Getting out of the clouds in a Ventus C

I promised to test one of the ideas for getting out of clouds alive (from the thread on Lucky Chuckar). This one involved gear down, full spoilers, full cross control, and manage speed with the elevator (by listening).

Results:
In the above configuration, the Ventus C has a strong and abrupt tendency to go into a steep dive with stick full back. closing the spoilers with controls still fully crossed results in a dramatic pull-up. I did not have the flaps extended for this experiment.

Conclusion:
maintaining a safe attitude and controlling speed in this configuration is impossible. It does result in a rather impressive rate of descent though....

I might try this again with spoilers fully closed one day, with fresh underwear...

Matt

Wow!!
Somebody please explain the aerodynamics for this.
The spoilers spoil the flow over the elevator when at extreme yaw?
Heinz




On Friday, May 8, 2015 at 7:50:32 PM UTC-7, Matt Herron Jr. wrote:
I promised to test one of the ideas for getting out of clouds alive (from the thread on Lucky Chuckar). This one involved gear down, full spoilers, full cross control, and manage speed with the elevator (by listening).

Results:
In the above configuration, the Ventus C has a strong and abrupt tendency to go into a steep dive with stick full back. closing the spoilers with controls still fully crossed results in a dramatic pull-up. I did not have the flaps extended for this experiment.

Conclusion:
maintaining a safe attitude and controlling speed in this configuration is impossible. It does result in a rather impressive rate of descent though....

I might try this again with spoilers fully closed one day, with fresh underwear...

Matt

Yes.

Bert TW
Ventus cM

Test #2

Yesterday I tested a variant of the first test; Gear down, flaps to +2 (not landing flaps), spoilers NOT deployed, stick all the way back and left, rudder full right. I held the controls in this position without adjustment/input.

Results:
Plane went into an aggressive slip to the left, nose low. We did a slow, steady turn to the right for 2.5 revolutions. During that time pitch was stable. The nose came up a bit, then went down. the nose went down, but then came back up. Nothing dramatic. I think I lost about 1000ft/revolution. I will post the trace today.

Conclusion:
I personally would try this maneuver in clouds before bailing out. It seemed stable, with a high rate of decent. I don't know if I had elevator authority, as the stick was all the way back. I need to test the slip in the other direction to make sure the behavior is also stable (I tend to always drop the left wing on stall). Your milage will of course vary...

Anyone else want to try this?

Matt

Update on test #2

Logger showed descent rate to be between 1500-2900 fpm. Turn rate was about 45 seconds per turn.

Matt

And if you try the more generally recommended approach of airbrakes out, hands and feet off? That seems to work in both the gliders I most often fly.

You should enter the recovery mode from an unusual attitude since you will probably be in an unusual attitude very soon after losing external visual reference.

Unless I have reason to think the cloud goes down to the ground, I would not consider bailing out unless/until the wings come off.

On Sunday, May 10, 2015 at 9:26:20 AM UTC-7, Matt Herron Jr. wrote:
Update on test #2

Logger showed descent rate to be between 1500-2900 fpm. Turn rate was about 45 seconds per turn.

Matt

Matt,

To be realistic and get a true sense of what will happen please do this with you eyes closed.

Richard

You first, smart guy.

On Sunday, May 10, 2015 at 5:50:09 PM UTC-7, Matt Herron Jr. wrote:
You first, smart guy.

Matt,

Seriously once you go into a cloud you will have no visual references. After about 30 seconds especially with the maneuver described you will have vertigo. What happens when you get out of the cloud? To establish your visual reference again may take another 30 seconds depending how serious the vertigo and what you do when you experience this. Things may get much worse. It is not just the aircraft that is the issue.

Richard

On Sunday, May 10, 2015 at 8:44:59 AM UTC-7, Matt Herron Jr. wrote:
Test #2

Yesterday I tested a variant of the first test; Gear down, flaps to +2 (not landing flaps), spoilers NOT deployed, stick all the way back and left, rudder full right. I held the controls in this position without adjustment/input.

Results:
Plane went into an aggressive slip to the left, nose low. We did a slow, steady turn to the right for 2.5 revolutions. During that time pitch was stable. The nose came up a bit, then went down. the nose went down, but then came back up. Nothing dramatic. I think I lost about 1000ft/revolution.. I will post the trace today.

Conclusion:
I personally would try this maneuver in clouds before bailing out. It seemed stable, with a high rate of decent. I don't know if I had elevator authority, as the stick was all the way back. I need to test the slip in the other direction to make sure the behavior is also stable (I tend to always drop the left wing on stall). Your milage will of course vary...

Anyone else want to try this?

Matt

I'd like to try full cross control vs full dive brakes with everything else the same.

Andy