That's where you got it confused.
The good or bad stability is relative.
The upward canted tip on wings and low positioned wings are not there for stability mainly.
When we will search on Google & Youtube about Dihedral Vs Anhedral wings then they'll all clearly say same thing about increasing or decreasing roll. That's good enough fo rme.
Wing shape & size changes the center of gravity & center of lift.
Low/mid/high mounted wings again shift the CG up/down.
When it comes to winglets, it looks small & simple, but multiple things matter there like the sweep angle of its leading edge & trailing edge, its length, the cant angle, the chord length. There can be many combinations of these aspects with different final effect. Cl & Cd (coefficientof Lift & Drag) are tabulated for each combo, that too at different AoA, So winglet-angle/AoA/Cl/Cd/roll-angle, It becomes a multi-dimensional matrix & graph.
If you wanna deep dive then this entire year 2025 will go into it everyday.
What have you written here:
Airliners even without top mounted wing and downward canted wing extensions, have "good enough" stability for crosswinds, plus tricks like tilting the nose of the airliner towards the head wind further helps.
This is an indirect sentence construction:
without top mounted wing = low wing
without downward canted wing = upward canted dihedral wing.
So your sentence translates to -
low mounted dihedral wing (like of airliners) have good enough stability for crosswinds.
And
i said same that dihedral wings add to stability.
So i suggest you use direct sentence construction & avoid repeatition.
Plus the upward wingtips in airlines are relatively quite small to not interfere much with aerodynamics while helping to reduce wingtip vortex.
That's a generic statement when you use the word aerodynamics.
The vortex creates drag & also downwash which decreases low pressue above wing & counters the lift of outer affected section.
Winglets reduce the drag & downwash.
But cargo jets, like c17, c5, ill76 etc All have top mounted wings to provide higher stability than airliners especially in crosswinds
Imagine this, the weight of fuselage hanging Below the lift generating by wings( like c17, c5 etc) vs wings below the fuselag( A380, 777 etc), due to torque the fuselage hanging Below the wings will act as a much better counterbalance and help in stability than latter.
Yes thats true due to pendulum or Keel-effect which happens in high mounted wing. If we make the wing dihedral then the center of gravity will go up reducing the keel effect & decrease stability.
So a cargo jet can choose b/w high mounted anhedral & low mounted dihedral.
But stealth fighter jet fuselages are flatter even after having high mounted wings. So the CG goes up & the Keel effect is low.
I noticed this picture yesterday of the Bird of Prey and wondered about the wing design and what advantages would come with this unique wing design compared to other aircraft? Source:(www.wired.com)
aviation.stackexchange.com
Regular, upward-pointing winglets have a number of disadvantages, one of them their induction of lift on the wing when their
rudders are deflected, which produces an
undesired rolling moment and
prevents rolling the aircraft into the intended turn. Downward-pointing winglets helped to make the aircraft flyable without computer control, because they help with
***directional stability** possible by their rear position due to the high wing sweep angle
rolling moment with
rudder deflection,
rolling the aircraft into the direction of the turn commanded by the
rudders.
I don't see anything new in the stackexchange answers.
You ignored an important aspect here that the person answered w.r.t. winglet used as rudder, like a V-tail.
I said this earlier also that the V-tail is not good for yaw as it produces rolling effect. And for pitch also the diagonal deflection of air has horizontal & vertical components. So an upward winglet has identical effect.
Every tapered corner creates vortex & adds to lift due to low pressure above surface.
Hence the chines or tapered fuselage becomes a lifting body, compared to simple cylindrical fuselage. This was seen in SR-71.
BoP's gull wing is not new but they obviously wanted to test combination of multiple things, its aerodynamics & stealth.
That's why neither downward canted wing extensions or upwards canted wing extensions are used in fighter jets.
F-4 Phantom had partially upward canted dihedral wing & anhedral tail-stab.
Harrier haad anhedral wing & tail-stab.
Who know the future where a jet with horizontal wing & anhedral winglet might be seen. I wouldn't bet on it.
It is bcoz of planform shaping fundamental started since 5gen.
