Questions on Stall

Question 1

Which aeroplane design has the highest probability of a super stall?

a) A canard wing
b) A T-tail
c) Swept wings
d) A low horizontal tail

Answer 1

The option “B” has been marked correct in the question database. However the T-tail on its own is not pre-disposed to the deep stall but it can make it worse if combined with a swept wing. It is the swept wing that will pitch up as it reaches critical alpha, and if the separated flow from the wing hits the tail then the aircraft will enter a deep stall. It is the inability to recover from the stall that defines the deep stall. Some swept wing aircraft have wing/tail configurations that allow the tail to be out of the wing downwash at the stall, so then even if it pitches up at the stall, you can still recover using elevators. The King Air 200 has a t-tail and does not deep stall, as it has a straight wing and pitches down at the stall. So the t-tail on its own is not a factor in the deep stall. Source: (http://www.atpforum.eu/showthread.php?t=1345)

In another question it is marked correctly as Swept Wing e.g.

Question 2

Which of the following aircraft designs would be most prone to super stall?

a) T-tail
b) Swept forward wing
c) Swept back wing
d) Pod mounted engines beneath the wing

Answer 2

Option “C” is correct and is marked correct in the database.