The discussion centers on the aerodynamic design of aircraft, specifically addressing the presence of three wings or wing-like structures, which include the main wings, elevators, and the empennage. Participants clarify that the empennage, located at the rear, provides stability and control over pitch and yaw. The conversation also touches on the B-2 stealth bomber's flying wing design and the Space Shuttle's unique lifting body configuration. Key insights include the importance of the empennage's positioning for stability and the historical context of canard designs in early aviation.
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Well, the B-2 is one giant flying wing.davo said:why do plains, shuttles, & man made things that fly have 3 wings? My parents told me it was so the craft doesn't go into a constant spin. But like i wanta know more like in layman's turms and in picktures and stuff. Can anyone help me please?
Not necessarily true. The shuttle is a lifting body. The entire fuselage acts as a wing.Astronuc said:The Space Suttle has a single pair of wings and tail. It mainly glides, or 'falls' to the landing site.
True the Shuttle's fuselage and wing undersurfaces are continuous. I only indicated that it had continuous wings as opposed to wings and elevators (in the rear). I think the Shuttle is mainly a glider. It is transported piggy-back on a special 747, or it lifts vertically on thrust.FredGarvin said:Not necessarily true. The shuttle is a lifting body. The entire fuselage acts as a wing.
That's what I assumed too.I can only assume that the OP is referring to a wing, a vertical and horizontal stabilizer.
FredGarvin said:The last time I saw anything with three wings was WW1.
Astronuc said:Well, the B-2 is one giant flying wing.
The three wings, I'm guessing are the pair of wings proper, which protrude horizontally or at a slight upward angle from the fuselage and provide the lift, the elevators, which are small wings in the rear of the aircraft which provide for control of pitch, and the tail and rudder which provide for turning and yaw control.
http://www.grc.nasa.gov/WWW/K-12/airplane/airplane.html
davo said:why do plains, shuttles, & man made things that fly have 3 wings? My parents told me it was so the craft doesn't go into a constant spin. But like i wanta know more like in layman's turms and in picktures and stuff. Can anyone help me please?
jambaugh said:Don't think of it as 3 wings but rather as two plane surfaces (horizontal wings and vertical stabilizer).
Then think of what you want an aircraft to do and what you want it not to do.
Empennage [ émpənij ] is an aviation term used to describe the tail portion of an aircraft. ("Empennage", "tail", and "tail assembly" may be interchangeably used.) The empennage gives stability to the aircraft and controls the flight dynamics: pitch and yaw. In simple terms the empennage may be compared to the feathers of an arrow, colloquially; "Tail Feathers"
Structurally, the empennage consists of the entire tail assembly, including the fin, tailplane and the part of the fuselage to which these are attached. On an airliner this would be everything behind the rear pressure bulkhead.
The front, usually fixed section of the tailplane is called the horizontal stabilizer and is used to balance and share lifting loads of the mainplane dependent on centre of gravity considerations by limiting oscillations in pitch. The rear section is called the elevator and is usually hinged to the horizontal stabilizer. The elevator is a movable airfoil that controls changes in pitch, the up-and-down motion of the aircraft's nose.
It isn't always the case, just most of the time. But for a demonstration of why, try throwing a dart backwards...davo said:thank you, also from what I've reserched it can be a called an empennage. Does anyone know why there alwase in the rear of the craft?
davo said:thank you, also from what I've reserched it can be a called an empennage. Does anyone know why there alwase in the rear of the craft?
Their location is always going to be a function of the forces created during flight. They are put where they need to be most effective. The original Wright Flyer used a canard system with the main control surfaces in front of the aircraft.davo said:thank you, also from what I've reserched it can be a called an empennage. Does anyone know why there alwase in the rear of the craft?
FredGarvin said:Their location is always going to be a function of the forces created during flight. They are put where they need to be most effective. The original Wright Flyer used a canard system with the main control surfaces in front of the aircraft.
There is always an uneasy tog-of-war between stability and manueverability.davo said:now if the empennage was moved to the front and the back wings are still in the back couldn't the craft have a better turning ratio?
ok thank you.DaveC426913 said:I think the general reason why it doesn't work well with the empennage at the front is that it is inherently unstable - it is a positive feedback loop. Controls are designed to rotate a craft out of true. As this happens surfaces at the front become more effective as they bite into the wind more, causing the rotation to be amplified.
Surfaces at the back, on the other hand, are in a negative feedback loop; they become less effective as the plane is rotated out of true. i.e. the craft tends to self-correct, wanting to return to true. This is the way to keep a craft stable.
Easy to experiment with. Stick your hand out the window next time you're passenging in a car.
What?davo said:just one question now that I took a better look at it. can i have the empennage in the rear but extend to the front?