Losing elevation at full forward throttle

[Motoguy199]

So the other day I'm flying at the soccer fields at 100' high. I'm watching my live feed about 1200' out returning back to me in GPS mode. I look up and it was on its way down and had dropped 40' when I let go of forward throttle. As soon is I let go it went back to 99'. Flying over grass was had to see the drop on live feed. So I ran it back and forth a few times and it kept doing this in GPS mode. I sent a ticket in and this was my response from 3DR what do you guys think.

"As you stated, the Solo should maintain altitude, but this doesn't work when using full performance and flying aggressively. When you were losing altitude and stopped pitching forward you can see that the Solo regained 4 meters but it didn't go up to the initial 40 meters.
When you're flying at a full performance and using full pitch forward it's recommended to also use the throttle to compensate for this loss of altitude."

 

[rrmccabe]

I have never seen this in GPS mode but its common in manual mode.

I am quite surprised actually and does not seem right. Out of curiosity what was your speed?

 

[Jubalr]

Hey Moto, here is where this was discussed and test results..
http://www.3drpilots.com/threads/altitude-not-holding-when-over-35mph.754/page-2

 

[Richard]

AH the classic question on flight dynamics. I learned this one back in "A" school in Pensecola, FL. Simple way to understand it... as it is shown in Jubalr's link. You need lift of course to maintain your AGL. if you hold your SOLO or any other quad copter or even a helo in your hands level AOA your machine will go up. If you apply forward motion by tilting it forward nose down your rotors are now angle towards the back of the aircraft and not face down applying downward force making you climb. so without constant downward force being applied you will lose altitude. That is why most of your combat helo pilots apply a large amount of collective when pitching nose down for speed without banging rotors on the ground. The same goes for reverse also.

 

[Raybro]

I have never seen this in GPS mode but its common in manual mode.

I am quite surprised actually and does not seem right. Out of curiosity what was your speed?

One of the reported improvements with the latest app update:

More power: The maximum continuous current the Solo is allowed to draw was increased to 42A to improve altitude-hold performance when flying fast upwind

They are listening Rich!

 

[rrmccabe]

Well @Raybro maybe that well help him. I don't ever remember altitude drop in GPS mode. Seemed to hold alt very well under all conditions with performance slider maxed.

Obviously, it was totally different in manual mode as it dropped like a rock.

 

[Raybro]

You think this update is addressing the problem in manual mode?

 

[rrmccabe]

I have no way of knowing. The last I heard was 3DR thought it was caused by possible baro misreadings at different pitch angles.

Like I said mine worked perfect in Fly mode.

 

[Raybro]

I have no way of knowing. The last I heard was 3DR thought it was caused by possible baro misreadings at different pitch angles.

Like I said mine worked perfect in Fly mode.

Yep, I just remember all the posts you made about it dropping in manual mode.

 

[Motoguy199]

Thanks for all the comments guys. I would expect it to drop in manual or maybe other modes but this is what I thought the GPS mode was for. I have flown this solo many times without this happening.

 

[Motoguy199]

Sorry rrmccabe. Flight speed was approx 30-33 mph

 

[rrmccabe]

Sorry rrmccabe. Flight speed was approx 30-33 mph

I personally think something is not right. I think that is the first I have heard of this.

 

[David Weston]

Also read a pretty convincing thread on AOG and baro sensor. Seems that location of the sensor at high AOG's causes a rise in baro which then tells SOLO it is climbing and wants to lower alt to correct for increasing baro. Also I think if I am not mistaken that it varies from one device to another so isn't common across all SOLO's, I think. Guess need to install a pitot tube... It has happened to other flying things as well, some I would guess had someone riding in it also.

 

[Dunginhawk]

Mine happened in GPS mode as well, at around 35 mph, but it also depends on wind, which helps pitch the bird down when the nose is already pointed down.
However, my GPS mode was also altered in Tower to allow me to fly faster, but it was still GPS

 

[Justin]

This just happened to me an hour ago. Flying with the wind at 14 m/s I dropped from 90m elevation to 70m with 30 seconds. I tested this in different directions and it only happened while flying with the wing. The current wind speed here is 8km/hr