flapped ships flight model question - OP can't land

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wickid
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Re: flapped ships flight model question - OP can't land

Post by wickid » Fri Jun 14, 2019 9:04 pm

Oh I see the OP was refering to the 15 meter Ventus. The Ventus 15 meter (like the diana) has quite a high wingloading. Also the airbrakes of the Ventus are large, probably too large for the 15 meter version as they also have to meet the certification standards of the 18 meter wing.

As for the pitch down. Flaps have multiple effects. When you extend them you are effectively flying with too high an angle of attack because the flaps provide extra lift. Therefor you have to lower the nose to prevent ballooning and speed loss. They also cause drag, which also means you have to lower the nose to maintain speed. But to help you with this, the center of pressure on the wing moves back so it naturally causes the nose to pitch down when you apply flaps. Most gliders do however require a bit of nose down trim with flaps L.

As for procedures on approach. Use the max glide angle flaps for the traffic pattern. So for the ASG29 use 4, antares Flaps 0, JS1 flaps 4, Ventus flaps 0 or +1, Diana flaps +8 or + 14.

Only on final and after you are sure you can make the field, put the flaps in the maximum positive setting (L or whatever it is on the plane you are flying). If it is very windy and turbulent and you need more aileron effectiveness you can use the flap setting just below that. Aim, just like you would in a flapless glider to approach with half speed brakes.

The target speed is a tricky one. The yellow triangle denotes the recommended approach speed at maximum weight with the flaps in landing setting. Usually you will be approaching without water ballast. So the optimum approach speed can be up to 10 kph slower. It is safe to always use the yellow triangle, but this may cause some floating on landing. I just hold off the plane until i make a two point landing. I don't try to hold it off too long as that usually results in a hard landing (This is what I suspect you are doing). Due to the bigger ground effect from the flaps it will float a lot longer and you are able to reach a higher pitch. When it doesn't want to fly anymore it will set the tail down and rotate around the tailwheel causing a hard impact on the main gear. I think that is why you find it easier to land with less flaps.

After landing it is easier to keep the wings level when you put the flaps full negative. On the ASG29 the outboard flapperons automatically move to full negative when selecting flaps L. The inboard flapperons move to about 50 degrees. They did this to keep better roll control with flaps L.

Hope this helps you
PH-1504, KOE
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lordauriel
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Re: flapped ships flight model question - OP can't land

Post by lordauriel » Wed Jun 19, 2019 11:54 am

many thanks for all the answers and input from all parties!!

I found out what was causing the "most" problems. I had the stick sensitivity at nonlinear setting 3 (third from the left). This gave me a bit better "realism" compared to real sticks which are linear, but also have much better resolution (well, inifinite really) and more range of motion than all but the most expensive home sim options (I guess the Virpil T50 with a 50cm extension rod bolted to a suspended table mount will NOT have this issue).

TLDR; I set the nonlinearity to the 1st setting from the left, juuuust enough to give enough control around the middle to avoid constant PIOs when holding off. This helped a lot.

What also dampened my confidence is the fact that I am not entierly sure why (not accusing here. Just stating that I don#t understand it) the yellow triangles are where they are in condor cockpits sometimes. Cirrus recoomended approach speed is 80, the yellow triangle is at 95 in condor, but the LS8 is totally correct (90 as in the handbook).

I just got to a point where I felt like I'm not sure anymore what to trust, in order to anchor myself at the things that are fact, and go from there.

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