Let DG1000S

[MDev]

I am in need of some figures for flap movement and elevator compensation when landing. Can anyone help?

M

[MDev]

After some time with this model and some help from Phil and Antonia (thanks) it’s all rather more obvious. This model does not need any assistance from the flaps for a run of the mill spoiler induced landing, which is a very controlled landing. 30 degrees of flap ensures a very steep landing, the flaps certainly slow the glider and I needed to hold up ele in to control it. So landings are now by the spoilers and if needed can be backed up with a variable flap operated by the side lever on the tx. No assistance from the ailerons or compensation from the ele is needed. Sorted.

I’ve been watching Pure Glide on YouTube, a NZ instructor who stated that using the flaps gives more authority to the ailerons when landing, but why?

M

[Jolly Roger]

I’m not sure why they’d say that and I’d love to hear an explanation.

Aileron authority increases with airspeed, but flaps are designed to lower airspeed. So on the face of it, dropping flaps should reduce aileron authority.

Extremely slow flying aircraft like the Just Aircraft Superstol, which use huge flaps (and slats) to lower speed to 25 knots or so, struggle with aileron authority. They use spoilers on the top of the wing tips to restore some directional control at these ultra low speeds.

One area where flaps do help roll control is by effectively introducing aerodynamic washout along the wing, so reducing the risk of tipstall. Crowbraking takes this one step further by raising the ailerons slightly as the flaps drop, and so increases washout even more. I’m a big fan of crowbrakes

Rog

[MDev]

The instructor went on to prove his point by using the flaps to land and coming to a stop and still balancing the glider upright by using the ailerons. I just can’t see the explanation for it?

M

[MDev]

Could the flaps give off increased washout when activated and increase the airflow onto the ailerons?

Just a thought.
M