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#1
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B2 Split Rudder
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. |
#2
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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. |
#3
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"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. |
#4
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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 |
#5
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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 |
#6
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"Cub Driver" wrote
Tucker said he spun the 49. Edwards did a spin too (his last flight)... |
#7
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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 |
#8
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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. |
#9
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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 |
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