B2 Split Rudder

[Emilio]

There was nice discussion on B2 Split Rudder use during climb earlier.

http://www.ammochiefs.com/Diego%20Garcia%204.jpg

The discussion made me think concerning B2 yaw control. In general, large
rudder input is needed for number of situations. First is the crosswind
take off and landing. For take off, most aircraft tends to weathercock and
large rudder input is needed especially when ground speed is low. B2 Split
Rudder is not effective for this, in fact do to its geometry, at certain
speed, rudder force can reverse! I suppose B2 simply don't weathercock. As
for crosswind landing B2 needs to be slipping on approach and not crabbing.
Am I right?

The other situation where large rudder input is needed is during spin
recovery. Was B2 ever tested for spin recovery? Or do the flight computer
simply will not let B2 into spin situation? What if split rudder gets
damaged on one side? Do you loose B2 at that point?

Emilio.

[Boomer]

being a flying wing, the B-2 has almost nothing for the crosswind to act
against.

--



Curiosity killed the cat, and I'm gonna find out why!
"Emilio" > wrote in message
...
> There was nice discussion on B2 Split Rudder use during climb earlier.
>
> http://www.ammochiefs.com/Diego%20Garcia%204.jpg
>
> The discussion made me think concerning B2 yaw control. In general, large
> rudder input is needed for number of situations. First is the crosswind
> take off and landing. For take off, most aircraft tends to weathercock
and
> large rudder input is needed especially when ground speed is low. B2
Split
> Rudder is not effective for this, in fact do to its geometry, at certain
> speed, rudder force can reverse! I suppose B2 simply don't weathercock.
As
> for crosswind landing B2 needs to be slipping on approach and not
crabbing.
> Am I right?
>
> The other situation where large rudder input is needed is during spin
> recovery. Was B2 ever tested for spin recovery? Or do the flight
computer
> simply will not let B2 into spin situation? What if split rudder gets
> damaged on one side? Do you loose B2 at that point?
>
> Emilio.
>
>

[D. Strang]

"Emilio" > wrote
>
> As for crosswind landing B2 needs to be slipping on approach and not crabbing.
> Am I right?

The wingspan dictates that slipping not be performed on "heavy" aircraft. You can
slip them, but not close to the ground during final. The B-2 is crabbed for a
standard procedure landing.

> The other situation where large rudder input is needed is during spin
> recovery. Was B2 ever tested for spin recovery?

No. The B-2, like all "heavy" aircraft, are never spun. The closest you get to
this, is what's called "Approach to stall." Basically you approach a stall,
experience stick shaker, and alarms, get a rapid loss of altitude, and those
that go further will need to eject if equipped, those that aren't can just enjoy
the ride down.

> Or do the flight computer simply will not let B2 into spin situation? What if
> split rudder gets damaged on one side? Do you loose B2 at that point?

Any aircraft can be made to spin. The software prevents the normal stuff.
There is a lot of redundancy in the B-2, and I don't think any one thing will
cause a loss given enough altitude and fuel to stabilize an emergency landing.

[Cub Driver]

On Thu, 8 Apr 2004 14:48:14 -0500, "Emilio" > wrote:

>I suppose B2 simply don't weathercock.

Without a conventional rudder, surely this would be nonexistent or at
least much reduced?

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com
Viva Bush! blog www.vivabush.org

[Cub Driver]

On Thu, 8 Apr 2004 14:48:14 -0500, "Emilio" > wrote:

> Was B2 ever tested for spin recovery?

Interesting question, given the problems Northrop had with its YB-49.
There's are interviews with the YB-49 test pilots at
www.warbirdforum.com/cardenas.htm and
http://www.warbirdforum.com/tucker.htm

Tucker said he spun the 49.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com
Viva Bush! blog www.vivabush.org

[D. Strang]

"Cub Driver" > wrote
>
> Tucker said he spun the 49.

Edwards did a spin too (his last flight)...

[Cub Driver]

>>
>> Tucker said he spun the 49.
>
>Edwards did a spin too (his last flight)...
>

Well, he *experienced* one. The pilot was Danny Forbes.

There is some question whether the airplane was actually spinning
(going down in a spiral), or revolving around its lateral axis. The
latter would also be a spin, I suppose, but not one that many humans
have experienced.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com
Viva Bush! blog www.vivabush.org

[Paul Hirose]

A 1999 B-2 flight manual in my collection says to hold stick slightly
into the wind during crosswind takeoff. Release rudder pedal pressure
after becoming airborne. The air data system will sense sideslip and
automatically weathervane the aircraft into the relative wind.

Crosswind approaches may be flown in a crab or with a wing low. Wings
should be leveled and crab removed before touchdown; slight elevon
will maintain wings level.

After touchdown, the flight control system ignores the yaw angle
inputs from the air data system, so it no longer tries to weathervane
into the relative wind.


Except for battle damage or collision, it's hard for me to imagine
both rudders on the same side failing. Although they normally operate
symmetrically, the upper and lower rudders are independent surfaces
with their own actuators. During takeoff they do move independently
when the stick is pulled back to rotate. The lower rudder goes to zero
and the upper rudder rises to help the elevons raise the nose.

--

Paul Hirose >
To reply by email delete INVALID from address.

[Cub Driver]

>A 1999 B-2 flight manual in my collection says to hold stick slightly
>into the wind during crosswind takeoff.

Well, presumably you'd want to do this so as to keep the windward wing
from lifting, so the plane won't flip. (Can you flip a B-2?)

Even if the plane weren't subject to weathercocking.

Again, a presumption: moving the stick to the left would only raise
the top of the port split rudder, not the bottom half. I assume
they're independent, as on the YB-49 and other Jack Northrop
all-wings.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com
Viva Bush! blog www.vivabush.org