.

It's a given that the P4P can handle the strongest wind since it has a higher max speed.

Not sure the MP is more stable, but it's at least "as stable" in the wind conditions of yesterday which were about 5 - 10G kts.

PhantomEvan · Apr 25, 2017

sar104 said:
That was my point - your test, with both aircraft side-by-side, should be a direct comparison. Another test, with just a P4P, for example, is not necessarily comparable at all.

I also forgot to mention that stability, in conditions where the wind speed is within the aircrafts capability to hold station, is a different metric than the maximum wind speed in which an aircraft can hold station. It is possible that even though a P4P can hold station in higher wind speeds than a Mavic, the Mavic is more stable than the P4P at lower wind speeds.

Well, I'm just saying judging on reviews I've seen, the p4p is more stable overall. And not to mention, your p4p is as stable as my old p3s. There might be something wrong with it. Mine has had heavier winds and never moved like that. Try a imu maybe?

PhantomEvan · Apr 25, 2017

AlanTheBeast said:
It's a given that the P4P can handle the strongest wind since it has a higher max speed.

Not sure the MP is more stable, but it's at least "as stable" in the wind conditions of yesterday which were about 5 - 10G kts.

And that's possible. It just might be because the p4p is bigger and it's easier to notice movement. My point is that my p4p doesn't move like that.
I'll have a video to prove and post when I get home this afternoon.

sar104 · Apr 25, 2017

AlanTheBeast said:
It's a given that the P4P can handle the strongest wind since it has a higher max speed.

Not sure the MP is more stable, but it's at least "as stable" in the wind conditions of yesterday which were about 5 - 10G kts.

RIght - I'm not arguing that the Mavic is more stable in those conditions - I'm just noting that these are somewhat independent metrics, and so it would not, necessarily, be inconsistent if it were.

AlanTheBeast · Apr 25, 2017

PhantomEvan said:
Well, I'm just saying judging on reviews I've seen, the p4p is more stable overall. And not to mention, your p4p is as stable as my old p3s. There might be something wrong with it. Mine has had heavier winds and never moved like that. Try a imu maybe?

I look forward to your video and I'll do an IMU before I go out next time. Note that the MP had a recent IMU and was performing similar to P4P.