Thinking about stalls

Hi All,

Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.

Both have constant rates of ascent and descent.

Question A: Which wing is closer to stall?
Question B: A big updraft occurs, which is more likely to stall?

If you vote first it _may_ lead to some good discussion later...

Cheers

WingFlaps wrote:
Hi All,

Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.

Waitaminute - how can a plane be in both conditions at the same time!?

Both have constant rates of ascent and descent.

But are they the same rates or different?
What are the angles of attack on the wings in both cases?
What are the indicated airspeeds - the same or different?

Question A: Which wing is closer to stall?

The left one. I think. Except if it's a biplane and Tuesday, in which case
it would be the red one.

Question B: A big updraft occurs, which is more likely to stall?

The one whose condition was closer to stall.
;-)

On Mar 13, 1:41*pm, Jim Logajan wrote:
WingFlaps wrote:
Hi All,

Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.

Waitaminute - how can a plane be in both conditions at the same time!?

Both have constant rates of ascent and descent.

But are they the same rates or different?
What are the angles of attack on the wings in both cases?
What are the indicated airspeeds - the same or different?

Question A: Which wing is closer to stall?

The left one. I think. Except if it's a biplane and Tuesday, in which case
it would be the red one.

Question B: A big updraft occurs, which is more likely to stall?

The one whose condition was closer to stall.
;-)

Aha, too deep for you eh? :-P

Cheers

WingFlaps wrote:
On Mar 13, 1:41*pm, Jim Logajan wrote:
WingFlaps wrote:
Hi All,

Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.

Waitaminute - how can a plane be in both conditions at the same
time!?

Both have constant rates of ascent and descent.

But are they the same rates or different?
What are the angles of attack on the wings in both cases?
What are the indicated airspeeds - the same or different?

Question A: Which wing is closer to stall?

The left one. I think. Except if it's a biplane and Tuesday, in which
case

it would be the red one.

Question B: A big updraft occurs, which is more likely to stall?

The one whose condition was closer to stall.
;-)

Aha, too deep for you eh? :-P

Much too deep. But if you want a straight answer, I'd say a climbing plane
would be more likely to stall if a big updraft occurs. The plane's inertia
comes into play and causes the airflow to slow up over the wings (maybe
even reversing direction!?) coupled with the pilot's Hawaiian shirt all
conspire to cause the lift demons to depart. I least I think so.

On Mar 13, 3:13*pm, Jim Logajan wrote:
WingFlaps wrote:
On Mar 13, 1:41*pm, Jim Logajan wrote:
WingFlaps wrote:
Hi All,

Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.

Waitaminute - how can a plane be in both conditions at the same
time!?

Both have constant rates of ascent and descent.

But are they the same rates or different?
What are the angles of attack on the wings in both cases?
What are the indicated airspeeds - the same or different?

Question A: Which wing is closer to stall?

The left one. I think. Except if it's a biplane and Tuesday, in which
case

it would be the red one.

Question B: A big updraft occurs, which is more likely to stall?

The one whose condition was closer to stall.
;-)

Aha, too deep for you eh? *:-P

Much too deep. But if you want a straight answer, I'd say a climbing plane
would be more likely to stall if a big updraft occurs. The plane's inertia
comes into play and causes the airflow to slow up over the wings (maybe
even reversing direction!?) coupled with the pilot's Hawaiian shirt all
conspire to cause the lift demons to depart. I least I think so.- Hide quoted text -


So, 1 vote for B1 and what about question A?

Cheers

WingFlaps wrote:
Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.
Question A: Which wing is closer to stall?

So, 1 vote for B1 and what about question A?

I don't know. Maybe the angle of attack on the wings can be determined by
the information you provide for both conditions, but if so it is beyond my
limited capabilities. As it stands, I'm inclined to say you aren't
providing enough information to make an informed decision.

Jim Logajan wrote in
:

WingFlaps wrote:
Hi All,

Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.

Waitaminute - how can a plane be in both conditions at the same time!?


Ken can probably explain it better than anyone.


Bertie

On Mar 12, 5:14 pm, WingFlaps wrote:
Hi All,

Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.

Both have constant rates of ascent and descent.

Question A: Which wing is closer to stall?
Question B: A big updraft occurs, which is more likely to stall?

If you vote first it _may_ lead to some good discussion later...

Cheers

The aircraft in climb will have the lower airspeed and therefore
the higher AOA. Lower airspeed means higher AOA to lift the same
weight. A cruising descent is a high airspeed, so AOA is much lower.
Both will be in a 1 G condition.
An updraft increases AOA, so the climbing airplane is closer to
stall. A cruising descent in the yellow arc, OTOH, might get the wings
torn off in a "big" updraft. Stall doesn't matter anymore.

Dan

On Mar 13, 3:41*pm, wrote:
On Mar 12, 5:14 pm, WingFlaps wrote:

Hi All,

Imagine a plane in 2 conditions.

1) Climbing with full power
2) Descending fast with 50% power.

Both have constant rates of ascent and descent.

Question A: Which wing is closer to stall?
Question B: A big updraft occurs, which is more likely to stall?

If you vote first it _may_ lead to some good discussion later...

Cheers

* * * The aircraft in climb will have the lower airspeed and therefore
the higher AOA. Lower airspeed means higher AOA to lift the same
weight. A cruising descent is a high airspeed, so AOA is much lower.
Both will be in a 1 G condition.

OK... but is the climbing or descending wing generating the most
lift?

* * * An updraft increases AOA, so the climbing airplane is closer to
stall. A cruising descent in the yellow arc, OTOH, might get the wings
torn off in a "big" updraft. Stall doesn't matter anymore.


Cheers

OK... *but is the climbing or descending wing generating the most
lift?

I agree, your original question is missing some critical information.
Such as:

1. are the airspeeds the same for each aircraft?
2. confirm that the decending aircraft is not already stalled
3. Do the airplanes weigh the same?


As for your question above, given that the airplanes are ascending or
decending at constant rates then the lift is equal to the wieght of
the airplane in both cases. If the aircraft are the same wieght then
the lift generated will be the same.

Brian CFIIG/ASEL