Linked Questions

8
votes
2answers
53k views

What are lateral, longitudinal and directional stability? [duplicate]

When we talk about aircraft having a stable configuration, it refers to lateral, longitudinal and directional stability. Can someone give a practical explanation of what those are and how they work?
43
votes
18answers
84k views

Do pilots adjust the aircraft's flight path to allow for the curvature of the Earth?

If an airliner is flying at approximately 500-600mph, it seems to me that there would need to be a significant adjustment for altitude so as to not fly off into space. Wikipedia says that there's an ...
36
votes
3answers
35k views

Are fighter jets designed to be so inherently unstable that a human can't fly one unassisted?

I'm told that in order to be more maneuverable fighter jets are designed in a way that makes them impossible for a human to control without the help of a flight computer. Is this actually true? ...
25
votes
5answers
10k views

Are passengers really not allowed to change seats before take-off due to weight and balance?

Just boarded an A320 with many open seats (Spirit), and the flight attendant said we may not change seats until at altitude due to weight and balance. Is he just trying to prevent pax from moving ...
18
votes
4answers
4k views

What does it mean when an aircraft is statically stable but dynamically unstable?

I am reading this book: "Flight Stability and Automatic Control", second edition, Dr. Robert C. Nelson. In the chapter 2, page 42, the author wrote: Note that the vehicle can be statically ...
18
votes
2answers
49k views

What is the “yaw damper”?

Some airplanes have a button for the "yaw damper." What is the yaw damper? When is it used? Is it ever required for certification or operation? How does it work?
12
votes
3answers
8k views

What are the pro/cons of polyhedral cranked wings?

Dihedral wings seems to be very common (almost if not all low-wing airliners, many modern gliders,...). Polyhedral seems to be less common and mainly found in relatively old aircraft (F4 Phatom, F4U ...
13
votes
5answers
4k views

Could a plane be constructed to be fly in fixed-stick roll-stable circles?

According to https://aviation.stackexchange.com/a/12511/973 it is not possible for a plane to aerodynamically recover from a roll disturbance. Is that an inherent limitation of how planes could be ...
12
votes
2answers
481 views

Why would a canard wing be more prone to icing than a stabilizer?

Someone said a canard wing is more prone to icing than a stabilizer. If true, what would explain this?
7
votes
3answers
7k views

What is the way to calculate the required twist of a flying wing?

I am interested in flying wings and a couple of weeks ago I started researching them. I found mh-aerotools.de website and think it's a great source. The website stated that flying wings need twist ...
8
votes
1answer
2k views

Why are aircraft designed so that the wing stalls before the tail?

I read somewhere that conventional aircraft are designed so that the main wing always stalls before the tailplane. Why is that? My concern is that if the wing stalls, suddenly the tail will push the ...
10
votes
3answers
1k views

Is it possible to balance a tail heavy plane with a vertical prop on its tail?

I've put together a model plane in the form of an angel, and the planform is quite tail heavy (please see pic). I'm trying to balance the plane with a lifting tail prop that makes the "apparent" CG in ...
1
vote
2answers
7k views

What does stick fixed and stick free longitudinal stability mean in simple terms?

What is the significance of stick fixed and stick free terms in aircrafts with mechanical control and modern fly-by-wire control?
0
votes
3answers
4k views

What is the difference between a forward, aft, high and low center of gravity?

I would like to know the difference between when the center of gravity (CoG) is forward and aft? And high and low? I already know that the lower the CoG, the greater the static lateral stability. A ...
4
votes
2answers
354 views

What can a new student pilot do on their own to prepare for class and instruction?

What is the best way to start for beginners learning to fly? I have a class set up and a instructor but not for another week or two. I just want to know if there is anything extra that I can start now,...
1
vote
2answers
467 views

Which kind of stability do aerobatic aircraft have? [closed]

I'm designing an aerobatic aircraft similar to EXTRA 330SC. I would like to know about stability: lateral and longitudinal, static and dynamic. I read that aerobatic aircraft have neutral static ...
4
votes
1answer
361 views

What is the rod attached to the top of the Bell UH-1N's rotors?

So, I was looking at an image of a Bell UH-1N, and noticed that the top if the rotor has a little stick or rod What is this rod for? I also see this rod on a RC helicopter.
1
vote
1answer
335 views

Can 'neutral static stability' only be achieved by constantly augmenting the control surfaces?

I watched a flight mechanics lecture that mentioned that some combat aircraft like the Hornet has a 'mode' where the on-board computer simultaneously and automatically adjusts all the control surfaces ...