Flight by the lake with Popwing

[icebear]

Since it is now apparent that the Gluonpilot is water-proof, I decided to fly over the lake where we spent a weeks holiday in the midst of the woods in Småland in south Sweden.

I have re-installed my GP in a slightly bigger wing - TechOne Popwing and after some trimming it flies very well.

It was a calm and nice morning and I laid out a route along the shoreline from the only good take-off spot in a filed to where we have our house and brigde/dock by the water.

Here is a short video from the event!

Enjoy!

/Björn

http://youtu.be/DzsFrd0peOo

[Tom]

Very nice video! My vacation looks so far away now

Altitude hold is OK now?

[icebear]

Very nice video! My vacation looks so far away now

Altitude hold is OK now?

Thanks Tom!

I increased throw to make the wing more responsive and it both tracks and keeps alt better. Still working a bit with altitude since the wing is not yet up to "Funjet standard"

/Bjorn

[icebear]

Hi,

After increasing throw I had much better tracking and alt hold. I have now also increased P-term in roll/pitchto 0,7 and 1,2 respectively and this has also improved further from what I can see.

Now to my question - the Popwing still does not reach desired altitude but lies just below - say 55-58 meters when alt is set to 60 meters. Is this something that can be improved? See attached screendump with alt curve.

I have added som up-trim (which was needed) but when entering flare the wing stalls so I need to go back a bit and I have also increased autp throttle to a good speed (about 50% throttle) but this has not helped reaching desired altitude.

Theory;

- The laps I have in my route are quite short so maybe the wing does not have time to stabilize around 60 meters.----> I could try to increase I-term in Pitch-Altitude

Any ideas welcome!

Cheers

Bjorn

[Tom]

Hi Bjorn,

Those few meters difference are the steady state of your system. The reason it does not reach the target altitude can be several:
- trim of elevator too low
- unsufficient P-term for pitch
- maybe 0° pitch is in reality -3° pitch?
- If you already increased throttle enough I can assume we can rule this out

In general you would need to add an I-term to your PID control loop, but this will add complexity for just reaching these 2 extra meters.

[icebear]

Hi Bjorn,

Those few meters difference are the steady state of your system. The reason it does not reach the target altitude can be several:
- trim of elevator too low
- unsufficient P-term for pitch
- maybe 0° pitch is in reality -3° pitch?
- If you already increased throttle enough I can assume we can rule this out

In general you would need to add an I-term to your PID control loop, but this will add complexity for just reaching these 2 extra meters.

Hi Tom,

Yes - I agree, it looks very stable around that altitude slightly below target. I think we also can rule out elevator trim since I already have quite a bit of "up" trim - to the point where I get a stall during flare.

I will try your suggestion to increase P-term further just to see what happens and I agree it might not be of use to add the I-term - in all other aspects I think the wing is very well trimmed now.

Now I am off to a weeks vacation in the Baltic and I hope to return with a nice video or two of the area...

/Björn

[icebear]

Hi again,

Managed a late night flight (we have loooong evenings here ) yesterday to test increased P-term for pitch.

I increased in steps from 1.1 to 1.3, 1.5 and 1.7. Already at 1.3 I get a slight oscillation in pitch which shows as quick corrections that causes a quick wobble every 2-4 secs. Video recording is good to pick up that...

Therefore, I have concluded that 1.1 is a good pitch setting and I am OK with a few meters off the target since everything else is fine. (Maybe thrust angle could be changed and/or more throttle...)

Now off to the Baltic!

/Bjorn

[Tom]

Have a good vacation!!!

[icebear]

Thanks!

Managed a flight over an ancient castle (Borgholms slott) today but scr***d up the video since the lens had shifted

Still AP picture attached!

More to come soon!

Björn