Landing Flaps Parameter Questions

Interesting Nathan - I am getting ballooning at the flare point. I have been chalking it up to too high a speed, too high a flare alt. I will now take a look at that SINK parameter.

Thanks,

Paul

Atico,

I noticed that your final glideslope of 11.4% is much steeper than what I have been using. I have been using around 5-6%. You also have a much larger field that lets you use a luxurious long approach.

For me sometimes the autopilot adds power during the final approach - maybe that’s because it is trying to maintain a 5% slope. I’ll try a steeper final slope as well. Thanks for the pdf of your parameters too.

Your autolanding was beautiful. It looked liked it was in a nice flare for quite awhile on final approach.

Paul

Can I simply use the LAND_FLAP_PERCNT parameter instead of the two FLAP_1/2_SPEED and FLAP_1/2_PERCNT schedule items?

Paul,

I am still in research mode on landing flaps and auto-landing, but what I did on the glide slope was calculate from DF logs the power-off glide slope in still air for my Radian Pro, and it was in that low double digits range, 10%, 11% or thereabouts. Dropping that substantially in my params would likely invoke motor to maintain such a shallow glide, which I would assume complicates everything.

Kelly

Yes, you can,

FLAP_1/2_SPEED and FLAP_1/2_PERCNT >>>> Set to 0
LAND_FLAP_PERCNT >>>> set the value you want, for example to start 60%

Regards
Atico

Thanks for your comments everyone.

Had two autolandings yesterday evening both with long overshoots of the landing spot.

The plane was flying faster because of the hot and humid air, and it never slowed down enough to deploy full spoilers. Even when I landed it manually I could not slow it down to the FLAP_2_SPEED.

No further testing until next week though as I have yet another TFR that closes my airspace this weekend.

Paul

Atico,

When does the LAND_FLAP_PERCNT parameter activate the flaps? At the DO_LAND_START command in the flight plan?

Thanks,

Paul

it does it at the beginning of the approach session, from the last WP to the starting point

http://www.sop-fpv.com/descargas/file/57-senda-de-planeo-en-autoland

Test whit this parameters and LAND_FLAP_PERCNT=60

What is your model airplane? weight, span

Atico,

Span is 51", weight about 27 ounces. Very clean, I later added a landing gear to make drag to help it slow down.

Please clarify exactly when LAND_FLAP_PERCNT lowers the flaps?

Paul

empieza probando con el 60% de movimiento de flaps

I meant when in the flight plan do the flaps deploy?

Thanks Atico, Paul

Can ArduPlane take fractional meters per second values like 8.5, 9.5, etc? It seems that when I look at the configration after, the values have been rounded to whole numbers like 9 and 10.

Had two good auto landings today both within 20 feet of the programmed landing spot.

What does this “Rangefinder Engaged” message mean?

The TFMini rangefinder works out to about six meters and the logs verify that.

rngfnd-412

Also, I have the pre-flare altitude set to 3 meters. I do not know how that 4.12 meters comes into play…maybe it is the distance from the ground when the DO_LAND_START command took effect?

Thanks,

Paul

Paul,
I’m also trying to get flaperons to work in autolandings, what was your final setup and settings to get it to work?

Kyle

Here Kyle is what works for me. Note that your airspeeds will be different for your particular airplane. Also, spoilerons are just like flaperons, they just move up instead of down.

Paul

The rangefinder is a TFMini, and it set to signal the pre-flare stage at 3 meters and the flare at 1.5 meters. And:

Does this airspeed sensor output look normal? Seems to vary quite a bit.

More questions:

(1) I thought that the LAND_FLAPS_PERCNT took effect when the flight plan reached the DO_LAND_START command. The logs show that the flaps deploy much later around the last waypoint before the landing spot. Can anyone tell me their experience with this?

(2) What causes the TECS_LAND_ARSPD to take effect? What triggers it? (In a video by Tom Pittenger at an Ardupilot meeting he said the DO_LAND_START command in the flight plan is just a “marker” and does not execute anything.) I thought DO_LAND_START started the landing logic and triggered the TECS_LAND_ARSPD but I must be wrong.

I think I have several mistakes in my parameters above. Do not use them until we sort out the events that cause the flaps to deploy and also triggers the TECS_LAND_ARSPD.

Thanks,

Paul

That airspeed relative to GPS speed does not look right to me. Here is a recent one of mine, which I don’t think is anywhere near perfect. I think the triple hump camel was from flying in circles while in RTL mode.

Kelly

Kelly,

Thanks for the plot to compare. I think the curves and zig-zags on your groundspeed to airspeed chart are similar to mine. I’ll bet if you zoom in on a small area they will look about the same. Unless there is something obviously wrong. What else could I look at?

Paul