Chukar's own account

Re the full-aileron cross-control suggestion a few posts up:

As I understood it, you were giving full rudder also?

Wow, I've never heard anything like that suggested before.

One thing I'd urge you to further explo how much variation in airspeed can be tolerated before the glider is no longer in a stable spiral? E.g. if the airspeed accidentally increases by X mph, do you the dynamics change enough that you go out of control? The dynamics that keep the various turning forces approximately balanced, and the various roll torques exactly balanced, may be extremely airspeed-sensitive.

I'm not guessing one way or the other, just curious.

S

(Continuing from previous)

Also the initial bank angle might matter. What did you use?

I know at least one glider where a full-deflection cross-control will result in no turn at all, at least at higher airspeeds. In one aircraft (not a glider) I could hold a full-deflection cross-control and would end up banked only slightly toward the high aileron, and going round and round in a turn in the opposite direction, toward the high wingtip, at least at low airspeeds. This situation was very stable.

You've certainly raised an interesting idea. I hope others explore and share.

S

My initial entry into the cross control is usually with wings level just initiate a forward slip. Second thought is that speed between 60-90 doesn't seem to change the dynamic much a little more buffeting and shaking the faster you go but that happens in the ventus with dive brakes open in level flight.

CH

At 17:40 24 April 2015, wrote:
My initial entry into the cross control is usually with wings level just
in=
itiate a forward slip. Second thought is that speed between 60-90 doesn't
s=
eem to change the dynamic much a little more buffeting and shaking the
fast=
er you go but that happens in the ventus with dive brakes open in level
fli=
ght.

CH

What about the sideslip IAS errors when trying to control airspeed by
flying
so cross-controlled in a spiral dive?

And are there issues with torsional stresses on the tail boom at 90 kts IAS

(probably more from pitot cross-flow errors) with sustained full rudder? I

have no idea whether that is a worry in the proposed scenario but I am
recalling the ETA that twisted off its tail in a spin recovery.

Eta twisted off the tail boom during a recovery from a spiral dive, not a spin. Huge difference in loads.

Bert
TW

On Fri, 24 Apr 2015 06:18:59 -0700, platypterus101 wrote:

Re the full-aileron cross-control suggestion a few posts up:

As I understood it, you were giving full rudder also?

Wow, I've never heard anything like that suggested before.

One thing I'd urge you to further explo how much variation in
airspeed can be tolerated before the glider is no longer in a stable
spiral? E.g. if the airspeed accidentally increases by X mph, do you
the dynamics change enough that you go out of control? The dynamics
that keep the various turning forces approximately balanced, and the
various roll torques exactly balanced, may be extremely
airspeed-sensitive.

I'm not guessing one way or the other, just curious.

I think you've misplaced this post. I haven't made and "full-aileron
cross-control suggestions" in this or any other thread.

What I *did* say is that my club requires members to do annual spin and
winch launch failure check flights. We do this at the start of each
flying season: members are not authorised to fly solo until these have
been completed. This sounds eminently sensible to me.


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