BRS and descent rate

"Paul Tomblin" wrote in message
...
In a previous article, "Roger Long"
om said:
"JJS" jschneider@REMOVE SOCKSpldi.net wrote in message
...
I had a flying buddy do something similar last fall in a Velocity.
Sort of a falling leaf maneuver that he inadvertently entered and
A Velocity is a Canard, isn't it? They have some weird issues with
mushing. Leaving my plane trimmed for the bottom of the green arc, I was

Yeah, they get into something called "deep stall". I don't know the
aerodynamics exactly - something about the wing and the canard being
stalled at the same time or something, but I do remember a test pilot (and
Shuttle astronaut) getting killed testing this phenomena on a canard.

Actually, the Velocity will not get into a "deep stall." There was one
example that did do this a few years ago -- twice! Both times the plane
landed in water and was salvaged. The pilot was unhurt both times. The
second time was deliberate. The test pilot even tried to climb out onto the
nose to break the stall. Although he was wearing a parachute, he elected to
ride the airplane down as it was descending more slowly than a parachute
would. A Velocity rep told me that this plane had been modified from the
original design. Mounting the airplane on a flatbed truck with a hydraulic
lift to raise the nose identified a problem with the trailing edge of the
wing. There was a lot of discussion about it in Velocity groups, but the
"deep stall" problem was peculiar to just this one airplane.

Canard aircraft are designed to have the canard stall before the main wing,
forcing the nose to drop and break the stall. Consequently you can never
achieve maximum lift from the main wing because the canard will always stall
before the wing can reach its maximum angle of attack. Canard aircraft
therefore need longer runways and often need more runway to land than they
need to take off. Soft field capability is also limited by the canard
design. OTOH canard aircraft have less drag in level flight since both the
canard and the wing generate upward lift. They tend to be much more fuel
efficient than their tail-feathered counterparts.

There are a few canard aircraft that do have a problem with deep stalls.
IIRC the Dragonfly is one. And of course the original Wright Flyer was not
only a canard design, but also was a pusher type with counter-rotating props
and a variable geometry wing -- just like the "advanced" designs that NASA
is looking at today.

C.J.,

Most of what you say is true. His was an early model without
vortilons and had the smaller main wing and larger fuel capacity. His
was a newly purchased airplane. He did not build it. He was doing
slow flight trying to find the edge of the envelope and determine a
safe minimum landing speed. He should have gotten specific training
in a Velocity. There have been many changes since these early ones.
See the following links.

http://www.ez.org/cp76-p2.htm

http://www.ntsb.gov/NTSB/brief2.asp?...LA019& akey=1

Anyway, my point was that I personally would not ride a mush all the
way to the ground.

Joe Schneider
8437R

"C J Campbell" wrote in
message ...

"Paul Tomblin" wrote in message
...
In a previous article, "Roger Long"
om said:
"JJS" jschneider@REMOVE SOCKSpldi.net wrote in message
...
I had a flying buddy do something similar last fall in a
Velocity.
Sort of a falling leaf maneuver that he inadvertently entered
and
A Velocity is a Canard, isn't it? They have some weird issues
with
mushing. Leaving my plane trimmed for the bottom of the green
arc, I was

Yeah, they get into something called "deep stall". I don't know
the
aerodynamics exactly - something about the wing and the canard
being
stalled at the same time or something, but I do remember a test
pilot (and
Shuttle astronaut) getting killed testing this phenomena on a
canard.

Actually, the Velocity will not get into a "deep stall." There was
one
example that did do this a few years ago -- twice! Both times the
plane
landed in water and was salvaged. The pilot was unhurt both times.
The
second time was deliberate. The test pilot even tried to climb out
onto the
nose to break the stall. Although he was wearing a parachute, he
elected to
ride the airplane down as it was descending more slowly than a
parachute
would. A Velocity rep told me that this plane had been modified from
the
original design. Mounting the airplane on a flatbed truck with a
hydraulic
lift to raise the nose identified a problem with the trailing edge
of the
wing. There was a lot of discussion about it in Velocity groups, but
the
"deep stall" problem was peculiar to just this one airplane.

Canard aircraft are designed to have the canard stall before the
main wing,
forcing the nose to drop and break the stall. Consequently you can
never
achieve maximum lift from the main wing because the canard will
always stall
before the wing can reach its maximum angle of attack. Canard
aircraft
therefore need longer runways and often need more runway to land
than they
need to take off. Soft field capability is also limited by the
canard
design. OTOH canard aircraft have less drag in level flight since
both the
canard and the wing generate upward lift. They tend to be much more
fuel
efficient than their tail-feathered counterparts.

There are a few canard aircraft that do have a problem with deep
stalls.
IIRC the Dragonfly is one. And of course the original Wright Flyer
was not
only a canard design, but also was a pusher type with
counter-rotating props
and a variable geometry wing -- just like the "advanced" designs
that NASA
is looking at today.

Roger Long wrote:

I prefer doing long controlled mush descents instead of classic stalls
because it provides more of the really valuable part of the stall practice,

That would be true if you want to practice stalls. I prefer to practice *recovery*
from a stall, or, better yet, stall *avoidance*.

George Patterson
If you don't tell lies, you never have to remember what you said.

Actually, that is exactly what I am practicing. When I look at how much
work and intent is required to stall a 172 I can't imagine doing it
accidentally. What I can easily see happening is letting speed get too low
while close to the ground and suddenly discovering that I have to tiptoe out
of the situation without dropping the nose while possibly maintaining some
directional control due to surrounding terrain.

The slow transition into the mush without using speed to zoom up slightly
into a more nose high attitude and shoving on the throttle and yoke at the
break provides much more time to experience the way the plane feels just
before the sink starts. Maintaining control in the sink is handling it at
the absolute minimum controllable airspeed. Riding the sink down engrains
the feel so that you are more likely to recognize it in time. Actually,
what it shows you is that you could easily not notice the sink and better be
paying attention during slow flight. There is much less buffet once the
mush starts and less in the transition to the mush than in the textbook
practice stall. If you were looking at a nude beach, you could easily miss
it

Transitioning out of the mush gracefully, perhaps with a direction change at
the same time, is the best part. Try arresting the descent and then
transitioning in and out of the mush.

This may be a 172 characteristic and I would only do it in a plane I knew to
break cleanly without wing drop. I don't think I would try it at my 200
hours in a 150 or 152 which will flip over much more readily in this flight
regime.
--
Roger Long

"G.R. Patterson III" wrote in message
...


Roger Long wrote:

I prefer doing long controlled mush descents instead of classic stalls
because it provides more of the really valuable part of the stall
practice,

That would be true if you want to practice stalls. I prefer to practice
*recovery*
from a stall, or, better yet, stall *avoidance*.

George Patterson
If you don't tell lies, you never have to remember what you said.

Roger Long wrote:

Actually, that is exactly what I am practicing. When I look at how much
work and intent is required to stall a 172 I can't imagine doing it
accidentally. What I can easily see happening is letting speed get too low
while close to the ground and suddenly discovering that I have to tiptoe out
of the situation without dropping the nose while possibly maintaining some
directional control due to surrounding terrain.

Ah. Different strokes, then. It's pretty easy to stall a Maule at low power settings
if you don't pay attention, but you'd have to be asleep to not notice. They tend to
buck a bit before they stall. You *can* get a pretty high descent rate at about 1.3
times the stall speed with full flaps, but the plane isn't mushing, and it handles
pretty well.

George Patterson
If you don't tell lies, you never have to remember what you said.

Roger Long wrote:

This may be a 172 characteristic and I would only do it in a plane I knew to
break cleanly without wing drop.

Y'know, what's up with that? I've had a few harrowing wing drops and,
although I've largely gotten past my stall fear, I'm starting to wonder
why coordinated flight doesn't necessarily guarantee a straight ahead break.

After one particular "oh ****" incident early in my training, I've paid
close attention to the ball when practicing stalls to avoid dropping a
wing. But some planes (I've only flown 152's and 172's) just seem to
say, "Nice job keeping the ball centered; now watch me roll over! Yee ha!"

I've asked various instructors about this and they just say, "Yeah this
one tends to do that." Hmm.

I know not all vehicles are created equal and there are other factors
like wind, turbulence, airframe wear, etc. Maybe it's the older
Cessna's? I haven't seen this with the newer S and R models.

-Scott

Scott Lowrey wrote:

Y'know, what's up with that?

Usually it's caused by the typical dings and such common to trainers. One of the
150's in which I trained would drop the left wing every time. Another would drop
either one, but the drop was pretty nasty. My '69 model wouldn't drop a wing at all.

George Patterson
If you don't tell lies, you never have to remember what you said.

Aircraft need to be tuned, like pianos. The angles of the wings, the flight
control surfaces, the cable tensions, and lots of other things can be
adjusted. It's a time consuming process and not a legal airworthiness item
so its rare for school and rental planes. The planes you are flying could
be fixed but it would come off the FBO's bottom line. OTH, maybe it's good
for students to learn to deal with wing drop. (Ingrain in your mind not to
use the yoke. Step briskly on the top rudder pedal "If you think you will
die, step on the sky.")

The significant difference between the 152 and the 172 is that the 152 will
flip over in an eyeblink with clumsy rudder usage but you would really have
to work at it to flip a Skyhawk.

I've heard a lot of reports of the new Cessnas being delivered terribly
rigged but they have probably gotten on top of that by now.

Little things can make a big difference. Our plane used to fly terribly.
Full right rudder trim all the time and you would still have your foot cramp
up after half an hour trying to keep the ball centered. On climbout, you
would have the pedal all the way to the firewall. Interestingly, when I
agitated to get it fixed, the board and a number of experienced pilots in
the club said, "Fix what? So, you need a little rudder, big deal."

We eventually got a new shop and a new maintenance officer (me). Our new
guy knew more than just how to take broken things out and put new ones in
like the pictures in the book. He replaced the little $100 piece of metal
that centers and aligns the nose gear. It was offset in flight and working
like a rudder right there behind in the prop blast. With a couple other
minor tweaks, it was a totally new airplane.

The difference was astounding. It was like going from a beat up old car
with misaligned suspension and a low tire to a well set up sports car.
Looking back, I can't believe I horsed that thing around the sky as long as
I did. Until you've flow a really well rigged plane, you have no idea how
enjoyable and sensual it can be.

--
Roger Long

"Scott Lowrey" wrote in message
news:JeCmc.43813$kh4.2295957@attbi_s52...
Roger Long wrote:

This may be a 172 characteristic and I would only do it in a plane I
knew to
break cleanly without wing drop.

Y'know, what's up with that? I've had a few harrowing wing drops and,
although I've largely gotten past my stall fear, I'm starting to wonder
why coordinated flight doesn't necessarily guarantee a straight ahead
break.

After one particular "oh ****" incident early in my training, I've paid
close attention to the ball when practicing stalls to avoid dropping a
wing. But some planes (I've only flown 152's and 172's) just seem to
say, "Nice job keeping the ball centered; now watch me roll over! Yee
ha!"

I've asked various instructors about this and they just say, "Yeah this
one tends to do that." Hmm.

I know not all vehicles are created equal and there are other factors
like wind, turbulence, airframe wear, etc. Maybe it's the older
Cessna's? I haven't seen this with the newer S and R models.

-Scott

Roger Long wrote:

The significant difference between the 152 and the 172 is that the 152 will
flip over in an eyeblink with clumsy rudder usage but you would really have
to work at it to flip a Skyhawk.

Interesting you say that. Now that I think about it, it was a 152 that
originally scared the crap out of me. It dropped left so fast and hard
that I felt like I did a 360 before I had time to react. When I
recovered, my heading had changed 180 degrees. The 172's were much more
docile when dropping a wing - still unnerving but not so surprising.

On the spin topic, though, I asked two different instructors (at two
different schools) for some spin recovery demonstrations. Although it
was probably frowned upon by the FBO's, both CFI's were happy to oblige.
We had a hell of a time getting the *152* to drop into a spin but
the 172 did it with ease.

Maybe it was instructor technique, maybe it was other factors...

-Scott

"Scott Lowrey" wrote in message
news:JeCmc.43813$kh4.2295957@attbi_s52...

After one particular "oh ****" incident early in my training, I've paid
close attention to the ball when practicing stalls to avoid dropping a
wing. But some planes (I've only flown 152's and 172's) just seem to
say, "Nice job keeping the ball centered; now watch me roll over! Yee
ha!"

Put vortex generators on that 172 and it won't do that. In my 182 you can
go into a 45 degree bank turn, full opposite rudder, full back stick and
idle power. The normal 172/182 will roll over into the high wing as it
stalls. Put VG's on the plane and you will just sit there in your 45 degree
bank dropping at 1500 fpm.