Linked Questions

13 votes
3 answers
4k views

Does static longitudinal stability require download on the tail?

After having encountered this meme too often for comfort, I ask myself today in order to have the possibility to explain the issue in detail.
Peter Kämpf's user avatar
7 votes
6 answers
2k views

Can induced drag be negative?

For an aircraft in straight and level flight, lift-induced drag is the horizontal component of the force perpendicular to the wing chord. Positively cambered aerofoils generate lift starting at small ...
James James's user avatar
7 votes
3 answers
5k views

Why does a Phugoid occur? How can it be eliminated?

My model aircraft seems to do phugoid oscillations and I'm having trouble landing. It is around 2 kilos, very high mounted wing, so bad landing takes out the underbelly everytime. I'm wondering what'...
NRB's user avatar
  • 71
4 votes
2 answers
11k views

How are empennage airfoils chosen?

Empennage airfoils are usually symmetric. What is the process behind choosing the airfoil used in the tail of the airplane? Is it related to the stability? And then how would the angle of attack of ...
Josh Fang's user avatar
  • 355
8 votes
1 answer
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 ...
Jacob's user avatar
  • 115
5 votes
1 answer
16k views

Where is the best center of gravity?

I'm designing a plane, and I have a question. What is the best place for the center of gravity, relative to the center of lift? I've heard that it's best put just behind the center of lift, but I ...
Nicholas's user avatar
  • 668
6 votes
4 answers
1k views

How does a tailplane provide downforce if it has the same AoA as the main wing?

If an airplane is traveling through a uniform environment and its main wing is parallel to its horizontal stabilizer, how does its tailplane generate downforce? Only explanation I can think of is ...
Kozakov's user avatar
  • 467
4 votes
3 answers
3k views

What are the disadvantages of a Tail providing lift? (tandem-wings included)

Most aircraft feature the tailplane configuration, which requires the main wing to provide higher lift than the weight of the plane itself, what seems counterproductive. Few aircraft have featured ...
zaumo's user avatar
  • 55
14 votes
1 answer
724 views

Does the wake from horizontal stabilizers merge with the wing wake?

There is already a long series of questions about the downwash and tip vortexes with nice images, but I'm going to add another one... Large airliners (A380, B747-8) have horizontal stabilizers ...
mins's user avatar
  • 72.9k
0 votes
4 answers
509 views

Why should I not use a "lifting tail" on my ultralight design?

In my misspent youth I designed and built many rubber, gas, and RC models. When I wanted good climb and glide I used a aft CG [60 to 80%] and a lifting tail. I had no stability or control problems, ...
Dunfam Ham's user avatar