|
Split-ailerons, need help understanding
|
|
Source：Internet Author：Unknow Pubdate：2008-10-29
|
|
dredogol (Computer)
11 Oct 08 1:08
Okay, I've been reading up on the Split-aileron patent #6491261, but I'm having a hard time understanding certain parts of the document.
I understand (now) that a split-aileron has an upper and lower hinge, where the upper panel can only move up, and the bottom can move both up and down. I also get the lower panel acts as a flap during landing, and the upper panel as an air-break.
During flight, the split-aileron can have both panels pitch up to act as a full aileron.
(so far, so good...)
One concept I can't grasp quite well is "adverse yaw". I understand it's when a plane points in the opposite direction before it begins to roll/yaw in the desired direction.
What I don't understand is how a standard aileron (one wing aileron fully up, other wing aileron fully down) causes "adverse yaw", while the new system (one wing aileron fully up, other at neutral position) does not cause "adverse yaw". 字串8
(Would appreciate it if someone could explain this (in basic English) to an aerodynamic dummy like me.)
Another concept I can't even possibly imagine, is how this new design can cause the plane to "yaw" to one side or the other. If I'm using a rudder and/or thrust-vectoring, then I understand. But how on earth does a vertical moving aileron cause the plane to move on the horizontal axis only?
Now, if this document is saying you can achieve yaw "with roll", then I understand. But is this document saying you can achieve pure yaw movement with just this aileron design?
Also, doesn't a regular plane with a tail and rudder allow for pure yaw action with no rolling, or is there some roll involved?
Lastly, probably really important, does this design consider JUST the B-2, X-36 and X-45A wing plan-view designs, or is it also considering any generic commercial wing design?
On the topic of these wing designs, I was wondering if split-aileron location on the tailing wing edge matters: 字串9
- (B-2) http://www.moog.com/img/2/b2_system.gif
I believe the split-ailerons are located on panels 4 & 5 of the diagram above, or is it just panel #5?. Anyways, I was wondering if having the split-ailerons just right of panel #5 on the side edge of the wing works?
My current wing design has panels 2-5 acting as elevons, and an extra panel #6 as split-ailerons. Do you know if this has any chance of working... or would it fail because they're too far on the wing edge?
- Again, thanks for any replies.
berkshire (Aeronautics)
11 Oct 08 15:47
dredogol
You need to get some primers on Basic aerodynamics.
You need to read up on secondary effects of Aileron And Rudder.
When an aileron is deflected downwards, it increases the lift on that wing, which also increases the drag causing the aircraft to turn opposite the direction intended. The rudder is then used to counter that effect, by yawing the aircraft. Aerodynamic fixes to reduce that effect are differential ailerons where the upward aileron goes up twice as much as the downward aileron comes down. Or spade ailerons where a drag surface is projected from the lower side of the upward moving aileron. 字串8
B.E.
rb1957 (Aerospace)
11 Oct 08 20:28
i can't challenge your reading the patents (since i haven't) but i would have thought that the two surfaces of a split aileron could move up or down ... both surfaces would move up (or down) together to function as a conventional aileron. the surfaces would move apart (the upper up and the lower down) to function as a speed brake.
thruthefence (Aerospace)
11 Oct 08 22:44
I think the old Northrop N-1M flying wing had split ailerons. A little dihedral, a little sweep in the wings, the thing opens up, the aircraft yaws, and the aircraft rolls right into a turn, no adverse yaw to contend with.
dredogol (Computer)
11 Oct 08 23:50
Okay... I've been talking to several of my buddies who were pilots, and they were having problems with this question of mine: 字串5
Lets say we have a plane with 2 canards up front, swept-back wings, 1 pair of split-ailerons, 1 pair of long flaperons (pitch up & down), no rudder, no tail, and no rear horizontal or vertical stabilizers. (Basically, just the Fuselage, 2 wings, 2 canards, and 1 engine.)
If possible, what combination of split-ailerons, canards, and flaperons would produce a pure left yaw turn (no rolling movement).
- Thanks
MikeHalloran (Mechanical)
12 Oct 08 8:25
Just opening one split aileron (symmetrically) should do it; yaw the aircraft directly, it skids some, and changes direction, sort of like an airboat.
Unlike an airboat, the aircraft doesn't have a stabilizing air-water interface to keep it level, so you should expect some pitching instability to keep your flight control computers busy.
Oh, wait; you're going to do this without flight control computers. In that case, bring lots of duct tape. 字串7
Mike Halloran
Pembroke Pines, FL, USA
MikeHalloran (Mechanical)
12 Oct 08 8:44
No, really; if you've never done it, go to, i.e., Florida, take an airboat ride, and sit where you can watch the driver work.
You're flying along, okay skimming, at maybe 20 knots, in a scow hull that lacks a water rudder, or even a skeg. To steer, the driver yanks the air rudder that's behind the engine and propeller hard over, and the boat pretty quickly yaws 45 degrees... but continues traveling in the original direction, so the rubes sitting next to the gunwales get whipped by the sawgrass as the boat slides over it and it gets folded over and sucked under the boat.
After what seems like a very long time, the boat's velocity in the original direction fades to zero, and the unmuffled engine sitting way up high on an improbably rickety structure, now running at full song^H^H^H^H blat, prevails, and the boat accelerates off in the new direction. 字串6
Now you understand why the boat's bottom has a little deadrise and soft chines, features otherwise useless in a scow hull; a hard chine would trip the boat in fast turns.
Mike Halloran
Pembroke Pines, FL, USA
thruthefence (Aerospace)
12 Oct 08 9:26
If you have enough sweep & dihedral, you should be able to keep the ball centered just with the tip-dragger "aileron". As the aircraft yaws, the opposite wing comes closer into alignment with the relative wind, the inboard wing gets less in alignment. Outboard wing develops more lift, inboard less. the aircraft naturally rolls into the wing with the deflected flight control.
swearingen (Civil/Environme)
13 Oct 08 13:39
Here's a shot of an A-6 Intruder on approach with his wingtip splits open...
If you "heard" it on the internet, it's guilty until proven innocent. - DCS 字串1
http://www.eng-tips.com/supportus.cfm - http://www.geocities.com/pentagon/bunker/7316/aboard.jpg
（Click：）
|
| Previous：Vertical Flight Next：Why flags flutter |
|
[ Add TO Favorites]
[TOP] [PRINT]
[CLOCE WINDOWS] |
|
